Finding "good" BMS boards

khauser

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Tried this at the end of my last thread, but either it wasn't getting seen there or no one has answers. Thought I'd try a new post to be sure...

[size=small]Anyone have suggestions on sourcing parts, particularly BMS's? Research suggests that many available BMSs ... suck. (That could be literal if they are draining the pack, LOL).

But I am not finding a whole lot of reviews, testing, etc, so its hard to know what one is getting.

I am aware that the term "BMS" is overused, and I know that I have to be sure the unit is meant to do all of the things I need, but how do we know if a unit is quality??

Thanks!
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I'm with you. I've always been suspicious of a 'unit like this' that you can't see what's going on. But its also a question of the type of battery. For my DIY powerwall - I use Batrium and it has good visual/data so you can test and see what's happening - but its a heavy-weight and not practical for an ebike.

For me smallerbatteries in my APC UPSsI've settled onChargery 'T' models ($120-$180 for 14s) as you can see what's happening. But even at $180 (compared to Batrium) its a lot of $ for an ebike or skateboard battery.

A 3rd option is no BMS but use a balanced RC charger. I use this for a portable power pack where I replaced the lead acid with my own 18650 3s... as the RC charger shows what's going on. I don't use it much and at 3s itcuts-out (low battery cut-off)before getting to the low enddanger zone of the cells.

I know some have created test rigs - and simply test any (no visual indicator) BMSs before putting them in use. But of course you don't know if they're still good a year later without test.

Thereare many scenarios and I'm curious to see what others have determined.
 
OffGridInTheCity said:
I'm with you. I've always been suspicious of a 'unit like this' that you can't see what's going on. But its also a question of the type of battery.

This is a smaller (than powerwall) 24V (72) always-available backup battery. Pretty low current needs .... under 10A easily, probably under 5. But based on another thread I am going to overbuild it (capacity wise) and keep it charged in the 75%-ish SOC area.

Since my plan isn't to charge / discharge on an as needed basis, I don't think I can forego a BMS.

I've seen a few smart BMS units that might be interesting .... but no reviews.
Here's an example: https://www.aliexpress.com/item/4001218262806.html?spm=a2g0o.productlist.0.0.38a8346cMicorv&algo_pvid=991427e5-2746-4ccf-8152-7739611f3ad4&algo_expid=991427e5-2746-4ccf-8152-7739611f3ad4-3&btsid=0ab6f83115942409448576954e8f3f&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_
 
khauser said:
OffGridInTheCity said:
I'm with you. I've always been suspicious of a 'unit like this' that you can't see what's going on. But its also a question of the type of battery.

This is a smaller (than powerwall) 24V (72) always-available backup battery. Pretty low current needs .... under 10A easily, probably under 5. But based on another thread I am going to overbuild it (capacity wise) and keep it charged in the 75%-ish SOC area.

Since my plan isn't to charge / discharge on an as needed basis, I don't think I can forego a BMS.

I've seen a few smart BMS units that might be interesting .... but no reviews.
Here's an example: https://www.aliexpress.com/item/4001218262806.html?spm=a2g0o.productlist.0.0.38a8346cMicorv&algo_pvid=991427e5-2746-4ccf-8152-7739611f3ad4&algo_expid=991427e5-2746-4ccf-8152-7739611f3ad4-3&btsid=0ab6f83115942409448576954e8f3f&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_
Agree you need a BMS - didn't mean to imply you don't.
Agree that I've not seen reviews on the above but personallyI like that it shows data... price is good...and you can check on the state of the cells to see if they are over/under/out-of-balance :)

I ordered this one -https://www.ebay.com/itm/312721653175+ a case for the LCD - but haven't tried it yet asI found Chargeryhttps://www.ebay.com/itm/193543710606a bit easier tosetup for my purposes.
 
Thanks again
Unfortunately the display for the one i linked is not available in a 7s unit.
Well, at least I'm in good company trying to figure this all out.
 
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