65mm BMS With Active Balancing?

[rg12]

Am looking for a 16S and 20S 100A (and above) BMS with active balancing that can fit the height of an 18650 cell.

Jikong, awesome but not even close to these measurements.
Daly, has an external active balancing unit that is 65mm but it's the size of a BMS and needs to be paralleled with a BMS (doesn't have to be daly's but still, two units the size of a bms so a no go).

Actually, other than jikong I didn't find a single company that makes active balacing bms.

 

[john61ct]

The balancer may only be needed a few times a year if the cells are healthy, and never while the pack is in use,

just make your balance lead wires accessible from outside.

Also your protective BMS should be easily replaceable.

Reliability and adjustability should be more important than size

 

[DogDipstick]

This one's at 75mm. Wide.

Overbuilt with all kinds of goodies.

I know I am not helpin much. But its good.

10mm off your requirement .



6s-21s. Bluetoof. 200A. Heatsink the size .. of something that might actual meet its spec. Given the fets inside and their waste heat.
https://www.lithiumbatterypcb.com/product/6s-to-20s-li-ion-or-lifepo4-smart-bms-with-150a-or-200a-constant-current/

They do what you want them to. They work as intended.

I dont know what you mean by ( your definition of) " active balancing. " or why you would need it . Given all the definitions out there. Lost in translation .


Of course Daly would have something pandering to that crowd.. that think they need it. Lol. Daly junk.


Just get good cells. Dont build with junk. They will stay balanced.

 

[TDA78]

This one meets most of your requirements but has 160 mA passive balance. I keep quality cells balanced within 7 mV with only 50 mA bleed while charging at 10A (tapers down to 2A at end of charge).

https://www.lithiumbatterypcb.com/p...fepo4-battery-bms-with-100a-constant-current/

 

[rg12]

This one's at 75mm. Wide.

Overbuilt with all kinds of goodies.

I know I am not helpin much. But its good.

10mm off your requirement .



6s-21s. Bluetoof. 200A. Heatsink the size .. of something that might actual meet its spec. Given the fets inside and their waste heat.
https://www.lithiumbatterypcb.com/product/6s-to-20s-li-ion-or-lifepo4-smart-bms-with-150a-or-200a-constant-current/

They do what you want them to. They work as intended.

I dont know what you mean by ( your definition of) " active balancing. " or why you would need it . Given all the definitions out there. Lost in translation .


Of course Daly would have something pandering to that crowd.. that think they need it. Lol. Daly junk.


Just get good cells. Dont build with junk. They will stay balanced.

that isnt active balacing...
It's not a definition i made or the internet made, its actually a thing, transferring current between cells instead of wasting energy with resistors to lower higher cells.

 

[DogDipstick]

that isnt active balacing...
It's not a definition i made or the internet made, its actually a thing, transferring current between cells instead of wasting energy with resistors to lower higher cells.
[/quote]

I know.

 

[john61ct]

I cannot see any practical advantage in itself to the feature of shunting energy from one place to another, not saying it's a bad feature but irrelevant.

Unless you are balancing while discharging to get longer range, but I see that as a fool's errand anyway.

It may not be the "official" definition but the actually useful feature to look for afaic

is that the balancing CURRENT flow is maintained at a constant maximum amps

even as the voltage delta closes between cell/groups.

Otherwise even if the balancer is capable of doing say 3A, as the process continues it gets slower and slower.

To me the whole point of using a dedicated balancer is to get the job done quickly, even if it's only used once in a while.

 

[amberwolf]

I cannot see any practical advantage in itself to the feature of shunting energy from one place to another, not saying it's a bad feature but irrelevant.

It's better than just wasting energy entirely as heat, which is what the resistive balancers do.

 

[john61ct]

Just speaking for myself, I've been pretty fanatically green since the first Earth Day but on grid power the mAh involved are barely rounding errors.

 

[lnanek]

the actually useful feature to look for afaic

is that the balancing CURRENT flow is maintained at a constant maximum amps

even as the voltage delta closes between cell/groups.

I've been using an inverter transformer active balancer which helps work around needing a high voltage difference (since it can boost the voltage from where it is transferring energy from using the transformers):
https://www.amazon.com/dp/B0B3D5JCRC

The typical flying capacitor active balancer is much cheaper, though, and just blindly connects all the cells in turn instead of draining the first 4 cells to run a microchip.

Only using it because I got an ancient used battery worth $1000 new for $200 off Facebook and the balancer can help the weakest p-group from hitting LVC as early as it would otherwise. I agree a new battery with matched capacity cells doesn't really need it.

 

[john61ct]

interesting!

If the pack is between 4S & 13S can the latter be used?

or the 24S unit for say 16S ?