PowMr Battery Equalizer 48V - Battery Voltage Balancer,for 4×12V or 8×12V or More Battery Bank Extend Battery Life 1 Year and More, Support Gel Flood AGM Lithium Battery HA02 Balancer

keeps my 4 battery 24v solar system batteries equalized.

works great I've had it for 3 years running nonstop in an offgrid solar system with 4 independent 12V lifepo4 batteries. It has VERY loud coil whine which doesn't matter if it's in a box and near a bunch of cooling fans but when I was testing it on the lab bench in my bedroom I had to stop the test because I couldn't sleep from the whine.

Excellent unit. very tight. Solid build.

This product works quite well and does what it should. I have it wired to two 48v battery banks connected in parallel. Each bank consists of 4 100ah 12v solar agm batteries in series. All 8 batteries within .1 volts of each other after 12hrs. There are only two downsides that I noticed.No. 1 - The plastic back that the equalizer snaps onto is quite cheap and fragile. One of the tabs broke off so it doesn't hold very well. Be careful when installing!No.2 - the equalizer does make a slight high whine but this is a minor issue for me and doesn't affect its operation or cause me any annoyance.Overall this is a great product so far. I would definitely recommend

The good: I wired this up to four 12V/200Ah LiFePO4 batteries in series, one of which was noticeably lower in capacity than the rest, and it took about a day to bring them all within 10mV of each other.The so-so: I can't really say that equalizing all the batteries at the top helped much with extending the usable capacity, but it did, at least, stop that low-capacity battery from hitting 17V+ while the other three were still at 13.6V or so. This equalier does - er, did - make a faint high pitched whining sound in operation but I didn't find it to be loud enough to be objectionable; YMMV.The bad: It caught on fire, obviously, but the actual cause is a mystery since the battery was balanced and around 60% SoC. There are two MPPT solar charge controllers set to 56.2V max that can supply up to 30A or so total (only 4 x 225W panels for each of them) and an outboard 54.6V / 15A charger as well, but it wasn't running at the time of failure, so it doesn't seem like it was a case of excessive current.Note that this same equalizer is marketed under various brand names but all look very similar - I wouldn't trust any of them at this point, but if you can't resist the siren song of a cheap price, I strongly recommend splicing a 15A fuse inline with each positive wire.

Overall I give it high marks.Pretty much all 12 volt LFP battery packs have internal cell balancing. However multiple 12 volt LFP batteries in series tend to become misbalanced over time, leading to a reduction in overall string capacity.This equalizer redistributes excess charge from the strongest batteries to weaker ones, eventually resulting in each battery having the same voltage.LFP batteries have a very flat voltage over a large range of charge/discharge. As the batteries near full charge or discharge the voltage change (and voltage differences between batteries) becomes noticeable.The photo shows the various equalizing currents being sourced or drained from each of the 4 LFP batteries using Hall effect current sensors on each of the battery connections during the end of a charging cycle.What I am especially impressed with is unlike the BMS balancers within each of the 12 volt batteries which use resistors to bleed off excess charge as needed, this unit actually transfers charge which does not generate the heat (loss of energy) that would be the result of the higher currents this unit can develop.The only minor drawback is the very small constant current draw this unit consumes. I measured about a 15 degree F increase in temperature on the case. This might equate to about 1-2 watts being consumed continuously regardless of equalization.

It works exactly as described

I hate Bashing, & I DO Want to Like the Product, but i WISH i knew what i am about post, BEFORE i Settled on this without spebding slightly more $ on MUCH Better quality.Being told the noise is "Appropriate", & Dismissed without regard, w/ My (& Anyone Else's) Huge Inventment in their builds & or Necessity of their Power Systems... Just Felt Funny in My Book tbh.Let me Point out it DOES REALLY WORK, & Nicely at That Actually. bBalancing 4x 12v LifePr0 100AH Batteries, & Confirmed working solid for over a week now.Initiates over 20mah difference, & up to 10a current, though only ever see 0.5-1a getting moved between the 4. Not Much Loss either, rather Efficient Design.(Hopefully This Doesn't change)Initial Connection did See Larger 5a-6a transfers, that lowered until all 4 were even, took only a few hrs, but i keep my system heavily maintained & monitored for optimal longevity.(Hopefully)Overall Build Quality FEELS Nice, Case is Solid, Mounting Tabs intact, No damage to the 8x Red & Black Wiring or Connectors but are VERY THIN. Be gentle with your install & that isn't the main issue.Like many ha e posted, the unit Has an Audible High-Pitch "Squealing". Not Faint, like you hear every once in a while from different devices, this thing is Decently LOUD, & is 100% Due to Poor Quality Components, & or (in my case) Very Poor Soldering & Build-On-Board Preparation.Again, Overall NOT a Terrible Balancer, & I AM STILL USING IT. It does work & Im Stuck with it as Running around for a small return is redundant.My Fault & Lesson learned.You Get Exactly What you pay For kiddos, So Choose Wisely.TOTALLY Keeping a close Eye on it,TOTALLY wish I spent 10%+ on a better unit.Though many look like clones & the same unit in the end, the last thing anyone wants is to jeopardize their system, No matter the size or necessity of it, on such a small component compared to the entire power system.Hope this helps someone, Decide for yourself. If anything use it for something cheap, & keep in in a shed outside of your home, with an extinguisher.. just incase.