I don’t often get the opportunity to do a full maintenance check on our batteries, but with Cheryl planning to be off the boat for 10 days in March, I wouldn’t be cruising, or baking cakes for that matter, so an ideal time to do it.
To do this I needed to run the batteries down to being practically empty.
The last time I did this was over three years ago so I was interested to see :
- how much out of balance they were,
- whether any capacity had been lost.
The simple answer to both questions is :- not enough to care about.
The result showed such a miniscule out of balance reading of 0.09% that I didn’t need to take any action at all. However, as I had got the battery to this state, I took the opportunity to add 1Ahr to the two lowest cells and 0.5Ahr to one other cell to restore the battery balance.
I used some software on my PC to show the voltage of each cell in the battery to aid me balance them.
I measured the capacity of the battery as I recharged them to full and found no measurable drop in capacity after 5 years of continuous daily use, which is very reassuring.
With Firecrest’s battery being out of balance by just 0.09% I can safely ignore the often-repeated myth that LiFePO4 batteries need re-balancing on every cycle.
There are two take-away points from this:
- Firecrest’s LiFePO4 battries do not appear to have deteriated at all in over 5 years of daily use.
- Re-balancing of our LiFePO4 battery does not need to be done often, even after 3 years it was not necessary.