Truck battery question

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jaeger

jaeger

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I know this is a pen forum but there are a lot of gear heads here to!

I have a f-150 with a battery that keeps going dead. I don't drive this truck every day so here is what is happening. I put jumper cables on it and jump started the truck. I drove it to have a load test on the battery and it checked out good with 700+ CCA and the alternator tested good. I drove the truck on and off all day, it started fine all day. I parked it for a few days and now the battery is dead again.
I thought a load test would determine the strength of the battery. Is there a chance that it has a bad cell(s) even though the load test checked out good?
 
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jaeger said:
I know this is a pen forum but there are a lot of gear heads here to!

I have a f-150 with a battery that keeps going dead. I don't drive this truck every day so here is what is happening. I put jumper cables on it and jump started the truck. I drove it to have a load test on the battery and it checked out good with 700+ CCA and the alternator tested good. I drove the truck on and off all day, it started fine all day. I parked it for a few days and now the battery is dead again.
I thought a load test would determine the strength of the battery. Is there a chance that it has a bad cell(s) even though the load test checked out good?
Click to expand...

Possible.
Have you considered there might be something draining the battery? Something left 'on' or a short somewhere?
 
I might be wrong but it sounds like you might have a short somewhere causing it to drain the battery when it is not being used.(just a thought) good luck
 
Might check the regulator. That could keep the alternator from charging the battery. Could you have a short somewhere?

Joe
 
One way to quickly check if this is the problem is to disconnect the battery when you think you'll be parking it for a few days. If you reconnect it days later, then it starts up with no problems, then its likely you have a short somewhere. If the battery goes dead while its not connected to cables, then its probably a cell.

My brother had a phantom problem like this one time. He installed a battery kill switch, and just turned the switch off when he didn't intend to use it for awhile. (This was a vehicle that was primarily used for hauling to the dump, not a daily driver.) The switch kept the battery from being drained due to the short, and as long as he started it reasonably frequently, he had no problems. I think he bought the switch from NAPA.
 
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Yep, sounds like a short --- or something staying on when you shut the truck off. I've had both things cause a similar problem. Electrical problems on motor vehicles can be a bear to find.
 
Open the positive lead from the battery and place a 12V lamp in series between the battery post and the just removed lead. You should see the bulb light if there is a draining load involved. OH, I forgot, be sure to do this without the engine running. Now go to the fuse panel and be sure there is a map of where all your fuses and circuit breakers go. If there is not one, draw one. DO NOT DO THIS WITHOUT A MAP!!! DAMHIKT either. Pull the fuses one at a time and check the lamp. When the lamp goes out, you have found your problem circuit. The factory map will tell you what is fed on that fuse. There may well be more than one parasitic load in the system. Your radio could well pull a small load to keep your preset stations alive. A stuck brake light switch is always suspect. That will not always turn on the brake lights but still pull power. Feel the switch, if warm to the touch, it may well be the problem. I do not believe you have a full short as it will blow the fuse. That is easy to find. Phantom loads can drive you crazy! Best of luck.
Charles
 
If your truck is newer the alternator and the regulator are all in one unit so if your alternator was checked under load and passed then the regulator is also okay. Charles way of testing is very valid, but careful if yo have an onboard computer and make sure that you don't accidentally touch the positive cable to ground or you will blow the board.
 
I have had an alternator that blew a transistor/diode and would Charge just fine worked great but as soon as you shut off the engine it would start draining the battery.
 
This does not directly address the issue, but it will help: Get a 12V 1.5 watt solar charger and plug it into the cigarette lighter, or if the cigarette lighter cuts off with when the key is off, wire it in directly to a battery line.

I purchased a '95 Ford Ranger in 2000 and used it for about 8 months before going back to Japan. I would come back stateside every year for about a month. The battery in my Ranger would be dead. in 2002, I got Walmarts best battery. 2003, it was dead; Took it to Walmart and got another one free; 2004, dead again! Got another one free; Also picked up a 12V solar charger, plugged it into the cigarette lighter and put the small solar panel on the dashboard. I have a car port, not a garage. There was enough light to keep the battery charged for a full year without use.

That 2004 battery is still going strong 8 years later. Last year, my lawn tractor battery got to the point it would not start my lawn tractor. The battery was purchased in 2005. I added a solar charger to it over the winter and the battery is doing well today.

I have not expected that batteries like this would last that long, but the trickle charge of solar panels do well in extending the life of them CONSIDERABLY! Especially when the vehicle is not in use regularly!


In your case, you do have a greater drain than normal. That does need to be addressed. Still a trickle charger will help.
 
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