Battery Balancer Image

Battery Balancer

How do I wire 12 agm batteries to a 24v inverter?

I have 12 used agm batteries that I want to configure to a single 24v batterybank. How would you wire this in the best way? Do I need balancers? If yes, how many?

mattie asked
nesswill commented ·

3 Answers

Lower battery high voltage light not switching off


Hi I recently boaght a 2.5kva 24V inverter running x2 12V 200Ah gel acid batteries in series. I connected the balancer precisely like the instructions stated but my balancer still shows high voltage on lower battery even if I switch the batteries over it still shows the same light. The other problem is that the green on/standby light never switches on. Can someone please steer me in the right direction. Thank you

jurgens asked

0 Answers

Pylontech battery balancing

Just added to US3000C batteries to an existing pair of US3000C batteries. Started balancing operation all commss cables removed as well as lines to inverter. balancing started as expected but after a few hours the 2 existing batteries continue to show discharging but the new batteries are in standby. Restarting the balancing procedure shows that the new batteries are still on 3 LEDs whereas the old batteries are on 5 LEDS. Balancing continues for a few minutes and then they go into standby again. Is this normal and do I just have to wait overnight for balancing to complete. Or is there something I’ve missed.

Roberto Znconato asked
lonso answered ·

2 Answers

How many BatteryBalancer parallel at 48V 4350Ah

Good day,

I use in a bigger installation 192 cells SOPzS 4350Ah, hence I have 8 set of 24 cells, which make already 24 BatteryBalancer...

...but how many BatteryBalancer should I put in parallel with this capacity?

Note: The load will be up to 12 Quattro 48/15000/200-100/100 starting with 6 for now.

Michelle Konzack asked
Michelle Konzack answered ·

1 Answer

Battery Balancer with BMV 712 on 48 VDC battery bank

In June '22, I bought 3 Battery balancers and a BMV 712. It seems the drawing, which came in the box, for 48 VDC, 3 parallel packs (each 4×12 V 115 AH), are not right. Victron BB.jpg I connected it as shown. After first switch on, some lights were on and from the balancer at the right (BB3) some smoke came out. I switched off immediately and checked the connections. I thought it was wrong and swapped the battery wire, Balancer 1 and 3. At Power on, all three green LEDs lighten up. The BMV 712 was working too, and over time the balancing percentage dropped to almost zero.

When I checked my Battery bank last week, Jan '23, I experienced some weird measurement. The voltage was very different, all three Batteries which connected to minus-bus bar had 15 VDC, the 9 others had around 13.32–13.67 VDC. This is happened awhile after the charging is finished and switched to floating voltage 55.2 VDC. I found online the drawing on Victron HP Victron BB2.jpg, so I installed the missing minus link. At Power on, the Green LED and Orange (high voltage upper battery) on BB1 (left) lightens and Green LED and Orange (High Voltage lower Battery) on BB3 (right) lighten up. At the BB2 (middle), all LEDs are off.

Has somebody an explanation for it? What did I wrong?

Just opened the case from the smoking BB3. The IC2 has a hot marker, but it seems it is just the enamel which smoked. I swapped the Position BB2 with BB3 already.

Thank you for any idea.

ipman asked
Stefanie (Victron Energy Staff) commented ·

4 Answers

Battery Balancer With Negative Ground


I have a battery array with 4x 12V AGM battery for an output of 24V that was discharging and charging not equally so we got ourself a battery balancer module. Problem is that the negative of the array is connected to the ground for lightning and safety purpose since the system is powering DC Pumps.

I cannot see in the manual if the balancer module can be used with grouned negative. If it is, what would be the ideal wiring.

Thanks !

moverm asked
moverm answered ·

2 Answers

Battery Balance too many batteries?


I have 48 x 12v AGM 135aH batteries and have them configured in 2s 24p. (3 x banks of 8 2s 8p).

The batteries are about 3 years old (used in a ups system)(All wired in series).

The 3 banks are connected together with 25mm x 6m Bars bars with positive feed on one end and negative on the other.

When I set them up they we fully charge and with 0.05 of volt of each other. I have 4 85/250 mppt charging these with a Mutiplus 5000Va /24 running ESS.

i have 3 x victron battey balancers 1 on each bank. They where in alarm state

I have disconnected and metered the batteries today and the batteries are at least 1.2v out.I am planning to get them all back up to fully charged using external charger

Am i expecting to much to have this amount of batteries in series parallel. They have been working great over the summer but maybe the have been getting slowly out of balance.

The only thing that has changed is I have started using a scheduled charge overnite from the the last 3 weeks.

Any thoughts would be greatly received.

Many Thanks

richie-gorrod asked
JohnC answered ·

3 Answers

Battery balancer wire gauge

Hi all,

I'm upgrading my battery bank to 2S4P 24v system using SBS 190F Batteries.

Ive just bough a battery balancer and will install it once the batteries arrive.

Will one unit be enough to balance the 4 strings?

What wire gauge should I use for it, +/- and mid?

Thank you

gabriele-rossi asked
kevgermany commented ·

4 Answers

Balancing 8x6v (48v) system with two balancers

first time poster looking for help with battery balancing

I am working on an electric boat conversion using 8 golf cart batteries (flooded lead acid 6v) wired in series. I purchased two of the HA02 balancers ( which each can balance 4 batteries of up to 12v each. i have wired the first to batteries 1-4 and the second to batteries 5-8. This is working well but it does still allow imbalances to occur between the first 4 and last 4 batteries in series.

I have seen people mention that it might be possible to balance all 8 batteries but it would require a 3rd HA02. I am not sure exactly how the wiring would look on this. Can anyone help me out?

second - I was thinking through how it might be possible to balance across the entire bank without adding a third balancer. I was curious if it might be possible to sort of parallel the Two balancers to monitor all batteries. My thought was to wire each input to overlapping pairs of batteries (therefore giving each 12v). This would be wired as:

balancer 1: 1/2, 3/4, 5/6, 7/8

balancer 2: 2/3, 4/5, 6/7, blank

in your opinion, would this work and be safe? Or are there other issues I am not seeing?

robert-martin asked
Mike Dorsett answered ·

1 Answer

Options for battery balancing 48V bank of 8x 6V batteries

The Victron battery balancer works with 12V batteries. Handling a 48V bank would take 3x balancers.

But, what about a bank consisting of 8x 6V batteries ? Our bank is 8x Crown CR-430 430AH batteries ...

halfwalker asked
Tom Ranson commented ·

3 Answers

Battery balancer on 4 x 6 volt batteries

I have 4 x 6 volt AGM batteries wired in series to provide 24 volts , my batteries are now 9 months old and considering a Victron Battery Balancer but i I have a few questions . Is it worth me fitting one now as my batteries are no longer new . A website i found shows one is required for each pair of batteries so i would require 2 units , is this correct . Would they still perform with cables between 1.5 and 2 meters long providing the cables were all identical lengths . Do they produce much heat . I found thi now but can see how it could possibly work when the connections from it go to a set of batteries that are al interconnected , how could it provide extra current to any individual or even pair of batteries , could someone please explain what might appear simple to them but illogical to me .


This is what i have at the moment so not sure if i will be able to use the Victron Banancer

ako asked
JohnC answered ·

2 Answers

Victron battery balancer wire length

Hello I am installing 12 lead carbon batteries in 48v exactly as Victron shows in the battery balancing info sheet. Due to where my batteries sit and the 3 balancers installation location the closest battery is about 2 feet away and the farthest is 10 feet. Do the wires from the balancers all need to be the same length or are they allowed to be different lengths depending how far away the battery connection is?



livibg-on-a-lifeboat asked
Alexandra answered ·

1 Answer

Can't turn of DVCC to balance Pylontech Cells

Hi Guys,

We had some strange high voltage (49,12V) alerts on a Pylontech battery set (6 x US2000C). 3 batteries were a few month's old and 3 new batteries.

We got some internal error's and high voltage alerts, so we contacted Pylontech technical support.

They told us the following:

"OK, please try the following method first:

1. Please use a DC charger with 53.2V and 2-3A to charge these battery together for over 8 hours. This will help balance the cell voltages. This is the best solution.

2. If you do not have a DC charger, please set the inverter in force charging mode for over 8 hours. This will also achieve the effect of cell voltage balance."

I wanted to go with option 2, so I can do it remotely..

Through remote VE configure, i changed the settings in the multi.

But the systems overwrites this... Because I can't turn off DVCC.

I don't think it's possible to do this another way?

So the only option I have is.
Go back to Venus OS 2.73 So I can turn off DVCC.

But the last to stored software versions are 2.87 and 2.85..

So I can't do that remotely? And I still have to go to the location to use a dc charger or use an sd card/usb to put software version 2.73 of venus os in the system.

Or am I missing something?

apacalipto asked
Alexandra commented ·

2 Answers

Initial Top Balancing Lifepo4 24v configuration

I have 4 SOK 12v 206ah batteries going into a 24v 412ah configuration to a Victron MP 3kw/24v

The SOKs have in-built BMS and have been sitting unused (in their shipping boxes) since late last year when I ordered them.

The voltage for each individual 12v battery is currently ~13.07 (two are at .07, one is .06 and one .08).

My question is what would be the best approach to do the initial load top balance? Should I use a bench charger device to bring each one up to proper voltage separately or will the Victron MP do the initial top balance correction even if they are in their ultimate 24v configuration? If the Victron MP will take care of it, are there settings I need to adjust from default for this to occur?

downgrader asked
downgrader commented ·

1 Answer

Cable or busbar for correct midpoint voltage?

In this section of the Wiring Unlimited book, the midpoint connections are illustrated as cables. Should the midpoints be connected to a busbar like the positive and negative cables in order to get the same midpoint voltage across each series?


damien-walker asked
johnsmith edited ·

3 Answers

94 Posts
87 Users

Topic Experts

95 Points
38 Points