bluetooth BMS?

flippy said:
there is very good reasons to go in higher voltages. first: much less amps. that means less peukert effect rubbish, thinner cables. less voltage loss and so on.

I'm well familiar with Peukert's law. Usually has a meaningful effect above 100kHz. Let me know the actual energy loss in % if it was ever observed and measured. I'm sure there is difference, just like adding a capacitor on your 12V car battery to save some fuel, but just how much? Is it worth all the trouble?
FIY, drop in the battery will be proportional to voltage, if capacity in Wh remains the same.

flippy said:
personally the main problem is that most scooters and stuff is made to run 40km/h and if the battery is full prehaps 45 for a few minutes slowly dipping into the high 30's when getting empty. that does not ride well or sell very well. it's also dangrous in the city being slower then cars. people will make dangerous overtakings just to get past you.
many people want more speed and keep that speed even if the pack discharges. so keeping 50km/h at all times requires basically a 72V battery or 20S instead of 16S.
replacing the original motor for a new one from QS is a expensive ordeal and usually means a lot of crap getting the rear brake to fit properly. adding the cost of a new motor, controller and battery makes it very cost prohibitive and most people will simply walk away from this. being able to reuse the existing motor makes a huge difference. but you do need the higher voltage to get the speed people expect across the entire voltage range.
So basically the only reason - slow motor? I know many are buying a factory-made ebike and then trying to make it go faster, but the vast majority of projects here involve fresh builds. I understand it is bit hard sometimes to find a motor with correct speed constant, also discussing it in chinglish with average sales guy who don't understand your questions, but it is well worth it.
For example I, if communication is difficult, usually order "24V" motor and then feed it 48V. Problem solved. Also some motors can be connected from Y to ∆.

Anyway, I am not pushing this 48V thing just to make you buy my BMS. This has been discussed many times already and is bit hard to understand, why are we still having this issue.

I have to confess my first ebike was also 20S. Just because I checked some threads here and checked what people are doing and later discovered I need more voltage. Later I learned my mistake and always planned ahead to stick with 48V.
 
In addition, it is much easier to rewind or reconnect existing windings to make things fast.

First and easiest option is to connect it from Y to ∆. This will give an increase of x1.73. But not all motors are compatible, testing needed.

Second option is to cut some poles and reconnect from series to parallel, like I did it few years back on my chinese foldable bike. This made it go 2x faster.
Description and photos here: https://bit.ly/2pPGKZK

This involves no tinkering with battery, BMS, charger, throttle or LCD. Nothing changes, only some soldering inside the motor. Also you need to solder a piece of wire of correct length on top of current shunt inside the controller. It's a one evening's project.
Wouldn't you agree this is much easier than spending months replacing all of electronics?
 
for fresh builds that is certainly the best way to go. but a LOT of people have a existing ebike/moped/scooter and want to upgrade it with a better battery, controller and gain more speed those people need 20S or more in order to get a cost effective solution.

note: there is more then just ES users. plenty of people need replacement parts for their moped and most of the original companies have already quit and people cant replace original parts. so they turn to forums like these for help (or local ones) or a business like mine that does the needed repairs and rebuilds of battery packs. and a standard recommendation i always give is to replace the shitty BMS with a decent one like the tinybms and that works just fine for rebuilding existing batteries but often people will ask for upgrades in speed. and then the story changes quite a bit and i cant use the tinybms anymore and have to resort to (dodgy) chinese electronics and build a fully custom battery.
 
flippy, but still, wouldn't it be easier to you and cheaper to your customer, if you modified the motor instead of replacing everything?
It does need some motor knowledge to understand what should be done, but after that it's a couple hour job.
 
the controller and battery needs to be replaced anyway in almost all upgrades. it is the same amount of work to build a 14S or a 20S battery. the cell count remains the same. also having to rip apart the motor is quite more labour intensive then just spotwelding the tabs in the battery slighty differently. also as you sad not all motors are compatible. it also reduces torque by 1.73.

there are many options to choose from, but often a 16S sulution is not possible due to the amount of labour, limitations of the motor and budget just to name a few.

a lot of people want a simple battery recelling, that is easy to do and i basically always use a tinybms for these. especially the (in)famous green 196 cell suitcases are pretty simple to upgrade and the tinybms fits perfectly inside. its perfect for these kinds of upgrades. but if you need more volts for more serious power and torque you need 20S or more in order to get the speed and acceleration people want.
then those chinese 32S bms boards are sadly the only option.

personally it sucks that for my own 2 govecs wich is basically the best built scooter you can buy i have to resort to using a chinese bms in order to get a 28S battery. everything inside it is built from proper stuff like mean well and sevcon.
 
circuit said:
As mentioned before, you don't actually need mosfets in the BMS, you can use logic power cutoff to achieve the same result without bulky mosfets and heat. If done this way, there is no current limit.


Please help me to understand this. What is your reasoning for going above 60V? Speed? You can have that with 48V, easily.

48 volts won't get me 120 mph. 48 volts probably won't get me 35mph...or at least it never has so far. My expectations are for car busting top speeds. None of my EV's go slower than 45mph....that pretty much means a rock bottom minimum of 16S and probably 20S. My latest build...50cc sized electric moped runs at 82 volts and 60mph. It's absolutely brilliant to leave the cars in my dust and to be able to out accelerate most of them.

And what Flippy said...
So many times cars try to do some kind of end run around me and into a turn off. It forces me to hit the breaks hard to avoid hitting them. If they can't out accelerate or go faster than me, that rarely happens. I remember my first EV at 48 volts topped out at 35mph and at half charge was doing 28. Every car on the road was passing me. That ended rapidly once I upgraded to 82 volts and could do 50! Once I had an idiot that clipped my handle bar with his car. I fortunately didn't wreck. Later I caught up to him at the next intersection. He kept at it. I couldn't get away from him and he had every intention of running me off the road! More voltage made that MUCH harder for anyone to ever repeat.

Frankly... a slow/weak EV is lame. So many times I see videos on youtube for some new EV. The people riding them have these big smiles on their faces as they creep along doing 20mph...like that's sooooo amazingly fast. Ummmm...noooo....it's lame and pathetically slow!
 
ElectricGod said:
48 volts won't get me 120 mph. 48 volts probably won't get me 35mph...

I don't want to look rude, but you seem to have some huge gaps in fundamental knowledge. While 120mph may be difficult with, say, 12V, it is more than doable with 48V, if you use your brain.
To americans more power somehow always boils down to adding more cylinders. The same is happening here on ES, only with voltage.

While I have never attempted to reach 120mph, which is a total nonsense for an ebike, my 48V bikes did way over 35, that you mentioned. Actually, even my chinese foldable ebike, priced at $600 on aliexpress, reaches close to 35 with factory 36V 8Ah battery, with only the motor being modded.
 
circuit said:
...... I understand it is bit hard sometimes to find a motor with correct speed constant, also discussing it in chinglish with average sales guy who don't understand your questions, but it is well worth it..... Also some motors can be connected from Y to ∆.

I have to confess my first ebike was also 20S. Just because I checked some threads here and checked what people are doing and later discovered I need more voltage. Later I learned my mistake and always planned ahead to stick with 48V.

I agree with Circut's input, but I don't discount EG's contribution. Finding a motor with the correct speed is or at least has been exacerbated by a limited range of affordable and compact higher amperage controllers. My (albeit limited) understanding is that motors are designed to perform more efficiently in either Y to ∆; conversions between the two, take the same problem-solving approach as raising the voltage.

The next step is to see ES examples of 3 to 6 kw applications in the 48 to 57v ranges, such as the bikes running tangent motors, albeit with cycloidal reduction to accommodate motor speed. Although, I expect many will take their inspirations from OEM EV manufacturers that continue to design high voltage bikes such as KTM.

Back onto the BMS discussion, I'm a big fan of the Energus product, seems to be a great design for EV and I like the integration of channels for contactors. Features like these could also be used to safely break down larger higher voltage packs for maintenance.
 
circuit said:
ElectricGod said:
48 volts won't get me 120 mph. 48 volts probably won't get me 35mph...

I don't want to look rude, but you seem to have some huge gaps in fundamental knowledge. While 120mph may be difficult with, say, 12V, it is more than doable with 48V, if you use your brain.
To americans more power somehow always boils down to adding more cylinders. The same is happening here on ES, only with voltage.

While I have never attempted to reach 120mph, which is a total nonsense for an ebike, my 48V bikes did way over 35, that you mentioned. Actually, even my chinese foldable ebike, priced at $600 on aliexpress, reaches close to 35 with factory 36V 8Ah battery, with only the motor being modded.

Let's stay on topic shall we?

120mph...is total nonsense to you. That's your opinion. Ask Liveforphysiscs if 120mph on an ebike is total nonsense. To people such as myself...no it's not nonsense at all. Your expectations are different than mine. None of that in any way shows "gaps in knowledge"....for either you or me. At most, it may show some evidence of choices made to attain certain goals. Choices such as using a readily available motor instead of winding one or having a motor already that works perfectly that you want more speed from....both are really good reasons to apply a bit more voltage to get more speed.

Anyway...back to BMS's!
 
Hi there

I need to change my bms, as I'm fed up with Adaptto failures, and plan to move to another controller (still not decided)

I have a 2wd bike with two batteries, 20s 9p front and 20s19p rear. Both must have a 150A bms, for backup reasons.

I need bluetooth at least (a screen + BT woud be perfect) in order to charge at around 25A max per bms (in case 1 of the 2 bms fails I can parallel the batteries and keep moving) (usual charge would be at 12A front and 23A rear.

Important : I absolutely need to be able to limit the cell voltage to 4.12, for a longer lasting battery.

What do you recommand exactly (a link to a seller would be much appreciated !) in the high quality range ?
 
csc said:
in the high quality range ?
define that please. i've got no issues with the chinese bms we're talking about here. there are higher rated versions as well, and you can set the cutoff voltage, balance voltage, shunt value and discharge current cut off to (more or less) whatever you want in software. they don't have a display, but to check the battery the android app works perfectly fine.
 
csc said:
Hi there

I need to change my bms, as I'm fed up with Adaptto failures, and plan to move to another controller (still not decided)

I have a 2wd bike with two batteries, 20s 9p front and 20s19p rear. Both must have a 150A bms, for backup reasons.

I need bluetooth at least (a screen + BT woud be perfect) in order to charge at around 25A max per bms (in case 1 of the 2 bms fails I can parallel the batteries and keep moving) (usual charge would be at 12A front and 23A rear.

Important : I absolutely need to be able to limit the cell voltage to 4.12, for a longer lasting battery.

What do you recommand exactly (a link to a seller would be much appreciated !) in the high quality range ?

The 50A BT BMS won't do the job for you since it's only 50 amps, but these others will. Just select the option that matches your needs.

https://www.aliexpress.com/item/16S-to-32S-2018-new-DIY-Lifepo4-li-ion-50A-80A-100A-110A-120A-smart-bms/32847205125.html?spm=2114.search0104.3.1.73717987mJe6xt&ws_ab_test=searchweb0_0,searchweb201602_4_10152_10065_10151_10344_10068_10130_5722815_10324_10342_10547_10325_10343_10546_10340_5722915_10548_10341_10545_5722615_10697_10696_10084_10083_10618_10307_5722715_10059_10534_100031_10103_441_10624_10623_10622_5722515_10621_10620,searchweb201603_19,ppcSwitch_5&algo_expid=fa52c63b-2e03-451e-981a-ad9bf93bb6b5-0&algo_pvid=fa52c63b-2e03-451e-981a-ad9bf93bb6b5&transAbTest=ae803_2&priceBeautifyAB=0
 
Izeman : high quality from China is OK for me

Thanks for the link Electricgod !

This one at 150A looks pretty much the same, isn't it ? the differnce would be in te mosfet ?

https://www.aliexpress.com/item/150A-8S-24S-Lithium-Battery-Protection-Board-Smart-Display-Balance-BMS-Coulomb-Meter-Ternary-lifepo4-iron/32849338845.html?spm=2114.search0104.3.2.456716d1kftscC&ws_ab_test=searchweb0_0,searchweb201602_4_10152_10151_10065_10344_10068_10342_10343_10340_10341_10697_10696_10084_10083_10618_10305_10304_10307_10306_10302_10059_10184_10534_100031_10103_441_10624_10623_10622_10621_10620,searchweb201603_25,ppcSwitch_4&algo_expid=277cffcb-274d-4aa8-89a9-d288d3414149-0&algo_pvid=277cffcb-274d-4aa8-89a9-d288d3414149&transAbTest=ae803_2&priceBeautifyAB=0
 
izeman said:
csc said:
in the high quality range ?
define that please.

For me it would mostly be about the quality of the circuit board and the accompanying software. I can always replace components like crappy FET's, resisters, and such as well as beef up high current traces and cooling since I'm only interested in them for personal use.

By quality of software I am referring to board configuration options, real time status display and usage metrics gathering and logging ability, not necessarily translation or UI layout. I guess it would be better to refer to what I need as a Battery Management and Analyzer System.
 
csc said:
Izeman : high quality from China is OK for me

Thanks for the link Electricgod !

This one at 150A looks pretty much the same, isn't it ? the differnce would be in te mosfet ?

https://www.aliexpress.com/item/150A-8S-24S-Lithium-Battery-Protection-Board-Smart-Display-Balance-BMS-Coulomb-Meter-Ternary-lifepo4-iron/32849338845.html?spm=2114.search0104.3.2.456716d1kftscC&ws_ab_test=searchweb0_0,searchweb201602_4_10152_10151_10065_10344_10068_10342_10343_10340_10341_10697_10696_10084_10083_10618_10305_10304_10307_10306_10302_10059_10184_10534_100031_10103_441_10624_10623_10622_10621_10620,searchweb201603_25,ppcSwitch_4&algo_expid=277cffcb-274d-4aa8-89a9-d288d3414149-0&algo_pvid=277cffcb-274d-4aa8-89a9-d288d3414149&transAbTest=ae803_2&priceBeautifyAB=0

Yes...more or less mosfets is the biggest difference. And the copper busses extend all the way too and there are 2 rows of copper reinforcing everywhere. This is from my 24S BMS. With all the mosfets populated, it is 300 amps. This is the 200 amp version. You get different grade of mosfets depending on the amperage too. This BMS has HY3410's on it (garbage). Using any kind of better mosfet would dramatically increase the current handling. And...in fact the 300 amp version does just that. All the empty spots are populated and the mosfets are something better too...don't remember what. With something like the CSD19536KCS populated on this BMS, there's no reason why 400 amps would not be doable. Out of China, these are probably one of the best BMS out there. Of course buying from Europe or USAe can get you a better BMS at significantly more cost. I'm pretty confident that these BMS will do just fine. My biggest complaint with this BMS is that there is no copper at P-. I power from P- and frankly all current from B- if you power your EV from C- still has to pass through P-. This is an easily fixed deficiency with adding copper under all the mosfet screws.

24S%20Mosfet%20board%20-%20top.jpg


mosfet%20board%20-%20bottom.jpg
 
how do you drill copper sheet for the P+ without crumpling the copper?
 
flippy said:
how do you drill copper sheet for the P+ without crumpling the copper?

Sandwich the copper between 2 pieces of wood and drill through the wood. It holds it all flat. You are duplicating the hole pattern of all those mosfets screwed down to the board.
 
Thanks electricgod, veryuseful info. I might try the 300 version then, do you recommand a particular seller ?
 
csc said:
Thanks electricgod, veryuseful info. I might try the 300 version then, do you recommand a particular seller ?

The 300 amp version has all the added copper except at P-...go figure!

Mine came from here.
https://www.aliexpress.com/store/2856009?spm=2114.10010108.0.0.1a977dcdqgUJOl
 
Thanks again

Do you confirm that it is possible to set custom balancing values, such as 4.11 balancing and 4.12 full charge ? I can't understand in the product description where that setting would be
 
ElectricGod said:
flippy said:
how do you drill copper sheet for the P+ without crumpling the copper?

Sandwich the copper between 2 pieces of wood and drill through the wood. It holds it all flat. You are duplicating the hole pattern of all those mosfets screwed down to the board.
ElectricGod said:
csc said:
Thanks electricgod, veryuseful info. I might try the 300 version then, do you recommand a particular seller ?

The 300 amp version has all the added copper except at P-...go figure!

Mine came from here.
https://www.aliexpress.com/store/2856009?spm=2114.10010108.0.0.1a977dcdqgUJOl

As per wiring instructions the Load should be connected to C-.
Thats the reason why this BMS has same number of Mosfets back-to front mounted.
If it is rated for 300A than it should be able to handle this current if wired up like this.

HTB1B7yzSVXXXXcrXXXXq6xXFXXX5.jpg
 
if you look further back you can see that the C- mosfets are different and not rated for the voltage unlike the B- side.
 
ElectricGod said:
This is truly confounding! This is a 32S BMS. That means it realistically needs to handle upwards of 140 volts depending on cell chemistry. So why does it have 100 volt mosfets (HY45N10's) on the C- side? Why no access to P- where it has 150 volt IRF4115's? There is no part of 100 volt mosfets that are OK in a 32S BMS designed for 140 volt continuous operation. I can't imagine what the manufacturer was thinking!

32S%20smart%20BMS%20-%20mosfet%20board%20closeup%20HY45N10%20mosfets.jpg
flippy said:
if you look further back you can see that the C- mosfets are different and not rated for the voltage unlike the B- side.

Yes the thing with those 100V FET's is indeed confusing, but if you think hard about it there should not be a problem, because the maximum voltage those C- FET's should ever see is just the voltage difference between a full and empty battery (if the charger gets connected).
Thats the way it works and i don't think the manufacturer would make such big mistake.

In case of 32S LiIon it would mean about 135V (when fully charged) minus 64V (2V per cell) if the battery is completely discharged which makes a difference of 71V and this is below the rating.

There is still the question why they were using the 100V HY045N10 instead of the IRF4115 ?

-> for lowering the losses!

The HY have 4,5 mOhm Rds while the IRF with it's 9,3 mOhm have more than twice the resistance.
So the C- FET's will produce less than half of the heat as the P- FET's do.
Or with other words: if you attach the load to C- (like described), than the accruing heat losses will be only about 50% more instead of attaching it between the two groups.
 
madin88 said:
ElectricGod said:
This is truly confounding! This is a 32S BMS. That means it realistically needs to handle upwards of 140 volts depending on cell chemistry. So why does it have 100 volt mosfets (HY45N10's) on the C- side? Why no access to P- where it has 150 volt IRF4115's? There is no part of 100 volt mosfets that are OK in a 32S BMS designed for 140 volt continuous operation. I can't imagine what the manufacturer was thinking!

32S%20smart%20BMS%20-%20mosfet%20board%20closeup%20HY45N10%20mosfets.jpg
flippy said:
if you look further back you can see that the C- mosfets are different and not rated for the voltage unlike the B- side.

Yes the thing with those 100V FET's is indeed confusing, but if you think hard about it there should not be a problem, because the maximum voltage those C- FET's should ever see is just the voltage difference between a full and empty battery (if the charger gets connected).
Thats the way it works and i don't think the manufacturer would make such big mistake.

In case of 32S LiIon it would mean about 135V (when fully charged) minus 64V (2V per cell) if the battery is completely discharged which makes a difference of 71V and this is below the rating.

There is still the question why they were using the 100V HY045N10 instead of the IRF4115 ?

-> for lowering the losses!

The HY have 4,5 mOhm Rds while the IRF with it's 9,3 mOhm have more than twice the resistance.
So the C- FET's will produce less than half of the heat as the P- FET's do.
Or with other words: if you attach the load to C- (like described), than the accruing heat losses will be only about 50% more instead of attaching it between the two groups.

Still...I want mosfets that can handle the full voltage that the BMS could possibly see. Not that I care over much really. I won't be using the C- mosfets anyway. Honestly, I go with the best mosfets I can get and at 150 volts that's the AOT2500. More than likely, when I get to use these BMS, the factory mosfets will get pulled and replaced. This will also make the BMS capable of much more than 300 amps and at significantly less heat than any other 150 volt mosfet option. Mu guess is that at 131 volts I'll be pulling something like 120 amps at least and more is possible.
 
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