New owner op driver for Dart

Hi everybody.. I just joined to basically be able to ask for occasional advice on my truck.(2004 volvo snl780 with D12 465 hp) I was company driver for Hostess Wonder Dolly Madison out of Ks.. First time owning my own truck and being responsible for maintenance and buying own tires ect.. All help is appreciated in advance..


Now we are having a bit of trouble with the electrical system.. Truck set for a couple of days at home and when I went to start it, wouldn't even click.. Had enough juice to light instrument panel, that was about it.. We knew at least one battery in set of 4 was weak, so I just went ahead and bought 4 new 1100 cca batts. Problem is, my little 12v cooler can only run on the new batts for about a half hour and the low voltage system turns off all the outlets it controls in the cab with an alarm. Cooler and small cooler could run all night with old batts.. Am wondering what might be the prob with new batts (3 or 4 days old to me) so that they can't even support the cooler for an hour before low voltage sys shuts cooler down.. Truck starts just fine and internal voltage with computer in truck shows batts at 12v ~ 12.7 volts with truck not running and about 14v with truck running. They checked alternator and charging sys at batts when put new ones in. Everything was okay. Suggestions or help please...

 

Thanks guys!! Finally broke down and had em retest the new batteries! Turned out they found one of the new batts failed the test. Replaced it with new one, but still seems like system not holding charge at high level for long! Need to find someone with a more thorough testing regimen! Test was done at Petro serv. gary, ind. Bunch of new guys for new truckstop. Generally did a good job with serv. work.

 

Thanks, this has turned out to be very rewarding and much of a learning experience. Bout the time I retire, I may learn what I need to know to make this work well.. Everything at Wonder Hostess was paper, everything at Dart is computerized. I don't really miss the paper too much, but the steps needed to do this right with computer is almost more than my memory can handle... Oh well...