I guess it was only a matter of time
A few weeks back my wife went out to start the Tundra and it was dead. I had her pull out the voltmeter and check the battery voltage and it was 0.8V.
When I got home I charged it with the FJ40 and started it up, then drove it to the auto parts store to have everything checked. He said my battery was a little low on charge but it was fine. Cranking Amps were down to around 500 from a CCA rating of about 700. Alternator checked out fine.
I went home, topped off the water in the battery and cleaned the terminals and greased them when I put everything back together.
It's been ok for the past couple of weeks except when I took a trip last week and it sat from Monday morning until Thursday morning. It was pretty slow to start. Overnight or over the weekend it has not really been a problem starting on Monday morning. Until the last week or so.
A few times now I've gotten in and turned the key to start and all the power is killed and the voltmeter on the dash drops to zero. So far the "fix" has been to open the hood, check the terminal voltage with a multimeter, which has ranged from 12.1-12.4V, and try starting it again. It starts up fine and is not an issue until it sits for a few hours again.
This morning I tried waiting for a few seconds and restarting it - as I waited the dome lighting and panel lighting slowly came back to life - and it kept dropping the voltmeter to zero until I gave in, opened the hood, checked the battery voltage again, and then it started up fine.
Should I just throw a new battery at it and hope it goes away? The battery was in the truck when I bought it 4 years ago so it could be aging, and by the cranking amps probably is. Or does it sound like a wiring issue?