[Shibbs]

I have a 03 ford f250 and the batteries will not stay charged. Both batteries and the alternator are about a year old. I can charge them and after a few hours the truck won't even try to turn over. Any ideas?

 

[DexterII]

First thing I would do is take it to an auto parts store or dealer, preferably where you bought the batteries, and have them load test them.

 

[Shibbs]

I'm charging them now to take them up there

 

[Brainbucket]

Tracing a battery draw is difficult. You say both batteries so I'm assuming that it's a diesel. With it running and after all the fuel heaters and glow plugs turn off, it should be charging between 13.5 and 14.5 volts. Turn it off and disconnect both negative cables from the batteries. Get a test light. Connect the test light between the negative cable end and the negative battery post. It should light up and around a minute or two it should go out. It will blink. That's the many control modules going to sleep. If it doesn't turn off, start pulling fuses one by one and reinsert them watching the test light. If it goes dim, wait to see if it goes out. It may blink. Also, I just had one in here that was killing the batteries. Turned out that the 4X4 relays were a ball of rust. They are beside the drivers battery. The owner would start the truck and the alt would be maxed out charging the batteries back up. It killed the 4X4 module. And by chance the instrument cluster took a dump which is typical of Ford clusters . I had to replace one battery, repair cluster, replace alt, and replace 4X4 relays and module. :vs_cool:

 

[Shibbs]

Thanks I'll check that out

 

[carmusic]

borrow a dc clamp meter and check how much current there is when truck is off, should be under 0.02A

 

[Oso954]

What charge rate do you use and for how many hours ?
Do you charge them individually or in parallel .

 

[ukrkoz]

 

[Shibbs]

10 amp and about 6 hours a piece

 

[randyhenke]

As mentioned measure amp draw and start pulling fuses it will be noticeable when you pull the right one.

Sent from my XT1097 using Tapatalk

 

[Shibbs]

Both batteries were shot thank God for warranty and thanks for a the tips