Choosing a BMS but im a noob

Hey guys, im nearing the end of my second build and one of the final touches is a BMS. i’ve been in contact with bestech and im not 100% sure the one the sales assistant suggests is the right one i need

I have 2 12C 6S lipo batteries in series to make a 12S battery powering each motor.

this is the info they gave me, i know i can bypass when discharging but i was concerned about charging, will this do?

my first time dealing with a bms so i appreciate the help

Screenshot_20190720-194926_Word%201 Screenshot_20190720-194926_Word

It looks like it can handle 60A+ charge current, which is a complete overkill. It’s pretty bulky. How much is the price? You would likely be better off getting the DieBieMS.

they keep dodging the price everytime i ask so i don’t know atm, should i ask for a lower amped bms, when i emailed them i said the max amps the batteries can draw was 150, is 60 enough? thats the max my vesc can handle, but if im bypassing when discharging does it even matter?

Your battery is rated for 12s 79.2A

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oh okay, so a 80A bms should be fine? thanks again btw

I think I’ve read that bestech won’t sell a single BMS, they only sell in groups of two? I may be wrong.

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What you have linked looks like a pretty advanced and beefy BMS. I suppose the price will be well above $200. It’s an overkill.

Are you looking for a smart BMS? If yes, DieBieMS is likely a better options since it fits the esk8 ecosystem. It can communicate with VESCs and if you get the Metr module, you can get the BMS data on your mobile phone. At $120 shipped it’s probably also a lot cheaper.

If you don’t want/need a smart BMS, you have a number of cheaper and more compact options, especially if you’re OK with bypassing discharge. In that case Bestech D140 is pretty popular.

In general, you’re looking for something rated 10A+ for charge and 60A+ for discharge. If you bypass discharge, then obviously discharge rating is irrelevant.

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That’s okay, I’m after 2

Pretty much bang on, the one thing I haven’t really understood is the communication protocol/smart bms, in this case with the vesc Like what would it be for?

Here’s an example:

The most important feature of a smart BMS is that it can communicate individual cell voltages to other systems.

This can be done in various ways. You can read more about it here:

The DieBieMS, in particular, connects to VESC via CAN. The VESC itself is not programmed to make any use of the DieBieMS data but it can forward the info to other devices that connect to the VESC, such as the Metr module.

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oh alright, i thing i get it better now. where would i get the DieBieMS, bestec or is it off someone in the forum? appreciate it btw

@Samau18 makes them. He might still have some from the last batch.

140 x 60 mm (it takes 10 secs to find on the forum using search, BTW)

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The DieBie is good, very advanced and such but the PCB is quite bulky, if you want a less smart one, I suggest SuPower @

BesTech does also have less smart ones like others have mentioned, I think they were trying to upsell you depending on what you said your requirements were

I have used those BMS’s in 4 builds now and they work wonderfully for a pretty fair price, much lower than the DieBie