LFP reverse polarity.

[Skyler]

I recently had a LFP battery fire while running/discharge.

Out of 24 cells only 6 salvageable. Three or 4 were reverse polarity. 60 amp fuse ground side and 60 amp DC breaker / kill switch before controller positive side did not blow or trip.

A 12S active cell balancer started smoking and caught on fire after awhile and after disconnect. I had about 5 minutes to push it home.

It smoked and ignited the plastic awhile I fetched a metal pail and placed over top by rail road tracks in gravel.

It went out quick as lithium iron phosphate needs external oxygen where lion has its own oxygen and can burn for days.

Why I bought them. They were out in rain about a week before recovering the 6 cells. LOL

8 Ah Headway cells used. Was 12S - 2P. 10 amp charger.

My guess the balancer did not keep up with the demands. I will need a 5 amp active balancer and 5 amp charger.

The balance could not keep up with the charge and discharge cycles. I ran a cell bank either too low or high ????

Reading was - negative 3V though on a couple reverse polarity cells ?????

Like to hear feedback on that. Above my head.

I am looking at 5 amp chargers and balancers so charge/discharge is equal. ???

Using 6S Lipo charger now and external balancer for 7S pack. I installed eight 3 amp fuses in a 7S - 8P - and 6 in a 5S - 8P. A123 LFP pack.

One more 5S - 8P pack to go. 56V - LFP.

Charging a 3S - 2P headway pack for 43V in series with the two 5S - 8P A123 packs.

I want to install 10 amp fuses to all balance wires for all my batteries.

LFP needs to charge fast or not worth the lower energy density , weight . bulk.

The greater charge cycles and charge speed are what make LFP better than Lico

That and a LFP fire can be stopped way easier than a Lion or LiPo fire can.

What do yo guys think.

Sincerely

Skyler.

 

[amberwolf]

If you had cells that actually reversed in voltage, then you have at least two problems. The cells were significantly different in capacity from each other, so that when some of them still had capacity available, others had already not only run out of capacity, but were now being driven negative by the current flow thru them from those cells with capacity remaining.

Your BMS (if any) did not work; it's either defective or the wrong kind for the cells or setup wrong if it's programmable--it's LVC should have stopped discharge on the cells long before they got that far.

Your controller (or whatever is being powered by the cells) should also have stopped discharge with it's own LVC. If it didn't, it's also defective, or setup wrong, or the wrong controller for the pack voltage used.


If you need a balancer, especially a high current balancer, the cells are very different from each other and aren't going to make a good pack together.

To make a good pack, choose cells that are identical (matched) in characteristics (internal resistance, capacity, etc).

If they're well matched you wont' even need a balancer until the pack ages so much (over years of time, many years for good cells used well-within their limitations, not pushed hard) that they begin to become different.

All the balancer does is make all the cells the same voltage at some point in the discharge curve. It does not fix anything, or make the pack better, etc. It can allow you to use a bit more of the pack's capacity depending on how bad the problems with the cells are.



Fuses on balance wires...there's a number of posts and threads about those that work out the details of doing it and what reasons there are for doing it (such as shorted balance wires, or an internal short in the BMS that could drain a group quickly...but a failed balancer can still drain the group, and yo0u can't fuse against that or the balancer will blow it just doing it's normal job).

Fuses on cells might (if setup properly, with the right values) protect against cells that suddenly fail very low resistance internally shorted from draining the rest of the cells in the same parallel group--but if the fuses are not very small, they won't blow under most of the circumstances in which cells fail this way and the rest of the cells will still drain. Threads about those, too.

None of these would have helped your situation, which was caused by cell reversal which was probably caused by badly mismatched cells.


Given the situation, mismatched cells, fire, and rain, I would not re-use any of the cells. It's probably asking for another failure that could lead to another fire.

 

[Skyler]

Thank you. that makes sense.

Looking at getting a Bluetooth BMS so I can monitor the cell voltages. I will try and find some new cells. I did wire 4 of the used cells for a 12 volt power supply for my lights which only draw about an amp or two. I use an external balancer to monitor the cells so they do not go below 3V.

I am looking at brand new 10 Ah Headway cells from e bay. Would you recommend these.

I was told that I could use a 5 amp active balancer with a Bluetooth BMS. I would like to monitor all cell voltages onboard and awhile charging. I still would like to charge at 10 amps if possible. If these cells are new than should work right ?

HEADWAY 38120S LiFePo4 Battery Cells 8 PACK 3.2V 10Ah SHIPS FROM USA | eBay

Find many great new & used options and get the best deals for HEADWAY 38120S LiFePo4 Battery Cells 8 PACK 3.2V 10Ah SHIPS FROM USA at the best online prices at eBay! Free shipping for many products!

www.ebay.com

For long trips it makes sense to charge at 10 amps as Lico can not do that. If I am hauling around the extra weight for safety and longevity (10 times the charge cycles) then charging at 3 to 5 times faster than Lico just makes sense.

Say I wanted to travel 100 miles. I would need to stop and charge several times. For a Lico pack the same weight to go 100 miles it would probably only need to charge one time but would take about 5 or 6 hours for 80%. . I cant imagine riding more than 20 miles or so without a 30 to 45 minute break so should get at least an 80% charge at 10 amps.

What do you think. I have seen many Lipo and lithium ion fires on you tube videos. Thay are almost impossible to put out. Not as easy as placing a metal pail over the pack like I did with LFP. All that burned was the balance board and plastic case. None of those Headway cells ignited proving my point.

Thanks and look forwards to your post. I have been riding e bikes for a few years now and recently ordered a 1,500 watt rear Hub motor for a full suspension mountain bike but want to make sure my batteries will safely power it before I finish the install.

Thanks and look forwards to your post.

Skyler.

 

[j bjork]

I was told that I could use a 5 amp active balancer with a Bluetooth BMS

Why do you need 5amp active balancing? Something must be very wrong.

 

[Skyler]

Why I need a 5 amp balancer is for used and tired lfp from Battery Hookup.

It is why their 8 Ah Headway cells were only $5 each. Now $5.50. I also bought 26650 cells when they had them. They seem to be a little more stable ; but the Headway cells not so much.

I got rid of the 6 Headway cells that I salvaged from the fire as even under a 1 or 2 amp load from 12V lights. The voltage dropped to around 6V after running the lights for a few hours. Was not me running them though so not sure but better safe than sorry.

I built a 3S - 3P Headway pack from the cells left over that did not burn but tested < 4 Ah when I got them from Battery Hookup. I have two 5S - 8P packs from 26650 cells and one 7S - 8P. All the same cells - 2.5 Ah - A123 cells.

For 56V I run 17S - 8P but for 43V I want to run the two 5S packs with the 3S Headway pack wired in series between them. Even at 3P those 8Ah Headway cells are the weak link so know better to run them too far without stopping and checking voltage with a balancer. I have not run the 43V yet but did run the 7S and 5S for 12S lfp. I need to finish installing 3 amp fuses to all the balance wires on the second 5S pack.

Obviously I wont be able to run a 5S active balancer with 3 amp fuses so will need to external balance. I used to run LiPo a long time ago so still have two 6S and two 7S external balancers. If I set the charger for 2.5 amps the external balancer seems to work but sometimes have to shut down the charger and let the balance catch up.

I only plan on running these batteries < 5 miles a day , Maybe 8 miles with the 17S - 8P packs but <5 miles for 13S with those Headway cells .I need better quality lfp cells, preferably brand new. At that point I plan on running a Bluetooth BMS and was considering a 5S active balancer but may not need it if the cells are really brand spanking new.
It is why I posted the link to those cells on my last post. I was hoping someone might have an idea if they are in fact brand new or garbage like battery Hookup sells.

HEADWAY 38120S LiFePo4 Battery Cells 8 PACK 3.2V 10Ah SHIPS FROM USA | eBay

Find many great new & used options and get the best deals for HEADWAY 38120S LiFePo4 Battery Cells 8 PACK 3.2V 10Ah SHIPS FROM USA at the best online prices at eBay! Free shipping for many products!

www.ebay.com

It states new but tested ??? Hope someone might know.

Thank you for your post. I am not a Greenhorn but not an expert either. Somewhere in between. I have been at it a few years. Started with SLA then LiPo and Lion. Then after watching fires on YouTube and that video I switched to lfp.

Dangerous vs. Safe batteries, Explosion and fire test! I tried posting the link but did not work.​

. I am kind of distraught since the fire. Would have been a lot worse if Lico or Lipo. Batteries did not ignite. just balance board and plastic case. Also mad as I paid over $100 for a 54.6V 15 amp lfp charger and about $70 for a 43.6V 10 amp charger from ali express which I will no longer use unless I can get new and stable cells to build a pack and expensive Bluetooth BMSs with active balancers.

Reverse polarity is way over my head and may never understand how that could even happen. I removed all active balancers but if I do use them again it will be when charging , not running and will extend the balance wires about a foot and place the balancers in a large glass ash tray. lol Thing is , it may not have been the balancers fault since reverse polarity caused the fire but they are still cheap and made in China so suspect.

I wish I had got more college time in as the method used for charging all lithium battery types just makes no sense. If I were to design a charger and BMS I would install a 15 amp fuse holder next to the BMS and all balance wires would be 16 gauge and when a cell reaches its full state of charge the voltage of the charger would drop equal to the fully charged cell. So if it was a 15S charger for example the last two cells would be 2S voltage and the last 1S. It would be impossible to over charge a cell.

For discharge the BMS would active balance from the top down at 5 amps. I am currently charging at 0.1 amp by hooking the balance extension wires to bolts. I drilled holes in a piece of trim so I can just charge the lowest cell in that 3S Headway pack.

It is extremally difficult to balance charge lfp with a 6S LiPo charger. It does not want to fully charge a pack.. The charger reads FULL with a cell about 3.38V and a cell at around 3.5V and a cell at 3.7V or higher. The external balancer does an even worse job. It is ridiculous.

For my 7S - lfp pack with the 26650 cells I use my 7S external balancer and set the LiPo charger to 6S LiPo so 4.2 * 6 = 25.2V / 7 = 2.6 charging volts. I will need more 7S balance wires and an extra bolt in the stick of wood for the 7S pack. LOL.

Looking at getting a new charger from Hobby king. If I can get the packs balanced then hopefully I will be able to use my 10 amp and 15 amp chargers when I am out riding again.

ToolkitRC M9 1~8S 20A 600W DC Multifunction Balance Charger/Discharger

ToolkitRC M9 1~8S 20A 600W DC Multifunction Balance Charger/Discharger. Hobbyking for the best deals in smart chargers, ac/dc chargers, and lithium batteries.

hobbyking.com

Thing is , it only balances at 1 amp. Good for new perfect cells if I get them but not for older cells with different capacity. I will need 5 amp balancers with 5 amp chargers and 10 amp fuses to all balance wires. That will cost a lot of $$$$$.

Then there will be a lot of extra work. I no longer trust active balancers or BMSs unless they are Bluetooth. I need to actually see all cell voltages from now on. I could still use active balancers but the plugs for those balancers will not plug in to my external balancer or the charge port on the charger. The active balance plugs are smaller with the pins and holes closer together. I will have to order balance plug extensions and cut each wire and wire up the plugs for the active balancers. Then I can check voltage with a meter before discharging to make sure the balancer did its job.

I rode around with the 43V set up and external balancer on board. 5 or 6 miles or so from about 60% to 30%. I could monitor cell voltage while riding. If I only charge from 20% or 30% to > 60% < 70% the cells seem to not require balancing. A full fast charge will sky rocket some cell voltages which is unacceptable to say the least.

The 5 in 1 cell checker/balancer is cheap but 7S. I charged at 10 amps for around 20% to > 50% Highest cell maybe 63% but all 50% or greater. It took the 6S RC LiPo charger about 14 hours to get those 3S - 3P Headway cells to get to 3.6V before that though.

My conclusion is you can get a lot of cycles off of used lfp but charging 13 to 17S lfp with a 6S LiPo charger is not the ideal SHITutation. Needed initially to get total balance but then keep doing 20 to 60% charges for minimal balancing. Might be able to get > 1,000 partial cycles though. Charging 13S lfp with a 12S lfp charger is actually better for old used cells as not such a sky rocket effect of a couple or more cells. Brand Spanking new lfp cells can discharge to 2.5V and fully charge to 3.65V. That would be < 0% to 100% even Steven cells. NO or minimal balancing. Not the case with used/OLD lfp.

You need to keep the charge and discharge curve a lot closer to 3.3V. Normal operating voltage for lfp cells. No lower that 3.1V preferably > 3.2V. Do not charge much greater than 60% as great risk of cells sky rocketing and throwing pack out of balance

12 * 3.65V = 43.8V / 13 = 3.369V.

Perfect charging voltage for old and used 80% or less capacity cells. I was hoping to hear some feed back on those nI ew 10 Ah cells from that link I posted from e bay. Also any other source for quality brand new or properly tested used lfp. When I spoke to the folks at Battery Hookup I was told they only check cell voltages. That makes sense as it takes a lot of time doing capacity tests and the cells are $5 or $5;50.

They did send me some replacements however so am not discouraging anyone from dealing with them. just expect to get what you pay for and use them like I stated above and can get some use from them. just do not expect them to hold up for a big road trip. Around 5 miles for cells that test < 50% in a 2 or 3P configuration and up to about 8 for the few cells testing around 70 to 75%. 2P. The A123 cells seem to be more stable at 60 to 80%. - 8P minimum. I would not go any less than that.

It is why I am seeking brand new. I would suspect the used cells probably have > 2,000 cycles or more or have been sitting on a shelf for > 10 years. With brand new 10 Ah - 1P should go 10 miles easily and still be > 3V per cell.

I will continue testing lfp under a wide variance of loads and charging methods and share the information here. I hope that it will be useful to someone. Please post any link for brand new lfp or used but properly tested for capacity. I would appreciate it.
.

Skyler.

 

[amberwolf]

Reverse polarity is way over my head and may never understand how that could even happen. I removed all active balancers but if I do use them again it will be when charging , not running and will extend the balance wires about a foot and place the balancers in a large glass ash tray. lol Thing is , it may not have been the balancers fault since reverse polarity caused the fire but they are still cheap and made in China so suspect.

It's because your cells are mismatched, so they don't have the same capacity. When you discharge the pack to the capacity of the higher-capacity cells, the cells with less capacity are overdischarged to the point where current still flowing thru them from the other cells charges them in reverse, which you can also think of as discharging them into the negative (like overdrafting your bank account).


The balancers don't cause the problem (but they don't fix it either).

A properly-wired up correctly-designed completely-functioning BMS that properly shuts off discharge when a cell hits LVC will prevent the overdischarge of the low-capacity cells.

A BMS that either isn't wired correctly (like using the charge port for discharging, or bypassing the discharge port for higher current, etc), or that is damaged (discharge port FETs stuck on), or that is incorrectly designed or built, such that it can't stop discharge once any cell hits LVC can allow overdischarge and even reversal of cells, and cause fires.



To prevent the problem you don't need balancers, you need matched cells, meaning cells that are all the same capacity (as close as you can possibly get them, identical if possible). And same internal resistance(as close as you can possibly get them, identical if possible).


Balancers do not fix differences in capacity.

Balancers *only* fix differences in voltage, *at a specific state of charge* (usually full charge).

So if you have 10 cells in series, 7 of which are 10Ah, 2 of which are 9Ah, and one of which is 7Ah, the *entire pack* is only a 7Ah pack, because if you try to take 10Ah out, the 7 and 9Ah cells will be destroyed and reversed, with the potential for a fire (even with LiFePO4).

All a balancer could possibly do with a pack made of those cells is to make them all the same voltage. For instance, if you fully charge it and it's balanced to say, 3.65v per cell, so all 10 cells are 3.65v. Then you discharge the pack by 6Ah...the 7Ah cell will be lower voltage than the 9Ah cells, and those will be lower voltage than the 10Ah cells, so the pack is now unbalanced in voltage again.

When the pack is recharged, the 7Ah cell will fill up first because it takes less to fill it up since it is "smaller", so it will end up higher voltage than the others, and charging will stop (if the BMS works like it should). The 9Ah cells will be fuller than the 10Ah cells too, for the same reasons. The 10Ah cells will be lower in voltage than the others, so the pack is now still imbalanced. The balancers will drain down the 7Ah cell until charging can restart, then as cells fill further the process will continue, starting and stopping until all cells are at the same voltage....but they will still be different capacities; you cannot change that.

 

[amberwolf]

. I am kind of distraught since the fire. Would have been a lot worse if Lico or Lipo. Batteries did not ignite. just balance board and plastic case. Also mad as I paid over $100 for a 54.6V 15 amp lfp charger and about $70 for a 43.6V 10 amp charger from ali express which I will no longer use unless I can get new and stable cells to build a pack and expensive Bluetooth BMSs with active balancers.

Reverse polarity is way over my head and may never understand how that could even happen. I removed all active balancers but if I do use them again it will be when charging , not running and will extend the balance wires about a foot and place the balancers in a large glass ash tray. lol Thing is , it may not have been the balancers fault since reverse polarity caused the fire but they are still cheap and made in China so suspect.

If no cells burned, then reversal probably didn't cause the fire.

The parts that caught fire would more likely be the cause of the fire.

There is a chance that a reversed cell's negative voltage across the electronics of a balancer or BMS channel could damage that channel, but I don't know if it would cause enough current flow thru the damaged electronics to heat them up enough to start a fire.

It's more likely that a wiring short or other fault (such as from a pinched balance wire shorting across cells) could cause a fire. That's been a strong suspect in a number of battery fires (it's difficult to know the exact cause since most battery fires dont' leave enough of the pack to diagnose).


Another thing that can do it is if the wires are too thin, so the current thru them heats them up enough (especially inside a casing or wrapping that traps heat, which is true of almost every battery) to ignite their insulation or something contacting them.

That can be the actual charging wires if charging at high current, or the balance wires if you have a high-current balancer, etc.

It can even be a poor solder connection or crimp in any of the high current connections--the resistance of the problem point creates heat, and enough heat in one spot can start a fire.


You can carefully examine the burned wires and parts and often see where the original ignition point was; you may have to view them in direct sunlight, using magnification of some type, to clearly see everything though. Overheating usually results in discoloration of metals that may survive the fire itself, and look different than the heating that happened to the rest of the burned parts from the fire itself.

 

[amberwolf]

I wish I had got more college time in as the method used for charging all lithium battery types just makes no sense. If I were to design a charger and BMS I would install a 15 amp fuse holder next to the BMS and all balance wires would be 16 gauge and when a cell reaches its full state of charge the voltage of the charger would drop equal to the fully charged cell. So if it was a 15S charger for example the last two cells would be 2S voltage and the last 1S. It would be impossible to over charge a cell.

If the charger voltage dropped to the voltage of just one cell, it would then drain the pack by discharging it thru the charger's output stage, damaging the charger, unless there is a diode between the charger and the pack to prevent that. ****

To charge using the method you're describing would require either a single cell charger that is switched between cells manually or automatically, either of which has potential for failure that can short out multiple cells together, creating a fire risk, or as many single cell chargers as you have series cells in a pack, connected in parallel to the cells. Both of these have been done; a decade or so ago there used to be a place that sold single cell LiFePO4 chargers with their Headways just for this purpose, because the HW cells were mismatched enough to require significant balancing, and this was just easier than using a balancing BMS to do that. There's some old threads from back then showing packs built to charge this way.


However, if all your stuff is designed and built the usual way most of the ebike-sized ***** Lithium packs of any flavor are, the BMS will just turn it's charge FETs off as soon as any cell hits HVC, stopping all charging current. (most chargers will "shut off" at this point and give you the "green light" indicating full charge, because they dont' detect voltage for this, they detect that current dropped below a certain point).

Then the balancers will drain down any cell that is above their balance-on trigger point, until the cell(s) are below the balance-off trigger point, and then stop draining.

Once none of the cells are above the BMS HVC point, and have dropped below the restart-charge trigger point, the BMS will turn the FETs back on, and charge current can then flow again from the charger.

This cycle repeats until the pack's highest-capacity cells are full. (the lowest-capacity cells, the ones with the worst characteristics, are filled first because they are "smaller".)



**** (the diode would need to be able to handle the full charging current, and be able to dissipate the total power that current thru it's voltage drop will cause, typically around 0.7v, less for certain kinds of diode. Assuming 15A charge current, that's 15 x 0.7 = 10.5W. Doesn't sound like much, but a typical soldering iron is only 15w, and it reaches hundreds of degrees F, enough to melt solder or set paper on fire, and the diode is far smaller than the soldering iron heating area, concentrating that heat into the smaller space, so you may have to have a heatsink on the diode and ensure it is in open air during charging).



***** I say ebike-sized because commercial OEM large-EV packs don't usually work this way, they typically have small boards to manage sections of a pack that are then managed by the main EV computer, and dont' have balancers because if a pack has become imbalanced it means there is a problem with cells and it needs to be repaired or replaced, so instead it disables the vehicle or restricts pack usage and sets an error flag / reports a problem to the user or service personnel.

Ebike packs are built using balancers because they dont' spend the time/money on matching the cells before building the packs, unlike the large-EV packs, and they use cells that dont' have as high a level of QC in the first place to ensure matched cells are easy to do.

 

[amberwolf]

I rode around with the 43V set up and external balancer on board. 5 or 6 miles or so from about 60% to 30%. I could monitor cell voltage while riding. If I only charge from 20% or 30% to > 60% < 70% the cells seem to not require balancing. A full fast charge will sky rocket some cell voltages which is unacceptable to say the least.

That's the other thing about large-EV packs that's different--many (most) of them don't use the full capacity range of the cells, simply because it's easier on the cells not to do so, and they are still likely to remain relatively balanced even as they age and become unmatched. The closer to full or empty a cell has to get (and the higher the charge or discharge current it sees), the faster it ages and the faster they all become unmatched and begin to behave differently.

 

[amberwolf]

I am looking at brand new 10 Ah Headway cells from e bay. Would you recommend these.

I was told that I could use a 5 amp active balancer with a Bluetooth BMS. I would like to monitor all cell voltages onboard and awhile charging. I still would like to charge at 10 amps if possible. If these cells are new than should work right ?

The ebay ad doesn't appear to say they do any testing ohter than "- All cells will be checked and voltage noted on box before shipping." That's not really testing, and does not do any matching of the cells (even if they were all identical voltages, they are not matched unless they are identical capacity and identical internal resistance, etc).

For long trips it makes sense to charge at 10 amps as Lico can not do that. If I am hauling around the extra weight for safety and longevity (10 times the charge cycles) then charging at 3 to 5 times faster than Lico just makes sense.

Different models and brands of cells of every chemistry have different charge rates available. For instance, some can charge at 1C, some only at 0.1C, some at 2C, etc. You have to look at the specific cell in question's manufacturer spec sheet to see what it is capable of, and under what conditions. (not what a seller says it can do, as they may not actually know, or could make mistakes or even outright lie).

There are also more chemistries than just LiFePO4 and LiCo, so unless you're restricting yourself to those two only, there are other options with other characteristics.

The ancient EIG NMC cells I used (C020) are capable of 1C charging (which is 20A for those cells), as an example.

Some of the generic LFP cells I've had in packs (like an old 18650 Vpower/CammyCC pack) could only handle 0.5C charging, and I don't think it was very good for them...but they weren't very good cells anyway.

At least some LTO cells can charge at very high (10-20C) rates.

Charging at higher rates (same with discharging) ages a cell faster; how much faster depends on the cell and the environmental conditions; some spec sheets show cell lifespan vs rates they're used at, some don't.

What do you think. I have seen many Lipo and lithium ion fires on you tube videos. Thay are almost impossible to put out. Not as easy as placing a metal pail over the pack like I did with LFP. All that burned was the balance board and plastic case. None of those Headway cells ignited proving my point.

Any cell (even lead-acid, NiMH, NiCd, etc) can ignite given the necessary conditions. How easy they are to put out can vary based on chemistry and size, but the fire can still start and given enough material involved may not be approachable, much less easily extinguishable.

There have even been Headway fires too, if you look around the forum there is at least one from some years back
Headway battery pack FIRE! <lot pics> It was probably not caused by the cells, it was thought to be caused by a shorted balance wire or interconnect or BMS failure, but it still resulted in cell fire.
Liveforphysics (who these days runs a commercial battery testing and design validation facility where they routinely test them to destruction in various situations) has a post in that thread with other failure info on HW

Headway battery pack FIRE! <lot pics>

Headway 40160S LiFePO4 battery pack [16S and 16Ah] Hi, Our daughters ran to our master bedroom while we were chatchit. They alerted us, shout "FIRE FIRE FIRE" and my mind was "oh shit". I ran to the garage, I saw the headway pack was on fire, I hurried pull the Yuba Mundo cargo bike to outside...

endless-sphere.com

There have also been fires with A123 pouch cells (Fisker?) that AFAICR were thought to be caused by manufacturing defects in the cell pouches or tabs possibly causing shorts between layers. Probably other LiFePO4 fires you can find from various causes.

 

[999zip999]

All batteries can catch fire it's a lot of stored energy you can start a fire with a little square 9volt battery.

 

[Skyler]

Ever hear of Lishen LTO ?

I just got a sweet deal from my cousin. He had a bunch of them for competition car audio. He was running a mini van with six 10.000 watt amps and 24 15" subwoofers. He has a gambling problem and lost some $$$$$ so unloaded them for $300. I got 24 of them now. The four are loose and rest at 5S 1P.

They are very heavy and large but 50,000 charge cycles. I ran them yesterday for 18 miles. They were charged 20S with my 54.6V charger. Drew had them in 5S with BMSs so I wired 4 in series. I watched a video where those things caught the discharge testing equipment on fire and the cells were barley warm at 400 amps. . Did not find it but found these.

SMC vs Zeee vs Lishen batteries heavy load test and internal resistance measurements.​

Lishen 18ah LTO 25C load test for 30 seconds​

I can not post direct youtube links. Like I said I am not a greenhorn. LOL. I helped hooking up my cousins first competition system. I just choose to keep much of my hearing as I age so. not into music that loud. He has a couple boxes of those Lishen cells. I doubt he will sell any more as he still dreams to compete but needs a gambling 12 step program.

I wish I could afford a 8 kilowatt QS motor. LOL, I should go with an electric off road dirt bike but was never a good driver on two wheels. A broken up body is not on my priority list. : content < 40 mph. 30 mph cruising is good out of the city.

54.6V / 20 = 2.73V. The specs say 2.8V is recommended charging current. They were still above 2V so 40V after 18 miles or so. My controller is a 36 / 48V and 38 amps for a 1,800W brushless chain. It actually is 26 amps * 50V = 1,300 watts but hit 32.5 mph with my GPS speedometer app. I averaged about 24 mph according to the app. There were more down hills than up though but top speed was on the flat as I coast down hills. The brushless chain is like a jake break on a truck which I like as easier on my brakes.

LTOs are very heavy and bulky. Good for longer trips but ridiculous for trips < 10 miles and light e bikes with geared hub motors. I plan on using them for my new 1,500 watt direct drive rear hub and my 3,000 watt brushless chain I have not built yet.

Most trips are short about 5 miles round trip. The old tired lfp should do the trick for awhile. I know now that they are unstable the farther they get from 3.3V in either direction so can accommodate for that. 3.1V to 3.4 seems to work well. Basically 30% of brand new capacity. Five miles for 1,000 or more cycles possibly. As long as I can continue to monitor voltage

Looks like 12 cells on lower bar and 8 on top Have to measure but guess is about 45 pounds. Since weight is centered cargo baskets will not be an issue..50V nominal operation as 2.5V and not 3.3V like lfp. Full charge should be > 53V. I could probably go with 21S and still reach 53V or greater as 54.6V 15 amp charger. I will need two 6S and a 9S BMS or reliable active Bluetooth balancer. I like to monitor cell voltages onboard. I tested with multimeter and used the calculator on my phone to measure

Thanks for your post.

Skyler.

 

[amberwolf]

There's some confusing things in your post, so I've asked questions inline below to clarify:

I got 24 of them now. The four are loose and rest at 5S 1P.

Are you sure that's how you have them wired up? 5S 1P is only five cells, which with LTO is only about 12v nominal. Most ebike controllers won't operate on that.

I can not post direct youtube links.

What are you doing, step by step, when you have a problem posting the links, and what specific error or problem do you get when doing so?


You should be able to post any link by just copying the URL from your browser URL bar and pasting it wherever you need it in your post. The forum software will take it from there.

If you prefer you can use the URL or Link button function and manually create a link, or you can Toggle BBCode mode and manually edit the BBCode of your post to create links, but the forum software does a pretty good job with standard Youtube links.

Example, a google search found this page for your second bold-text link "Lishen 18ah LTO 25C load test for 30 seconds", so I just pasted the URL into my post:

54.6V / 20 = 2.73V. The specs say 2.8V is recommended charging current.

Do you mean charging voltage? (current is typically measured in Amps rather than Volts, and can be much higher than 2.8A for all of the LTO I've seen. (Most of the LTO stuff I've read of can have much higher charging currents than discharge, which I find strange, but is just how that chemistry works).

They were still above 2V so 40V after 18 miles or so. My controller is a 36 / 48V and 38 amps for a 1,800W brushless chain. It actually is 26 amps * 50V = 1,300 watts but hit 32.5 mph with my GPS speedometer app. I averaged about 24 mph according to the app. There were more down hills than up though but top speed was on the flat as I coast down hills. The brushless chain is like a jake break on a truck which I like as easier on my brakes.

What is a "brushless chain"? I haven't heard of this type of chain before, or motor if that's what you're referring to. If not, it would be helpful if you could explicitly define what you've got. Pictures of the motor and drive system would help.

If you mean a brushless motor running the wheel via a chain drive, that's something different.

 

[Skyler]

Are you sure that's how you have them wired up? 5S 1P is only five cells, which with LTO is only about 12v nominal. Most ebike controllers won't operate on that.

Drew had them in 5S with BMSs so I wired 4 in series. 20S 1P 18AH. Drew is my estranged radical cousin. LOL. Was about 45 pounds in a heavy duty basket. why I will be bolting them to the frame.

Do you mean charging voltage? (current is typically measured in Amps rather than Volts, and can be much higher than 2.8A for all of the LTO I've seen. (Most of the LTO stuff I've read of can have much higher charging currents than discharge, which I find strange, but is just how that chemistry works).

Yes voltage of the charger. Current is 15 amps which is no problem for LTO chemistry.

What is a "brushless chain"? I haven't heard of this type of chain before, or motor if that's what you're referring to. If not, it would be helpful if you could explicitly define what you've got. Pictures of the motor and drive system would help.

It is chain driven with a 11T motor and 60T wheel sprocket. My phone is dead so cant take pictures. I built several. I run a 1,000 36V Unite chain around town with a 26 amp controller. Good for 26 mph on flat. I run my 1,800 watt brushless motor out of town. The 3 kilowatt motor will do about 46 mph when I build it but doubt I will have the guts to try it. It might be awhile as building a 1,500 watt 26" hub in a full suspension mountain bike first. The ad says 35 mph.

Not everyone realize how dumb e bay sellers are. Look at the ad.

Black 48V 1800W Brushless Motor For Electric Go Kart Scooters E-Bike Bicycle ATV

brand new
Made of high quality material, super durable to use
Model: BM1109 48Volt 1800Watt
Rated speed: 4500RPM
Rated current: 26.7A
Type of motor: DC, Brushless
9 tooth sprocket for T8F chain


Motor specification:
unload current rated speed rated torque rated current power motor teeth type of chain
Brush 48v 1000w : ≤2.8A 3000-3360RPM ≥2.82N.m 27A ≥77% 11T T8F
Brush 24v 250w : ≤1.6A 2650-2950RPM ≥0.8N.m 13.7A ≥76% 11T 25H
Brush 24v 350w: ≤2.2A 2650-2950RPM ≥1.12.m 19.1A ≥76% 11T 25H
Brush 36v 350w: ≤2.0A 2650-2950RPM ≥1.12N.m 12.6A ≥77% 11T 25H
Brush 36v 800w: ≤2.6A 2755-3045RPM ≥2.3N.m 27A ≥77% 11T 25H
Brush 24v 500w: ≤2.8A 2400-2650RPM ≥1.79N.m 27.4A ≥76% 11T 25H
Brush 36v 500w: ≤2.0A 2400-2650RPM ≥1.79N.m 18A ≥77% 11T 25H
Unite Brushless 48v 1800w:≤3.0A 2800-3300RPM ≥3.5-12N.m 26A ≥78% 9T T8F
Boma Brushless 48v 1800w:≤3.0A 4300-4500RPM ≥3.5-8.8N.m 28A ≥78% 13T T8F


26.7 * 48V = 1,285 watts

However my GPS speedometer app reads 32.5 mph on flat with 15S - lfp. With 17S lfp or 21S LTO looking at 35 mph easily. It just is NOT an 1,800 watt motor at 48V.

1,800 watts / 26.7 amps = 67.4V. Yea. Not even close. Most of them are 4,500 rpm but they make a few rated 2,800 to 3,200 rpm. ( see motor specifications above) I got that so gearing is 35 mph at 48V. However might need 56V battery to do that. 48V = 32.5 mph 1,285 watts.

The 1,000 watt brush is rated at 35.6 amps so 36 * 35.6 = 1,281 watts. It does not come close to the torque of the brushless motor though. I even ran the brush at 56V and the brushless smokes it at 48V. Gearing is a factor though but brushless has more torque per watt and slows an ebike down hills when letting off the throttle.

I was thinking about running two of them. Front and rear. About 10 years ago when the batteries died people in rich neighborhoods were throwing out those razor kids scooters which had 24V 250 watt motors. I was board and had extra time on my hands so hooked two with same chain and wheel sprocket to a 1,000 watt 48V controller in series. Parallel overheated about a block LOL. I was kind of green then but experimenting. I upgraded the brakes and sold the 20" bike for $200 to buy my first 1,000 watt 26" direct drive hub motor.

I could run two of those 1,000 watt brush but like a thumb throttle and brush controllers > 1,000 watts have a speed control knob but can still do front and rear with dual 1,000 watt brush controllers and single thumb throttle as long as one battery sharing common ground the signal wire from the throttle on controller #1 to #2 makes it work. I even did it with a 750 watt chain gear reduction motor rear and 350 watt Bafang front. Bafangs are geared at 21 mph and chain in back was 23 mph gearing. Nice in grass and dirt with both wheels spinning knobby tires.

UNITE MY1020 35.6A 1000W 36V ELECTRIC MOTOR W BASE F SCOOTER GOKART W CONTROLLE​

Code: Mot-MY1020-1000-36-CP+Controller
Add You

I could even hook up the 35.6 amp brush in front to the forks with the 1,800 watt motor in rear but have a 36V 20" 800 watt direct drive which will be very interesting at 56V in the front. 800 / 36 = 22.2 * 56V = 1,244 watts. Not sure what the rpm of the 20" hub motor is but an example of how my experiments have evolved 10 years or so later. LOL.

Glad you posted.

Skyler.






Skyler.

 

[Skyler]

I got the 1,500 watt kit working but am waiting on a rear brake part to test it. Hub kits have changed since my first. I am using my 17S lfp 56 volt batteries.

Item specifics​

Condition
New: A brand-new, unused, unopened, undamaged item in its original packaging (where packaging is ... Read moreabout the condition
Brand
Unbranded
Part Type
Conversion Kit
Voltage
48V
Compatible Bike Type
Array
Color
Black
Set Includes
Array
Battery Type
Lithium Ion (Li-Ion)
Material
Array
Energy
lithium battery
Motor Power
48V 1000W/48V 1500w
Max load weight
550 lbs
Speed
0-35MPH
Motor Rotating Speed
490 RPM
Axle Length
8.27” x Φ0.39"

Specifications:

heel type: Front/Rear Wheel

Motor: Brushless Gearless

Material: steel, aluminum alloy, rubber

Wheel Size: 26"x1.75"

Width of Wheel Hub: no less than 1.2"

Width of Tire After Inflating: no less than 1.6"

Motor Power: 1500W / 48V or 1000W / 48V

Motor Rotating Speed: 490 RPM

Motor Torque: 45 N.M/74.5 N.m

High Motor Efficiency: 88% ~ 90%

Controlling Device: 48V

Axle Length: 8.27” x Φ0.39"

Rear Dropout Spacing: 5.3"

Spokes: Steel, 12G×0.1"

Max load capacity: 551lbs

Net Weight: 24.3lbs

Weight of Single Wheel: 19.8lbs


Package Includes:

1x Brushless Gearless Motor Front / Rear Wheel

1x Intelligent Motor Controller

1x Pedal Assist Crank Sensor

1x Cable Ties & Plastic Coil

1x Pair of Handle Bars (included Twist Throttle)

1x Controller Bag

I finished the wiring a little while ago. I think I got robbed on the controller. It is all Chinese and no manual or wiring diagram was included.. The wires to the hall and phase were hooked up and the twist throttle. I just had to plug in the display. My guess is 8 or 9 mosfets and suitable for 800 watts maximum. The controller is just too small for a 1,500 watt controller and controllers are always rated 5 or 10 amps less than the fuse which is only 35 amps. Should be about 50 for 1,500 watts.

For $209 + shipping $222 total I am just hoping the motor is 1,500 watts and not 1,000 or 800. I got the wheel to spin but seems gutless. It spins slow even at full throttle. My question is , does the display make it go faster.. Is that the brain or controll module for the intelligent controller ?

I never had an intelligent or programable controller in the last 10 years building e bikes. I am very familiar with Bafang and e bikeling kits with display modules and also sensor less greentime controllers but not programable intelligent controllers. With the ebikling display module it turns the system on. My first two hub kits , 1,000 Watt direct drive and 800 watt had a power switch on the controller and both were the same size. Neither had a display module.

Even though I dont know about this new controller I kind of do. I have watched a lot of youtube videos and know there are different power levels. I think it could be the + and - buttons. What I do not know is how to set them yet or what is default when the unit is off ?????

Why I said things have changed. I am in new territory now. The throttle on the intelligent controller works without the display The e bikeling don't. It turns the system on. and the e bikeling module does not have the + and - with the power button in the middle.

I want to test this intelligent controller. The kit was advertised as a 1,500 watt and 35 mph kit. That is what I paid for. The chances are I will upgrade to a 50 amp 2,000 watt hub motor controller. The reason is I have another ebike. It has a 700c ebikeling 500 watt 22 amp motor up front. It is not suitable for hills as I am about 250 pounds. Plus I run heavy lfp batteries.

I got a rear Bafang for it which was rated at 500 watts but the numbers on it look like a 350 watt Bafang as I have a couple of those laying around as well. I got it running with a cheap $12 Chinese controller about 12 amps. LOL. The front ebikeling don't run as the ebikeling controller took a shit. LOL

I still can not post any links. Yotube or ebay. Could be a setting on the computer. Not sure. The youtube video I am interested in is this.

Can one Speed Controller Run two Hub Motors???​

A google search also brings up this.

Pratik R. Sonawane​

April 26, 2021​

Related Topics​

yes, but it depends on the power rating of the controller used in the system.
the controller is the device used to control the bldc motors.
now let’s take an example
if a bldc hub motor has a voltage of 36v with a power of 250w then which controller is suitable for the motor?
of course, the same power (250w) or even more (+250w) than that of the motor so that the system becomes more stable and reliable.
in short, the controller will operate efficiently.
but what will happen by adding one more motor having the same power (250w) with the controller!
let’s understand
a driver system must have to share the total load of 500w so that the two motors can run.
now, observe that the controller(250w) already is operating at its maximum limit and it is already sharing the total load of 500 watts (250w extra) which may cause major damage to the controller. because it is not sustainable for two motor demands.
there are two possibilities either the controller will get heat up or it will get damaged.
then how to make it sustainable?
to operate these two motors on one controller, we have to replace these existing controllers with the new controller which has a power rating of 500 watt or more
so the conclusion is :
yes, we can run two motors on one controller but the condition is the power of the controller should be equal to the power of the motor.

welcome to feedback form
is it helpful to you?

yes, thanks
no

I would like to do this with the intelligent controller for the Bafang and ebikeling motors as they are both about 18 amps and the fuse on the intelligent controller is 35 amps. It should theoretically work if that guy is correct.

Maximum current on controller would be 30 or 32 amps with a 35 amp slow blow fuse so. 30 amps * 48 volte = 1,440 watts. 15 amps for each motor in parallel. 56V * 30 amps = 1,680 watts.

I have the power level meter in that one video . It measures amps , volts and watts plus peak values. Peak power of e bikeling geared 500 watt motor was > 700 watts and during take off up to 10 mph. Then level off at around 400 + watts. Bafang was about 75 watts less but geared lower than ebikeling so greater torque. Bafang was 26" and ebikeling 700c so effected gearing as well.

About 21 mph and maybe 24 mph so about 3 mph difference. Only brush motors can share same sprocket , chain and controller. Hub motors I guess can share same controller for front and rear motor. My guess is the lower geared rear Bafang would turn first and the front hub turn slower up until maximum gearing and the higher geared motor will increase top speed. Both freewheel motors so zero drag.

I got a gy who does brakes and about to get the full suspension ready for a test drive for the 1,500 watt kit. I have 17S lfp and 24S LTO but still might get those 10 Ah Headway cells. Me and my friend will be watching a lot of battery building videos on yotube.

I want to get a spot welder. The A123 cells I got have tabs about 1/2 inch so soldered 10 gauge wire for the series connections across 16 cells at a time 8 positive and 8 negative. Only 8 for the positive and negative power side. three amp fuses for every balance wire. 60 amp for the negative power side. 40 amp DC breakers for the geared dual 500 watt motors and a 60 amp DC breaker for the 1,500 watt kit.

Please tell me what you think.

Skyler.

 

[amberwolf]

Brushed controllers can run multiple non-identical brushed motors in series or parallel, splitting either speed or torque (voltage or current) between the motors.

Brushless controllers cannot correctly run multiple brushless motors unless they are the same motor design/poles, and are rotationally locked to each other, such as the rotors being bolted together or being on the same shaft, or chained together without any lash, so that they maintain the same phase angle / position as each other, otherwise they cannot be correctly driven by the single controller, since it has to know the position of the rotor's magnets relative to the stator teeth (phase windings), to know which phase windings to send current thru at what instant to keep the motor spinning.

If there are different numbers of poles between the motors, the controller will send pulses incorrectly to one of them if it is using sensors from the other for rotor position. If it's sensorless and detecting phase feedback, it will send pulses incorrectly to both of them because it's detecting *all* of the poles from both motors and trying to send pulses to match them...but neither motor has poles to match what's being sent... Same thing if it's sensored and you wire up halls from both motors to it.

You can test it out even with two identical motors each running a separate (but otherwise identical wheel, on one controller. If it doesn't damage the controller (unlikely but a possibility), it will probably have periods when the wheels change relative rotational position (lose sync) because of differences in the tires, road surface, etc., and one or both motors will run rougher; if the sync is far enough out it will even oppose the other motor because the driving pulse will be on the wrong "side" of the magnet, causing it to brake rather than accelerate.

It may still "run"...but probably not like it should.


There are dual-motor controllers out there, and those will correctly run two motors, because they have separate power control sections to drive each motor, and separate position detection systems to monitor each.

 

[Skyler]

Ok. Thanks for the information. It was helpful. It is why I wanted to check with you.

I was wrong. The Bafang on the back has a 18 amp controller. Not a 12 amp. I will order another 18 amp for the e bikeling 700c motor and put it up front and use a single throttle. I am testing the new 1,500 watt kit. Hopefully it will run and go > 30 mph. It says in the specifications 35 mph. The controller looks small for 1,500 watts.

I have a full basement. I could safely charge LiPo as a concrete floor. I could stick two 6S Hobby King LiPo packs in a LiPo bag and ammo box with some holes drilled in the top. Then place a metal garbage can over it with a few holes in the top of it with metal screening so no sparks escape. Only way to safely charge LiPo without baby sitting it.

Or I could get some new high capacity 26650 cells > 3 Ah and build a 12S 5P pack. It would be considerably lighter than my 13S - 8P pack I am running now. More suitable for my lighter bikes with geared hub motors.

I am also looking at an ebike with 12S LTO. It will fit over the bottom bar for lower center of gravity. It will weigh around 23 pounds. However looking at 30V. 2.5 * 12 = 30V. Currie makes a 24V 900 watt motor. I could put two on a reinforced rear rack like my 1,000 watt 36V 20" chain drive. Then one up front off the forks.

900 watts / 24 = 37.5 watts * 30 = 1,125 watts * 3 = 3,375 watts. They make 4,000 watt brush controllers that are inexpensive but use a speed control knob which I am not found of. I think I saw a regular 1,000 watt brush controller that uses a 3 wire thumb throttle.

I just threw out a 800 or 1,000 hub motor controller that uses a 4 wire throttle. It would not work. I had a 43 volt battery hooked up and the display on the throttle only read 29V and did not work. I prefer a simple sensor less controller. Greentime makes several models and had god luck in the past with them. It got too late last night and was drinking a lot of beer so testing that 1,500 watt kit today.

When I built that chain drive I was going to cut a small piece of 4 by 4 pressure treated and sand with a belt sander at the perfect angle to fit between the frame behind the seat and the steel tubular rack frame. Then run two 1/2" carraige bolts down thru. I did not have a 4 by 4 so used the 1 - 12" PT deck railing.

I just got a heavy duty Haro 20" BMX frame for $40 I still have to pay for. It will be for the 3,000 watt brushless chain drive. Looking at a 1,000 watt - 36V motor for the front of the Haro for a whopping 4,666 watts and 56 mph gearing. LOL

1,000 watts / 36 = 27.7 * 60 = 1,666 watts + 3,000 = 4,666 watts

Glad you posted.

Skyler.

 

[amberwolf]

They make 4,000 watt brush controllers that are inexpensive but use a speed control knob which I am not found of.

Easy to fix. Wire up your choice of style of potentiometer-based throttles in place of the potentiometer they use in the knob.

4 by 4 pressure treated

"pressure treated" what? (you may know what you're referring to, but you have a tendency to leave out important words in your posts that tell us things you know but we don't).

 

[lnanek]

I think that's a type of wooden board. 4" by 4" are the dimensions other than the length. Pressure treated refers to soaking it in anti-termite chemicals at high pressure to make it survive longer outside and exposed to damp.

 

[Skyler]

Yea.

If you look at the second picture in my last post up close you can see the reinforcement. A custom cut and sanded fitted 4 by 4 with two 1/2" carriage bolts are the upgrade but the rear brake must be custom installed upside down underneath. The steel rack cold beu replaced by a 4 by 6 piece PT. or two pieces of PT. 3/4" plywood with two brush motors and a single wheel sprocket.

The extra payoff is two motors double as a chain tensioner. By grinding slots in the wood with a jigsaw when you move the motors apart you tighten the chain. Pushing them together allows you to remove the chain to fix a flat tire.

It is a no brainer to custom build a dual motor rear e bike and adding a front motor would be childs play to me. I will provide photos when I do. A front chain drive is not even close to my first rodeo.

However the 3 kilowatt brushless motor has to happen first as I got the Haro BMX frame which is special. Haro is very heavy duty trick BMX popular in 90s and 2,000s. Perfect for the 4 horsepower motor on the back. Obviously not a dual motor in the back. However the front could get a 36V Unite brush 1,000 watt motor so 1,660W @ 60V + 3,000.

Thank you guys for sharing.

Skyler.

 

[Skyler]

I rode the 1,500 watt kit yesterday and I was correct about the controller. I have never and never will hook up pedal assist and or brake sensors. My rule of thumb is the KISS method. (keep it simple stupid) In my opinion it is ust more things that could go wrong.

It has 5 assist levels #1 being enough to roll the bike maybe 5 mph. When I press #2 there is a power surge and noticeable acceleration. Very quiet and smooth. I am happy about that. Unfortunately I never got to level #3 as am having problems with the tires and looks like more brake adjusting is required.

The stock tire that came with the kit is too skinny for me and wanted to match the front so switched it with another 26" wheel from a 700c hybrid ebike I am working on that has a 350 watt Bafang motor. It is not a really wide tire but am having spots that bubble out as not staying seated. I may have to try another tire or put the stock tire back on. I might even move the kit to the other bike which is the hybrid that uses the skinner tires. Needless to say I am a little disenchanted about that.

I am also very skeptical about the controller. A 35 amp fuse. WTF. Since I am running 56V I should still get > 1,600 watts.

56 * 30 = 1,680. That is if the controller is 30 amps. I have been searching youtube for the exact kit and not found anything. The writing on the controller is Chinese. Also disenchanting.

I also have another rule I like to follow. If it is not broke don't fix it. > 1,600 watts should be capable of 35 mph. The big question is how hot the controller gets = or > 30 mph. Also whether or not the fuse blows. I defiantly will not replace with a 40 amp fuse if the controller is hot. I will replace with another 35 amp fuse and order a better controller.

QQLADY Ebike Controller 48V/64V 1500W 45A Dual Mode Sensor Sensorless Brushless DC Motor Controller for E-Bike Scooter Motorcycle Controller 1500W Brushless Motor Controller​

Brand: QQLADY

That looks like a great match for the motor but not ordering unless I need to as many other ebike projects and want those 10 Ah Headway cells. I also want a decent spot welder as would like to start building and selling 26650 lfp packs for a modest profit.

Hope to hear from you guys regarding the matter. Thank you guys for following my post.

Skyler.

---

It is 8:22 PM. I just got back from testing the 1,500 watt kit. It is about what I expected from a 30 amp controller. 54 kph. 33.5 mph. It is close to what was advertised but at 56V , not 48V. The stock tires are thinner and smooth which could add 1 mph maybe. Also the extra battery weight is a factor and my 240 pounds. A 150 to 180 pound person with light LiPo packs on a lighter ebike would hit 35 mph easily on the same road.

The display where you set the power settings 1 thru 5 is also a speedometer but in kph. My 1,800 watt brushless motor read 32.5 mph on the same road. That was with 20S LTO. Voltage drop under load is greater with lfp than LTO. I think 50V - LTO = 56V lfp.

I just put the full suspension down in my basement for some time out. I am fixing the tire on the bike with the 1,800 watt brushless motor. It is much lower and easier to ride. I am only 5 foot 8" . Also am upgrading to a larger cargo basket for about 50 pounds of laundry. I cold not do that with a taller bike without a calamity

. Feel free to post anytime. I will be comparing 56V 17S - lfp with 20S - LTO soon. I have a 54.6V 15 amp portable charger. I just need to install 5 amp fuses to all 1.2 amp balance wires. I do not need any more fires.

Skyler.

 

[Skyler]

Easy to fix. Wire up your choice of style of potentiometer-based throttles in place of the potentiometer they use in the knob.

Looking but not seeing it. Is it the same as a thumb throttle ???

 

[lnanek]

Cheaper throttles use Hall effect sensors, more expensive ones use potentiometers. I think either sensor can be used to make a twist throttle or a thumb throttle.

 

[Skyler]

Yea. Thanks.

Right now I have 6 e bikes I am working on. All running or just need a little work. Three are dual motors and single throttle. One needs a cheap 350 watt controller. I also have a 3 kilowatt brushless chain drive to build.

Looking at a future build though with three Currie 900 watt 24V chain drive motors. Two rear and one front. A 5,000 watt brush controller will power all three. That is when I will need the more expensive thumb throttle to replace the speed control knob. 900 watts / 24V = 1,125 * 3 = 3,375 watts. 46 or 47 mph. I would like to keep the 3,000 watt brushless motor about 42 or 43 mph. The three brush motors is about a year away though as not top of my priority list. Could make a nice winter project though. Looking at about 10 e bikes total.

Thanks for posting.

Skyler.

 

[Skyler]

I just ordered 63 more A123 cells from Battery Clearinghouse.. The reason is I built a total of four lfp packs. Two - 5S - 8P - A123 cells. one 7S - 8P - A123 cells. One 3S - 3P - 8Ah - Headway cells ( used and < 50% capacity.) Even though I have two 48V ebikes running I mostly just ride the 20" ebike with the 36V - 1,000 watt motor and 800 watt controller. Therefore I am mainly running the two 5S packs in series with the 3S Headway pack. Since I am charging 13S lfp with a 12S lfp charger I no longer even need to balance with my external balancers. However when I do run the two 5S packs in series with the 7S pack for 56V and 17S I then need to charge and balance the 5S packs in parallel so they are about the same voltage as the 3S pack. 43.8V / 13 = 3.36V charging voltage. It has been about six run and charge cycles and the packs including the 3S - 3P Headway all rest between 80 and 90% without any balancing. It is a no brainer to build a 6S - 8P pack with the same A123 cells to put in series with the 7S - 8P pack for 13S - 43V. I will then have 13S - lfp to run and 13S lfp fully charged on stand by. I cold even haul 13S - 8P in a rear basket for longer range like up to 15 miles. Specifications: wheel type: Front/Rear Wheel Motor: Brushless Gearless Material: steel, aluminum alloy, rubber Wheel Size: 26"x1.75" Width of Wheel Hub: no less than 1.2" Width of Tire After Inflating: no less than 1.6" Motor Power: 1500W / 48V or 1000W / 48V Motor Rotating Speed: 490 RPM Motor Torque: 45 N.M/74.5 N.m High Motor Efficiency: 88% ~ 90% I have been thinking about an identical front hub for a dual 1,500 watt ebike. One reason is the controller that came with the kit is probably only 30 amps as the fuse is 35 amps. It hit 33.5 mph but only for a few seconds.. My guess is it will over heat if cruising for a long distance > 30 mph. Also dual motors will be great for climbing steep hills. My question is could I run both controllers with a single display and twist throttle. Since it will have pedal gears and start out with power level 1 which is a modest 5 to 10 mph there should be no issues with the front drop outs as long as I get decent torque arms. I can take pictures of the plugs and post them as will be working on the bike. I need to move the controller as looking at a battery case for 12 Lishen LTOs on the bottom bar for lower center of gravity vs. all 20 LTOs on the top bar and front basket. I ordered two 6S - LTO balancers so I can slide in a 6S - LTO pack on each side. The battery case will not be removable and will have hinges and a lock to slide the 6S packs in. An 8S - LTO pack will sit in a lock box on the top bar. I plan on doing this for several ebikes that I want to run 20S - 50V - LTO with. I have a 54.6V - 900 watt -15 amp charger. My main concern is the wiring. I would rather not have to cut and splice the wires for the single throttle and module which controls the 5 different power modes. I would like an adapter even if I have to make one. As long as I can plug a single module and twist throttle for two identical controllers I am happy. I am looking at ordering the front 1,500 watt kit next month. By that time I will have the battery boxes finished and the 6S - lfp pack done for my 36V ebikes. Please let me know. Thanks. Skyler.