Preventing Flyback Transients when in absorption multiplus

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mattguy asked Jan 4, '24

Preventing Flyback Transients when in absorption multiplus

Hey folks,

I've posted here a few times regards brief (<1s) voltage spikes I'm seeing during absorption of my internal BMS LFP battery.

In summary lowering the absorption from 14.4 to 14.06 (nominal 12.8v battery) helps a ton. The absorption cycle holds the voltage steady as a rock, but when large loads are placed on the battery such as fridge cycling, water pumps and macerator use it can style cause a spike after the load is removed.

At first I was very worried about cell balance issues, but I recently learned of flyback transients and was wondering if

1. These could be the cause as they only seem to come around when absorption current is very low ( <1amp) and after the fridge or pumps have cycled?

2. Is there anything I can do to prevent this?

3. Still a cell balance issue?

Thanks all

battery charging multiplus ve.bus lifepo

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Answer 1 · 2024-01-04T23:58:30Z

mattguy answered · Jan 04 at 11:58 PM

Spike right after load at 15:45 ish. Absorption cycle 1h so this is right at the end. Peak voltage this cycle was 14.17, which is fine, but sometimes the spime can be as high as 15+ volts

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