Battery Charging

[Mike Wenrich]

Hooked up my camper, plugged it in to 120V and turned on the refer. Sometime after that it defaulted to 12V and ran my batteries down overnight. Charging them now, I hope...with the charger leads connected to the driver side. But for quite some time the brake lights stayed on after connecting. Went off after about 10 minutes. Then I opened the passenger door and they came on again. So I looked for a fuse disconnect in the box and I can find a fuse for everything but the lighting and/or brake lights. This is on a 2014 3500. Anyone have an idea what is going on? And how I can bypass the lighting? If I disconnect the batteries I can only charge one at a time. At least that is what my brain tells me.

 

[AH64ID]

Is it brake lights or parking lights?

It's possible it's just a computer gremlin from the batteries being low.

I'd give it 8-12 hours on the charger and see where things are at.

 

[Ltngdrvr]

Hooked up my camper, plugged it in to 120V and turned on the refer. Sometime after that it defaulted to 12V and ran my batteries down overnight. Charging them now, I hope...with the charger leads connected to the driver side. But for quite some time the brake lights stayed on after connecting. Went off after about 10 minutes. Then I opened the passenger door and they came on again. So I looked for a fuse disconnect in the box and I can find a fuse for everything but the lighting and/or brake lights. This is on a 2014 3500. Anyone have an idea what is going on? And how I can bypass the lighting? If I disconnect the batteries I can only charge one at a time. At least that is what my brain tells me.

Yeah, not brake lights, it's the running lights, and they always stay on for a bit due to the delay and the activity in the truck. I wouldn't worry about it for the time charging the batteries, and yes the charger will work faster if you disconnect one battery and charge them separately, unless you have a high amp charger.
And, if the charger isn't a smart charger, be very careful to not overcharge them.

 

[Mike Wenrich]

It's brake lights for sure. I've got the charger on 40 AMP so I hope that's okay with the cables connected. Never had to charge two batteries before at the same time except with a trickle charger on the military 24 volt Jeep. Also never had to jump start one of these trucks. So maybe a single 12V battery is insufficient. Learning as I go.

 

[JR]

In general low and slow is the best for battery longevity. 10 amps is widely recommended for charging starting batteries. Your batts should be around 80Ah each, charging at 10a max would take approximately 8 hrs per battery. It doesn't hurt leaving them connected to charge.

 

[Mike Wenrich]

I'll reduce it to the 15 amp rate and see how that goes. Would like to leave on my trip in a couple hours. We shall see if the beast will turn over by then.