Periodic maintenance charge for balancing with generator auto start

Q&A and troubleshooting
, , , ,
1

Hi all,

I have a battery bank of 6 strings of 2 Victron Smart LFP-200a batteries (not the NG ones) in series together with a Smart Lynx BMS. I use the generator auto start function of the Cerbo. They are fully cycled as much as three times a day. I programmed the periodic run once a week with the option ‘Run until battery is fully charged’ in order to sufficiently balance the batteries.

I have noticed that this condition only goes to 100% and stops with the tail current criteria. It does not spend the full 2 hours in absorption until CVL drops and batteries are balanced.

Is there an easy way to program the full 2 hours absorption within the generator auto start functionality? Perhabs another way to do it? I would prefer not to use Node-Red but just go with the standard settings of Cerbo and Lynx BMS.

Thanks in advance!
Simon

2

That’s a heavy load for the batteries. For best life, you should only be cycling once a day!!

Best to look for a minimum run time in the cerbo settings for the generator, and set that to give the required absorption time.

3

Hi Mike,

Thanks for replying. I will try the minimum run time but it is not ideal as the load can be high, leaving no current for the battery to charge. Solution is to take a large minium run time but in most cases you will have the generator running too long.

I think it’s strange that 2h absorption time is not incorporated in the ‘Run until battery is fully charged’ setting as it is crucial to ballance the batteries in an application of cycling on a generator.

4

It is best to balance the Batteries from a Solar source, as this requires time spent at low battery loads.

If your site load is high, then this is ok to keep a diesel generator running efficiently. (min load 25% of generator VA rating).