Question about smart bms

Im just using an old LED supply I had laying around. Meanwell LED drivers ftw.

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Nice looking charge port. Interested to hear how your testing pans out.

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Oh shit. Just found out my charger might be a ripoff :rofl:
Got this one straight from mr @Kaly himself well over a year ago when I purchased his carver xl Never got around using it til a couple of months ago
It’s supposed to be 8a but :exploding_head:
Now I need to get my watt meter rolling lol

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??:thinking: don’t gets it

How your testing goes with your watt meter

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Ah. Yeah. I need to buy me another plug to match my charger/port and we’ll be golden

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At least it puts out the right voltage :laughing:

I got a “50.4V” charger from bkb that forgot about the .4V

@Esk8_Spirit


not so unfortunatly

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Two things. First that among us we have 4 xiaoxiang BMS’ and 2 show charging current 6,5a while the other 2 show 8.2a with the same charger. So we are trying to figure out what’s going on. It’s not limited via BMS, it either is charging the same, just showing wrong amperage on some BMS or the BMS is limiting the charge because of resistance… I tried to measure it with my mutlimeter and when I add it in series with the needeles it only charges at 1,3a, I am told it’s resistance… The second thing and for all of you the MOST IMPORTANT one, I will let you know on a little secret. Most chargers have potentiometers inside, 2-5 usually. One controls the amperage, one controls the final voltage, other can control the fan or very often one controls 2-10% trickle charge at the end, that limits when the charger goes into slow charge before your battery is fully charged, give time for potential balancing. If you find the exact same charger in a store as you have with different voltages/amps (they will always be in the similar price ball park). Find the one where the wattage (volts*amps) is the highest and divide it by your final battery voltage. That is the max official amperage you can overclock your charger to. Move the potentiometer (while charger on) until your BMS (if you can trust it:) shows desired amperage. Do the same with desired final voltage. That way you can limit your charge via the charger any way you want and you can be charging only to 4,0 or 4,1 volts, or even overcahrging to 4,3… without the need of BMS. If a company is selling 3 chargers that are exactly the same and one is 5a, one 6a and one 7a, you can set the 5a one to 7a. This might not work with all the chargers but so far all I have tried had it. And check for heat (all normal chargers have heat sensor and would shut off if overheated anyway) Use common sense, don’t touch anything inside the charger other than the potentiometers. I claim no responsibility for anything :slight_smile:

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turn the nob inside and set it to 50,4v :slight_smile:

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It’s either the charger set to 50.0 volts or most likely one of your series reaches top when the overall voltage is around 50 volts and BMS stops charging. WHat BMS do you have and how are your series voltages?

Thank you for sharing your knowledge

Unfortunately this charger I’m using and have beef with is shut sealed. I would literally have to break the abs housing to gain access to the potentiometers inside :neutral_face:

Honestly. I think the damn thing is just a 6a Charger lol.

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Never tried the lower amp sealed once, always ones with a case that can be unsrecrewed. Fastest one sealed I have seen was 5a and it gets hot as hell too :slight_smile: You should check your series, that is most likely the problem. Balance them out and it will get better for some time hopefully.

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Most off the time calibration was a little bit wrong in the factory. You can calibrate the bms in the app or windows program

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Yeah wat Pjotr said.
Me and a friend we bought the same charger (10S 5A) and after measuring mine did 4,7A max and a his only 4A. On top of that I had the calibrate the smart BMS because mine was ‘supposably’ charging at 4,5A but it was 4,9A according to my multimeter

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Quick update

Definitely the bms.
Got watt meter hoked up @48.8v it reads 6.3a while bms still reading 4.8 :disappointed_relieved:

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Tap on config on the app and go to the current calibration tab, try put the charge current to 8000 mA. I think that’s what I did for mine. It was charging 3A and I was bitching to the manufacturer that produced the charger. But it’s actually the BMS.

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Can’t find that option in the app

Here are the parameters


Sorry I meant the iOS app.

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Ah shit. I gotta pay $5.99 for the app now :weary::rofl:

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