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EM3EV's battery with smart BMS

alfantastic

10 kW
Joined
Mar 29, 2011
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524
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UK
I recently bought one of Paul's super shark batteries, fitted with a smart BMS. Excellent battery BTW, for anyone searching for their next pack.

I have the 2A charger, which charges to 100%. I have one question, which I didn't want to pester Paul with, as he is a busy chap.

Does a smart BMS balance the cells as it charges, or only at the end of a full charge?
 
Depends on the BMS model used, should be adjustable and able to observe / verify from your phone or PC

 
You can verify with the BMS app (swipe a few screens over to get to the 'setup' list), but if your BMS is set up the same as my EM3ev packs, it should start balancing at 3.9v/cell. So, starting at around 75% charge.
 
can anyone link to the exact model(s) BMS they use?

is that start balance parameter and others adjustable?
 
The Smart BMS EM3EV use will balance at charge above 50%. I have his triangle 14S7P Battery and i charge to 90% using the adjustable charger and it balances nicely.
 
lowrider13 said:
The Smart BMS EM3EV use will balance at charge above 50%. I have his triangle 14S7P Battery and i charge to 90% using the adjustable charger and it balances nicely.
As I haven't got the adjustable charger, can I assume that if I switched off charging at 80% manually, the BMS would have managed to balance cells from 50% to 80% ok?

Also, what would constitute as an unacceptable difference in voltage between cells 1%, 2% etc...?
 
0.01V delta is a common start-balance trigger

The more precise the better for ending, 0.001V would IMO be great.

But all depends on balance current available vs time available, how imbalanced the pack is, gets worse with age etc
 
I just bought a 14s5p Jumbo Shark battery from em3ev and I didn't realize it had this smart BMS until stumbling across this thread. Does anyone know what the password is for the app or is it different for each battery? I can get past this screen by entering anything but the next screen just looks like it has garbage data.
batt.jpg
 
The password is the last 4 digits of the battery's identifier in that list.

So, for your battery, the password is 0274
 
Note for the OP - The BMS as described CAN balance starting at 50% charge, HOWEVER, the default setting may be 75%, meaning that is where it DOES start balancing. It is adjustable.

So if yours is at the stated default setting and you stop charging at 80% the balance has only been happening during 5% of the charge cycle.
 
The current BMS that EM3ev is using will not balance the cells until they reach 3.9v per cell or 54.6v for a 14s battery...this is as of November 2023.
 
The current BMS that EM3ev is using will not balance the cells until they reach 3.9v per cell or 54.6v for a 14s battery...this is as of November 2023.
Does this also apply to May 2023 since the Vdelta stays around 7-8mV @ 54.2V
 
Does this also apply to May 2023 since the Vdelta stays around 7-8mV @ 54.2V
You'd have to ask EM3ev to make sure your battery has the smart BMS but if it does, the closest it will balance the cells is to have them all within a .010v range. For example...my lowest cell group will be 3.920 and my highest cell group will be 3.930.
 
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