110 Volt Fridge

[Blue~Go]

I did the same as you, Hoosier, but opposite: I cut a hole in the wall between the refrigerator compartment (where I'm putting my refrigerator) and the lower stove compartment so that I could get the remote compressor in there if I wanted to. If I don't put the compressor there, no harm done, as it will just be insulation board on the 'fridge side, and drawers (or oven) on the other side.

I really like that I can just insulate the WHOLE box, not worrying about compressor air flow (at the refrigerator box). Boats often have remote compressors.

Scott: I'm sure it would not be nearly as dramatic, but one time I had to drive across the Mohave in summer without working air-conditioning (at least I was driving to my favorite A/C shop!). It was almost hotter with the windows open because it would just suck hot air in from the forward regions. Not that there are any big gaps in my doghouse seal, but.... it's just HOT up there. If I closed the windows and ran the dash vents/fan instead, that "wall of heat" didn't come in.

That said, I'm SURE that two open front windows driving 65 mph are about a hundred times more negative pressure than a wee little passive fridge vent. But I guess just by nature I'm suspicious of possible negative pressure while driving (specially on dusty roads). Of course your variable scheme addresses that.

I do have a BD35 running now, albeit cooling a smaller box (but that box has virtually no insulation, being a cooler shaped unit). It was only when I was temporarily trapped in 105º temps that I really didn't want any added heat of that volume (small). I actually ended up shutting off the refrigerator, but that wasn't due to heat put into the rig, but rather I felt bad for it trying to run with 105ºF intake air! Just didn't want to put the strain on it. And I'm rarely in hot places that are also rainy so I can't open windows.

If the roof vent weren't already there, I'm sure there's NO WAY I'd be adding one. So that kind of makes me just want to cover it up and use inside venting. But it is there! So until the day comes to actually install the Vitrifrigo, I can go back and forth at will, consider all schemes, etc. It's not waffling if you're not even supposed to be making a decision yet, right? Why no, it's just thoughtful planning

[HoosierB]

So the recommended hookup is a direct connection from AC/DC fridge to the batteries? Bypass the "brown box" circuit altogether? What type of setup (distribution post/fuse block or whatever) is used and where?
My original plan was to install a shorter route under the chassis from fridge to original lug in the brown box with a larger gauge wire. Even use the OEM fridge wire terminal above the gen-set box for the ground connection.

[Blue~Go]

I did some research into that, including speaking with engineering dept. at Danfoss. Because of course if you follow the instructions of every electronic item that tells you to connect right to the battery you will have, a) four million lugs on your battery posts, and b) a lot of unfused or improperly fused wires. So you have to figure out (or find out) what they really want.

In this case, what they really want is a quality electrical supply with very little voltage drop, and no spikes or surges when other things come on or off.

I have already removed my brown box, but there is no way I would have wired my expensive refrigerator (with expensive, electronically controlled compressor) to it. Not because it's a brown box, but because that brown box has about 30' of 8AWG wire going to (and from!) the batteries which also handles all the charging and every other load for the brown box. That wire run alone (IF it were ONLY supplying the fridge) is at their absolute max spec (due to voltage drop). But of course it's not alone. It supplies everything else! And then if one were to run another wire from there to the fridge, it'd be close to ANOTHER 30' (like say if one were to use the original 8AWG refrigerator wire). Ugh!!!

Since I already have a more robust distribution center (essentially heavy bus bars right by the batteries), I'll just run dedicated cables to a fuse there that only serves the refrigerator (that means either fairly heavy cabling if I go "around the horn" or somewhat lighter cabling if I cut across under the rig, which is probably what I will do).

But if I were keeping the brown box? Hmmm. Well, I wouldn't. But let's say I did. Choices:

1) Run heavier cabling from the brown box to the battery area (along wall behind couch, in loom). So heavier cable, shorter run (can be determined by calcs what best size for length is).

2) Properly fuse the batteries.

3) Run heavy duplex cable (consult voltage drop calcs) from brown box under rig over to refrigerator area on its own dedicated circuit (it does already have its own fuse on the brown box).

Or you could run heavy cable under the rig right to the battery area (adding fusing/bus bars/power post/etc. as necessary).

That electronic controller wants to see nice, steady power, and no low voltage (either from low batteries or from voltage drop). That's the key as I understand it.

I actually even took steps with my two portables (which both run the Danfoss BD35 compressor). They give you a skinny (14 gauge?) long cord with a cigarette lighter end. Then of course you have "your" wire from the cigarette outlet to wherever it goes. What could possibly go wrong?

I kept the portable cords just in case I should need one, but then made my own cords with 10AWG duplex cable (I have one portable in the Chinook and a smaller one in the car). I hard wired both of them to a fused bus bar/power post. Now they don't do funny things due to voltage drop and I imagine the compressor controls should last longer. If I do need to use them in a true portable configuration, I have the regular cords. And no more cigarette plugs vibrating loose on bumpy roads either.

[Mbelse]

Don't get me wrong an inverter has several good uses. It is just odd to me to basically take power, and down change it several times to what I consider a core system (the fridge). If the inverter fails or goes on the blink the fridge which wouldn't go down now would. It just feels odd to me that's all Almost all inverters I have seen draw current when on even if they aren't supplying power. Again only my opinion but a constant loss of 2-5W is a bit high and avoidable.

There is also the possible issue that 110v fridges may not be optimised for van use whereas a 12v naturally is.

As I said I have an inverter and a mains hookup so I am not against them but I made the decision from the outset to use the mains to supplement the 12v systems and support them rather than relying on it. I also decided to heat the van using a diesel air heater as I had one spare and use gas to cook with. Jury is still out on how we plan to heat water when a solar water heater won't play ball in the colder months.

For reference I have run a 12v fridge all day every day since last year in our van powered by the house battery and solar cells. Not had any issues with running the house power out. I am based in the U.K. so it's not like we get an abundance of sun and heat. I have the 200A alternator on a split charge marine spec system that diverts 50A peak from the engine to the house systems when we are running the engine. The alternator is designed for this load so there is no issue there.

I do like the idea of taking a domestic fridge like this and installing a decent 12v Dan Floss compressor in it and stripping out the 110v unit though. Our local fridge service place would do that if I asked (they rebuilt and gassed ours last year). Then you get a huge fridge at low cost with the advantages of a 12v supply system.

[pdemarest]

My rig has been mostly sitting since our big May trip to Yellowstone/Black Hills. In order to see if I could get my freezer down below 12 degrees I've been experimenting with a sheet of bubble foil that I had left over from making sun shields for my windows. I inserted the sheet on top of the water tray that sits directly under the freezer. The refrigerator section gets all of its cold from the bottom coils of the freezer. After a series of trial and error I managed to find a dimension for the bubble foil that fits in the water tray and blocks most of the bottom of the freezer coils. By turning up my temperature control from 3 to almost 5 I now have a freezer that is at 0 degrees and a fridge at 34. Yes, the compressor has to run more but the freezer being at only 12 degrees prior to this was not acceptable. We found that frozen foods started to taste a little "off" after being in the freezer for over a week, even though the unit would still freeze ice cube trays, and ice cream would be practically liquid. I went on a government website (USDA?) and found that frozen foods have to be kept at 0 degrees or they start to spoil after two weeks. So, I finally have a freezer that functions well without freezing everything in the refrigerator section. Look for me in the ice cream aisle loading my cart with Hagen Daas!!!

[Blue~Go]

Yay! Many of these units use a "spillover" system to cool the fridge, so you get that problem (that you have now solved).

Which campsite do we come to for the ice cream?

[chin_k]

I think Paul only want to see us in the cashier lane to hand over our wallet to pay for his ice cream.

[pdemarest]

Hey Chin_k - that would be most appreciated!

[eporter123]

I just moved an old 110 V dorm fridge to the garage. It came with my ambo back when I bought it, as the PO had it hooked up to the existing inverter. I'll eventually go to a dual battery & solar panel setup on the Chinook, so maybe I'll just build around the dorm fridge. Why not?!

[pdemarest]

Hey ereporter - I think you'll enjoy the switch to an electric fridge, even if its a 110 volt only. The primary advantages are that the unit will actually keep food cold even when the outside temperatures are in the 100s plus you don't have all the drama of "will it start up in LP mode?" and "do I really want a small fire going inside my rig?" or "I'm low on LP so do I run my heater or my fridge?" A dorm fridge should be a pretty low draw so it should work as long as you get sufficient battery power and solar panels to feed them.