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cdav3435 avatar image
cdav3435 asked

Battery Balancer Design - Conflicting Product Manuals

Hi everyone,

Trying to plan a new battery deployment for my off-grid cabin.

I'm planning on installing 4x Victron Smart Lithium Batteries - 12V/200Ah - in a 24V system (2p2s)

I'd also like to include a battery balancer to keep the two sets of series batteries balanced. As per the Battery Balancer manual, bridging the middle connections should allow a single Battery Balancer to manage all 4 batteries.

Picture from the manual for reference:

1635056013391.png

This design makes sense to me, I understand that the midpoint connections must be sized appropriately to handle load should a battery fail. However, the manual for the Victron Smart Lithium batteries mentions that midpoints should not be connected together:

1635056133800.png

Can someone provide some insight here? I don't understand why the batteries shouldn't be connected like this. Thanks for any help you can give!

Lithium BatteryBattery Balancer
1635056013391.png (87.2 KiB)
1635056133800.png (16.7 KiB)
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2 Answers
nickdb avatar image
nickdb answered ·

Lithium requires a battery manager. Why would you want balancers when charging is managed intelligently with a BMS?

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cdav3435 avatar image cdav3435 commented ·
I'm planning to use the Lynx Smart BMS with a few Lynx Distributors. Are the Lithium batteries capable of balancing between separate batteries in a series? The documentation only really mentions balancing between the internal cells - or maybe I've misread that...
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leftcoastman35 avatar image
leftcoastman35 answered ·

Hi, did you ever get an answer on this? I have a similar setup on my boat and the battery-level voltages for each battery in a serial pair drift apart at high SOC.


Previously I would disconnect all the batteries and charge them 1 at a time, but obviously easier if I can just install a balancer to prevent the problem from occurring.

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