12V Fridge connection

Electrical issues, both 12 volt and 120 volt
Post Reply
slapthecat
Seasoned Traveler
Posts: 130
Joined: Wed Dec 25, 2013 4:18 pm
B190 Year: 1990
WBCCI: 0

12V Fridge connection

Post by slapthecat »

I'm upgrading the fridge in my 1990 to the Dometic 2354 3way fridge. What has anyone done about getting the 12V line to the fridge?

From what I've read, the 2354 needs a constant 12V for the electric controls, so I'm thinking I can take a line from the coach battery directly to the fridge. If I run it in 12V mode while driving, the coach battery will be recharged as I go, otherwise it will have the 12V to run the controls for everything else.

Thinking I can take the 12V feed where the coach battery and shore power switch (not quite sure where that relay is on my rig yet...)

Any thoughts?!?
thanks
User avatar
skater
Site Admin
Posts: 2569
Joined: Thu Mar 08, 2007 1:00 am
B190 Year: 1991
WBCCI: 13270
Location: Annapolis, MD

Re: 12V Fridge connection

Post by skater »

If you run one from the battery, be sure to put a fuse on it.

But I'd try to run a new wire from the fuse panel, or even a nearby circuit if you have one. It doesn't draw much power so it shouldn't be a problem to add it to an existing circuit.
1991 Airstream B190 - bought, 2005; sold, 2011; bought 2017
1995 Airstream Excella 30' trailer

WBCCI #13270, Washington, DC Unit
Mgittrich
Seasoned Traveler
Posts: 103
Joined: Wed Jul 24, 2013 9:01 pm
B190 Year: 1993
WBCCI: 0

Re: 12V Fridge connection

Post by Mgittrich »

I just removed my microwave to replace it. Now that it is out I can tell you that there are a lot of wires where the microwave was. I'm sure you can find an existing circuit and ground there. I'm assuming your microwave is located directly above the fridge. This would be the easiest place to grab a continuous 12v circuit. A likely candidate would be the circuit used for the heater, range fan, and outdoor light near the side door. I believe the wire color is blue, at least in my 93, and it is fused in the converter. According to my owners manual the existing amp draw is around 5.5 amp and the circuit is fused at 15amps so anything you add should be ok.

Mike
slapthecat
Seasoned Traveler
Posts: 130
Joined: Wed Dec 25, 2013 4:18 pm
B190 Year: 1990
WBCCI: 0

Re: 12V Fridge connection

Post by slapthecat »

The fridge is just about mounted - working on re-routing a few wires... fun!

What I'd like to do is add a circuit to the DC converter to run to the fridge. Where I'm stumped is how to add a circuit to the DC converter! Mine has 4 (or 5?) fuses mounted with a wire connected to each - where do we get additional terminal blocks to add another circuit? What am I missing here?!?
EricZ
Weekend Camper
Posts: 51
Joined: Sat Apr 21, 2012 9:07 pm
B190 Year: 1993
WBCCI: 0

Re: 12V Fridge connection

Post by EricZ »

In my 1993 Airstream 190, the stock 12v house-battery fuse panel had quite a few circuits, including a few that were unused.

When I upgraded to a more modern converter/charger, it included a nicer drop-in replacement fuse panel that had even more circuits. I'll never need them all.

If I recall correctly, however, I solved the problem you're addressing by making a "dummy relay" that was always on, feeding power to the existing fridge circuit even when the ignition was off. I pretty much never run my fridge on 12v, so there's no risk in my case of leaving it on 12v and draining my house battery. And by running a separate circuit, your doing essentially the same thing anyway (if I understand you correctly).

If I recall correctly, for the dummy relay I popped the cover off a standard Bosch relay (the same kind of relay that was there before) and wedged something to hold the contacts always on. I then put the cover back on, clearly marked it as "Always On" (so I don't later try to use it in place of a functional relay), and plugged it into the original relay socket.
Mgittrich
Seasoned Traveler
Posts: 103
Joined: Wed Jul 24, 2013 9:01 pm
B190 Year: 1993
WBCCI: 0

Re: 12V Fridge connection

Post by Mgittrich »

In my 93 I have a 5 pin relay.

Terminal number 87 is hot when the ignition is running. The b190 uses this terminal to power the fridge.

Terminal 87a is hot when the ignition is not running.

To create an always on circuit you should be able to wire 87 and 87a together and use the existing wire running to the 12v element. Alternatively you could simply splice the wire attached to 30 to 87 and remove the relay altogether.

This link on relay basics may be of help to you

http://www.teamrocs.com/technical/pages ... basics.htm


Mike
slapthecat
Seasoned Traveler
Posts: 130
Joined: Wed Dec 25, 2013 4:18 pm
B190 Year: 1990
WBCCI: 0

Re: 12V Fridge connection

Post by slapthecat »

The Resolution:
I am planning to do the converter upgrade in the next month or two, so I did my work anticipating that.
I ran a new wire from the converter box (taking a feed directly from the battery + cable, which will be moved to its own circuit on the new DC board) to the fridge 12V+. I ran a new ground wire from the fridge 12V- to the coach battery. Made sure to wrap and cable tie everything nicely inside and out.

There was a pre-existing hole in the floor of the van under the couch that I used to get the 12V+ out from the converter. I added a hole just behind the wheel well to get wires to/from the fridge compartment on the passenger side. Also used this hole for the new fridge's drainage hose.

Did my first weekend camping with the new Dometic 2354 a few days ago, utilizing 12V, 120V, and propane along the way. Everything worked great!!!
Post Reply