Active cell balancer...that works?
- Thread starter Newenough
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I have the individual 3.2/3.7V balancers capable of up to 4A. However, I've never seen more than 1.2A under severe imbalance. Their claim of 10mV voltage difference is valid in my experience.
These are DUMB balancers. They just do it. They don't interface with a BMS.
newbostonconst
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You can stack them also....So say a 1 amp one is $10 and a 2 amp one is $50....you can put on 2 one amp balancers. Since you are concerned on price.
newbostonconst
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I would go with the biggest one I could find....I don't see harm in going big....It can correct battery cell differences before irreversible damage happens.
@snoobler Very interested in the active balancer you posted. Do you know what voltage difference will cause the balancer to start balancing? I have tried some of the cheaper $10 boards from eBay but they dont actually do anything until a 100-200 millivolt difference is detected, which seems way too high to do much good. I'm reviving this thread because I tried emailing the seller and they have not responded. Thanks in advance.
From the site:
"Keeps Your Batteries Voltage difference Within 10mV! "
My cells were always within .01V, so I have no reason to believe they don't meet that requirement.
If you emailed ECPC, you need to call them. Carl is the common point of contact. He's an OLDer gentlemen, and I have found his handling of email to be sub-optimal.
I have no personal experience with them, but Heltec-BMS sells a handful of active balancers up to 5A I believe. Not aware of anyone on the forum who has tried one.
Thanks! Maybe I'll give them a call if I decide to go this route. Always surprised by how little documentation is available for these BMS and balance boards.
To clarify my question a bit; my understanding is that these balancers remain in a low power standby mode until a certain threshold is reached for the voltage difference between cells. Once that threshold is reached, they start balancing. The cheap ones I have tried dont do anything until a 200mv difference is detected but also claim that, once activated, will balance the cells to within 10mv. That 200mv threshold seems too high to be useful for a lithium battery so I am looking for something better.
There's a link to the manual on the product page.
Not great, but it's my understanding is these ALWAYS balance any time the cells are more than 10mV apart. Period.
They do regularly emit a high pitched tone as well. Kinda unpleasant if you're right next to it, but it's part of how they work.
Not great, but it's my understanding is these ALWAYS balance any time the cells are more than 10mV apart. Period.
They do regularly emit a high pitched tone as well. Kinda unpleasant if you're right next to it, but it's part of how they work.
grizzzman
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Intrusting......He has been fast to respond to my e-mails. Go figure.
adriansantos
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Initially i thought battGo battery monitor with balancer was ok, but found its really slow and just a passive balancer. saw youtube videos by j.legazpi which convinced me to buy this active balancer. says 5a. Just installed it today and will see the result. Hopefully Mr @Will Prowse can do a deep analysis on this unit. There is no brand, just a generic one online
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I am running two 8s qnbbm in series on byd's , as stated above only getting under 2amp transfer with up to 60mv imbalance. That being said the qnbbm's are balancing all cells at once, so the combined transfer could be as high as 10-20amps at one moment on 16s. Each individual qnbbm modual will either draw or supply voltage to a common rail which is ac current. The amount of current which is either drawn or supplied is determined by a multiple of the common rail voltage.. So the ac voltage on the comon rail is an average multiple of the battery voltage and the qnbbm's balance to that average. This is my understanding of how they balance..
Maast
Compulsive Tinkerer
Here's a photo of the QNBBM balancers linked earlier on my test bench. I'm very happy with the balancers, the highest amperage I've seen on one is 1.5A on a cell that was .2V off the others (cell was at 2.9 when its neighbors were at 3.1v-3.2v on a discharge test.
They do a very good job of keeping cells in balance but anything more than a 3ish AH mismatch between cells (which is actually a heck of a lot) and it can't keep up with a high rate discharge. I posted a thread a couple weeks ago giving details on a test I did on active balancers with high and low discharge rates.
They do a very good job of keeping cells in balance but anything more than a 3ish AH mismatch between cells (which is actually a heck of a lot) and it can't keep up with a high rate discharge. I posted a thread a couple weeks ago giving details on a test I did on active balancers with high and low discharge rates.
Thanks for the details and photo. I have one cell out of 10 packs that's way high in ralation to the rest (400mv). If I'm charging at 1.25 amp per cell this should work correct?
Edit - on the discharge (.025c per cell) everything is fine.
Edit - on the discharge (.025c per cell) everything is fine.
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Maast
Compulsive Tinkerer
Yeah, it'd be more than enough to handle that mild of a mismatch.
schmism
Solar Addict
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The one I'm useing and works as advertised. Note: If you deny the location permission it will not connect via bluetooth.
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