Domestic battery gone flat

Leighb

Leighb

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Went on board today, first time aboard after new hip fitted in December, switched on domestic battery, and no juice /forums/images/graemlins/frown.gif

Checked batteries to see if yard had disconnected, but all OK there, checked voltages, domestic battery 2.95 V, engine battery 12.9

Both were fully charged at the end of November, and AFAIK everything switched off, main switches certainly off as are all the circuit breakers.

Where should I look for likely leakage? Both batteries brand new last August.

I have a BEP battery monitor fitted which draws 22 mAmp, but by my calculations it should take over 6 months to flatten a 110AH battery.

Any ideas?
Will it have wrecked the battery?
 
Can't help with the source of the drain, but as regards condition of the battery, from my own experience (don't ask) I'd say charge it up and it'll be OK.
 
It is always worth checking that all connections are tight and clean and dry as loose connections cause resistance and dirty/damp connections provide a leakage path.

I found that a few of my connections arround the batteries were loose after the winter. (could have been like it for months of course!)
 
If your battery monitor has been on all the time then I suspect that will be the drain. I calculate in excess of 60 AH in four months - that's a big chunk out of it. It probably won't have done the battery any good but since it was new it probably hasn't done much harm either. Give it a long slow charge and don't leave it uncharged for four months with the battery monitor on.
By the way - good luck with your new hip.
Morgan
 
Agree with your figure (>60AH). 70% of rated capacity is a reasonable amount to expect a battery to usefully hold when fully charged so, when you consider the length of time since the last charge and the constant 22mA drain since that time, then this is surely the problem.

Maybe a good equalization charge as well to make sure all the cells have recovered (as much as they're going to /forums/images/graemlins/frown.gif).
 
Thanks, I will make sure batteries are disconnected next time, only excuse is the hip op interfered with proper laying up.
 
[ QUOTE ]
After four months? What do you expect?
Time was when we carried 'em home for a discharge/charge cycle all winter . . .

[/ QUOTE ]Not so easy with a dodgy hip, though.

I reckon a better way might be to leave them on board with a well-regulated (or very small) solar panel keeping them topped up.
 
connect the batteries after a charge.. meaure the current in the battery lead.. if it shows anything significant.. you have a circuit engaged.. slef discharge of lead acid batteries is well documented though as well..

dont expect miracles.
 
Both batteries the same age, only domestic flat. Wonder what else is drawing current? Do you have a properly installed car radio (yellow memory lead)always live. Any other stuff with a memory, tv aerial amplifiers, bilge sensors, alarms, (assume the monitor was checking both batteries)> If you disconnect the negative battery lead, is there any sparking? even a faulty diode in your shore charger will do this sort of thing. suspect you have taken some time off the longevity of the battery even if it seems to come up to spec, it may have a high internal resistance and be unable to perform properly. Keep an eye on it and don't rely on it as a backup starter.
 
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