misty01

This will be lengthy, but is needed for the help I need.
2014 Ram 3500 - 6.7
It's cold, but this shouldn't happen. (-29C or -20F)
The problem started when the temp plummeted.
After charging my batteries, I put the key in the ignition and when I turn the key to the "pre heat" stage, I lose all power in the batteries. When I checked the power in the batteries before starting - 13.7 or 8. After cycling the pre heat, drops to 10.8.(I heard an audible click when the voltage dropped)
So, I charged the batteries again. Pulled the neg off one of the batteries and checked for a draw. With the setting on 10amp on the multi meter, I got 0.09 - 0.12. doesn't seem to be a bad draw(I think). Boosted the truck and got it running and checked the power at the batteries again and got 14.8 - steady. Seems to be a good steady current to the batteries.
Batteries? Alt? I'm hoping Alt, (cheaper than 2 batteries, but!!)

BILTIT

Does it start?

if 14.8v running than it is not the alternator.


Sounds like the normal cold start intake heater draw etc. do you plug the block heater in at those temps? you really should.

We were at -32C this morning.

misty01

Yes, have it plugged in. Oil and Coolant at +25 when I had to boost it to start.
Tnks Derek

BILTIT

So it cranks but no start or just won't crank after preheat?

My guess is batteries or crossover cable/connections. Find a load tester and test each individually. You can also try and measure voltage at each batt while cranking, might show the crossover cable being bad.


I went through a few months of starting/voltage hell last fall. New batts and a new starter made it start way better than it ever has. My symptoms where a little different though.

kodiakken

Your Batteries are pooched.
If you boost it and it starts that is your proof.

misty01

Thanks Derek and Ken.
Was leaning towards batteries.

torquefan

90 to 120 milliamps seems a bit excessive for draw, but it can be difficult to get an accurate reading on a newer vehicle, with many modules that can take a long time to power down, and then can wake up again as soon as they sense any change in voltage.

You would need to start with one battery disconnected and isolated from the electrical system. Let the vehicle sit for a couple hours with the key out and the doors closed. Now you need to rig up a plan to disconnect the one remaining battery and install the ammeter in series without interrupting the circuit. The usual target for draw is 50 mA or below.

Having said all that, for your particular problem, i would have the batteries tested first.

misty01

One more thing:
charged my batteries up last night. just checked them now and only 11.4V. Without trying to start it up.
Pooched batteries??
Going to do another draw test though.

Busboy

My sons 2013 batteries only lasted 2 years from new, I didn't believe him when he told me his batteries were toast, replaced batteries and all was good again.

misty01

I believe it Busboy.
charged my batteries up. 13.54V
undid the ground on drivers side, let sit for 40 mins.
parasitic draw was 0.03A. The problem with getting this, was letting it sit for some time (which I really didn't let it sit that long last time)
V on batteries after waiting and testing = 13.04. Batteries don't hold a charge.
Going to humor myself and load test them tomorrow anyway.
-2C right now.

Cmow

I am a fleet manager in Edmonton I look after 10 RAM 5500's 2010+, I used to buy batteries every two years, switched to AGM now its every 3, but the warranty is way better on them so it works out. I talked to a guy at intersate, he said batteries never last more than 2.5 years in these parts.

Glad you got er going!

kodiakken

Cmow
What are AGM batteries?
I am drawing a blank.
Ken.