Batteries discharging after sitting 4-5 days??

[50dan]

Hi, new to this site and looking for help. Truck is a '95 F350 and batteries keep discharging after 4-5 days of not being used. This is the 2nd time now. First time 2 weeks ago I put 2 brand new batteries in and it fired right up and ran fine for a week of using it. But now that it sat for 4-5 days without being used and it's totally dead again. Took the alt. off and had it tested it is fine. Tried to jump it and not enought juice to start, but I did notice the "wait to start light" is bright for the first 2-3 seconds of being on then it goes dim like something is drawing juice from somewhere. Anyone have a clue where to look or had this problem before??

[fordnut85]

If you got something pulling juice this is the easiest way i have found to locate it.

Disconnect BOTH neg. battery cables.
Place a test light between the neg. cable and the neg. post of the battery
the test light will glow bright if there is a load pulling current.
next have a buddy watch the light and start pulling fuses one by one
if the light goes dim when a certain fuse is pulled you will know the load is on that circuit and you can start chasing there.

Try that and post your results

[mschn99]

first of all, do you have any aftermarket add ons (alarm, etc) that would cause a draw....

Secondly, Duane has a good method for checking for draw above, but not foolproof....The only way to accurately check for draw is with a DVOM and measuring in miliamps.....

If you dont feel like putting a lot of time into figuring out this problem, your best bet would be to buy battery disconnects. They are terminal ends with green plastic nobs. You turn the knobs to disconnect or re connect the batteries....biggest drawback on a truck your vingage is loss of radio statios and clock each time, since the older trucks dont have much for learned stratagy...

If you want to chase the problem down and fix it, let me know and ill get into further depth, but the first thing you will need is a DVOM or some other form of ammeter...

[fordnut85]

Marc's right, that is a cheap, easy, shadetree fix. Putting a DVOM on it can tell you more than the old test light theory

[50dan]

Thanks for the replies.

Only accessory is an electric dump bed, but it was put on brand new last year.
I'll try the procedure you stated above, but do I have to recharge the batteries for this to work? Thanks!

[fordnut85]

Any elec. test should be done with a fully charged battery/s