US - Bestech CHARGE ONLY BMS modules

Blowing away original post and restarting.

Not mentioning names, but some people (scepterr, b264) were angry about the original module choice so I asked bestech for additional quotes for various modules:

Price indicated above is raw price, it will be a little more once shipping + fees are added in.

Please cross reference the above with detailed specsheets here:

Once you’ve decided, please fill out this form.

If ordering more than one model, just submit it again for the other modules.

@gravitycarve @702vegas @deucesdown @Mobutusan @Jreamer

everyone listed here, sorry but can you please resubmit?

Order is paid for, see here for finishing details:

Dec 11 edit:

Ordered some more, please see here to order:

1 Like

I’ll take 2. Not sure what I’ll do with 2 but you know.

1 Like

@briman05 @Space_Cowboy You guys want me to get one for you?

just edited post, please record yours in the form, thanks

hey literally just sent you a PM. Yes I’ll take one thanks

1 Like

on my first attempt i burnt it out, so it’s good to have a backup.


@thisguyhere did you see the size on that one? I think this would be a better option and higher charge current in smaller package

i basically asked them for the least expensive charge-only module, but let me ask about this one.

1 Like

Yeah, the only reason I didn’t pull the trigger on this is because it’s not a rectangle and I’d prefer it to be the size of either 1, 2, 3, or 4 18650 cells for ease of packing an enclosure

I’m pretty sure that’ll be rectified shortly :wink:

Right on, when I get back from my skate I might have to join in then :stuck_out_tongue_winking_eye:

Guys, can someone give me (noob :slight_smile: a quick rundown, why it is okay for my battery to have a charge only bms? Is discharging monitored by Focbox? I am guessing the advantage is the smaller size of the bms?

You set battery limits in the software so you limit how much current it can possibly draw and you can install a fuse incase of some catastrophic failure.
Using discharge through BMS can cause a myriad of issues and just one more thing to fail, for our purposes the discharge on BMS acts basically as a fuse, since we already set battery limits in software, you just can’t be careless and enter ridiculous numbers

Aw man I’m trying to get one that has discharge too cuz I want that protection. That’s too bad



hahahah I meant over-discharge protection but that is quite the loop key

You set voltage cutoff’s in software too… And you would typically always set them higher than the BMS so the BMS wouldnt shutoff your board…so not using the BMS over discharge protection

How does this work exactly? I’m thinking a bulk charger (not psu), if set to 4.2v/cell, will maintain constant current until 4.2v/cell, then switch to constant voltage. If bms kicks in overcharge at 4.1v, we never get to the CV part of the charge?

When does balancing kick in?

So then, if using a 4.2v/cell bulk charger with the bms set to 4.1v cutoff, assuming the balancer kicks in, it’ll have to deal with the full current of the bulk charger as it’s always in constant current phase, and the 84ma/cell balancer probably won’t get a chance to completely balance before overcharge protection kicks in. Am I crazy?

So then the charger needs to be adjusted to slightly below the overcharge cutoff of the BMS. And it can’t be an adjustable PSU like meanwell, because adjusting the PSU voltage to perfectly match the BMS overcharge cutoff sounds difficult at best.

Am I overthinking this?

Anyway, I’m in, thanks.

Can you dig up some adjustable bulk chargers to match? :wink:

Oh can these BMS’s parameters be adjusted by user?


90% of the laptop style 42V2A I’ve seen have a pot inside that’ll let you tune the voltage

BMS config is set at the factory,can’t tweak anything afterwards

@scepterr do you think I’m crazy on the rest of that post, or fairly accurate?

Lol my 2A and 4A charger has 3 pots, the 3rd one I tried adjusted the voltage, don’t know what the other 2 do but for sure I didn’t put them back where they started. I’ve found the voltage quite a pain to adjust precisely, especially on the 4A chargers… Maybe because I messed with the mystery pots lol.

I guess I need an adjustable DC load sigh.