Hello all. So I finally was able to come back to my (new to me) boat
after 7 months sitting on the dry, only to find no electrical
systems were working at all.. hmm.. I checked the batteries
and voltage on the terminals and it was 4V (!) .. Ok.. time to do my part for the economy and get new batteries
. They were indeed old anyway (I just bought the boat
last year and the previous owner had no idea how old they were).
Nevertheless I was a bit ticked. I mean, I have got solar
.. I figured that would take care of the batteries during my absence. But ok, they were old, a cell died, what do I know. Move on with life.
I got new batteries installed a couple of days ago. I am still on the dry trying to get ready to launch so I am connected to power and of course my solar
panel and wind
generators are running.. I kept my eye on the voltage and most of the time it fluctuates between 13.2 and 13.8V .. so I figured batteries are charging
. I would like to see the charger
getting closer to 14.2V since I read that near the end of the charging
process, this kind of extra tension is required to be able to squeeze in those last electrons (or is it to take OUT those last electrons :-) .. but ok. I assumed all is well.
Last night I wanted to do a test. I disconnected shore power
so the only thing generating anything would be the wind generator
. It wasn't particularly windy so I basically left the batteries carry the load overnight. My small fridge was running (EDIT: and my AIS
transmitter which you can't really switch off) but that was about it. When I went to sleep, voltage read 12.8V .. which as far as I understand constitutes a "fully charged battery".
This morning I wake up 8 hours later to find the voltage at 12.2V which according to my readings is about 50% charge gone, and the point where most people say "time to charge those batteries again" to take good care of the batteries long term.
So I am thinking.. I have got 480Ah combined (2 x 240) .. You mean to tell me my fridge and AIS
ate 240A over 8 hours? It is a really small unit (albeit old). I really had nothing else running overnight, not that I can think off. Am I right to be concerned something here is draining my batteries, to the point where it is conceivable that solar and wind (in Greece) wouldn't be able to keep them charged over the mild winter?.. that would explain the battery
failure in the first place (compounded by the age of the batteries of course). Or am I overthinking this?
EDIT: I just did another test and cut off the switches and the voltage immediately jumped up from 12.19V to 12.34V ... that's a biggish jump isn't it? the fridge was already off .. hmm..