12v Fridge Power Issues

[iruninca]

Hi all! I'm new to the forums. My wife and I purchased a '72 Safari that has been partially renovated, but needs a lot more work still. We live in it full time.

We were living in a 16' R-Pod, so this is a big upgrade for us! However, we're having power issues. I'll give you some background.

We have a Dometic CFX 65DZ "Electric Cooler", which is a super efficient chest fridge\freezer that runs on 12v or 120v. We're off-grid and using solar, so 12v is our best option. In the R-Pod I installed a cigarette lighter plug on a 15' wire to the fuse panel, and it ran perfectly fine off that.

Then I moved the fridge into the Airstream. It runs perfectly fine off the built in cigarette lighter plug, but if I add my extension cable to it, it shuts off every time the compressor tries to power up. So it seems that the dip in voltage is forcing it to shut down. Then it turns back on and tries again, doing this power cycle every minute or so.

So I know the cigarette lighter extension works separately, and I know the built in 12v plug works separately, but they don't work together. I'm getting a solid 12v+ on my multi-meter through the whole system, but something's misbehaving. I know just enough about electrical to get into trouble, so don't I won't be offended if you suggest "basic" stuff. Give it to me straight. Any advice or suggestions??

Thanks!
Alex

[DKB_SATX]

Your multimeter should be giving you more detail...

Do you mean a "solid 12V" is 12.6V? Or 12.0? And is the voltage at the 12v socket the same as at the battery terminasl? Or is there some drop in the wiring?

My first guess would be that the built-in 12v "cigarette lighter" in your older Airstream may not be giving you a really good electrical connection and while the voltage measures out, the resistance is too high between the socket and the plug that either the drop from the long cord or from the 2nd connector (or both) is enough to keep it from delivering enough power to the fridge. Bigger wires and fewer connections between the battery and the fridge may be enough to resolve this problem.

Does your Safari still have its original single battery? That's going to limit your overnight run for this fridge, though the chest-type fridges tend to do really well at staying cold if they're not in a hot location or direct sun.