Reliable BMS for the battery pack


My BMS from Deligreen 14S 100A died after using it for ~45 min riding in total. My battery pack is still working as I have measured each row of cells (14S7P). Does anyone have a recommendation for a reliable BMS?

not the exact answer, but assuming it died cuz you used the bms for discharge (as well as charge) those of us in the eSkate world with high power builds bypass the bms for discharge because most bms that could handle the output current we need are too large and bulky…

i have seen a couple posts here where someone else has mentioned doing the same thing, and the vesc would be able to soft cut you if you really ran the battery down… however the obvious is that the vesc would only monitor total pack package and not each group if there was an instance where one group started to drift during discharge…

In my build I used bms for charging and bypassed it for discharge.
I also have bms output driving vesc enable signal so it protects the battery better than just vesc.

I run LLT smart BMS + LEV200 contactor on my efoil and same BMS on some other battery builds. Works well, can recommend them.

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Hi Larsb,
Thanks for the tip. LLTs biggest smart BMS (6S ~22S) specifies to handle 250A constant current and its huge 24x9x2.5cm! Will order one.
Do you use the contactor as emergency battery disconnect?

Yes, bms switches contactor coil on/off which breaks all circuits, i have a manual on/off switch also in the same line. With this setup only small current goes through the bms and you can get the cheaper (but smart) ones

There has been a lot of discussion about this in other threads. You can’t simply cut power to the motor under load. The back EMF will destroy any electronics upstream of your motor. You must set the throttle to zero, waith a couple of seconds and then cut power.

This is true in general but it really depends on esc, my esc has survived several cutoffs, but it’s designed to be able to withstand it.

Larsb: can you explain what is this “heating function” on the BMS? (I have conntacted LLT but they could not explain… )

Where is the “LED power indicator connection port for power display” located mentioned in the description?


Can’t say, i don’t have these as called heating function. LLT have many variants, can you link the exact bms you bought?

What does the text mean if you translate it through google translate?

EDIT: i checked LLT:s site and it’s a port for battery heating through PTC heating film. LLT needs to give you some data on which heating film, how much output this port can do and where in the app the limits are set for the heating.

Google translate said “heating”. I have also asked native speaking Chinese colleague which said the same.

Here is the link:

EDIT: did you find the LED port?

No, it’s not on any of the pictures. I guess it should be either a 2 pin (if it’s can H/can L or just batt plus and ground) or a four pin connector with markings on the pcb for either communication plus voltage or plus and three leds