How is this for a power system? Solar vs battery balance?

[LosAngeles]

How is this for a power system? Solar vs battery balance?

Hi all

Have owned a couple RVs, and now designing (with Hallmark) a 9.5’ Everest pop up truck camper.

How is this for the balance of 200 watts of solar and 200 amp hours of (probably Lithium) batteries?

I’m aware that the Lithium are very expensive, but they can be run down to 90% depleted without any damage….. plus they last many times longer than wet cells, so in the really long run, probably (hopefully) no more expensive. The Battleborn batteries (likely get these) have a built in battery management system that makes sure the battery can be used (or discharged) at temperatures as low as -4°F. However, the battery will not accept a charge below 25°F. The BMS also makes sure they dont over charge or under charge.

Planned system:

Propane for stove…. and Truma Combi. (hot water and air.)
(of course 12v needed to run the Truma Combi too)

7.2 CU side by side. 2 way compressor. Novacool RFS7501 fridge.

Maxx fan.

Interior LED lights.

Solar System: 2 X 100 Watt Soft Panels on roof.

Xantrex 817-2080 Freedom XC 2000, 2000 Watt Pure Sine Wave 12 Volt Inverter/Charger

Victron BMV 712 Battery Monitor w/ Bluetooth Lifepo4 Ready

2 (two) x Battleborn 100 amp hour (each) Lithium

Other occasional loads:
Small microwave. Blender. computer maybe.

We camp 4 seasons…. sometimes below freezing. Sometimes higher altitudes. Sometimes in cloudy Pacific NorthWest. So the ability to discharge the Lithuim 90% with smaller bulk and weight has advantages.

We mostly boondock. We prefer the quiet.
Occasionally we stay someplace for 2 nights, but often drive around a bit, to explore, each day (so the F350 would also help charge up the batteries)

Thanks for any and all thoughts.

J.

[LosAngeles]

Thanks everyone for the great thoughts..... Matt at Hallmark suggested that with that big fridge.... 380 watts solar (two 190 x Grape panels) plus a 200 amp hour lithium.

I think we will also carry a generator just as backup.... in the optional cargo storage bins off the back of the Hallmark. The Honda 2200 fits perfectly, they say.

[jimh406]

OP is probably fine for two days that include driving. I’m assuming there isn’t a lot of sitting inside with a popup. I’d rather have a small generator and gasoline for backup power than more solar or more heavy batteries. A generator is by far the fastest way to get the power back.

[adamis]

I have gone down the original poster's steps part way at least...

I bought my BattleBorn LiFePo4 100AH battery last Fall to replace two 6v Lifelines. That alone saved me almost 130 lbs in weight. It includes a BMS system that has already saved my investment multiple times already. The battery even comes with a 10 year warranty which is fantastic. I think many people already understand it but for those that don't, 100AH AGMs only have about 50AH of useful capacity. 100AH LiFePo4 have close to 100AH of capacity. You don't need the same amount of battery AH because you get the actual rated capacity without concern of damaging it by drawing it down too far.

I also just installed 200w of solar on to the rough (with the ability to add another 200 watts without much trouble). The panels I purchased are the Renogy 100w flexible panels designed for RV roofs. I attached them using Eternabond tape around the edges of the panels. Made it 300 miles without any problems so far and no additional hole penetrations into my roof. I am however keeping a close eye on them until I'm confident.

I am now in the mess of switching over to LiFePo4 chargers since my old chargers were designed for AGMs. Unfortunately the camper and truck went into storage so I haven't gotten to fully debug the system.

That being said, my impressions are that 200w on a 100AH battery for most typical usage is a LOT of power to work with. Using the compressor fridge does increase your power draw. 3 Tons (member on the forum) just texted me today about helping a neighbor do a cargo trailer build and he reported 40AH of draw over a 24 hour period with a 7.4 cubic foot compressor fridge. This is in high dessert country with high temps so might be a good baseline for extreme situations. A single 100AH BattleBorn would be able to handle this draw and 200w of Solar could likely keep up on sunny days but it is probably cutting it closer then you want. I think the 200AH you are looking at (2 Battleborns) and 300w to 400w of solar is probably your ideal situation.

That being said, it is a large investment up front for that much solar and battery. If you just go with a Propane fridge, your power usage goes to almost nothing and you have 100AH of reserve to power everything else. I know compressor fridges have their benefits but once you learn how the Propane fridges work, and understand it's limitations, they are pretty darn bullet proof and require almost no electricity.

Anyway, my 2 cents for what it's worth...

[dave17352]

Double at least on the solar, unless you plan on only two day trips.

[3_tons]

I the real world a panels advertised gross wattage will seldom be achieved - for overall averaging purposes I subtract 25% or even more depending on weather conditions (less in the Nevada desert)...Everyone’s experience can vary, so based on my 10yrs with 440w of solar and two 6v GC’s, I would suggest to OP having for more solar and an MPPT type controller to help exploit peak harvest hours while avoiding white knuckle stresses...I agree that Li will greatly reduce recovery times and solar wattage requirements...Li will be my next power supply...

[towpro]

I would also add more solar. and I am happy with AGM, my built in charger is very close to the voltage my AGM wants to see, Lithium should really have a Different Charger.

I run 180Ah AGM batteries, and 300w of solar. I can watch Satellite TV for 2-3 hours, run fantastic fan, run water pump, refreg on Gas, LED lights and still have plenty of power when we wake up in AM (70%). during the day the North Carolina sun brings that back up to 100% by early afternoon. in middle of summer 200w was enough but with panels on front slop of RV I had to try to face south when parking RV. Once the days got shorter in Sep/Oct we were getting close to not fully recovering, especially of we had much rain that day so I went with 300w. I have room and wiring for one more but never got around to it. Now I live in Central Florida so the requirements have changed, need to run AC more so less off grid camping but the sun is brighter down here so my solar requirements have gone down.

in fact when I store my rig I don't even hook it to electric. in summer its always 100% ready to go, in winter with cover on RV (and battery switch turned off, but solar is wired direct to battery) it keeps RV at 100%

[accrete_]

Greetings,seems like ages since visiting the forums though we’ve been exploring lots since our retirement. My wife & I currently travel in our TwoVanConvoy consisting of a Chevy Express AWD & Promaster, both nicely converted for full time adventures.

I’m i the research phase of our next rig-build and learning heavily toward a pop up TC & visiting both the Hallmark & Outfitter facilities this week.

In context of the OP our Promaster has 160watts solar & 190ah AGM bank to power our ARB 35qt chest fridge and change our gadgets. As I post we’ve been 100% off grid for 301 days traveling in Nevada, Arizona, New Mexico & currently camping near Pike’s Peak as we make our way to Denver for the visits.

We are always back to 100% charge by mid day even when it is overcast with such a low draw (ave of ~.5ah & have yet to notice bank below 12.4 volts even in winter months)

One thing we will do our best to incorporate is a top loading relatively small 50 to 85 quart compressor fridge rather than a front loading unit due to the greater efficiency.

YMMV
Thom

[time2roll]

Geewizard wrote:
I have 220W of solar and it's a Tundra T42 refrigerator. In use since about 2007.

http://www.marinespecialists.com/Tundra/frige.html

Yes and the OP's Novacool RFS7501 fridge is almost twice the size. Not that it will use twice the power but still need a bit more and 9% less solar.

I would still plan on going a few more watts. Maybe some portables to tilt to the sun in winter. Max out a TC is not really a huge system. The lithium batteries will harvest more power from solar.

[Geewizard]

Kayteg1 wrote:
I wonder if in E. Washington you need refrigerator at all? 😉
Try to take vacations in south states and park you camper in 120F weather, when side with refrigerator will reach 150-160

LOL! No thanks! I only vacation where the temps don't go above 90F.

[crosscheck]

Geewizard wrote:

time2roll wrote:

Geewizard wrote:

time2roll wrote:
Compressor fridge? Yes plan to max out the roof with solar.

Nope. I do fine with my existing solar and two 100AH batteries powering my Tundra compressor fridge.

OK how many watts solar and what fridge model is it?

I have 220W of solar and it's a Tundra T42 refrigerator. In use since about 2007.

http://www.marinespecialists.com/Tundra/frige.html

I owned a NovaKool 7500 fridge/freezer for 5 years dry camping almost exclusively without a generator on 330w solar, 4 6v AGM batteries. No problems. Check out the history on our blog.

Dave

[Kayteg1]

I wonder if in E. Washington you need refrigerator at all? 😉
Try to take vacations in south states and park you camper in 120F weather, when side with refrigerator will reach 150-160

[Geewizard]

time2roll wrote:

Geewizard wrote:

time2roll wrote:
Compressor fridge? Yes plan to max out the roof with solar.

Nope. I do fine with my existing solar and two 100AH batteries powering my Tundra compressor fridge.

OK how many watts solar and what fridge model is it?

I have 220W of solar and it's a Tundra T42 refrigerator. In use since about 2007.

http://www.marinespecialists.com/Tundra/frige.html

[time2roll]

Geewizard wrote:

time2roll wrote:
Compressor fridge? Yes plan to max out the roof with solar.

Nope. I do fine with my existing solar and two 100AH batteries powering my Tundra compressor fridge.

OK how many watts solar and what fridge model is it?

[Geewizard]

time2roll wrote:
Compressor fridge? Yes plan to max out the roof with solar.

Nope. I do fine with my existing solar and two 100AH batteries powering my Tundra compressor fridge.

[time2roll]

Compressor fridge? Yes plan to max out the roof with solar.