Ford F350 Battery or Altenator Problem

[CharlieTR]

Can someone tell me what to check for on a battery problem.
The truck will not start and the message center on dash read "Check Charging System" I took one of the two batteries to O'riellys and they charged it, same problem when I put it back in.
I only have a 2 amp slow charger, I left it on the other battery about 16 hours last night. The fully charge LED did not come on. Is there something I can get to test the Altenator? I think the problem may be caused by not running the truck enough. I only ran the last three weeks on the weekends about 30 minutes. Not sure that is enough, last time was only at idle.
One battery is new and other is original, but I had green indicator in its window. Any help would be greatly appricated!!!

Thanks,
CR

 

[slowzuki]

I have always read, in a dual battery system where they are in parallel to give 12 v, you need to replace in pairs. One of them being partially bad will shortly ruin the other new battery.

BTW not likely the alternator, likely the one old battery the culprit.

 

[Egon]

For interest consider disconnecting both batteries and take them to a shop for a load test to see what condition they are in.

At the same time check both ends of the battery cable conections as well as the starter connections.

 

[tcartwri]

I have always read, in a dual battery system where they are in parallel to give 12 v, you need to replace in pairs. One of them being partially bad will shortly ruin the other new battery.

This is exactly right, and it will be the new battery that is ruined to add insult.

To test the alternator, simply put a meter on the battery terminals while the truck is running, and you should see 13.8 to 14.1 volts.

 

[Phils]

My '03 Ford 7.3L F250 has a 90ma phantom draw, to keep electronics alive I'm guessing. It's enough to draw down the batteries over a month or two and prevent starting if the weather is cold. This seems to be common on these trucks. Also, it takes a minute before the alternator starts charging. I have a friend at auto auctions state that most diesel Ford trucks need a jump start. He dismissed many because they didn't stay running when the jumper cables were removed until he learned about the charging delay.

I added an Edge Evolution tuner to my truck and it ALSO has a 90ma draw which, combined with the truck's draw, will get the batteries too low in 3 to 4 weeks. I queried Edge on that and they confirmed the draw and suggest disconnecting the unit if the vehicle will be parked for extended periods. I usually do that.

I also have a solar panel on the garage roof (60 watts, not those little 2 watt kits) to keep the batteries charged since the truck doesn't get a lot of use.

And the previous mentions about keeping the batteries matched is true too.

Phil