Battery life, when it's disconnected from the camper

[jawilson]

I have a group 24 battery on my trailer that is approximately 5 years old. I can't attest to how it was taken care of before I bought the camper, but in the past 1.5 years it has been charged/recharged in the appropriate manner.

About 6 months ago - at the end of the 06 camping season - I removed the battery, placed it in my basement on a board and hooked it up to a BatteryMinder Plus. It's been on a continuous trickle charge with desulphation the entire time. Now I want to test it's strength.

I remove it from the charger and let it sit for about an hour. At that time it was reading 12.83 volts using a digital multi-meter. I've been checking it every day since then and after 7 days it now reads 12.51 volts. To me, that sounds like a weak battery; I don't believe that a battery with no load on it for 1 week should have dropped that far, but I could be wrong. Does that sound right to you? Should the voltage be higher then that, or does the battery seems solid based upon those numbers?

[wavery]

I have a group 24 battery on my trailer that is approximately 5 years old. I can't attest to how it was taken care of before I bought the camper, but in the past 1.5 years it has been charged/recharged in the appropriate manner.

About 6 months ago - at the end of the 06 camping season - I removed the battery, placed it in my basement on a board and hooked it up to a BatteryMinder Plus. It's been on a continuous trickle charge with desulphation the entire time. Now I want to test it's strength.

I remove it from the charger and let it sit for about an hour. At that time it was reading 12.83 volts using a digital multi-meter. I've been checking it every day since then and after 7 days it now reads 12.51 volts. To me, that sounds like a weak battery; I don't believe that a battery with no load on it for 1 week should have dropped that far, but I could be wrong. Does that sound right to you? Should the voltage be higher then that, or does the battery seems solid based upon those numbers?

The proper way to check your battery is cell-by-cell with a hydrometer. You can get them at any auto parts store or Walmart.

The hydrometer will tell you if you have a weak cell. A weak cell will pull all of the other cells down. As long as all of the cells read in the "Good" range, your battery is fine. You will notice some discharge, no matter what. Keep the top of the battery clean and dry. Dirt and moisture will discharge your battery.

[wynot]

I have a group 24 battery on my trailer that is approximately 5 years old. I can't attest to how it was taken care of before I bought the camper, but in the past 1.5 years it has been charged/recharged in the appropriate manner.
 
About 6 months ago - at the end of the 06 camping season - I removed the battery, placed it in my basement on a board and hooked it up to a BatteryMinder Plus. It's been on a continuous trickle charge with desulphation the entire time. Now I want to test it's strength.
 
I remove it from the charger and let it sit for about an hour. At that time it was reading 12.83 volts using a digital multi-meter. I've been checking it every day since then and after 7 days it now reads 12.51 volts. To me, that sounds like a weak battery; I don't believe that a battery with no load on it for 1 week should have dropped that far, but I could be wrong. Does that sound right to you? Should the voltage be higher then that, or does the battery seems solid based upon those numbers?

I suspect that you're fine.  It seems like the hybrid/deep cycle batteries have a higher voltage (in excess of 12.6 V) when charged, but then seem to settle down to around 12.5.  Personally, I'm not a fan of trickle charging, and just put them on the charger about every month or two in the off-season.  I have two 5 year old Grp 24 batteries that are still quite viable even with my "abuse".  You're not trying to keep it ready for high drain starter usage, but just to make sure that you don't suddenly go from 12.6V to 10.5V immediately (dead cell).

[tlhdoc]

I went out and checked the date on one of my batteries.  It was made in January 2001, so it has completed 5 camping seasons and I am hoping for a 6th.  I charged it yesterday and then checked the voltage 24 hours later and it was at 12.8.  I know if it is cold they read lower.

[jawilson]

Let's see, 5 years x 20 trips per year x 4 days each = an awful LOT of camping. Maybe I should buy the type of battery you have -- that would last me for 10 years!  

[wynot]

Let's see, 5 years x 20 trips per year x 4 days each = an awful LOT of camping. Maybe I should buy the type of battery you have -- that would last me for 10 years!

And Tracy dry camps a lot more than the average person, too...
 
Of course, I think you're running Grp 31s, aren't you Tracy?