Using not standard BMS on a LIFE04 battery

[_Chris_]

Hi I couldnt find the answer to this question in the forum already and I am sorry if it has already been covered somewhere but is it possible to use a battery management system from a different manufacturer on a battery. What I mean is say I want to get more current of a cheap Chinese battery quickly by getting rid of its existing BMS and putting a better high output current on in its place. Is it just a straight changeover for equivalent cells?

Does anyone know of any good quality ones to use preferably that are adjustable, I know the ping ones are but that is only by using solder for increased current. It would be better to turn a potentiometer or set a digital controller etc.

Thanks in advance.

 

[dogman dan]

Excellent plan, it will quickly hammer your battery into a pile of dogshit. The bms is limiting current for a reason.

Unless you got A123 cells, don't try to pull much more than 2c from most bike batteries. 10 ah at 2c is 20 amps.

I don't know of an adjustable bms, but you can adjust current on a controller with a direct plug in cycleanalyst, and a compatible controller.

So if you were to put a high current bms on the battery, you could then dial in max current with the CA. Provided of course, you have a battery that can take it.

 

[_Chris_]

Maybe longevity is not my plan. i dont want a conservative BMS

 

[dogman dan]

The remove the bms, and let er rip. Let it live fast, die young, and leave a good looking corpse.

If you wish, you can always put it back on for charging and balancing purposes.

Chances are, you will move to lico next, and run with no bms. Have voltage monitoring of course.

 

[dnmun]

Maybe longevity is not my plan. i dont want a conservative BMS

did you even try soldering the shunt. i assume you have a ping pack which is what you are referring to with the cheap chinese comments?

how much current did it pull before it cut out on you that caused you to decide it had to be increased? i was under the impression the small BMS would deliver 40A before cutout.

did you measure that and attempt to solder the shunt to increase it? how much solder equates to how much current and can you show a picture of your battery and BMS if you have one?

 

[_Chris_]

Maybe longevity is not my plan. i dont want a conservative BMS

did you even try soldering the shunt. i assume you have a ping pack which is what you are referring to with the cheap chinese comments?

how much current did it pull before it cut out on you that caused you to decide it had to be increased? i was under the impression the small BMS would deliver 40A before cutout.

did you measure that and attempt to solder the shunt to increase it? how much solder equates to how much current and can you show a picture of your battery and BMS if you have one?

Ping is a good supplier and a good battery, I am thinking about trying something else and matching a better BMS to a not as well known battery.

I am trying to work out if a proprietary packaged battery in a can could use an alternate better BMS for slightly higher current

 

[dnmun]

usually the BMS overcurrent limit is set to prevent the output mosfet current capacity from being exceeded. that is why the shunt is larger and the current capacity is so much higher on the hi current BMS that ping and others use.

you can solder up the shunt or add a small piece of wire to decrease the shunt resistance so the BMS doesn't detect the higher current but the mosfets could end up over loaded and then shorted and then you have no output control. that means no LVC or short circuit protection and in some BMS designs you would lose HVC control too.

if you do follow up on this keep the current numbers tabulated as you solder up the shunt and take pictures to document the correlation between solder and the increase in current at cut off. that helps others if they do the same thing and people know how much is too much when they finally start losing mosfets.

 

[_Chris_]

Thanks for that, can you briefly use no BMS to exceed the max amperage for a minute or 2?

 

[dnmun]

it is just easier to put a jumper across the BMS if you want it to bypass. no need to remove the BMS to exceed the current capability of the battery.

i am gonna do that on this D131. put a short lead on the B_ terminal of the BMS with an Anderson connector on it, and on the P- terminal put another Anderson so that if the BMS fails and it will not conduct current you can bypass it by connecting the two anderson plugs and bypass the BMS output mosfets.

 

[d8veh]

Tell us which battery you want to use. Some are already struggling at their designated ratings. If you increase the current more, you'll get massive voltage sag and balancing problems.

 

[scriewy]

it is just easier to put a jumper across the BMS if you want it to bypass. no need to remove the BMS to exceed the current capability of the battery.

i am gonna do that on this D131. put a short lead on the B_ terminal of the BMS with an Anderson connector on it, and on the P- terminal put another Anderson so that if the BMS fails and it will not conduct current you can bypass it by connecting the two anderson plugs and bypass the BMS output mosfets.

if you bypass the BMS but keep the balancing leads attached, is the LVC still in effect ?
Of cours the BMS wont be able to cut the current off because it is not runing through the FETs, but will it turn off the FETS any way ?

if it will switch off the FETs then i can run a bulb or LED through them and this warning of light going off will be great when i hit LVC.

 

[_Chris_]

i should have asked this a better way guys. I would like to have a 10 ah 36v battery with a high discharge rate. Is It better to mod a cheap lifepo4 battery to get more juice or use a better different type chemistry. Not A123 or lipo as options either because I dont want to use those.

 

[dnmun]

sure you can modify it so you can get more power by adding another 10Ah in parallel and then you can pull 45-50A

 

[_Chris_]

sure you can modify it so you can get more power by adding another 10Ah in parallel and then you can pull 45-50A

Thanks dude.