Help: DC Power cuts out under load

Freep wrote:
Thanks for the suggestions, everyone.

I methodically pulled all the fuses from the PD4045. Interestingly enough the fridge has no fuse in that panel. I am able to reproduce the issue by putting the fridge on DC power.

I shorted the battery bypass and I still get the issue.

I did clean and reconnect battery contacts and the chassis grounding wires.

I have not been able to locate an inline circuit breaker.

I think I could be having a battery issue or maybe there is a circuit breaker under the bathroom sink that is out of reach/view. When the power cuts I hear a thunk from the lifeline AGM battery. This is a sound I usually hear when the battery is low and bulk charging starts. I was told by lifeline that this sound is normal when charging.

The power can be out for several seconds. When it comes back on I hear a little click under the sink. Could that be a circuit breaker?

It's going to be raining here for the next few hours so I'm going to take a break before pulling the batteries. I think I'll connect them one at a time to see if the problem follows a specific battery. If it's a battery issue, I doubt it's both of them.

At this point I really hope it's a battery. I have no idea how I'm going to get access to the wiring under the bathroom sink.

When you say you put the fridge on DC power, you’re meaning you have a 3-way fridge, and you’re switching it to DC cooling mode, right? If so, that suggests the DC heating element on the fridge MAY be the source of the problem. I say “may” because the DC heater has a fuse on the fridge control board, and you would think that fuse would blow if the heater was shorted. That s where all of the fridge fuses are BTW, on the fridge control board. That’s why there aren’t any on the converter panel.

There are some DC connections behind the fridge that should be checked for tightness, since they could be causing this. The main DC connector that has the wires feeding the control board is just a two wire, compression-screw type. If the screws are loose, it could draw more amps than normal, and might not blow the fuse on the control board. The DC heater is definitely the biggest load when it’s on.

Here’s what mine looks like, the black and white wires you see are direct from the battery, with the black wire running through what used to be a self-resetting CB at the battery box. I replaced it with a manually resettable CB a few years back. There are of course more wires coming out the other side of this connector that go to the control board.



I think the click you’re hearing under the sink is likely the self resetting CB, and if that’s where the battery box is, that’s another clue that it’s a CB. Those are typically placed close to the battery compartment.

What’s your bathroom sink vanity look like? Is the sink removable, or is it a single piece molded sink and cabinet? A picture might help.

Bud, thanks for posting what I sent you in a PM last night. I meant to post it on the topic myself, but fell asleep before I could do it, :z

:):)