I am trying to figure out if my batteries are getting tired. I have measured their voltage with a digital meter and they are reading 12.6v.

When I cycle the key, and let the grid heater kick in-the voltage drops to 10.4v while it heats, then jumps back up to 12.4v when the grid heater finishes its cycle. Both battery measure the exact same.

The reason i am asking-i've been noticing some slower cranking speeds and recently, my Espar heater has been acting abnormally-stopping working about 1/2hr into its opperation. Since i don't have a code reader for my espar, i cant tell why its stopping working.

Can someone verify their voltage for me?

 

that sounds about right. my passenger side battery died on me about october on the 06 so i would test your battery with something other then a volt meter. the battery testing tools put a load on it to chek. the grid heaters do draw alot

 

don't you have to change them both at the same time? or the new one will always discharge to the older one?

 

I have a digital volt meter in my truck and see about 10.5v when the grid is on.

MikeyB