Solar/12v AC/DC Refrigerators

[Happy Camper Vintage]

Newbie to this forum!! I'm restoring 3 vintage trailers and have pulled all of the old propane refrigerators out. I'm planning to replace them with 2 way AC/DC ones. Does anyone have any experience with SunStar/Voltray or Unique brands of these types of fridges?

 

[Kevin D Pem]

Nice to have you here. I am into vintage, what years are your trailers?

 

[Happy Camper Vintage]

Thanks! I have a ‘63 Kenskill, and 2 Shastas - a ‘73 and ‘76.

 

[Kevin D Pem]

cool! So you have been at this for a while. I take it there is no way to salvage and use the original refrigerator, to bad.

To date I have had 56 terry, 58 vagabond, 73 streamline(looking at 72 right now), built from flatbead 60 seista(long story), and am now working on 83 alpinelite fifth I also live in.

Although restored value is higher if original equipment is kept, vintage trailers are a blank slate. I incorporate nowadays solar, low freq low voltage inverters, and 115vac appliances. My choice fridge at this moment is the 7cf avanti fridge. I like 115vac appliances for a reason, they all have consumer tags to let you know how they compare. I do not care how much power is used to cooI the fridge when running, do care how long it takes before the next cycle. That tag tells me a lot.

my seista had an almost 4cu refrigerator in it. minumum solar was 460 watts to keep everything running. The fifth lost one of my solar controllers leaving me with 280 watts. However the 7cf refrigerator and TV, and computers, and tablet, all run without a hitch on the one 280watt panel while I wait for a new controller for the other panel. Also a big factor is 115vac appliances are much cheaper.

 

[Happy Camper Vintage]

I guess I haven't figured out enough about solar yet to know if I need a 12v specific fridge or a more expensive inverter for a cheaper fridge. I just replaced the converter and got 2 6v Crown AGMs to start. Would like to be able to run on solar as necessary when boondocking or possibly full time down the road. This one in particular that I'm putting solar on will need to pull quite a load. The other campers are smaller.

 

[Kevin D Pem]

What do you consider quite a load.?

 

[Jim]

I guess I haven't figured out enough about solar yet to know if I need a 12v specific fridge or a more expensive inverter for a cheaper fridge. I just replaced the converter and got 2 6v Crown AGMs to start. Would like to be able to run on solar as necessary when boondocking or possibly full time down the road. This one in particular that I'm putting solar on will need to pull quite a load. The other campers are smaller.

Keep in mind that the inverter will draw power and generally the larger the inverter, the larger the draw. When you're calculating battery reserves, it can be frustrating to see a bunch of power going nowhere except to have the inverter sitting around on standby.

Good luck, and Welcome to RV Forums!

 

[Kevin D Pem]

Keep in mind that the inverter will draw power and generally the larger the inverter, the larger the draw. When you're calculating battery reserves, it can be frustrating to see a bunch of power going nowhere except to have the inverter sitting around on standby.

Hi Jim,
Your comment is true for older inverters and cheap new ones. The new ones that use a FM frequency to form the sine wave use a very low amount of energy at standby. My inverter is a 3000 watt inverter and draws less than 1/2 amp on standby (6 watts). Unless I am welding or running my table saw the transformer and switching bridge hardly gets warm enough to start the fan. we know that heat is wasted energy.

Because inverters and controllers are a new breed of animal, and the advantages far outweigh any short comings, It might be better to point out the reasons one might want to go solar. Below is my list.

1. Batteries last longer when maintained by solar. Keeping in mind I am talking off grid.
2. Inverters produce cleaner wave form than generators. Barring the use of inverter generators, Oh yes! inverter.
3. An inverter has better control over under charge condition than most any other means of limiting battery discharge past 50% discharge. With the exception of charge controllers. You can use the circuit on a charge controller with a relay to kill the power to the supply if using 12 volts or?? but the relay uses more power than the inverter.

The down side?
1. You still need propane for heating.
2. Still need a generator for A/C because they are better run through the night.
3. Running a fridge 12 or 115 requires a fair bank of batteries. If well insulated (remember the yellow tag) a fridge can be on a timer to limit night use, saving the battery bank. ( for lead batteries below 80% charge is a cycle). Flooded batteries typically have under 400 cycles by manufacturer labels. you can double that for AGM. Cycling the bank daily requires new batteries every 1.5 years.

 

[Jim]

Your comment is true for older inverters and cheap new ones. The new ones that use a FM frequency to form the sine wave use a very low amount of energy at standby. My inverter is a 3000 watt inverter and draws less than 1/2 amp on standby (6 watts). Unless I am welding or running my table saw the transformer and switching bridge hardly gets warm enough to start the fan. we know that heat is wasted energy.

I mention it only for consideration when sizing the battery bank. I don't know what model battery she purchased, but if (for example) the 2 batteries in series provides her with 225 amps, and she adheres to the 50% discharge limit, she will have approx 115 amps to draw from.

At 1/2 amp draw from the inverter, she'll loose 12-15 amps a day. A 3-day camp trip at 15amp a day = 45Amps, or almost 40% of her storage.

On my last RV, I installed a 2,500 watt, Ames inverter that drew 4+amps an hour and it hurt to add that all up over a 3 day camp trip. Yes, it had a sleep mode that only pulled about 1/2 amp, but that wasn't enough power to keep the clock on the microwave running.

As I said, I mention it only because it should be included when sizing the battery bank. The type of appliances she chooses to run and the number of items she uses, and the amount of time the inverter will be on, will all have to be factored in when choosing the best solution.

 

[Kevin D Pem]

I mention it only for consideration when sizing the battery bank. I don't know what model battery she purchased, but if (for example) the 2 batteries in series provides her with 225 amps, and she adheres to the 50% discharge limit, she will have approx 115 amps to draw from.

At 1/2 amp draw from the inverter, she'll loose 12-15 amps a day. A 3-day camp trip at 15amp a day = 45Amps, or almost 40% of her storage.

On my last RV, I installed a 2,500 watt, Ames inverter that drew 4+amps an hour and it hurt to add that all up over a 3 day camp trip. Yes, it had a sleep mode that only pulled about 1/2 amp, but that wasn't enough power to keep the clock on the microwave running.

As I said, I mention it only because it should be included when sizing the battery bank. The type of appliances she chooses to run and the number of items she uses, and the amount of time the inverter will be on, will all have to be factored in when choosing the best solution.

I got you. I only wanted to give the upside as well to a complete system. To point out Your example even a modest panel will add more than the inverter will waste in any given day, even if the sun don't shine. Remember also she wants to use electric fridge and will have to add power to the bank just to make it through. No matter what type she uses.

All the information she can get will help her in making her choices.