I went to leave work yesterday, got in my truck and turned the key. Ugh, I got the dreaded dead batterys click. Tried to jump it with a 1/2 ton Chevy and no luck. AAA got there and tried with a booster pack and the tow truck's battery. Nothing. I just replaced one of the red top Optimas last summer, but the other one I put in back in 2005. When one battery dies in these trucks will it kill the other one? Are both batteries supposed to be replaced when one dies? Tomorrow I'll pull both out and have them tested at Autozone. Truck is a '95 PSD.

 

I think you should replace both with matching batteries.
Are you sure it is your batteries and not the starter?

 

Guess I'll find out for sure when I pull the batteries. Last summer I also pulled the starter and had that tested. It was good.

 

leave the door open and crank it over...does the dome light dim reeeeeeeeeal low?

 

I'll check after work thanks Cope

 

No problem, let us know what you find

 

Although I am no Battery engineer, but have experienced working with Deep Cycle batteries in commercial/Industrial equipment for 9 years. Generally, a weaker/older battery will pull down a fresher battery, to it's own level...layman's term. I would replace Both batteries new when they are needed. Yes, not the cheapest way to go.

 

I've seen this several times as well. Even a slightly bad ground on one battery will really put a dent on the cranking power too.

 

So when you tried to jump, it still wouldn't even turn over? That sounds like something other than battery problem. A while back my starter was turning over slow, but the battery voltage checked out about 12.6... I then checked the voltage at charging and it was good. So I took the starter off and had it tested. Checked out ok, but I bought a new one anyway, cause I couldn't think of anything else it could be.... Parts guy thought I was crazy. Put the new one in my truck though and all was good. Starters can go bad with out totally dieing. Sometimes they start pulling too many amps and get sluggish.

 

that is true, some times you can still get a few more starts out of them with a BFH while cranking.

 

Give the starter the old screwdriver test.

 

For the OBS PSD battery setup, it is "best practice" to replace the batteries as a matched set. Same chemistry, same OEM, same size, same rating...as noted above, when one develops an issue, it will impact the other.

Mine started acting up about 10 days ago and gave up the ghost over the weekend. Turned out ONE had developed a bad (shorted) cell. Both are getting replaced come payday (and yes, I'm planning on using that AAP coupon code as I can't find a more cost-effective deal.)

 

Definitely replace them in pairs. If they were stone dead, it takes a a long time with jumper cables to get them up enough to crank the beast over.

 

I'll throw my 2 cents in as well!! Definitely replace BOTH batteries if one is bad.

I replaced both of mine about 2 years ago. I threw the "good" on in my wife's van when hers needed replacement. It gave up the ghost within a year. The new ones are a little on the weak side (850CCA), but are still going strong. 3 year free replacement and 8 year prorated replacement.

Unless I'm within the three year period, I probably won't opt for these again. They are Energizer from Sam's Club (cheapest I could find on short notice). They do ok, but I think they are just slightly underpowered for what the truck really needs.

 

AAP coupon code?