Battery Equalizer 48V, Voltage Balancer for 24V,36V, 48V and Any N×12V System, LiFePO4 /Lead Acid/Lithium/Gel/SLA/Ni-Cd/Ni-MH Battery Balancer

I've got 4 LiFePO4 12V batteries in use to power a Ryobi riding mower. I was charging the batteries with a NOCO 4-bank charger, but the batteries kept getting further out of balance after each charge. Rather than going through the considerable hassle of removing all the batteries and connecting them in parallel for a few days, I decided to try this device, which can be used while the batteries are still in place in the mower. It works very well. It's a passive device which is powered by the batteries themselves, drawing a very small amount of current while connected. It can balance up to four batteries. It does so by looking at the voltage difference between the batteries and routing current from the highest to lowest. Simple and clever design, IMHO. After being connected for several days, all batteries were within .01V of each other. Nice.

I had noticed that batteries at the end of my string had voltage variance only after a couple weeks so I started to look for solutions and can across this unit. It has been in use for 3 weeks now and working well. I keep an eye on it with my bluetooth shunts and all are now staying with in a couple thousandths of a volt.

Was very skeptical about whether or not it would function as advertised. To my delight it does function as advertised. It's keeping my 48v battery bank within 0.2 volts of each other. Before installation battery voltages were anywhere from 1 to 2 volts differential. Would have given a 5 star rating if the leads were longer. Should probably given it only a 3 because I feel that all of the available battery equalizers are over priced. 5 to 10 dollars worth of components for $50 to $70 dollars , retail??? Does work though. For how long? We will see.

Did the job

Bought 2 and 1 has completely stopped working. Unable to get support or a new one from the seller/mfg...

No complaints about this item it's been running for months now and batteries are all keeping in check with each other. It does make a high pitched noise that I can hear but doesn't bother me.

easy to connect to batteries

This device is absolutely mandatory if you are assembling a set of four 12V batteries to make up a 48V battery which will be charged as such. The issue is, despite how carefully you balance the batteries individually prior to assembly over time their individual levels of charge and their invividual voltages will diverge. This is because the batteries will always have small differences in internal resistance and battery health. So, over time, different voltages will be expressed across each battery when charging. This results in differences in each battery's charge level. Now, when you discharge the pack the weak cell(s) will drop out and drop the voltage of your pack below the specification of your inverter or solar charger/inverter and it will shut down. This problem is much worse if you are using Lithium batteries with individual internal BMSs. When that battery voltage drops below the BMS protection cut off voltage it will turn that battery off. This instantly kills your 48V battery. Often, this will occur when the other batteries are great. This dramatically reduces the energy extraction potential. It can also damage your batteries by both overcharging and over discharging. You have two choices to avoid this. You can disassemble and balance your individual batteries very often. But, that will never produce optimum results because the individual battery charge levels will quickly diverge. Choice two is use this excellent device. This battery balancer has a rather simple circuit inside and a bank of capacitors. Basically, what it does is draw a very small current pulse from the battery with the highest voltage to charge the capacitor bank. Then, toggles and dumps this voltage to the battery with the lowest voltage. This is done many times per second. The result is that it will balance a mildly divergent four battery pack very quickly. Though it will also balance packs with larger charge and voltage level differences this unnecessarily heats up the balancer which isn't particularly good for it. So, balance before installing. If you balance your batteries and install this device it will keep your batteries balanced within a few hundredths of a volt and the charge levels virtually identical. It doesn't matter the battery type. There are no settings. The voltage balancing action is relative to the cells. It's really a miracle device. It will dramatically increase the total energy available from your pack. The one downside, if you are not regularly charging your battery pack this devjce will slowly discharge it. It's an active device. Thus, it does use a small amount of energy. One important point, when installing do not allow any positives on the device to touch any negatives. It was create a nasty spark and can damage the device. I'd recommend putting a piece of tape on the terminals of all either positive or negative leads. Connect all of the other leads, then connect the taped leads one by one to each battery. If your needs match what I described above this is perfect for you. It easily gets five stars.

arrived quickly, east to set up. got it two weeks ago and is working very well .

if you are using lithium batteries this is a must. Hook it up to them before you install and then like every other month use it or just leave it hooked up you will see that each battery is a slight difference in voltage hook this up and overnight they are all the same. Great unit I have two now as i have lithium's in golf carts and boat.

Had to return as it produces a ~12kHz LOUD transformer wining noise regardless of if the batteries are unbalanced or balanced. Balancer works well to <0.01VDC and might be ok if you're not in the same room as it.