sabconsulting wrote:
DWeikert wrote:
sabconsulting: I'm not sure the wiring is that critical. #14 wire should be sufficient even if the batteries are on the opposite side of the camper from the fridge. Average current draw on my model is under 4 amps. I can't imagine the startup surge being enough to need more than 14 gauge.
When I fitted my CR140 I wired it into the same wiring that had been running my absorption fridge - on turning on the power nothing happened - no lights inside, nothing. Went through a couple of control units until their support engineer suggested trying thicker cable. As an ultimate test I used a jump start cable direct to the battery to see if it worked and it did. It actually sparks when you connect it up due to the current draw as the capacitor charges.
Turned out that the fridge power was not running directly from the battery, but was going via the 7-way connector at the back, so probably nearly 20ft of cable between the two. I replaced it with a thicker gauge of cable directly from the battery and it then worked fine.
The issue is not the average current draw, but the instantaneous current draw when first powered up, combined with the unit's battery protection circuitry. Charging that capacitor via a long cable causes a voltage drop to under 11.5 volts for a few milliseconds, enough for its battery protection circuitry to shut the whole thing down.
Not sure what gauge of cable I used in the end, but it was just a bit thicker than the cable Shadow Cruiser originally used (they seemed to use the same cable size for everything).
My report on installing a Waeco CR140
Steve.
Thanks for the followup. Not sure what size wire Northstar used in my camper but when I went to pick it up they had mistakenly installed an absorption fridge and they just swapped it out with the correct unit using all the same wiring. Also, my fridge is about as far away from the camper batteries as it can get and still be inside the camper. I can imagine the startup surge causing a drop in light wire, especially if it takes a circuitous route with maybe one or two less than ideal connectors along the way. I do agree that you need a reasonable size wire to handle the surge, but I just wanted to clarify that you don't need to go to down to 4 or 6 to handle the load. 12 or 14 should be sufficient. IMHO of that is.
PS: My cr1110 has a low voltage cutout at 10.5v. Something I hit too often before I added the second solar panel.
