More power problems

Electrical problems, what a pain. We had an issue with our new NL 811. Dealer finally tracked it down to the power receptacle on the camper that you plug the truck in to. Fixed that, no more issues for us. Good luck.

Maybe the initial diagnosis of a shorted cell was correct......and it is intermittent.

battery has a cracked plate

More observations that lead me to a conclusion (I think). TC was frigid when we got to rest stop last night but didn't want to run the furnace on 10v cause it might lead to CO detector screaming on the middle of the night. I ran the truck for 30min until it was acceptable. I shut off the truck and the batteries we re at 10.4v. The furnace ran intermittently all night. At one point I checked and the battery was at 12.4v. This morning I checked 2x be for leaving. The first time it said 10.4v. The second it read 11.7v.

My conclusion is that I have 1 cell that is intermittently faulty. But, since I have 2 batteries, I don't understand why voltage wouldn't be either 12v read from good battery or an average (1.4+12.5)/2=11.5v. I'm not sure why it reads 10.4v unless one has 2 bad cells.

If you think it is one battery, disconnect the one you think is bad and see what happens. If it still does it try the other battery and see about that one.

You could also toss in another 12V battery that you know is good (one out of another vehicle as it does not have to be a camper battery for a test) and see. This would eliminate the two batteries in there now.

A wiring question... the batteries are wired independently to the panel (I believe). There's a bunch of leads with some connected to each battery. I get a little nervous every time I remove the batteries that I'll mess up what goes on each terminal. It seems though that so long as I have + leads to the + terminal and - to the -, it shouldn't matter how it was originally wired. Correct? In other words, could I move all connections to the outboard battery and just the hookup leads to the inboard? Obviously it would have to physically fit, but + is + and - is -...what difference does it make?

bkenobi wrote:
A wiring question... the batteries are wired independently to the panel (I believe). There's a bunch of leads with some connected to each battery. I get a little nervous every time I remove the batteries that I'll mess up what goes on each terminal. It seems though that so long as I have + leads to the + terminal and - to the -, it shouldn't matter how it was originally wired. Correct? In other words, could I move all connections to the outboard battery and just the hookup leads to the inboard? Obviously it would have to physically fit, but + is + and - is -...what difference does it make?

The answer is it kind of does matter. With parallel batteries you want each power source (i.e. solar, converter, truck) and the load (output) to have a positive on one battery and a negative on the other. This balances the batteries in terms of total wire length in each circuit.

If you connect to just one battery then use jumpers over to the other, it will see less charging and discharging than the primary one you're connected to.

Just label all of the wires with a +1, -1, +2 and -2 so you keep the groupings the same if you go to a single battery and back to 2.

bkenobi wrote:
A wiring question... the batteries are wired independently to the panel (I believe). There's a bunch of leads with some connected to each battery. I get a little nervous every time I remove the batteries that I'll mess up what goes on each terminal. It seems though that so long as I have + leads to the + terminal and - to the -, it shouldn't matter how it was originally wired. Correct? In other words, could I move all connections to the outboard battery and just the hookup leads to the inboard? Obviously it would have to physically fit, but + is + and - is -...what difference does it make?

Doesn't sound correct. I would run each battery to a common buss bars using equal length conductors. Then go from there to each device i.e.: camper 12v distribution panel, charge controller(s), inverter (if used) With two batteries in parallel you want the 2 batteries to become 1 larger 12v battery bank with draw being equal between them and not be charging/drawing different loads from each.

It sounds like a you might benefit from someone more familiar with wiring to help clean up your system.

I do not understand the wiring from the description given, but if the batteries are parallel wired and you are measuring different voltages on them, then they are not (effectively) parallel wired - even if one is bad. I also don't understand why they would be independently wired to the panel. Sometimes that was done in boats in the past so you could run on one at a time (using a 1 <-> 2 type battery switch) but that practice has been given up as a bad idea. If the battery shop actually load tested them, my best guess is that there is a wiring problem somewhere.

I didn't want to put too much detail in the OP to scare responders away. I have had a lot of issues from day 1 (some my dault, others aren't clear). I know 1 or 2 times the fridge was left on auto by the SO (she was told, but forgot when loading). There have been other times where we went from fully charged to 10v for no reason. I've had the batrekies tested 2 or 3 times. I'm planning on solar or generator, but want this sorted before I complicate things. I don't like masking priblems.