How Screwed are my batteries

[Heath68]

Hi everyone... yet another problem I'm hoping people can advise me on.
I had 1kw solar and am adding another 1kw a fisher panda 5kw genny and upgrading the controller to the victron cerbo and GX50 display.
They are half way through the install and I am on shore power in the boatyard (out of the water). Suddenly I hear a click as a fuse pops and about 30 seconds after that, the display comes up with a low battery warning... and another and another. The display shows 10.9v. I ring the people doing the work and he asks me to look at the shore power fuse board and sure enough its clicked, i turn it back on but the green light does not light up on the inverter (so the power supply problem is external). He sends out a guy about 30 mins later who switches the supply back on and we're back in business. The inverter then spends the rest of the night panting hot air like an idiot whilst trying to recharge the batteries from their low of 10.9v back to the normal level. Now I know jack about lithium ion batteries but what I do know is that if drained too much the batteries might be damaged or totalled. Looking at these two charts does it tell anyone if I should be worried about the 700ah bank I have? Has it done any damage?
I was concerned that they had drained really quickly, but looking at the decline it seems to have gone on unnoticed for the time when they were working on the boat.
Thanks for any advice, they're back in work on Tuesday and I'd like to be a little clued up.

Heath

[markcouz]

At 10.9V you are unlikely to have caused any serious damage, but you don't want to do it again!

I suggest having a cutoff system set at 11.6V (2.9V per cell), as there is very little energy left between that voltage and 2.5V per cell where permanent damage will occur.

Your second graph shows a normal charge profile where current is stable and voltage climbs slowly, until full charge is approached where current tails off as voltage climbs quickly to final bulk charge voltage.

I think you will find that you are OK.

[Heath68]

Originally Posted by markcouz

At 10.9V you are unlikely to have caused any serious damage, but you don't want to do it again!

I suggest having a cutoff system set at 11.6V (2.9V per cell), as there is very little energy left between that voltage and 2.5V per cell where permanent damage will occur.

Your second graph shows a normal charge profile where current is stable and voltage climbs slowly, until full charge is approached where current tails off as voltage climbs quickly to final bulk charge voltage.

I think you will find that you are OK.

Thanks very much mark.. I think they said I can set rules in the system for certain situations, that's certainly one I will endeavour to add. Once again thanks for the advice. Heath