something is sucking my battery down!!!!

jaysmooth77 · Feb 22, 2016

I put a new alternator and battery on my 99 f150 and something is still killing my battery.i just bought this truck so i decided to pull radio to check wires,there was alot of loose bare wires back there.can that cause a short and drian a battery over night?

shanky887614 · Feb 22, 2016

is it an aftermarket radio?

DPG · Feb 22, 2016

If you mean there is exposed copper showing then yes this could cause a short and drain your battery. It could also start a fire if the correct fusing isn't in place, so I would insulate these urgently! If you still have problems then check that your alaternator is charging your battery correctly (ie. check the voltage at your battery with your engine running above tickover), and also maybe check what current is being taken from your battery when everything is switched off.

Also check for a boot light which is stuck on, etc. Daz

BlueToBits · Feb 22, 2016

I would be tempted to ensure everything was switched off then try pulling off a battery terminal and measuring the current between the cable and the battery post with a DC clamp meter or, providing there wasn't a massive spark, a multimeter on the 10A range. There will be a little current for the clock and alarm etc, but if there was any more than milliamps I would start pulling fuses whilst watching the display.

DPG · Feb 22, 2016

Kind of what I said in post 3. Daz

Barry White · Feb 22, 2016

I believe the F150 has the ford smart charge system (its too smart I think)
Is the battery light on on the dash?
Have you measured the voltage across the battery terminals with the engine running? it should be above 14v
Never jump start a flat battery connect the jump leads and start donor car leave running for 15 mins to charge flat battery before trying to start. ( failing to do this can cause the alternater to go over voltage and damage its self)
The vehicle battery needs to be a silver calcium battery or again the alternator can be damaged.
(I have a focus and have had the above problem after jump starting a mate)

see below link for more info

http://www.valeoservice.com/data/master/webfile/2945759434DDE6E8714173.pdf

and sorry about this but couldent resist