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COVID Greetings (And Help with RV Solar Setup?)

nktio

New Member
Joined
Apr 9, 2020
Messages
23
Hello!

Hope everyone is hanging in fine with the pandemic. It's a good time for DIY projects, at the least.

I'm a starving artist in Portland, OR living full time in a 25ft class A RV (1981 Holiday Rambler Imperial, nearly identical to the model doing car stunts in the Kenny Rogers movie 6 Pack:
). I've been living in it for about 2.5 years, renting space and hooked up to shore power, but my intention from the start has been to upgrade it to an off-grid roving mini-home. However, I haven't had the extra funds to make any substantial effort towards that, so I've just been researching and thinking about the logistics off and on.

58870219_10157060797555561_7324816867900522496_o.jpg
(My camper. The current location gets much more sun on the roof).

But now that the COVID-19 crisis has shaken things up, I find myself temporarily unemployed and taking care of my mom who was diagnosed with cancer right before the pandemic ramped up (yeesh). I've got extra time on my hands, no rent to pay, and that sweet sweet CARES Act $$$ coming in (eventually?), so I figure now's as good a time as any to make the initial push towards the off-grid dream camper. Keeps me occupied and optimistic, too. Been watching a lot of Will Prowse's videos and others to figure out what I need. Altogether I'm hoping to have a 12V starting system for less than $1000.

So far I've ordered a 200 watt mono panel (intend to get at least one more): https://www.ebay.com/itm/Kosta-200W-200-Watts-Solar-Panel-12-Volts-Battery-Monocrystalline-Charger-Marine/

This EPEVER MPPT 30a charge controller (appealing for the li-ion charging and custom charge settings up to 17V): https://www.ebay.com/itm/313042542593

And I'm eyeing this 1500 watt inverter (appealing for the 16v and 10v cuttoff range, since I'm looking into Li-NMC batteries):
https://www.ebay.com/itm/VertaMax-1500-Watt-Pure-Sine-Wave-Power-Inverter-DC-to-AC-Car-RV-w-LCD-Display/

The biggest uncertainty is the batteries.
I've been eyeing a 4s bank of these LG li-NMC batteries: https://batteryhookup.com/products/new-lg-chem-n2-1-3-7v-120ah-cell-module
Seems like an absolute -steal- for 120ah if I can make it work, but it'll require an adequate BMS, creativity/extra cost with the assembly and terminal connections (since the tabs were cut short), and custom settings on the MPPT controller if it's in a 4s configuration. Does anyone have any experience with batteries like these? Would it be worth it? Is 3s or 4s better for a 12v system with a max draw around 1500w? Any advice appreciated.

Otherwise I'd like to just go for a 100ah LiFePO4, and get a second or 3rd down the road. I've been eyeing some in the ~$500 range, but if anyone has any they're looking to sell for cheaper I'd definitely be interested ?.

Other things I need or am thinking about down the line:
-Automatic transfer switch to switch back to shore power when needed. I may be able to hack the RVs built in components to achieve this-- I don't use the gas generator, for instance, so I may be able to run the inverter through that line. Unsure if it has a built in transfer switch between shore and generator though, more research needed...

-Fuses, breakers, etc. Components to fully and efficiently integrate solar into the existing RV electrical system. My existing 12V fuses are in an awkward place under the fridge, but the breakers are in a closet at the rear inside the bathroom, which I think is a good spot for the solar components/batteries. So I'll have to run a cable from there. Alternatively I could put everything in the outside-access compartment that currently houses the gas generator, which would be good if there's a built in transfer switch for that line, plus it'd take up less living space.

-Right now the converter for the 12V components and coach battery charging is in the under-fridge compartment with the fuses, and it plugs into an AC outlet which shares a breaker with other outlets....I suppose I could keep that as it is and power the 12V components that way through the AC inverter (with the solar batteries separate from the coach battery so there's no charging loop, maybe even just scrap that coach battery..it sucks), but it seems super inefficient to do that DC>AC>DC conversion....maybe I need to just scrap that converter and figure out a different solution.

-More panels
-More batteries
-fix and reseal my roof so I don't need a tarp over it in the winter

Glad to join in on this community, any input or tips appreciated!

Nolan
 
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Hmmm, now I'm thinking it might be best to go for a 24v system, with a 7s configuration of those LG cells. This would double my battery capacity and the voltage range would sit much more pretty with common 24V components, and it'd surely be more efficient. Seems like it's much easier to find 7s BMS for Li-ion at a decent price too (since the amp requirements for a 1500w max load are lower). I'll need another solar panel for it to work though, but i think I could still come out around $1000 for the whole system and have double the battery capacity and double the solar input...so I think it might be worth a shot !
 
Yes, the tarp is not a permanent fixture ? I need to reseal my roof before I mount the panels, but I can certainly start acquiring and testing the hardware before then.
 
Ok, I've decided to go for the 24v design and ordered 7 of those LG modules. Figure less than $400 for a 24v 120ah lithium battery (over 3kwh) is a deal I can't pass up, and seems like they're selling fast ? Supposedly they've never been cycled, too.
 
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