Is my Duralast Gold battery hurting my voltage?
I have an Excessive Amperage 250A alternator, one Duralast Gold Size 65 battery under the hood wired in parallel with two Kinetik HC1800 batteries. I have the 3 batteries connected - to - to - and + to + to + (I have two runs of 1/0 going the length of the car), but only the Duralast under the hood is grounded to the chassis. My voltage driving around is usually 13.8V at the amplifier (with the stereo turned down all the way, but on).
I took my car to Advance today. I unhooked the two 1/0 runs at the Duralast that connect it to the Kinetiks. They tested the battery and came up with 12.59V and 958CCA. I kept it disconnected from the Kinetiks and I had the guy test one of the Kinetiks. The Kinetiks were still wired in parallel with eachother when he did the test, but not grounded to the chassis because only the Duralast is. The test gave 13.06V and 1095CCA. I wish I disconnected the Kinetiks from eachother and had him test them separately, but they were closing in like 2 minutes.
What can you guys tell me based on these tests?
Thanks a lot.