Am I asking too much from my batteries?

[phil_phil]

I replaced both my batteries with 850cc costco batteries. The stickers on them say that they are from March 2012, I bought them last month so I'm as sure as I can be that they are new.

I put them on a smart charger to top them up, 4 hours on the first one, I took them off the truck and charged them in the garage. The first one was at 12.3 volts when it started and was at 12.9 when it ended.

I took the second battery off the truck and it took 5 hours to reach the same voltage.

The first battery is at 12.63 volts now (5 hours later), and from charging the batteries last time I know by morning it will be no higher than 12.5.

I have read that 12.5 is a 50% charge for a battery. Am I expecting too much for my batteries to be above 50% 18 hours after charging without being connected to the truck?

They seem to normalize at 12.3 when both are connected to the truck. That's the minimum Ed at ficmrepair.com has listed for a battery voltage to keep the warranty on the repair I just had done to my ficm, so if the batteries are there now, what happens in a year?

[Fantom]

I've replaced my costco batteries 3 times in the past year. So I'm wondering if maybe they're just not up to being used for a diesel?

[cweiss87]

A good battery shouldnt drop below 12.6 for quite awhile. 5 hours is to short a time for them to drop. I can let my truck sit for days and they will still be 12.6.

Sent from my SGH-T759

[phil_phil]

Thanks for the quick replies.

Hey Fantom , just wondering if it was a voltage problem that had you returning the batteries?

Ps. I’ve got a white 2005 super cab, glad to see you guys made it out alive, the pictures hit pretty close to home when I saw it was pretty much the same truck I drive, hope you and your dad are doing better.

Phil

[HeavyAssault]

I think you must be confusing a standing battery voltage and the voltage when installed in a truck. I run high 13s for battery voltage using a CTS with the motor running.

[phil_phil]

Hi HeavyAssault, my batteries are 12.3 with the truck off and 13.5 to 14 volts when it's running. After bench charging my batteries are reading 12.56 off of the truck after sitting all night.

Phil

[HeavyAssault]

Originally Posted by phil_phil

Hi HeavyAssault, my batteries are 12.3 with the truck off and 13.5 to 14 volts when it's running. After bench charging my batteries are reading 12.56 off of the truck after sitting all night.

Phil

I think everything is just fine.