Off Grid Campsite

[Solarsurfer992]

Hi. I am planning a system to power my travel trailer at an off grid campsite.
Initially 400w of panels, MPPT controller with 2x100wh LiPo batteries and a 2000w pure sine wave inverter. Panels, batteries etc to be mounted on a small shed 25 to 40’ from the trailer.
Trailer requires about 40 amps DC power 12v (peak usage) plus 120v TV and laptop, USB chargers etc.(will not be using AC, microwave etc.). Trailer has a 12v deep cycle lead acid battery on board. The converter requires 8 amps at 120v for battery charging.

Intent, due prohibitive cost of wire for running 12v over that distance is to power the trailer with the 2000w inverter using the onboard converter to maintain charge for the onboard battery using the heavy duty 30 amp AC power cables that came with the trailer.

Mounting panels on the trailer is not an option as I intend to sell it and but a bigger one soon at which time I would need to upgrade solar power system.

Proposed system is based on calculated requirements and a practical budget, system can evolve as
needed. I am not looking for suggestions to build a gold standard system, just practical advice and suggestions to keep costs low and work satisfactorily.

 

[registered-bum]

Would the shed be capable of supporting the solar panels and housing the batteries, solar charge controller and inverter?
Any worries about leaving the panels and electronics in the shed when you leave?

That would allow you to run a 120v AC circuit in a buried conduit from the shed to the trailer.
If the trailer's DC circuit is 12v and 40a - then the AC circuit would be supplying 12v x 40a or about 480w - then adding for efficiency losses (multiply by 1.25) an AC load of about 600w. Not sure about Canadian ver of the NEC but I'm thinking a 12/2 w ground would be sufficient for the 40-60 ft run between shed and trailer.

 

[12VoltInstalls]

just practical advice and suggestions to keep costs low and work satisfactorily

Intent, due prohibitive cost of wire for running 12v over that distance is to power the trailer with the 2000w inverter using the onboard converter to maintain charge for the onboard battery using the heavy duty 30 amp AC power cables that came with the trailer.

The panels (if commodity 100Wx4) in series will be ~88-ish volts and will do fine 50’ to the trailer. No loss in practical terms if you use 10ga solar wire. One 100’ spool would do it. Then you put the SCC and inverter in the camper, bypass the onboard converter, and use the batteries directly in the RV’s oem location. You won’t even lose ~3% of the panel’s output over that short distance but the converter and lead battery charging will lose 33% or more.

You don’t want to run the onboard converter because of efficiency losses.

 

[Larry-Cleveland]

Think about keeping everything 12 VDC. I have a 19" 12VDC TV (I have a 10' screen in my theatre at home) and it looks just fine. It also has a DVD player built in. Axess $125 on sale.

Your laptop is taking 110 AC down to a lower DC voltage to run and charge. Just get the 12 VDC adapter.

 

[Solarsurfer992]

The panels (if commodity 100Wx4) in series will be ~88-ish volts and will do fine 50’ to the trailer. No loss in practical terms if you use 10ga solar wire. One 100’ spool would do it. Then you put the SCC and inverter in the camper, bypass the onboard converter, and use the batteries directly in the RV’s oem location. You won’t even lose ~3% of the panel’s output over that short distance but the converter and lead battery charging will lose 33% or more.

You don’t want to run the onboard converter because of efficiency losses.

I keep swapping plans on this, I don’t want to actually mount anything on the trailer itself. Hadn’t realized such a loss with the converter and inverter. Having the third battery in the system wouldn’t balance that out? Planning to build a secure enclosure to house everything at the trailer and hooking it into the onboard system.

 

[Solarsurfer992]

Would the shed be capable of supporting the solar panels and housing the batteries, solar charge controller and inverter?
Any worries about leaving the panels and electronics in the shed when you leave?

That would allow you to run a 120v AC circuit in a buried conduit from the shed to the trailer.
If the trailer's DC circuit is 12v and 40a - then the AC circuit would be supplying 12v x 40a or about 480w - then adding for efficiency losses (multiply by 1.25) an AC load of about 600w. Not sure about Canadian ver of the NEC but I'm thinking a 12/2 w ground would be sufficient for the 40-60 ft run between shed and trailer.

Yes, intend for the shed to be strong enough to support all the panels on the roof with the inverter and batteries inside. Running a length of 10/2 or 12/2 to carry the 120v is a good idea, still trying to decide if this will meet my power needs or should I follow some other suggestions and stay with an all 12v system.

 

[Solarsurfer992]

Think about keeping everything 12 VDC. I have a 19" 12VDC TV (I have a 10' screen in my theatre at home) and it looks just fine. It also has a DVD player built in. Axess $125 on sale.

Your laptop is taking 110 AC down to a lower DC voltage to run and charge. Just get the 12 VDC adapter.

Looking at 12v TVs here in Canada they start around $250. I may have to take a southern vacation and pick up a few deals while there.

 

[Rednecktek]

Without mucking about with trailer guts, your best option will be to put all the parts and batteries and such in the shed and just run an outlet over to the camper parking spot. Make yourself a shore power spot. Then when you change campers you just plug into your own shore power.

 

[HighDesertOffgrid]

Running a length of 10/2 or 12/2 to carry the 120v is a good idea, still trying to decide if this will meet my power needs or should I follow some other suggestions and stay with an all 12v system.

No reason to add 12v equipment. More power loss going from 12v to 120v to 12v again.. Drive a 4x4 into the ground and mount a 30 amp rv supply. 10-2 w/g direct burial Romex will be adequate, inexpensive, and even run microwave in the future if you want. I would opt for a 3-4k inverter, but 2k is fine for what you want to do. Cheers.

 

[Rednecktek]

The panels (if commodity 100Wx4) in series will

You're going to want a LOT more solar than that. A bog standard rackmount battery is 5kwh and 400w of panels will need 20 hours of good sun to recharge, plus whatever you need to run the MargaritaMaster-5000 in the camper.

 

[seneysolar]

You're going to want a LOT more solar than that. A bog standard rackmount battery is 5kwh and 400w of panels will need 20 hours of good sun to recharge, plus whatever you need to run the MargaritaMaster-5000 in the camper.

Yeah 400w is pretty light. Using 100 watt panels isnt ideal either if you dont need the small footprint. For comparable costs you can probably get a couple 365w or larger panels.

Im a fan of pole mounts but they can be pricey if you use something other than the U-bolt style. I like the DPW mounts. Youd be really happy with at least 4 panel mount.

 

[12VoltInstalls]

Make yourself a shore power spot

Ya. Though at the low price of panels and the ease of installing a decent pair of mppt’s I’d just add a few more panels, ignore the distance inefficiencies (which while real are more a mental hurdle / dichotomy than an actual ‘problem’), mount the charge controllers in the RV, bypass the 50% loss potential ‘converter’ (which is a real thing), and use a decent inverter ~2500W and call it good.
I wish the MPP Solar 1012LV was available as a “2512LV” but I think the only reasonable alternative (because it doesn’t exist) is Victron at 12V.

A couple pieces of equipment in the RV - to me- ymmv) seems so easy and inexpensive- outbuildings and worrying about ‘loss’ just seems (to me) to be a lot of fuss for a simple yet effective ~1500W of panels need imho.

Yeah 400w is pretty light. Using 100 watt panels isnt ideal either if you dont need the small footprint. For comparable costs you can probably get a couple 365w or larger panels.

Having initially- 5 years ago - started with 200W in a minimalist system (which met both my goals and my budget at the time) and scaled up in several steps to where I am now… my thought is 1000-1200W is a good starting place if you actually want to ‘live’ offgrid with it. By the time I hit 800W of panels I realized that panels are everything. You get plenty/excess in sunny/summer, but you can’t make up for the 5% days fall-spring if you don’t have the panels. Once you get ‘enough’ it is so obvious because it’s a such a dramatic difference.
400W is maybe 2kWh daily in good sun, while 1200W (that cost very little more w/ 300W panels) is 6kWh production in good sun and maybe 1.5kWhr on moderate (not dark) cloudy days.

Once you get enough to actually use the electricity it’s much less stressful and enjoyable.

 

[Rednecktek]

wish the MPP Solar 1012LV was available as a “2512LV” but I think the only reasonable alternative (because it doesn’t exist) is Victron at 12V.

There's also the Ionic in 2kw and 3kw low frequency. I just got mine powered up today.