Batteries draining at night, runs good all day
 

The past few cold mornings my 01 ram has had to sit on the charger for a bit to start. The truck will roll over but not near enough to start. Charge it a bit and it starts and runs great. Took it to local auto zone and they tested the batteries. 12.8 each and auto zone said the alt is charging good as well. Must have a draw somewhere? Any common things to look at first? grid heater? Bummer right before deer camp next week. Need to tow the Travel trailer a few hundred miles.

do you have an aftermarket stero system? check the grid heater relays?.. check and clean all your ground wires and battery terminals as well

This may sound stupid....Check that you glove compartment light is off when you close the lid...

I know a friend that spent a fortune on a battery drain, and here it was the glove compartment light draining the battery...

No, it's only stupid if you check all the hard stuff first, then check the glove comp. light.
My truck is doing the same thing, but it takes about a week to bring the battery low enough to no start. I disconnected the negative side of the battery,
connected the alligator clip on my test light to the neg battery terminal and
stuck the handle on a ground next to the fuse block. You'll have to disconnect both battery negative cables. The test light will stay on until you disconnect whatever is draining the batteries. I'd pull the fuse to the interior light first so you wont get a false reading. The hot wire to the radio might also keep it lit dimly. The radio might be faulty, draining the battery. The engine computer or transmission computer( if you have an automatic ) could
be at fault. I only suggest pulling fuses because that is the easiest and fastest way to check the most circuits. Like Dave said, check the glove compartment light, and anything else that operates with the switch off.
It might be faster to take the cables off at night and reconnect them each
morning than charging the batteries. Hope you find the trouble soon.

Did they load test the batteries, or just check the voltage. A bad battery can show good voltage, and drop out when it is called on. A properly charged battery should, ideally, read 13.2 volts. Unhook the passenger battery and see what happens the next morning. Plug it in too, if you can. If the passenger battery is bad, you will start right up, if the driver's battery is bad, you'll get nothing. If they would run a ground cable between the batteries you could then unhook the driver's battery ground and see what happens while trying to start on just the passenger battery.

Unhook one battery- it's the poor (or cheap) man's battery load tester.

Thanks guys. I will get to checking on it. I checked the codes in the odometer for the heck of it. p0216 comp code and p0234. RRRGH. That p0234 is a thorn in my side. [duhhh] POSSIBLE CAUSES


Wastegate mechanical failure
Wastegate stuck

Take the alt. off and go to a auto parts store. Have them check for any blown diodes. They are like electric check valves. Electric flows in one direction only. Blown diodes will drain overnight and cause a low voltage battery in the morning.
Good luck.

Thanks hhrumph

I learned a cool trick to find a drain to the electrical system. Turn off truck. One at a time, take a fuse out of the fuse panel and check for current draw by putting the probes for an ammeter on the two connectors for the fuse you took out. If you see amps on the meter, you now know what circuit is drawing current. No amps, no problem, return fuse. Don't forget you have a fuse box in the cab and another one under the hood.

Somethin else to consider is your cable ends. They can be bad and cause starting problems.

Also, have you put the ammeter on the batteries in the a.m to see how they stand for voltage?

I would check all the simple and free stuff first, then go towards faulty parts, etc. When it is cold out stuff shrinks, heatin up the cables with current may cause a connection to occur after a bit...just thinkin on it for you.

My batteries were doing the same thing. It ended up being my brake controller. I have just unplugged it for now.

As mentioned by others. Test batteries separatelly and bench test alternator. clean all heavy electrical connections making sure wires are not internally corroded.
The starting system is not difficult if understand basics.

Slick! I'll remember that one. I think most aftermarket radios list the "off" current draw for the clock and presets memory. I wonder if the ECM needs some current for memory when off?

There is a set limit on battery drain in the FSM, anything higher is considered parasitic draw and is usually the culprit if the batteries are good. The draw down voltage keeps the memory in the ECM and radio current.

Dodge's spec has always been a maximum of 30 milliamps draw after all the modules have timed out. I would disconnect one battery from the system, then put the ammeter in series between the other battery's negative post and cable, and let the vehicle sit for an hour with doors closed and key out of ignition. Install a small jumper wire in parallel with the ammeter (in case the ammeter times out and shuts off during the waiting period). After waiting the hour, remove the jumper and see what your draw is.