3 Way Power on Fridge?

[fansill]

Good Morning All,

I was scanning through some older posts about fridge operations and had a question. Years ago on our 1976 Winnie, the fridge could run on Propane, Shore Power, or DC. Our next 3 RV's only had the first two options for power. Why don't they offer the DC option on newer coaches?

Just curious....

Faith

[KJINTF]

I would guess that the current draw from a 12Vdc source is very high and could easily drain even the largest battery system. Costs money to add the 12Vdc heating coil to the refrig and the extra fuse and heavy duty wiring to the coach. Most coaches run the refrig on propane plus have a large inverter or shore power to supply the 110Vac.

Bottom line cost the manufacturer money

[stuhly]

We had a Georgie Boy years ago that had that feature. It was unbelievable how fast Refig on 12 volt would kill the batteries

[wa8yxm]

Quote:

Originally Posted by KJINTF I would guess that the current draw from a 12Vdc source is very high and could easily drain even the largest battery system. Costs money to add the 12Vdc heating coil to the refrig and the extra fuse and heavy duty wiring to the coach

Very good guesses, Very very good in fact. Plus one more issue NOTE that this all affects the "Bottom line" as well.

In days of old Gas engines (And Diesels) had GENERATORS, not alternators, Now, I would rather not go into all the differences but it was around 1960's that they came out with the first Alternators.

Generators were kind of hard to kill, for one thing the regulator controlled the maximum current they put out, and did it very well.

Alternators.... Do not have externl current regulation and thus rely on internal regulation.

They are designed to do a quick recharge of the starting battery.

Providing over 300 watts (roughly 30 amps) constant load to the fridge. Not really in their design spec.

Early alternator failure was one side oe effect of the 3-way Fridge.

But the 6 to 8 G wire is a high cost item too.

[Gary RVRoamer]

It's the size of the fridge, which in turn dictates the size of the 12v heating element needed to operate the cooling unit. They still make 3-way (12v) fridges, but only in smaller sizes, up to around 4-5 cubic feet. Most RVs of more recent vintage have bigger fridges that are impractical to operate from 12v - too much power draw.

Besides, propane is a very efficient way to provide the required heat.

[TXiceman]

Larger frigs now and also DOLLARS.

ken