Cool Boondocker class C RV

[Mudd]

I was passing through El Paso with my wife and our 3 pups and happened across an RV with solar covering the roof. We also have an RV but I haven't had the chance to put panels or a split unit on it yet. Seeing his Rig was an inspiration so I wanted to share with y'all. He said he had 20kwh of lipo4 storage and no propane. His Rig is the class c and mine is the older 5th wheel.

 

[Lt.Dan]

Damn, 20kwh in something that small, it must take weeks to charge lol.

I like the truck! I have a 96 myself ?

 

[Mudd]

Damn, 20kwh in something that small, it must take weeks to charge lol.

I like the truck! I have a 96 myself ?
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Thanks man your Obs is sweet too. I forgot to ask about the panels but his entire roof was covered. Being so small I bet his batteries never get below 50%. I was really surprised when he said he had 32 200ah cells.

 

[HRTKD]

Wow! He certainly has the top of the RV well covered in panels. And mini-split on the back.

 

[eXodus]

Damn, 20kwh in something that small, it must take weeks to charge lol.

He probably hooks to power in various RV parks / EV chargers, whenever he goes dumping.

I'm thinking about doing the same process. I got 5-7 days between water fill ups and dumping, during that time I'm in civilization anyhow.
Getting some AC to DC chargers to top of the batteries while at the RV-park.

So you don't need size the solar to cover your whole need - just enough solar to keep you afloat between fill ups.

 

[Short_Shot]

If it's got 4x 435w sunpower panels that's as much as 6-7kwh per day of charging and will fit on 14 feet of 7 foot wide roof.

20kwh of battery is not at all unreasonable if you need to get through a few cloudy days and are full electric.
That'll run AC, water heat, and your induction stove needs for a long time.

I've drawn up some slide out panel stuff for that much solar on top of an 11 foot squaredrop. Two panels side by side on the roof and two under that come out like awnings. Presto. 1700w.

 

[chrisski]

I've drawn up some slide out panel stuff for that much solar on top of an 11 foot squaredrop. Two panels side by side on the roof and two under that come out like awnings. Presto. 1700w.

I’d like to see the idea for the awning like panel. The ones I’ve seen like PVC pipes that hold panels over a window don’t look good for the nightly winds I’ve seen in most place.

 

[Short_Shot]

I’d like to see the idea for the awning like panel. The ones I’ve seen like PVC pipes that hold panels over a window don’t look good for the nightly winds I’ve seen in most place.

Just aluminum on heavy duty slides.

Most folks put them away in the wind.

 

[Lt.Dan]

Just aluminum on heavy duty slides.

Most folks put them away in the wind.

What happens when they are out when you aren't there?

If it's got 4x 435w sunpower panels that's as much as 6-7kwh per day of charging and will fit on 14 feet of 7 foot wide roof.

20kwh of battery is not at all unreasonable if you need to get through a few cloudy days and are full electric.
That'll run AC, water heat, and your induction stove needs for a long time.

I've drawn up some slide out panel stuff for that much solar on top of an 11 foot squaredrop. Two panels side by side on the roof and two under that come out like awnings. Presto. 1700w.

I have 2880 watts on my roof, and 13kwh of battery, and when I go dry camping, it is a struggle trying to keep the battery charged with everything you listed. We typically dont run the AC when dry camping, but the water heater, fridge, lights, TV, inverter standby, etc kill my battery fairly quickly. Hell, the inverter stand by on my rig uses 3kw per day. Having an extra 7kwh of battery would help, but I don't think I could make it more than 2 cloudy days without plugging in, or some form of generator usage.

 

[richard cabesa]

I’d like to see the idea for the awning like panel. The ones I’ve seen like PVC pipes that hold panels over a window don’t look good for the nightly winds I’ve seen in most place.

Here is my version, held up fine in 35 mph winds in Death Valley


It gets me to 800 watts on a 22' RV

 

[eXodus]

I have 2880 watts on my roof, and 13kwh of battery, and when I go dry camping, it is a struggle trying to keep the battery charged with everything you listed. We typically dont run the AC when dry camping, but the water heater, fridge, lights, TV, inverter standby, etc kill my battery fairly quickly. Hell, the inverter stand by on my rig uses 3kw per day. Having an extra 7kwh of battery would help, but I don't think I could make it more than 2 cloudy days without plugging in, or some form of generator usage.

Waterheater can be a huge power draw. Did you measure it? I'm running mine on propane.
I don't need hot water all the time.

I'm currently thinking about small logic device which turns on the Electric Water heater as soon as the Battery is fully charged. Demand Side management.

 

[Lt.Dan]

Waterheater can be a huge power draw. Did you measure it? I'm running mine on propane.
I don't need hot water all the time.

I'm currently thinking about small logic device which turns on the Electric Water heater as soon as the Battery is fully charged. Demand Side management.

It draws 1200-1300 watts. Typically I leave it on 24/7. Even from when I leave home to go dry camping/boondocking, so its constantly hot and only comes on every few hours to maintain temp. I figure its the same reasoning as your air conditioner at home, is it more energy efficient to maintain the temp of the home, or to shut it off when your not home, but have to run it for much longer once you get home to bring it back to a comfortable temp? I also like that if I want to take a shower, I dont have to wait 20-30 minutes for it to get warm before I can jump in, or wash dishes.

I like the logic device, but again, I'd hate to go to use the hot water, only to find it cold because the battery never got fully charged. Obviously you'd have an override switch, so I guess thats not that big of a deal.

These discussions make me want a tankless.... lol

 

[jimcalf]

Don't forget that he might also have a 2nd alternator. A hefty Balmar type can push 1800 watts just idling the engine. Much more when driving. I used to have a Winnebago Travato B-van, and the lithium versions of that have about 12kwh batteries at 48v and an alternator that produces up to 4500watts charge from. It only has 200 watts of solar! If that is his primary transportation, I bet he has a 2nd alternator and really only depends on the solar for when not driving. That rig looks to be about 24' long and 8' wide. You can fit a lot of panels on that much space!

I can only fit 800W on my small trailer roof, and still have room to maintain anything. Planning on 230ah, 8S2P for 11kwh pack, and yeah, I'll be topping off with a portable gas genny or occasional nights with shore power. Unless you have a ton of roof space, solar is just one more way to add a little juice, and not one I can solely depend on.

 

[eXodus]

I like the logic device, but again, I'd hate to go to use the hot water, only to find it cold because the battery never got fully charged. Obviously you'd have an override switch, so I guess thats not that big of a deal.

It should be programable - so you set whatever charge level you like. IF battery > 80% water heater = yes

On my water-heater you can set the electric setpoint and the propane setpoint to different ones.

Pretty simple, I got my propane set a 110-120F and the electric one at 140F.
So if the electric doesn't run - the propane kicks in to keep the water warm. Never cold water - but optimizing solar production.

I figure its the same reasoning as your air conditioner at home, is it more energy efficient to maintain the temp of the home, or to shut it off when your not home, but have to run it for much longer once you get home to bring it back to a comfortable temp

For the A/C your assumption is true - since the systems compressor needs some time to create pressures and is less efficient at higher differentials.

But for a resistant heating elements it doesn't makes any difference. No need to heat during times - where you don't use it.
You might also pack your waterheater into more insulation - that helps with power usage.


Usually the battery should be charge by early afternoon - then the waterheater kicks in - and heats up for a nice shower on the end of the day.
Then it shuts of for the night and the next morning - if the battery is still sufficient - it heats electric in again, if not - the propane takes over.

 

[noenegdod]

is it more energy efficient to maintain the temp of the home, or to shut it off when your not home, but have to run it for much longer once you get home to bring it back to a comfortable temp?

From an efficiency stand point it is always more efficient to leave it off and only turn it on when you are there. From a comfort perspective it is much better to leave it on and have it down to temp when you arrive. How long are you gone for? How long does it take for the temp to rise when it is off? How long does it take to recover when it gets turned back on? What is your tolerance to the recovery period? Those are the basic parts of the equation as to whether you should turn it off or leave it on.

 

[Short_Shot]

What happens when they are out when you aren't there?


I have 2880 watts on my roof, and 13kwh of battery, and when I go dry camping, it is a struggle trying to keep the battery charged with everything you listed. We typically dont run the AC when dry camping, but the water heater, fridge, lights, TV, inverter standby, etc kill my battery fairly quickly. Hell, the inverter stand by on my rig uses 3kw per day. Having an extra 7kwh of battery would help, but I don't think I could make it more than 2 cloudy days without plugging in, or some form of generator usage.

Insulation, how often you use it, and how large the space is makes the biggest difference. Most RVs have remarkably bad insulation.

As does the type of air conditioner.

You also don't need to run the water heater forever, just before you need it. Leaving it on 24/7 is just silly. Your inverter is also likely much larger than you need, adding significant standby power draw.

If you turn off the water heater, then swap between the induction stove and water heater, and have enough insulation AND a really efficient AC you can get a much smaller inverter.

Swapping as much AC stuff for 12v as possible also helps greatly for dropping the inverter draw.

If you're having that much issue with that much solar you've got other things to address.

 

[HRTKD]

When I'm boondocking in single digit temps, the water heater stays on. I don't want to take a chance of it freezing. Otherwise, in more normal weather, I turn off the water heater until I need it. Patience is a virtue. Planning ahead is a skill.

 

[Short_Shot]

When I'm boondocking in single digit temps, the water heater stays on. I don't want to take a chance of it freezing. Otherwise, in more normal weather, I turn off the water heater until I need it. Patience is a virtue. Planning ahead is a skill.

Yeah but you can set it to a lower temperature for freezer protection and crank it up before using it.

 

[noenegdod]

You also don't need to run the water heater forever, just before you need it. Leaving it on 24/7 is just silly. Your inverter is also likely much larger than you need, adding significant standby power draw.

Swapping as much AC stuff for 12v as possible also helps greatly for dropping the inverter draw.

This is all based on the assumption that some or all of the components I am talking about are in the conditioned space.

Basically 100% of the stand by consumption of the inverter results in heat. As well, the losses converting 12-120-12 all result in heat. The stand by losses of the water heater go somewhere as well so the colder it is, the less loss you have. Computers, tvs, lights all contribute to the heat load and you have to then consume more energy to remove that heat via the AC which operates off the inverter and creates additional heat that needs to be removed as well.

@Short_Shot is 100% correct. Use as little as you can, reduce 120vac loads as much as possible to avoid conversion losses and turn everything you can down or off when you dont need it. It will pay dividends. Every joule of energy consumed ultimately turns into heat. Some of that energy, such as the energy going into driving the compressor on your AC will remain outside but basically everything else you consume that is in the space will require removal so the less you use the less you have to remove.

 

[HRTKD]

Yeah but you can set it to a lower temperature for freezer protection and crank it up before using it.

In four years, I haven't seen a temp setting. It may be there, but it's not obvious or readily accessible. The water heater is one item in the trailer that I haven't had to repair. I do drain it after each outing.