question

halfwalker avatar image

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 ...

Battery Balancer48v battery
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3 Answers
Mark avatar image
Mark answered ·

I have a system with 8x 6V AGM batteries, wired in 2 parallel strings of 4 batteries - for 24V.

I have had very good success with using 2x HUAXIAO HA02 energy transfer transfer type battery balancers, one for each 24V string: http://www.huaxiaotech.com/product/83.html.

There seem to be a few brands of this same/similar unit out there, so be wary as I am not totally sure if they are all from the same manufacturer/same performance.

The same company (HUAXIAO) also sell a unit that will directly balance between 8 batteries - for your setup I would try to source one of these units: http://www.huaxiaotech.com/product/81.html.

In my setup I didn't really want the battery balancers connected/active when the battery is not being charged as they are not required during that time and they draw a small load (probably no big deal, but I still don't like it) - so I added 8x 8A 24V DPDT relays which are controlled by the MPPT relay, when the battery bank voltage goes above ~26.8V the battery balancers are connected/activate. This works really well and the energy wasted by the relay coils is no big deal since they are only energized while there is good solar power/battery voltage is high.

I have also independently fused all 16 wires to protect for any kind of fault and added 8 small battery voltage meters to independently monitor the voltage for each battery side by side.


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robert-martin avatar image
robert-martin answered ·

Thanks for bringing up this topic. I am also working on a similar solution for an electric boat conversion using 8 golf cart batteries (flooded lead acid 6v) wired in series. I purchased two of the HA02 balancers (https://www.amazon.com/dp/B07L8WKKC3/ref=cm_sw_r_cp_tai_LG1AFb4RAXD3P) 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?

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halfwalker avatar image
halfwalker answered ·

So it seems that the Victron balancers will only work between two 12V batteries. Knocks them out of handling 6V batteries unless we do it with pairs of 6V batteries. Without using lots of balancers, it would only be working between pairs of batteries, NOT between the batteries in any given pair.

There is another balancer out there that will handle 6V batteries though

https://zhcsolar.com/product/ha02-battery-equalizer/

One would need two of these to handle a bank of 8x 6V batteries. The balancing would be between two sets of 4x batteries, no balancing between those two sets. Adding a 3rd HA02 would allow one to balance across all 8x batteries.

It will pass up to 10A between batteries for balancing.

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