When is it time to replace the batteries?

[Domi]

We are getting ready to do some camping with out electrical hookup. Generally a weekend and we do have portable generators. Ran a test this weekend with the batteries running the furnace over night and the held up okay and it was still running in the morning but the battery lights at the panel only had one light on. Measured the system voltage with one light and it was 10.8V and that was with the furnace running. Turned the furnace off, the second light came on and measured 11.8V. Charged up full and read 12.8V. Currently 2 batteries in parallel.

Looks like we can do one night with temps into the 40's at least which is fine that is all we really need. Can charge them up with the generators during the day.

My question is, how does one tell when it is time to replace the batteries short of them just not working when you get there? Reading prior threads it does not look like a time issue so are there any tests one can perform to see the health of the batteries, or is it take them out and have them load tested once a year at NAPA?

Thanks for the help.

John

 

[hoefler]

Batteries start to go down in 3-5 years. The only way to realy see where your batteries are, is to have them fully charged and load tested.

 

[cookie]

One night with the furnace running is all I would expect from the batteries.
As far as frequency of changing, I change batteries at five years whether they are still running strong or not.
I don't want wait till they die and scramble to find new ones when I am in a bind.

Peace
Dave

 

[farside291]

Most auto part stores will load test the batteries at no charge.

 

[mlpeloquin]

Or purchase a load tester. That way you do not have to remove and reinstall the batteries just to have them tested. They do not cost much.

http://www.harborfreight.com/catalogsearch/result?q=battery+load+tester

 

[rxbristol]

Or purchase a load tester. That way you do not have to remove and reinstall the batteries just to have them tested. They do not cost much.

http://www.harborfreight.com/catalogsearch/result?q=battery+load+tester

Thanks, I didn't know they were that inexpensive and light weight.

 

[Bohemian]

If your converter is cycling on and off frequently on normal light loads then more than likely it's time.

 

[LBR]

The 2 fully charged batteries in my diesel truck got to where it couldn't start after 4 days of setting. The amp draw was only .3 amp and I had checked it 5-6 times, so I suspected a shorted cell in one.

Had the batteries load tested...first dropped to 9.85 volts and held pretty steady at 400 amps. The second immediately dropped to under 6 volts before the guy could load even more than 150 amps.

The shorted cell in it was killing my good battery....good idea to have them check occasionally.