LFP reverse polarity.

[Skyler]

I was hoping to keep this post going but seems I am the only one posting here.

If anyone reads this I do have a question. I am not familiar with BMSs as used active balancers in the past or externally balance with one of my balancers or my LiPo chargers in charge balance mode.

However after two issues with cells reversing polarity I would like to protect my LTOs for longer running time and distance without any issues. I stopped running active balancers during discharging but would like to get 5S active balancers with quality BMSs.

I see these Daly BMSs a lot when searching and wonder if anyone else here has used them and if they are good. Also I see they have two things sticking out. Is that Bluetooth ? I want the Bluetooth option but not sure how it works. I currently do not have cell phone service so not sure if I can use the Bluetooth option with no service on a cell phone.

Please let me know , someone.

Skyler.

 

[Skyler]

Is this any good ???

Would anyone recommend it ???

 

[fechter]

The sales sheet states

It is specifically designed for battery welding (18650, 14500 battery, etc) and can be used to weld nickel strips with thickness between 0.05 and 0.2 mm for nickel plated steel or between 0.05 and 0.15 mm for pure nickel strip. With the built-in LED light, you can even work at night.

So if you only need 0.15mm nickel, it might be OK. I use an old JP welder with some small Lipo cells for power and it does 0.2mm nickel with no problem.

 

[Skyler]

So if you only need 0.15mm nickel, it might be OK. I use an old JP welder with some small Lipo cells for power and it does 0.2mm nickel with no problem

Yea. I bought the cheapest ebay spot welder they had about two years ago.

.

Cheap Battery Spot Welder 18650, Yes its awesome​

That is the yotube video.

I never hooked it up. I am thinking about handing it to a friend of mine if he will build a couple packs. I have a bunch of 18650 cells I bought a few years ago and some 26650 cells I got a few months back.

The 18650 cells will be for a friend who needs at least 36V. I have a 10S 36V BMS and will pass that to another friend I ordered a 36V 500 watt motor for because he fixed the spokes on the geared hub in the back of my Giant and hooked up my pedal chain and made all the gears work. I never take advantage of people. I help people especially when they work on my bikes.

I ordered two motors this month and a controller.

 

[richj8990]

"Suspension forks are not suitable for a 1,500 watt motor even if I start off with pedal and assist level 1"

What fork do you have on the bike. You can put two torque arms on it. I've gone up to over 1000W with a front hub drive and nothing happened to the fork, the dropouts are fine. The controller wires will start melting before the dropouts snap, as long as the axle is in OK and you have two torque arms, not just one. Some $100 fork that came with the bike may not cut it, especially if the dropouts are not thick like they should be, as in around 1 cm wide. Otherwise the horror stories you have read about are from people not using any torque arms. You use two, nothing bad is going to happen. Just don't ride like a maniac in traffic.

 

[Skyler]

Otherwise the horror stories you have read about are from people not using any torque arms.

I snapped fork dropouts at least 3 times. One thing I do before riding a front hub is elevate the front wheel and practice turning it with the thumb throttle as slowly as possible to start.. The feather touch technique. I also always use two torque arms if possible. I still snapped cast aluminum forks. Not steel or forged though.

you use two, nothing bad is going to happen. Just don't ride like a maniac in traffic.

Well. The bike is not mine, It is for a friend and I talked him out of a front 1,500 watt motor. He was going to order a hub kit this month but changed his mind. I think he is waiting another month.

He has a beach cruiser. It is steel so could spread the rear a little maybe if necessary. 1/8 or 3/16" . If still not enough he is willing to get a mountain bike from Walmart. He still wants the 1,500 watt kit. But talked him out of front. It may even fit without spreading. Not shure

I got a 500 watt 36V motor ordered for another friend and the 48V 1,000 watt motor and controller for the front of my flagship full suspension bike with the 1,500 watt rear hub kit and 30 amp controller. 30 amps is barley 1,500W at 50V. 1,440 watts @ 48V. It is the main reason for the front chain drive. About 26 amps * 55V. 1,430W + 1,650W = 3,080W. approx. 33 - 35 mph gearing.

Hopefully by this time next month I will order a spot welding machine. I failed to solder 26650 cells as solder wont stick. I have a whole bunch of 18650 cells also that need building. I did not get rid of all my 18650 when I switched over to LFP and LTO. I do not want to use my portable spot welder but may get some one else to try it. I did order 0.15 nickel strip I will know if it works soon. However I do not trust some $24 spot welder. I want a AC spot welding machine. Looking at 0.2 or more capable thickness.. Not 0.1.5. Budget < $200 if possible. Any help with that would be great.

Thanks for posting.

Skyler.

 

[Skyler]

WOW

They sent me a 36V 800W motor instead of a 500W. Will be > than a kilowatt at 48V. The 500W was only 18+ amp and the 800W is 29+ amps.

It is for a friend of mine that works on my brakes and pedal gears. He has a 120T #25 wheel sprocket.

Alfa wheels. ebay. Thumbs up to them.

I also got my 48V brush Unite motor with controller for $72 mounted on front of full suspension. Work in progress. The 48V controller is 30 amps so 55 * 30 = 1,650W, The same as the rear 1,500W controller. The unite motor says 20+ amps though so not sure. It might only pull 20.8 * 55 = 1,144W. Does anyone know. I will find out when I hook it to my power meter.

Either way it will still help to share the load with the rear controller for steep hills and > 30 mph loads on flat. That is the main purpose for it. I am going with #25H chain and a 89T sprocket. The rear hub is advertised for 35 mph but I only got 54 kilometers per hour when I tested it awhile back. 54 kmh = 33.554 mph. That was with knobby tires and a slight incline though.

I saw another 1,500 watt kit advertised for 37 mph with a 35 amp controller instead of the 30 amp I got. Same price too. It wont really matter though if I get the front chain working as will be at least 1,000 watt more and at least 50 amps total.

Skyler

 

[Skyler]

Cant take pictures as phone disappeared a week ago and tablet this week. I got a camera or two I can dig out but both need a card for storage. Forgot what it is called.

I am not going with 22S 55V LTO. 21S just makes more sense. It will work perfect with my 54.6V LFP charger as

54.6V / 21 = 2.6V. - about 80 to 90% charged.

54.6V / 22 = 2.48V - under charged ; Maybe 40 or 50%. full.

It is a no brainer.

Not happening for awhile though as I want to build one more LFP pack, 6S 8P to go in series with the 7S 8P. I need two sets of 43V as still running 36V ebikes most of the time. I am still running the two 4S LTO packs with the 7S LFP in series. The other 43V set up is the two 5S LFP and 3S in series.

All the LFP packs are 8P with A123 26650 cells from battery clearinghouse except for the 3S which is 3P 8Ah Headway cells used from Battery Hookup. The cells were all about 30 to 40% capacity so why I went with 3P. All the LFP packs will charge to at least 80%

I will be getting a real spot welding machine next month. Looking at around $250 and up to 0.3 mm nickel strip minimum. Then I will build the 6S LFP and then start building and selling LFP packs. It might be October before I can afford the two 6S LTO BMSs and a 9S for 21S LTO 52.5 working volts. Until then if I need >50V I can use the two 5S LFP in series with the 7S for 17S or can run the two 6S LTO packs in series with the 7S LFP.

17 * 3.3 = 56.1V

12 * 2.5 = 30V + 7 * 3.3 = 23.1V = 53.1V

Mixing LTO with LFP works great for short distance as long as both chemistries are charged to about 85% or above but if going long distance 13S LFP with my 43.6V 10 amp charger works for recharging in about an hour or less or 20S LTO with the 15 amp 54.6V charger in even shorter time.

Charging voltage for LTO is 2,8V maximum so 21S LTO is 2.6V per cell and 52,5 working volts which is better than 50 or 48V. That way I can still use the 54.6V charger as I paid > $100 for it.

Skyler.

 

[Skyler]

Yea.

Not sure about about all you who post here on ES but I am not stupid or a greenhorn. I just never spot welded a battery. We got serious issues with mentally challenged people like this guy promoting complete garbage for $$$ or whatever reasons from ebay sellers that push complete Chinese GARBAGE.

Here it is exposed!

Cheap Battery Spot Welder 18650, Yes its awesome!​

Yes. Please type it in and watch.

I did EXACTLY as he said after watching the video about a dozen times before hooking up.

The result was flames shooting from the unit while spot welding.

I threw it in a dumpster and wish I could do the same for the guy in the video.

I have a witness as was not brave enough to even try spot welding with such a calamity.

I might even get kicked off youtube as threatened to kick his sorry ass for posting such a fallacy on youtube unless he removes it.

This forum and all e bike builders who may wish to successfully spot weld a EV battery pack in the future certainly deserve a lot better information.

Hope it will save at least someone from being ripped the F off in the future.

I would absolutely appreciate any links to DECENT RELIABLE spot welders in the $200 range for up to 0.3 mm or more welding.

My opinion may not be viable to some extent as not spot welded but an AC battery welding machine seems to make a lot more sense than any battery powered or DC portable device but again I am a greenhorn when it comes to spot welding period.

Any feedback / help will be appreciated as have a lot of 18650 and 26650 cells to spot weld and sick of not getting er done.

Please let me know.

Skyler.

 

[Skyler]

Yea.

Not sure about about all you who post here on ES but I am not stupid or a greenhorn. I just never spot welded a battery. We got serious issues with mentally challenged people like this guy promoting complete garbage for $$$ or whatever reasons from ebay sellers that push complete Chinese GARBAGE.

Here it is exposed!

Cheap Battery Spot Welder 18650, Yes its awesome!​

Yes. Please type it in and watch.

I did EXACTLY as he said after watching the video about a dozen times before hooking up.

The result was flames shooting from the unit while spot welding.

I threw it in a dumpster and wish I could do the same for the guy in the video.

I have a witness as was not brave enough to even try spot welding with such a calamity.

I might even get kicked off youtube as threatened to kick his sorry ass for posting such a fallacy on youtube if he don't remove the video.

This forum and all e bike builders who may wish to successfully spot weld a EV battery pack in the future certainly deserve a lot better information.

Hope it will save at least someone from being ripped the F off in the future. Or starting a fire they are not prepared to put out.

I would absolutely appreciate any links to DECENT RELIABLE AC spot welders in the $200 range for up to 0.3 mm or more welding nickel strip.

Please let me know.

Skyler.

 

[Skyler]

LTO is the only chemistry that can survive reverse polarity I read. Not sure where but I know for a fact LTO also reverts back by itself. About three days. It was youtube. The guy hooked a resister to short and drained to zero and tapped the terminals from a charged cell.

I tried something different. I hooked the resister to the positive side of both batteries and then a wire with gater clips to the negative terminals. The negative voltage trickled down toward 0 slowly but still took over 24 hours. Probably like 30.

Today it was about + .06V and charged to over 2V in NIMH manual mode 0.5A. The other LTO flipped back by itself a day before as was not as far in the negative. I think they were about negative 1.8V and 0.8

I will now need to fully charge and monitor each cell. Rated at 50,000 cycles these things are as close to indestructible as any other chemistry. Looking at two 6S and a 10S for 55V. I will want a 80 amp fuse on each negative power wire. I use a DC breaker if no fuse between controller and battery for positive side. If controller has a fuse I get a 35 amp toggle switch from auto parts store for about $8.

I need to get a BMS and also want 5 amp active balancers so need to replace all the 5 amp fuses to 10 amp first. I think I will run 22S and order a 58.8V charger.

58.8 / 22 = 2.67V.

Skyler.

 

[Skyler]

Looking at ordering one in October and a second in November.

• Voltage: 52 V
• Capacity: 10 AH
• With Built-in High quality BMS ,Battery have overcharge, over discharge, over current, short circuit, charge equalization of automatic identification and protection circuit.
• Battery Size :88*145*260mm
• Type :LiFePo4 Battery pack
• Weight:5 Kg
• Standard Charge Current 3A
• Max Charge Current 30A
• Max Charge Voltage 58.4V DC
• Battery Resistance ≤10mΩ
• Rated Discharge Current 30A( can be customized)
• Max continual Discharge Current : 60A
• Pulse Discharge Current : 100A
• Discharge Cut-off Voltage :42.5V
• Charging method : CC/CV(Constant Current Constant Voltage)
• Lifecycles : More than 3000 times .

5 kilograms = 11.0231 pounds so 11 ponds for 10 Ah

20 to 22S LTOs are just too much weight for an e bike. The LTOs are 900 grams each so

900 * 22 = 19,800 grams to pounds = 43.651528 pounds so with boxes and hardware at least 45 pounds.

So the question is did I waste > $600 on those LTOs. The answer is NO.

The reason is simple. Most of my trips with an ebike is < 10 miles or about 6 to 8 miles round trip. I rarely travel 20 miles or 36 to 40 mile round trips but might in the future with two of those 10 Ah packs which will only be about 22 pounds. My 15 amp 54.6V portable AC charger will charge two packs in an hour or less to at least 85%.

• Max Charge Current 30A That is the rating for one 10S pack. 54.6V / 16 = 3.4V. Perfect for a quick charge to get home. I can then plug in the 58V 16S chargers that come with each pack for over night charging.

I am building a 10S LTO pack with a 5 amp active balancer and 10S BMS for full protection. I am leaving the two 6S LTO packs as is but adding active balancers and BMSs for full protection.

10S LTO = 19.8416 which is just shy of 20 pounds. 12S = < 24 pounds by just a little. 23.8 pounds. about 25 pounds with the boxes.

I have been wanting to order the Currie 24V 900 watt motor for a long time and am looking at around Christmas time and plan on ordering two. With a brush motor two can be run to a single wheel sprocket and single Kelly controller. I could even put a third in the front as 100 amp controller will easily run three 900 watt motors.

The bottom line is LTO is the perfect choice for 24 to 30 working volts as < 25 pounds and LFP for 36 to 52V as also < 25 pounds.
LiCo or Lion , LiPo may be 10 pounds less but the extra charge cycles and safety factor LTO and LFP make that 10 pounds worth it.

There is the perfect charger for 12S LTO. 33.6V at 10 amps.


I might as well make two 12S packs and use all the LTOs I ordered but only run one 12S pack at a time so 25 pounds of battery instead of 50 pounds. 12 * 2.8V = 33.6V. 4.2 * 8 = 33.6V. That is why that lion charger will work perfect for 12S LTO.

900 / 24 = 37.5 * 30 = 1,125W * 2 = 2,250W. Three motors will push 3,375 watts.

9/24/23 - 9:31 PM.

I found a 20 Ah LFP pack just now. I figured if they sell 10Ah then they should sell 20 Ah. Adding the picture below. Ordering it Friday. If it is as advertised it should fit all my 48V needs It is also less than 17 pounds.

• Voltage: 48 V
• Capacity: 20 AH
• With Built-in High quality BMS ,Battery have overcharge, over discharge, over current, short circuit, charge equalization of automatic identification and protection circuit.
• Battery Size :260*200*100 mm
• Type :LiFePo4 Battery pack
• Weight: 7.6Kg
• Standard Charge Current 5A
• Max Charge Current 30A
• Max Charge Voltage 58.4V DC
• Battery Resistance ≤10mΩ
• Rated Discharge Current 50A
• Max continual Discharge Current : 62A ( can be customized)
• Pulse Discharge Current : 200A
• Discharge Cut-off Voltage :42.5V
• Charging method : CC/CV(Constant Current Constant Voltage)
• Lifecycles : More than 6000 times .

I might still buy a spot welder but may wait until January 2024. Building packs could still land me a profit but a winter project.

I want to build a 24V ebike first and get BMSs and balancers for 12S LTOs + the 33.6V charger.


Skyler.

 

[Skyler]

I finally did get the 10S 5 amp LTO balancer in. I hooked it up with 10 amp fuse holders and fuses but they were not what I expected. The fuse holder wires were way too thick. 10 gauge silicone wire. For balance wires 18 gauge is as large as I want.

Anyway the unit did not work at all and not sure if some of the fuses blew or not as hard to see. Anyway the space the fuse holders and thick gauge wire caused the pack to not even fit in the box. I unhooked the whole thing and used 18 gauge speaker wire to standard 6S balance plugs so I can charge with two separate 6S external balancers.

I have four external balancers. I also have a 6S and 8S 1.2 amp active balancer. I can use both external and active balancers at the same time however it is not enough, The fact that two of the 18 ah Lishen cells reversed polarity and reversed back and a third cell was drained to close to zero volts have caused those cells to become extreamlly unstable when trying to get a full charge.

When charging with my 2 amp 28V charger I get three cells > 3V with the lowest about 3.2V and the other two 3.6 and close to 4V.
When I finally got them all to 2.9V to 2,56V I ran the pack approximately 3 miles and all cells were 2.48V to 2.55V. I then tried to re charge them and the 3 cells were all > 3V with the rest normal about 2.55 to 2.65V. I run the 10S - 25V pack in series with a 6S 15V LTO pack for 16S LTO. - 40V.

I charge the 6S packs which I have two of with my 6S LiPo chargers. 4S LiPo * 4 = 16.8V / 6 = 2.8V. Both packs are very stable and require none or very minimal balancing. It is just the three cells in the 10S pack that sky rocket when charging. I am supposed to get a replacement 10S 5 amp balancer. For now I am attempting to re wire the 10S - 5 amp balancer for 5S as the bad cells are all on one side. the other balance plug has all good cells just as stable as the two 6S packs.

I had a useless 6S active balancer which lights up for days and wont balance. I had it hooked up with an external balancer like I did with the 8S 1.2 amp active balancer with an external balancer. I am in the process of wiring up the 10S 5 amp balancer which might or might not work. Lord knows when or if I will get a replacement so can only hope for the best.

Here is the information I got from doing an Ai search on charging LTO cells that go too high in voltage.




OK. That is a lot of information. I am looking into that battery stack monitor now. I do not see how a four wire sensing method could work or even how to hook it up but will continue to research it. Until then I will finish wiring the 5 amp active balancer and hope for the best.

Worse case scenario I have two 18 Ah Lishen cells I cant use as the bolts where the nuts go on broke off from over tightening. If I can get the same size bolts at a hard ware store they will screw in a little as the bolts snapped off low enough to get a couple turns with the exact size bolts but will have to use JB weld or something similar so they will stay in there.

That will replace the two cells that reversed polarity but will still have a cell that charges to around 3V which is way too high for LTO. It is a last resort move however as I really want to keep using the 10S pack the way it is.

Right now after over night balancing with the 8S active and external 5 in 1 Turnergy cell balancer the pack is stable between 2.6 and 2.5V and ready for discharge. After that I can try the 5 amp active and external balancer on that side and use the 1.2 amp and other external to balance the good side. Hopefully it will work but not getting my hopes up.

Any help with this will be greatly appreciated.

Thanks.

Skyler

 

[Skyler]

I get it. I am the only member here on ES that actually runs LTO. Everyone here on ES runs 18650 Lion or LiPo.

Maybe 5 or 6 out of 100 members run LIFEPO4 and I am the only person on ES that runs LTO.

That is cool I guess.

All I know is I will balance the bad cells in that 5S string of cells in question. That is by HOOK or CROOK.

I just got finished hooking up the questionable 10S 5 amp active balancer in parallel with a 8S - 1.2 amp active balancer and two external balancers.

I bought a bunch of 6S extension cables and parallel cables.. The parallel are two male off one female so took the extra extensions and made female to female and made to make and made it work. Not sure if the 10S -- 5 amp balancer even works.

What I do know is I am ordering a 5S - 5 amp LTO balancer to find out. The only order I plan on for this month.

Since the other 5 cells seem to balance perfectly then if I can actually get a working 5 amp 5S active balancer I could hook that up to the side where the cells tend to skyrocket when charging.

Thanks.

Skyler.

 

[fechter]

Yes, you're the only one I can think of actually using LTO. I have some surplus cells just to play with but not enough for a bike pack. The downside of LTO is the low cell voltage and relatively low energy density. Roughly twice as big and heavy as Li-ion for the same energy. These would be ideal for stationary applications like powering a house.

 

[amberwolf]

Regarding cells of any chemistry that are unbalanced after use if they started balanced when the pack was built:

This means that the cells have different characteristics (internal resistance, capacity, etc) and will only become more different from each other over time.

That means that the balancing problem will become harder to correct, taking longer and longer for a BMS or other balancer to fix.

If the cells weren't all identical when they were brand new (not just same voltage, but same characteristics), they aren't matched, and will always be different, grow more different over time, and have problems remaining balanced,


Also, balanced only means that at some specific SoC, the cells are all the same voltage. If they are not exactly the same voltage at *all* states of charge, from empty all the way up to full and everywhere in between, they are not able to all supply the same amount of current (or drop in voltage as they do), and not able to all supply the same capacity, so the pack as a whole then only has the capacity of the lowest cell (or group if there are multiple parallel cells), and can only supply as much current without voltage sag as the cell with the highest resistance.


Balance problems are only a symptom of unmatched or defective cells. (assuming no defective balancer that is draining cells constantly when it shouldn't).


Cell reversal is usually a symptom of the same problem, usually caused by cells being so much lower capacity than the rest of the cells in series with them that as the pack is discharged, they discharge to empty but the pack is still being drained, so those low cells are now being charged in reverse, and become reverse voltage.

 

[floydr]

they discharge to empty but the pack is still being drained, so those low cells are now being charged in reverse, and become reverse voltage.

Shouldn't a BMS prevent this from happening? LVCC?

 

[amberwolf]

Shouldn't a BMS prevent this from happening? LVCC?

If one is present, and is correctly functioning, and is correctly connected to the cells (no broken balance/sense wires, etc), and if programmable is correctly setup, yes.

Several things can keep a BMS from being functional enough to prevent this (or other issues):
-- It's discharge FETs (or contactor) could be stuck on or shorted, so it literally can't stop discharge from happening.
-- It could be bypassed in that regard by a user (most often done by a user when the BMS is trying to protect them from a cell problem but the user wants to use the pack anyway, sometimes done by a user when the BMS can't handle the current the system requires, like when they do a shunt mod on the controller or replace it with a higher current one than the system came with, etc).
-- Balance / sense wires to a cell could be broken, so the BMS cannot detect a cell's voltage (and it is poorly designed so that it doesn't shutdown from this fault, which is common).
-- internal fault on the sense electronics or bug in the firmware for MCU-based BMSes that either doens't sense correctly or doesn't respond correctly, or even crashes / hangs.


AFAICT from the little info posted by Skyler, when they had the cell reversal they did not have a BMS.

 

[Skyler]

I did manage to balance the pack. I bought 24 Lishen 18 Ah LTOs brand new with my stimulus check about two years ago during the COVID19 era,

I ran them a few times but are rated for 30 to 50K cycles. Yes I did have two cells reverse polarity as ran them in series with LIFEPO4 and screwed up on the charging somehow. I made a couple mistakes. I am human.

The only BMS I would own would be an expensive 80 amp with Bluetooth so I can monitor all the cells. It would cost a fortune to add a Bluetooth BMS to all my packs. I have 22S LTO split into three packs and 20S LIFEPO4 split into four packs.. The LFEPO4 all used from Battery Hookup or Battery Clearinghouse.

All packs now are externally balanced with standard 6S and a 7S balance plug that works with 6S LiPo chargers that can balance , active balancers. as well as four external balancers. The active balancers plugs are different so wired them up to standard balance wire extensions.

I had to tape up two female to female as my two Y connecters were one female to two males. The pins being male. The plug on my chargers were male or pins showing. I am not sure which is considered male or female. I just know how to wire them up so I can parallel charge with up to four balancers if needed.

I can balance from 3S up to 7S and for the 10S - LTO pack I use two 5S balance plugs for that. I stated on my post that I ran two active balancers and two external to balance 5 LTO cells as three out of five were unstable and sky rocketing to >3V when hooked to my 28V 2 amp charger.

Now all 10 cells are between 2.58 and 2.6V. I can only hope it will be easier to balance in the future. The LTOs will not self discharge but the used LIFEPO4 cells are self discharging noticeably. I am using the LIFEPO4 for light duty and < 5 miles and the LTOs up to 10 miles maybe 15 if the cells allow it. I will soon find out. I can with the right Y cables add a BMS in the future if more affordable.. A 10S five amp active balancer might work or not.

The 10S 5 amp was in parallel with a 8S - 1.2 amp as well as two different model externally cell balancer monitor. It worked but not sure if the five amp is doing anything or not as no lights. The 1.2 amp active balancers have red LED lights showing operating or function exists. No clue with the 5 amp.

Looking at future batteries for my larger e bikes with 1,500W motors. I am thinking about brand new 10 Ah Headway cells.
16S or 52V is about 1/2 the weight of 20S - 50V LTOs. I will order 16 either this month or next month. Also a 700c 1,500W rear hub kit for Christmas. Shipping is faster and cheaper for me also as made in USA. Not China.

Thanks.

Skyler.

 

[calab]

The only BMS I would own would be an expensive 80 amp with Bluetooth so I can monitor all the cells.

How often are you monitoring the cells?

 

[Skyler]

How often are you monitoring the cells?

I have been charging the two 5S 8P A123 packs and 3S - 3P Headway pack with the 8 Ah cells. in series with a 10 amp 43.6V charger. 43.6V / 13 = 3..35V. All cells have 70% to 80% which works for up to 8 miles. I check all cells in each pack after charging and sometimes I balance with external balancer when charging. The A123 cells are 2.5 Ah each so 8 * 2.5 = 20 Ah NEW.

3 * 8 Ah = 24 Ah NEW for the Headway cells. By only charging 70 to 80% it keeps cells from over charging. Sometimes I take them down stairs and parallel charge the two 5S packs with my 400 watt Mega charger and the 3S with my 200W Skycharger and use a external balancer for each pack or balance charge with the chargers. I do that after about 5 or 6 cycles with the 10 amp charger.

Those packs are self discharging some so sometimes I top them off before discharging. I have had them awhile My 7S - 8P A123 pack was also built from the same 2.5 Ah A123 cells.

The LTOs are two 6S and a 10S. I can run the 10S and one 6S for 40V or all three for 55V.. The only issue I have had is with the 10S pack which was two 4S packs I ran a few times in series with the 7S - 8P LIFEPo4 pack and somehow forgot to charge one of the 4S LTO packs and was when two cells reversed polarity. They reversed back and used the NIC setting to get it back > 2.5V and was no self discharge. but think they are the cells that skyrocket but not 100% sure.

I am always checking the packs with an external balancer to make sure the packs are balanced.. I even bring an external balancer with me when out riding to check the 10S pack. I am supposed to get a replacement 10S 5 amp active balancer but have little faith in those. The first one did not seem to do anything to stop those cells from over charging > 3V which is no good at all for the health of the cells.

I will be very happy when I order the 16 10 Ah HEADWAY cells. I happen to have four 4S active balancers so could make four 4S packs but would rather build two 8S packs as I can mount one on either side of the triangle with a custom rack. I can charge with my 54.6V 15 amp 900W charger out on the road. 54.6V / 16 = 3.41V . That would charge from approximately 20% to 80% for out on the road and should only take 30 to 40 minutes.

For overnight charging I will order a proper 58.4V charger. It just makes sense to use what I have for out on the road as paid > $100 for the 900W charger and 75 to 80% will get me at least10 miles with brand new Headway cells. Weight will be around 22 pounds so about 11 pounds on each side of the triangle.. Much lighter than 50 pounds 22S LTO.

Thanks.

Skyler.

 

[calab]

To many lego's in the box my friend, not my cup of green tea. I have to grab a scrap sheet to keep track of it all, hope the dollarama pen writes.

I am always checking the packs with an external balancer to make sure the packs are balanced.. I even bring an external balancer with me when out riding to check the 10S pack.

Thats good your always checking the packs. I hope your getting good wh/mile range, keep track of it. How far you ride on a charge, note winds. Note how it changes over time. I am tracing my route today, hoping its over 30 miles.

For overnight charging I will order a proper 58.4V charger. It just makes sense to use what I have for out on the road as paid > $100 for the 900W charger and 75 to 80% will get me at least10 miles with brand new Headway cells. Weight will be around 22 pounds so about 11 pounds on each side of the triangle.. Much lighter than 50 pounds 22S LTO.

Having one good charger is good, I like my Satiator charger but its got it cost.

Take a look at this site

Li-Ion LiFePO4 Battery Cells - High C-Rate Li-Ion Cells - LiFePO4 Battery Cells

Panasonic NCR18650PF Battery Cells, 18650 Li-Ion Cells, Polymer Li-Ion/LiFePO4 Cells, High C-Rate Polymer/Cylindrical Li-Ion/LiFePO4 Cells

bmsbattery.com

I have purchased a lot from these guys, they are good for stuff to. Its the only throttles I personally use, thumb universal and controllers. I might try their spokes for cheapie hub lace.

EVFITTING Official Store - Amazing products with exclusive discounts on AliExpress

Discover the wide range of from AliExpress Top Seller EVFITTING Official Store.Enjoy ✓Free Shipping Worldwide! ✓Limited Time Sale ✓Easy Return.

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I believe you can specify your charger requirements and they will build, but do check the shipping prices before you get to excited about their prices.

 

[Skyler]

Very nice cells but the shipping for those is ridiculous. $117 for 34 cells to make 17S - 2P. Total is about $280. The Headway cells are $21 shipping. in the US. Looks like shipping is from China or something. I wonder if I could find those cells here in the US. I will look. I did not even know 32700 LIFEPO4 cells even existed. I will do an extensive search.

I did an Ai search. They do have those cells in the US but double the price so not worth it. If you find them at the same price with free or $20 to $30 shipping I will order 34 cells for 17S 2P - 56V.

Thanks.

Skyler.

 

[calab]

So more B.C.H or you through with those guys?

 

[Skyler]

So more B.C.H or you through with those guys?

Who ? Don't get what you said.

I was talking about US vs China for LIFEPO4 batteries and shipping.



Skyler