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Jebby14

Windsor Ontario

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Posted: 07/29/19 11:19am Link  |  Quote  |  Print  |  Notify Moderator

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


If it moves and it shouldn't..... duct tape
if it doesn't move and it should.....WD40
if all else fails .....BFH


pianotuna

Regina, SK, Canada

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Posted: 07/29/19 11:50am Link  |  Quote  |  Print  |  Notify Moderator

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



Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp hours of AGM in two battery banks 12 volt batteries, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

wanderingaimlessly

SOBOVA

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Posted: 07/29/19 12:54pm Link  |  Quote  |  Print  |  Notify Moderator

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.

Jebby14

Windsor Ontario

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Posted: 07/29/19 01:25pm Link  |  Quote  |  Print  |  Notify Moderator

^ 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.

TurnThePage

North ID

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Posted: 07/29/19 01:48pm Link  |  Quote  |  Print  |  Notify Moderator

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.


2015 Ram 1500
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Lwiddis

Mojave, Kern County, CA

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Posted: 07/29/19 03:04pm Link  |  Quote  |  Print  |  Notify Moderator

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


Winnebago 2101DS TT & 2020 Chevy Silverado 1500 LTZ Z71, 300 watts solar-parallel & MPPT, Trojan T-125s. TALL pole for flags. Prefer USFS, COE, BLM, NPS, TVA, USF&WS, state & county camps. Bicyclist! 14 year Army vet - 11B40 then 11A - (MOS 1542 & 1560)


Boon Docker

Mountain Foothills of Southern Alberta

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Posted: 07/29/19 04:31pm Link  |  Quote  |  Print  |  Notify Moderator

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.

caver

Missouri, The Cave State

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Posted: 07/29/19 06:25pm Link  |  Quote  |  Print  |  Notify Moderator

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.

naturist

Lynchburg, VA

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Posted: 07/29/19 08:08pm Link  |  Quote  |  Print  |  Notify Moderator

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)?





rbpru

North Central Indiana

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Posted: 07/30/19 07:57am Link  |  Quote  |  Print  |  Notify Moderator

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.


Twenty six foot 2010 Dutchmen Lite pulled with a 2011 EcoBoost F-150 4x4.

Just right for Grandpa, Grandma and the dog.


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