diy solar

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going all electric on travel trailer - fridge, stove, water heater

aaryno

New Member
Joined
Jul 10, 2021
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8
after a propane fire we have ditched the tanks and are converting all electric with our 400w (so far) and 100 Ah lithium (so far). the plan is to upgrade batteries first and solar second after we get appliances but so far i’m not sure what to get. especially for hot water…

here are my picks so far. i’m having a hard time
calculating the loads for these but i figure i’m using ~5A for the fridge 24/7. thoughts?

portable induction cooktop $350
https://www.campingworld.com/portable-induction-cooktop-200-115225.html

12v fridge $990
https://www.campingworld.com/furrion-10-cu.ft.-built-in-12v-refrigerator-stainless-steel-125371.html

hwh $600 https://www.campingworld.com/dometic-wh-9gea-6-gallon-xt-water-heater-gaselectric-121677.html

appreciate any guidance about what to expect or how to search for these and size out the electric.
 
Do you plan to camp primarily off-grid? Or are you mostly plugged in with an occasional one night without power?
 
The site doesn’t say what kind of fridge that is. For $900 since you’ll already have an inverter for other stuff WHY not get a 120V fridge? And if you’re ditching propane why purchase a combo water heater?

I’d just fix whatever went unmaintained and stay with propane. Use a tankless water heater. Electric ovens are power hungry
 
Before you get too far down the trail, do a real energy audit. You may be surprised at the size and cost of the battery bank you will need. Totally doable, just not cheap. So figure out what you would really need and then size a bank. If it fits in your budget you are good to go. I see a water heater, what about space heating?
 
disclaimer - the propane issue was traumatic. members of my family were running for their lives away from flames 20 feet high. i know that propane has greater energy density and may be safer as well but there is a line in the sand about not using propane.

to answer some questions:

Q: off grid or plugged in?
A: off grid almost exclusively

Q: space heating?
A: not worried about space heating, at least not now. we live in hot desert and are used to sleeping in a tent

Q: why not get a 110v fridge?
A: this is where you can help me out. i had a propane/110v fridge and switched to 110v running through the inverter after the fire and it drew 28A from our battery and drew it down to nothing in hours. is there a problem with my inverter? it’s a unique 9.8 cu ft fridge from lowe’s. My read on 12v fridges is that they should draw
about 2-6A.

Q: why purchase a combo water heater?
A: i’m having a hard time finding a 12v water heater. open to suggestions!!
 
Q: why not get a 110v fridge?
A: this is where you can help me out. i had a propane/110v fridge and switched to 110v running through the inverter after the fire and it drew 28A from our battery and drew it down to nothing in hours. is there a problem with my inverter? it’s a unique 9.8 cu ft fridge from lowe’s. My read on 12v fridges is that they should draw
about 2-6A.
Any absorption fridge will need 350 watts power at about 70% duty cycle.

Best to look for a replacement residential compressor fridge to reduce the electric energy needed by about 80%. This will still be a large draw and may take all the energy from the first 500 watts of solar to run 24/7.
 
Interesting approach. Sorry to hear about the fire. If you don’t mind, what happened?
 
disclaimer - the propane issue was traumatic. members of my family were running for their lives away from flames 20 feet high. i know that propane has greater energy density and may be safer as well but there is a line in the sand about not using propane.

to answer some questions:

Q: off grid or plugged in?
A: off grid almost exclusively

Q: space heating?
A: not worried about space heating, at least not now. we live in hot desert and are used to sleeping in a tent

Q: why not get a 110v fridge?
A: this is where you can help me out. i had a propane/110v fridge and switched to 110v running through the inverter after the fire and it drew 28A from our battery and drew it down to nothing in hours. is there a problem with my inverter? it’s a unique 9.8 cu ft fridge from lowe’s. My read on 12v fridges is that they should draw
about 2-6A.

Q: why purchase a combo water heater?
A: i’m having a hard time finding a 12v water heater. open to suggestions!!

Understood. I truly believe that propane can be very safe (ex-FF here). But trauma can outweigh logic.

Water heaters are generally 220VAC. For an on demand, most are between 7-11kW. You may be able to find a low flow rate one that pulls a little less. That will be the biggest draw on your list since you aren't going for a space heater. Take a look at your loads and add up a good watt hour estimate. Then we can look at bank size. Since you will be off grid, what are your charging capabilities with your vehicle? If there is any way to do a dual alternator that would be a big help. With the loads you propose, household sized inverters are what you should be looking at. While what you want to do is somewhat ambitious, without AC or heating it is totally doable.
 
Interesting approach. Sorry to hear about the fire. If you don’t mind, what happened?
one of the tanks fell off the tongue while driving. at speed it didn’t ignite but when i stopped, the hole that wore through the bottom ignited and shot up a 20’ flame. my wife reached over the seat and unbuckled our baby and she ran down the highway with jane while our 3 boys ran ahead of her. i ended up falling on the road beside the tank and watched while it burned off, worries the second tank would explode, and when the propane ran out, ran around and secured what i could and stomped out the grass fire in the forest by the road.

we regrouped and decided to limp along without gas and ate out of an ice chest and took cold showers for 3 weeks. ironically, we cooked outside with a second propane stove.
 
Understood. I truly believe that propane can be very safe (ex-FF here). But trauma can outweigh logic.

Water heaters are generally 220VAC. For an on demand, most are between 7-11kW. You may be able to find a low flow rate one that pulls a little less. That will be the biggest draw on your list since you aren't going for a space heater. Take a look at your loads and add up a good watt hour estimate. Then we can look at bank size. Since you will be off grid, what are your charging capabilities with your vehicle? If there is any way to do a dual alternator that would be a big help. With the loads you propose, household sized inverters are what you should be looking at. While what you want to do is somewhat ambitious, without AC or heating it is totally doable.
i have a 2000w renogy pure sign wave inverter now. anticipating this may not be enough for our all-electric life ahead.

i wasn’t planning on charging with the vehicle. i have a generator that give us about 40A.

once i gave up trying to keep the propane/110v fridge going through the inverter we were almost always at 99% with very few draws (a 12v router, some fans, some LEDs). so in terms of balancing the equation and figuring out how much battery bank and solar we need, these three new appliances are all of it.

to be clear i don’t have any electric appliances - i’m trying to get my head around what i need still.

as far as the hot water heater goes, i thought it would be too much electricity to heat the water on demand, so tankless wasn’t on my radar. in fact, i have a tankless propane heater and was curious whether i could convert it.
 
Standard RV water heater that has electric is 1440 watts and will run fine on the inverter and will consume significant power to have hot water. If you have a tank WH with propane only you can add a 400 watt element in place of the drain plug.
 
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Standard electric water heater that has electric is 1440 watts and will run fine on the inverter and will consume significant power to have hot water. If you have a tank WH with propane only you can add a 400 watt element in place of the drain plug.

Wow, I the ones I had seen are a lot more than that but I do see ones out there in the 1.5kW range as you say. That is much better for an RV. I don't think there is any practical way to convert a propane on demand to electric.

I still don't think a 2kW Renogy is what you are going to want. If the fridge turned on while you are heating water you'd have a problem. Plus with an all electric set up I think you want a decent quality inverter as if it fails you have nothing.

So, we still need to start figuring out what your power needs are. Let's say for example you need 1/2 of hot water use per day. 1.5kW *30 mins will be 750 watt hours. Induction cook tops seem to vary in power draw quite a bit and we have no idea how much you cook. We cook full on meals but you may just make coffee in the morning.

The fridge is a little easier. Figure between 50% duty cycle in cool weather and 75% in warm weather. That should get you in the ball park.

Charging is obviously important to go all electric. This depends on how you camp as well as how much power you use. In my van I am not bothering with solar because I move every couple of days and my power use is low so the vehicle does a good job of keeping the battery charged. So look at how you camp and how much you can get from your alternator. The only other options for boondocking are solar and generator. For me, one of the first things I look for in a camping spot it shade. I don't always find any of course but if I can I do. Since you said largely desert then perhaps solar will augment your alternator enough and you can get by like that.

But it all comes down to defining the problem. Do a good energy audit, then figure out how much power you need to produce and store.
 
Taking a better look at the flash heater that I saw, it is 1.41kW output but says 30 amp at 120VAC for current draw, which is 3,600 watts. That seems more believable to me. That would make 1/2 hour use per day come in at 1800wH.
 
Oh, for a tank style heater. That makes more sense. I don't think that a tank style will be very efficient, especially in a camping situation. The less hot water you use, the more power effective an on demand heater is. So in a home that uses hot water a lot the power saving will be less. But in a camping situation where you are using as little hot water as possible due to both water consumption and power use an on demand heater will use much less power.
 
Wow, I the ones I had seen are a lot more than that but I do see ones out there in the 1.5kW range as you say. That is much better for an RV. I don't think there is any practical way to convert a propane on demand to electric.

I still don't think a 2kW Renogy is what you are going to want. If the fridge turned on while you are heating water you'd have a problem. Plus with an all electric set up I think you want a decent quality inverter as if it fails you have nothing.

So, we still need to start figuring out what your power needs are. Let's say for example you need 1/2 of hot water use per day. 1.5kW *30 mins will be 750 watt hours. Induction cook tops seem to vary in power draw quite a bit and we have no idea how much you cook. We cook full on meals but you may just make coffee in the morning.

The fridge is a little easier. Figure between 50% duty cycle in cool weather and 75% in warm weather. That should get you in the ball park.

Charging is obviously important to go all electric. This depends on how you camp as well as how much power you use. In my van I am not bothering with solar because I move every couple of days and my power use is low so the vehicle does a good job of keeping the battery charged. So look at how you camp and how much you can get from your alternator. The only other options for boondocking are solar and generator. For me, one of the first things I look for in a camping spot it shade. I don't always find any of course but if I can I do. Since you said largely desert then perhaps solar will augment your alternator enough and you can get by like that.

But it all comes down to defining the problem. Do a good energy audit, then figure out how much power you need to produce and store.
i can’t address this whole post right now but wanted to quickly point out some facts:

family of 6 with 4 kids and we don’t want to shower that much because it means more water. but there are 6 of us.

we have 400w solar right now and i can add 400 more in the future.

for the sake of a routine, this would be max usage:
coffee in the morning
skillet breakfast in the morning
full dinner in the evening (2 burners 15 minutes)
(no oven)
one shower in the evening

we can skimp on morning breakfast (cold brew, instant, propane grill outside)

we can shower less (attractive since it uses
previous water anyway)
 
one of the tanks fell off the tongue while driving. at speed it didn’t ignite but when i stopped, the hole that wore through the bottom ignited and shot up a 20’ flame. my wife reached over the seat and unbuckled our baby and she ran down the highway with jane while our 3 boys ran ahead of her. i ended up falling on the road beside the tank and watched while it burned off, worries the second tank would explode, and when the propane ran out, ran around and secured what i could and stomped out the grass fire in the forest by the road.

we regrouped and decided to limp along without gas and ate out of an ice chest and took cold showers for 3 weeks. ironically, we cooked outside with a second propane stove.
Fear is a great motivator. I would be afraid of poorly mounted tanks for sure. Afraid of skipping any steps in securing the tanks. Afraid of leaks in the future sure.
electricity can make VERY short work of a home as well… and if safety isn’t followed with electricity, it can kill you without burning anything.

Don’t be afraid of the energy source. Be afraid of poor safety features.

If you do go away from propane for the energy… be ABSOLUTELY CERTAIN each and every safety procedure is followed with the conversion. If something is too expensive… don’t cheap out on safety.
 
Danfoss (compressor name) 12-24v/110v fridges use the least power, just google them until you see the size you want.

This forum has a lot of builds, i like the isotemp water heaters

thanks, that helps, too. this 8 cu ft norcold
DC advertises 5.7A during “standard” mode.


with that and a 4-gal hot water heater like this, https://marinepartssource.com/waterheater-slim-15l-4-gallon-115v-750w-601521s000003
which says it draws 6.5A… i’m not sure how much it would draw over a full day if it were emptied once.

plus the portable induction stove i listed at first (say we run it 20 minutes a day at max power) which lists 1800w output (does that mean it draws ~16A at 110v?)

i can begin to see that i’ll need at least another battery and i’ll have to keep the inverter running all the time to have hot water. i found a calculator on this forum and will plug in these loads when i have access to a computer. https://docs.google.com/spreadsheets/u/0/d/1-KuUF_V-Mmn2sYBIzFw4UNvpCZq2KWwKkjLdCw-7W20/htmlview

is the renogy 2000w pure sine inverter going to be enough? guessing not if the stove alone has 1800w output. is the renogy brand decent quality?
 
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