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Discussion Starter #1
First conversion is going well. Time for ELECTRICITY! I am a novice so I welcome any feedback on my design. I have a simple system because I'm going to use propane for most heavy power things (cooking, fridge, heat, water heater). My biggest questions are... is my wire sizing ok? do i need a battery kill switch on the power input side (solar, alternator, shore)?

Thank you. This forum has been such a great reference, you all have so much knowledge.

63306
 

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  • Starter battery should be fused.
  • Solar could be fused.
  • Future inverter should be fused.
  • Could be 10awg to solar, maybe even 12.
  • DC loads after panel could likely be 16, maybe 18 but I wouldn't actually go smaller than 14awg to save future headaches. The smaller stuff gets fragile.
  • Depending on length of runs, some of the other 8awg may want to be larger. 8awg is minimum for 40a
 

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Discussion Starter #4
Thank you. When you say starter battery and solar should/could be fused, I'm guessing you mean before the charge controller?

I have a big roll of marine grade 12awg, as I understand it will not hurt anything to use that to all my dc loads?

I will switch most of those 8awg to 6.

  • Starter battery should be fused.
  • Solar could be fused.
  • Future inverter should be fused.
  • Could be 10awg to solar, maybe even 12.
  • DC loads after panel could likely be 16, maybe 18 but I wouldn't actually go smaller than 14awg to save future headaches. The smaller stuff gets fragile.
  • Depending on length of runs, some of the other 8awg may want to be larger. 8awg is minimum for 40a
 

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Discussion Starter #5
No one (in their right mind) uses a propane fridge these days. Go with native 12v and do it correctly.
I just want to be as off grid as possible as easily as possible so was planning on getting a 3 way fridge but only hooking up propane and 12v. Propane just seems so cheap and easy to find anywhere vs upping $$$ my battery and solar.

But thank you for the feedback, I will relook at options and how quickly a pure 12v fridge will drain the battery.
 

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I just want to be as off grid as possible as easily as possible so was planning on getting a 3 way fridge but only hooking up propane and 12v. Propane just seems so cheap and easy to find anywhere vs upping $$$ my battery and solar.

But thank you for the feedback, I will relook at options and how quickly a pure 12v fridge will drain the battery.
The problem is the performance. It takes a long time for propane fridges to cool off things added to the fridge, they also struggle maintaining temperature control when it gets hot.

You NEVER want to run a propane fridge on anything but propane, the two or three way functionality is terribly inefficient. There was a time when propane fridges were the best you could do off grid, those times are past. This was a time when a good price for a solar panel was $4 a watt or more. Now you can get a 12 volt compressor fridge and run it off a single 100 watt panel in the summer and a 200 watt panel will most likely do it in the fall and winter.

Get a little more solar and a 12 volt fridge and you will be much happier. you can thank me with a cold beer that you can chill in that fridge in less than 2 hours instead of 5 or more.

Solar is a one time cost while buying propane is ongoing, but that isn't the reason I am suggesting a compressor fridge. They are better in just about every conceivable way. Cool faster, more efficient, more powerful cooling when really hot. They also don't need to be vented outside.

I had a propane fridge in my last class B rv. It was completely functional and I tore it out to use an ice chest instead. When I wanted to use the RV it took most of a day to get cold. In the hot summer I had to drink coolish beer. It wasn't malfunctioning, it just is designed for a constant load. An RV is not the ideal place for a propane fridge, they are well suited to an off grid cabin in the woods, and they are quite reliable, so I am not against them entirely, but they are a bad idea for a camper van.
 

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Yes. Fuses before the controller, especially the battery. Best practice is to fuse everything. Some don't fuse the solar. Most quality controllers are okay with a wide range on the solar side and will mostly 'ignore' excess. Switches are for convenience. Could use breakers as a two birds solution.

If you already have the larger wire, that's definitely your cheaper option than buying more. You can always use larger wire than necessary. Smaller than required can lead to failures and fires.
 

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Hi,
I've had propane fridges on past RVs and they are a major pain.
Van has to be level for them to work.
They are so slow to cool down that it can take hours before you know if you have leveled the van well enough for the fridge to work.
Big holes in the side of the van for the air intake and outlet.
In electric mode, they use SO much juice that you can't really run them except on shore power.
I was so, so happy to be rid of a propane fridge on our current van conversion.

An efficient 12 volt compressor fridge takes about 40 amp-hrs out of your battery in 24 hours -- not really hard to plan for and easily supplied by solar if you want extended off grid time.


Some thoughts on your electrical ..
So, your shore power connection is only used to power that small (7 amp) CTEK battery charger? This is an unusual setup -- most people want to be able to use the shore power connection to run 120 VAC appliances inside the van. In yours, the 120 VAC appliances inside the van would only be run off the inverter -- this would work, but is unusual. The charger size is also small -- most people use a charger rated at 20 or 30 amps. If your battery needs 70 amp-hrs of charging, its going to take 10 hours+ on the charger.
The way I read the specs, the CTEK charger only provides 7 amps charging, so not sure why you need a #8 wire and 40 amp fuse in that line? Seems like it could be smaller -- #14 ish?


I would look into an inverter/charger -- this combines the inverter and the battery charger into a single unit. It simplifies the wiring, and it handles the safety issue of changing where the ground is bonded to the neutral when you go from shore power to inverter power. In your diagram, the inverter/charger would replace the CTEK 7002 charger and the inverter.


The 125 amp-hr battery seems kind of small. Only about 60 to 70 amp-hrs of this is usable if you want descent battery life. If your loads are small, this might be OK. But, if you go with a 12 volt fridge, you will need more battery.

On the wire runs where a battery is the source of the current (eg the ones to inverter and to the DC panel), the fuse/breaker should be as close to the battery as possible. This protects against a short to ground along the wire.

One of your 12 volt loads on the 12 volt fuse box is a water heater. This could be a large load depending on what kind of water heater it is? This might make the 40 amp fuse coming into the 12 volt fuse box to small? This fuse (and wire) should be good for the sum of all the 12 volt loads you expect to use at the same time plus a bit of margin.
The 12 volt water heater also makes your 125 amp-hr battery seem a little small again? Heating up 5 gallons of water from 50F to 120F takes about 900 watt-hrs, or about 75 amp-hrs.


Gary
 

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Discussion Starter #9
Thank you JRacca! Great information. I will share a beer or 3 with you anytime.

Looking at 12v fridge options i'm now torn because most look like they are coolers and it will blow my layout design because a tall skinny fridge would fit sooooo well. Can you recommend a 12v fridge that is designed more like a fridge than a cooler (ie tall not wide)?


The problem is the performance. It takes a long time for propane fridges to cool off things added to the fridge, they also struggle maintaining temperature control when it gets hot.

You NEVER want to run a propane fridge on anything but propane, the two or three way functionality is terribly inefficient. There was a time when propane fridges were the best you could do off grid, those times are past. This was a time when a good price for a solar panel was $4 a watt or more. Now you can get a 12 volt compressor fridge and run it off a single 100 watt panel in the summer and a 200 watt panel will most likely do it in the fall and winter.

Get a little more solar and a 12 volt fridge and you will be much happier. you can thank me with a cold beer that you can chill in that fridge in less than 2 hours instead of 5 or more.

Solar is a one time cost while buying propane is ongoing, but that isn't the reason I am suggesting a compressor fridge. They are better in just about every conceivable way. Cool faster, more efficient, more powerful cooling when really hot. They also don't need to be vented outside.

I had a propane fridge in my last class B rv. It was completely functional and I tore it out to use an ice chest instead. When I wanted to use the RV it took most of a day to get cold. In the hot summer I had to drink coolish beer. It wasn't malfunctioning, it just is designed for a constant load. An RV is not the ideal place for a propane fridge, they are well suited to an off grid cabin in the woods, and they are quite reliable, so I am not against them entirely, but they are a bad idea for a camper van.
 

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Discussion Starter #11
Thank you Gary!

Yes, I agree I should probably up the battery charger but I don't see using it very often and I don't plan on running very many 120v appliances. Its mainly there to keep the battery charged while in my garage. I have a few years until I can live in this full time so setting it up as a 3-5 day vehicle right now that I will use every couple weeks or so.

The inline water heater is propane, just needs a small 12v load for the controls. I should have been more clear.

Thanks for the other electrical advice!


Hi,
I've had propane fridges on past RVs and they are a major pain.
Van has to be level for them to work.
They are so slow to cool down that it can take hours before you know if you have leveled the van well enough for the fridge to work.
Big holes in the side of the van for the air intake and outlet.
In electric mode, they use SO much juice that you can't really run them except on shore power.
I was so, so happy to be rid of a propane fridge on our current van conversion.

An efficient 12 volt compressor fridge takes about 40 amp-hrs out of your battery in 24 hours -- not really hard to plan for and easily supplied by solar if you want extended off grid time.


Some thoughts on your electrical ..
So, your shore power connection is only used to power that small (7 amp) CTEK battery charger? This is an unusual setup -- most people want to be able to use the shore power connection to run 120 VAC appliances inside the van. In yours, the 120 VAC appliances inside the van would only be run off the inverter -- this would work, but is unusual. The charger size is also small -- most people use a charger rated at 20 or 30 amps. If your battery needs 70 amp-hrs of charging, its going to take 10 hours+ on the charger.
The way I read the specs, the CTEK charger only provides 7 amps charging, so not sure why you need a #8 wire and 40 amp fuse in that line? Seems like it could be smaller -- #14 ish?


I would look into an inverter/charger -- this combines the inverter and the battery charger into a single unit. It simplifies the wiring, and it handles the safety issue of changing where the ground is bonded to the neutral when you go from shore power to inverter power. In your diagram, the inverter/charger would replace the CTEK 7002 charger and the inverter.


The 125 amp-hr battery seems kind of small. Only about 60 to 70 amp-hrs of this is usable if you want descent battery life. If your loads are small, this might be OK. But, if you go with a 12 volt fridge, you will need more battery.

On the wire runs where a battery is the source of the current (eg the ones to inverter and to the DC panel), the fuse/breaker should be as close to the battery as possible. This protects against a short to ground along the wire.

One of your 12 volt loads on the 12 volt fuse box is a water heater. This could be a large load depending on what kind of water heater it is? This might make the 40 amp fuse coming into the 12 volt fuse box to small? This fuse (and wire) should be good for the sum of all the 12 volt loads you expect to use at the same time plus a bit of margin.
The 12 volt water heater also makes your 125 amp-hr battery seem a little small again? Heating up 5 gallons of water from 50F to 120F takes about 900 watt-hrs, or about 75 amp-hrs.


Gary
 

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Lots of cheap chinese 12v compressor fridges now available on amazon and elsewhere...i have not used one.

The propane solenoids use a lot of power, they have to be "on" for propane to flow. I think turning propane on/off with a valve is better.
 

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I just want to be as off grid as possible as easily as possible so was planning on getting a 3 way fridge but only hooking up propane and 12v. Propane just seems so cheap and easy to find anywhere vs upping $$$ my battery and solar.

But thank you for the feedback, I will relook at options and how quickly a pure 12v fridge will drain the battery.
Just triple that solar and battery pack and you should be fine. It is far to small to be useful for real off grid use with a propane or electric fridge.
 

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That;s a good idea to buy a 2nd "fridge" to use as a freezer. Maybe I will buy this one and try it, only bring the "freezer" on longer trips. This is especially important to us this summer since we are not eating out. Van with freezer allows us to go away for 9 days or more and not need to buy anything on the road but gas... It could be wired to only run when the engine is running and likely stay freezing as well.

125 AH should be more than sufficient with those accessories if you drive a little everyday. I have 100ah and similar use and find driving at least 30 min a day is sufficient. If you plan to stay put for days at a time you need more battery. The AGM bulk charge rate from the alternator is 30-50 amps so just a little driving every day keeps the battery at 90% or more. Due to our activity preferences/camping style we never keep the van sitting for days on a trip unless van is parked at a trailhead and we're backpacking or something and then just enough solar to keep the fridge running is needed.

 

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I agree with the others regarding the 12v fridge

I have an ARB in our van & 1 in our cabin. We have 1 - 100W solar panel @ our cabin & a 130Ahr battery. The solar panel keeps the battery charged for the fridge use

I have tested these ARB fridges & they get down to minus 18 C, so could be used as a freezer

The TF130 uses the same compressor as the ARB, so I would assume it is also very efficient on 12v

Cooking, Heating, Hot Water I think propane is a good option. But best to go 12v for the fridge
 

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Thank you JRacca! Great information. I will share a beer or 3 with you anytime.

Looking at 12v fridge options i'm now torn because most look like they are coolers and it will blow my layout design because a tall skinny fridge would fit sooooo well. Can you recommend a 12v fridge that is designed more like a fridge than a cooler (ie tall not wide)?
Truckfridge has models that are 15 inches wide and are quite efficient. I have one sitting on the bed in my van that I will be installing tomorrow. It is replacing a chest style. I know a lot of people like the chest style, but with my layout it takes up floor space I don't have. (I know because I am remodeling after using a chest style for 9 months in this van) I have two chest style fridges and one is an ARB50 which is being used as a freezer at home during this coronavirus thing and a smaller dometic unit (CDF11), which I may carry as an extra freezer and just keep it in the rear storage area. This way I have one fridge (TF49) and either my ARB or Engel as extra fridge or freezer depending on need.

I am not sure how tall you are looking for and how much space you need. What I have also seen done is stacking two small units on top of each other such as the engel units, You can have two freezers, two fridges, or one fridge and one freezer. But that is an expensive solution to be sure.
63349

Truckfridge 15 inch wide units are the tf 49 and tf78, with the 78 being the taller of the two as it is 34 inches high and holds 86 liters, versus the tf49 which is about 21" high and holds 49.5 liters. You won't find many fridges much narrower than than 15 inches in either compressor or propane. What model were you considering for a propane fridge?

You don't have to size based on the worst case scenario. I also keep a soft sided cooler bag that collapses to almost nothing in my van that can be used to carry drinks down to the beach, park, etc, but can also keep some extra food on ice for a few days if needed. Buying a bag of ice every now and then is better than taking up space you don't need with a fridge that stays empty most of the time. My use case doesn't justify a larger fridge. Most of the time I used the 11 qt dometic.
 

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The weather can have a large impact on refrigerator power use. Summer temperatures in this area can easily double the power consumption compared to other seasons.

When I suggested buying 2 of them, I meant the 130 liter units, not the little ones. That way you can put things like coffee, break, potato chips, spices, paper plates, etc in either the refrigerator temp one or the freezer temp one. Anything in any way food or cooking related.

It routinely hits 100 - 105 F here all summer (even hotter in the van), so items that I might normally have in a cabinet / pantry in a house would go into the refrigerator of freezer.
 
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