Battery Charge Life

[Reardon]

Hi

My AC shore power line was not connected well and my Carver 404 batteries were dead in the morning. Charged them back up and no problems. I thought that only going one night (maybe 18 hours) with no charge didn't seem like that long for the batteries to beable to hold a charge. I don't think there was much pulling on the batteries (maybe fridge, etc) over night that would have drained them.

Battery configuration is 3 batteries - 2 shared for engines and house, the other for generator.

How long will your batteries hold a charge, if there are no demands on them?

Thanks
Rich

[Viper]

...How long will your batteries hold a charge, if there are no demands on them?...

Months!

The key words here are "no demand." That means no electrical flow, as if they were disconnected. The amount of time they hold a charge and still remain "technically" charged depends on a few variables including battery age and condition, temperature, habits/conditions under use, charge/discharge cycles, etc. As an example, I leave my batteries on board throughout the winter months disconnected. Come Spring time, they are still fully charged.

How long they last with something running depends on the same as above plus the load specs of the items running.

[tomschauer]

Reardon, the quick answer is a good battery(s) fully charged with no load will hold charge for a couple months with temp and battery condition variables.
You state you may have had the fridge etc on. In my experience a fridge will drain a regular starting battery in about 8 hours. A deep cycle a bit longer. Also many variables as far as reserve amps, temp, load etc. Just to be safe, I would put a load tester on each battery to make sure they weren't damaged by the full drain down.

[AaHubb]

Hi from another 404.
You didn't specify what size batteries you have so it's hard to give a good answer. It also depends on how they are connected, one or two banks. Note, if two banks never use the 'BOTH' setting on the selector switch unless you cannot start the engines from one bank. The Norcold refr draws about 4 amps from the batteries so that would be ~70 amp hours over an 18 hour period. Guessing at a pair of group 31 bats w/120 amphours each you should have had enough reserve to start an engine. Remember usable battery reserve is half the listed amp hour rating. I have two group 31 bats in parallel for starting and 4 6v golf cart bats connected series/parallel for the house plus another group 31 for the genny.
..Aaron

[SplashyLady]

The frig is a big power draw! The newer ones are better, but some of the older ones can kill a battery overnight with no problem. I usually don't turn the 12v breaker for my frig on - mine can usually use some defrosting anyway! The frig will stay cold for a day or two with no AC power, and if you run the genset once or twice a day it will keep your frig pretty cold.