solar

[Jebby14]

how much solar is too much/not enough/just right.

seems like every calc I look at is different. looking for some real world advise.

trying to keep a regular group 24 deep cycle preforming under light load. Fridge controller, water pump for the toilet, co detector and maybe a light for a min or two. plus any parasitic draw.

would be nice to get enough extra that a rainy day doesn't leave me dead in the water.

thinking 100W should be ok, 200w being ideal. <100 likely not worth the time and money IMO

[bartlettj]

I live in the PNW and have 100W and 2 2GC batteries. My use case is 3 day trips dry camping throughout the year and one or two extended trips where I either have shore power or the truck alternator to charge. This works ok for me, but the panel won't keep up with daily demand in the winter if I use the furnace or not. The main reason I added the panel was to keep the batteries ready to camp while the trailer is parked, which it does well. If I was full time I would want at least 250 watts.

[Jebby14]

Thanks guys. as always the feedback is appreciated.

[Vintage465]

What ever you do...........do a fair amount of research prior to shelling out cash an punching holes in your rig. I think the whole thing starts around getting quality controller mounted close as possible to your battery/s and BIG wire to where ever you mount your panels. Assume what ever you put in won't likely be enough and leave yourself an out to add more to what you've installed. Solar is a kick. Short of running your A/C unit, there is really nothing that can't be powered by some good batteries and a stout solar set up. I love solar. I'm currently 300w and 4 each, 6v Golf Cart Batteries. I plan to add one more 150w panel and clean up the install that the dealer did when I bought my rig. They did OK, and it works good, but with just a little more leg work it could work much better.

[TomG2]

"how much solar is too much/not enough/just right."

About like asking, "How long should a piece of string be?"

I get by with a single Group 27 Deep Cycle battery and a single 50 watt panel for weeks at a time. I watch a little television, recharge my phone and other electronics, and operate a couple of lights at night. Others would need ten times that if they want to make coffee, run a refrigerator, and light up the night sky.

[rbpru]

The use of solar obviously depends on the sun. How sunny it is when you camp.

Our trip to AZ was quite different from our trip to the WI woods.

[naturist]

I found a book and website that makes it simple. Here

I have but a single battery and like the OP use power lightly. The site I referenced recommended 200 watts for a single 100 AH flooded cell battery, 400 watts for two such batteries. I’ve just started using that system and it looks like it’ll keep my battery topped up easily even on partly to mostly cloudy days.

I think you’ll find 100 watts lacking if there are any clouds or your rig is shaded in your site (and don’t we find shady sites more pleasant in the summer heat)?

[caver]

I have about a 180watt? folding panel about the side of a small folding table. It does me fine and have two Trojan T105's. The downside is the panels are heavy and a little awkward to store under my bed storage.

[Boon_Docker]

I have 200 watts (flat mount on roof) with MPPT controller charging a pair of GC2 batteries (230 AH total). I boon dock for weeks at a time and have never ever had the batteries drop below 65%.

I would say go with 200 watts.

[Lwiddis]

One solar watt per battery amp hour is good for me....in Southern California....and a pretty fair “middle” ground.

[TurnThePage]

I acquired two free 75 watt panels over a decade ago. Combined with a (not so free) MPPT controller, they've been more than enough for our various excursions ever since. We always camp in at least partial shade, and still can watch a movie or two at night, along with charging phones, running the water pump, etc., etc., and still the (two 6v) batteries are usually close to topped off before the next night.

[Jebby14]

^ Thanks guys. not a hurry this is likely my winter project, I just know that everything I read is conflicting. a pair of golf cart batteries and 100 watts of solar is well within the realm of possible. No intent to keep my current battery, just need a benchmark and that's whats on there now.

[wanderingaimles]

Trying to stay with a single group 24 battery is tough.
Even with a single 100 watt panel being sufficient, a single day of rain eliminating the benefits renders your actions near useless.
To go frugal, and have meaningful benefits,,,
If you can, switch to a pair of GC-2 batteries and your single 100 watt panel. When you select the controller get at least a 30 amp unit, so you can add to the system as finances allow.

Your single group 24 only yields about 76 Amp hours of power.
Most sources say you should not routinely draw it past one quarter of that amount, one third at most,
so you have 25 amp hrs available normally before you start damaging your battery.
A pair of GC-2 batteries wired in series will give you a total of about 210 Amp hrs, of which 50% is usable with no damage to the batteries.
4 times the readily available power.
$180 for batteries in conjunction with a single 100 watt panel will give 4 times as much available power as you currently have, as well as the ability to regain much of that power by solar in a single day. You can hit a rainy day or two without running out of power at your old use rate.

[pianotuna]

Hi Jebby14,

Start with the energy audit.

I'd recommend upgrading the battery capacity. A single group 24 may not be enough.

The bare minimum for solar is 60 watts per 100 amp-hours of capacity. The realistic maximum for battery charging is 150 watts per 100 amp-hours of capacity.

This web link may help:

https://freecampsites.net/adding-solar/

Jebby14 wrote:
how much solar is too much/not enough/just right.

seems like every calc I look at is different. looking for some real world advise.

trying to keep a regular group 24 deep cycle preforming under light load. Fridge controller, water pump for the toilet, co detector and maybe a light for a min or two. plus any parasitic draw.

would be nice to get enough extra that a rainy day doesn't leave me dead in the water.

thinking 100W should be ok, 200w being ideal. <100 likely not worth the time and money IMO