Hot Rod Forum banner
1 - 7 of 7 Posts

·
Registered
Joined
·
228 Posts
Discussion Starter · #1 ·
Hello All,

I have a CJ7 and run two group 24 batteries. One is over 8 years old the other is 3. I use a basic marine 1/2/both switch to manually select them. All custom cables, all great condition and clean.

I really thought the 8 year old battery was bad and was ready to replace it but it turns out the newer battery is the bad one. Both batteries test at +12.5-7 volts but the newer battery will not crank the motor. It clicks like it it completely dead.

I have swapped cables, no different. The main wire to feed the interior/accessories is post marine switch and both batteries power the headlights etc perfect.

If new batteries weren't 200$ each i would just replace both. Anyway, have you ever had a instance where a battery show full voltage but can not deliver any amps?

chris
 

·
Race it, Don't rice it!
Joined
·
8,814 Posts
Yep.
Put a DVOM on the battery and crank, if you see it drop below 12 within a few seconds, it's a lead brick.
If no crank at all, Lights will also put a load on it, in that case it should 12 or better for 15 minutes.
 

·
Registered
Joined
·
228 Posts
Discussion Starter · #3 · (Edited)
Yep.
Put a DVOM on the battery and crank, if you see it drop below 12 within a few seconds, it's a lead brick.
If no crank at all, Lights will also put a load on it, in that case it should 12 or better for 15 minutes.
I turned on the headlights for 30 minutes and then tested,, the newer battery is still 12.3 volts and lights bright but will not turn the motor , just a click. I cleaned all terminals and switched the cable from bat1 to bat2 and still no crank. It is not in the cables because the 2014 battery still fires right up.

newer battery drops to 2 volts when cranking,,, old battery drops to 9.5 while cranking. I guess it is just toast.



Chris
Motor vehicle Hood Automotive design Automotive exterior Vehicle
 

·
Registered
Joined
·
228 Posts
Discussion Starter · #5 ·
Newer bat have warranty ?
yes,, but no.. Called deka and they are nice but of zero help. I have to take it back to the seller with receipt. I would think a huge company that can verify the date code would just warranty the battery out and make good on it. I think it was from wal-mart but i can't find the receipt and WM customer service is ehhh at the store. I went ahead and bought 2 new batteries from Oreillys today +$400.

At least from Oreillys i can go to any store anywhere and they can look me up with the phone number.

If i get another 8 years out of the new batteries i will be happy, I wanted to run the old battery until the very end just to see how many years it would last but since i get way out in the mountains and desert i figured not to press my luck.
Chris
 

·
Registered
Joined
·
15,298 Posts
Battery’s can read 12.5 with no load on them, it really doesn’t tell you the charge strength only the pressure. Volume counts, in this case amps, that is what does the heavy lifting. So this is the reason for load testing.

An example of mine from last spring was getting the Harley off the charger and out for a ride. It would light the lights but not crank the engine, crap I let it get sulfated. Turned out apparently everybody in Puget Sound had the same problem as after a lot of computer hunting and phone calls with every battery store telling me they were out of stock I found one at a Pacific Power store about 40 miles away. The guy said he’d hold it for me so wifey volunteered to drive given that the battery store was close to one of here favorite malls. So that riding day was lost between battery and mall shopping. But I’m retired so my weeks are 6 Saturdays and a Sunday so if the weather is good anyday works for me.

Bogie
 
1 - 7 of 7 Posts
Top