Solar or Generator for Boondocking

[Ace_]

This is for a truck camper, no a/c. This would be to keep batteries charged. I was putting together a solar kit (on paper, for purchase at a later date) and started thinking about a generator and whether that is a more efficient/effective solution.

I live in the PNW and some of the solar mfg./retailers state there is less sunlight, so the solar panels will be less efficient than in other parts of the country. I was going to put together a 200watt system, probably roof mounted.

Then I got to thinking that a 2kw generator would cost (maybe) less than the solar panel set up and put out probably close to 1500 watts, 12 amps. So, will the generator recharge my batteries (two deep cycle) in an hour where the solar would take a full day of full sun (realizing the amps used per day is unknown, just wondering about the efficiency between the two)?

When boondocking, especially when no one else is around, I don't mind running a quiet generator for an hour or two.

Solar panel specs:

Max System Voltage (IEC/UL): 600V
Voltage at Maximum Power Point: 18.0V
Maximum Power: 100 W (0%, +6%)
Current at Maximum Power Point: 5.56 A

Seems to me with the panels in full sun I could get 3-5 amps (per 100 watt panel). With the generator I'm guessing 12-15 amps (1.5-2 times what the solar would give me, assuming two 100 watt panels). Does that seem right?

Thanks.

[Ace_]

Ha! Nice one.

[time2roll]

pnichols wrote:
You might be thankful you had a genny along then ... for both battery charging and air conditioning in the potentially warm and humid conditions. 😉

First OP needs an air conditioner....

[Salvo]

I spend 6 or 7 weeks every year at the Gorge. There's plenty of sun. In fact, I'll camp in 50% shade to keep MH cooler.

Most of my power usage is after the sun goes down. It doesn't matter how much solar you have. The weakest link in most cases is the battery. Once the battery drops to 12.0V it's advisable to start the gen or go to bed. My 130W solar has no problem charging the 220AH battery from 50% soc (even in PNW). That's why I preach a balanced system.

Ace! wrote:

From what I gather though, my conditions will provide much less solar energy for the panels than someone in So Cal. It still may be overkill though.

[pnichols]

smkettner wrote:
Worst case you roll out.

You might not be able to just "roll out".

Suppose, for example, you are boondocking at Dubinky Wells in Utah and get unexpectedly caught for 2-3 very cloudy days during their August monsoon season such that it was best road-wise to stay put until the weather blew over.

You might be thankful you had a genny along then ... for both battery charging and air conditioning in the potentially warm and humid conditions. 😉

P.S. We've never been caught in those conditions (yet) ... but we have been rockhounding in the Dubinky Wells area in the summer. We didn't camp overnight out there but were equipped to be able to in safety and comfort ... if needed, just in case. BTW, you can do a lot more from an RV than rockhound in that remote pristine area.

[time2roll]

Depends on conditions you are preparing for. Lazy Summer days are different from staying warm in sub-freezing conditions. Worst case you roll out. I would start with solar. Get the generator if on a real expedition or full time in the RV.

[Ace_]

Salvo wrote:
Not sure you need that much solar. I've been using 130W for 8 years. It's adequate for us. The 2 x 6Vs (220Ah) are in absorption by 1 pm.

It's important to have a balanced system. 400W solar and 220AH battery capacity is not balanced. There will be a lot of wasted solar energy. You'll need 440 AH.

Ace! wrote:
Thanks. I've been able to mock up a 400 watt system which should be in the $1,200 range and I can buy a sub-$1,000 generator too. I guess that should put me in a good position for a week or more without shore power...or at least I hope it will.

From what I gather though, my conditions will provide much less solar energy for the panels than someone in So Cal. It still may be overkill though.

[pnichols]

MEXICOWANDERER wrote:
Prepare for the worst...

I agree 100%.

What this means with regards to electrical power for an RV when not on hookups is:

1) If you cannot afford both initially, or don't want to mess with a permanent solar setup initially ... begin with a good battery and generator setup for your RV. If you have the relatively small amount of extra money required, add plug-and-play portable solar right after a good battery and generator setup.

2) When you have a larger amount of money plus personal knowledge and time, or plus access to a competent RV solar installer ... add permanent solar after doing 1), above.

IMHO, having solar only ... whether with or without a good battery setup .... is non-hookup RV'ing on borrowed time. Eventually you're going to get caught with both your batteries' energy and the sun's energy too low. Our RV has three (3) non-solar ways of keeping it's 230 amp hour battery bank charged up rain or shine, day or night.

P.S. Of course a lot of folks borrow a lot of time. 😉

[Salvo]

Not sure you need that much solar. I've been using 130W for 8 years. It's adequate for us. The 2 x 6Vs (220Ah) are in absorption by 1 pm.

It's important to have a balanced system. 400W solar and 220AH battery capacity is not balanced. There will be a lot of wasted solar energy. You'll need 440 AH.

Ace! wrote:
Thanks. I've been able to mock up a 400 watt system which should be in the $1,200 range and I can buy a sub-$1,000 generator too. I guess that should put me in a good position for a week or more without shore power...or at least I hope it will.

[MEXICOWANDERER]

Hope for the best

Prepare for the worst...

[Wet_Coast]

Quick rule of thumb:

amps at 120V= amps at 12v multiply by 10

[tpi]

Ace! wrote:
BTW, I don't have a microwave or A/C; although I am considering a television.

Can someone check my math. If a 120V television has an energy consumption of 25W, is that about .2 amps? Seems like the draw would be higher than that.

It would be .2ish amps at 120 volts. At 12 volts it is 10X that amount..somewhere around 2, 2.5 amps.

[JiminDenver]

Newer flat screens can be very low draw. Last year we used a 150w inverter for out 19 inch flat screen and portable satellite system.

By the way, you don't have to have a inverter to enjoy TV. Buy a TV that uses a power brick on the cord and replace it with a 12v cord with the proper end to fit the TV. You will lose less power by not having a inverter with its loses creating 120Vac only to be converted back down to 12v by the TV power brick.

They also make 12v TVs but they tend to be more expensive.

We had a tiny rechargeable TV that ran off of 12v, then a larger TV/DVD combo with the cord replaced. We went to a 120Vac TV since the satellite uses 120Vac anyways.

[pianotuna]

To much attitude and full of questionable opinions.

PFitt wrote:
Read up on Handy Bob's Solar blog. Everything you need to know on solar, batteries and best equipment to use. He's off-grid fulltime!!
https://handybobsolar.wordpress.com/

[Ace_]

BTW, I don't have a microwave or A/C; although I am considering a television.

Can someone check my math. If a 120V television has an energy consumption of 25W, is that about .2 amps? Seems like the draw would be higher than that.

[PFitt]

Read up on Handy Bob's Solar blog. Everything you need to know on solar, batteries and best equipment to use. He's off-grid fulltime!!
https://handybobsolar.wordpress.com/