cancel
Showing results for 
Search instead for 
Did you mean: 

How Much Solar?

3TV
Explorer
Explorer
I'm getting a new truck camper and plan on adding a 170 watt solar panel on the roof, which got me to thinking, why not add another 170 watt panel, or two more panels? Is there an advantage to having 340 watts, or 510 watts, or am I wasting my time and money. The camper will actually have a cover on it when stored, so solar panels wont be used when stored, and it will be plugged in to a battery tender. But when in use, would the extra panel allow me to use items like the DC TV, and still keep up with battery charge by using the solar panels? What do you people think?
2019 Ram 3500 Crew Cab Laramie SWB 4x4
2020 Lance 825
2021 Grand Design Momentum 350G
16 REPLIES 16

MEXICOWANDERER
Explorer
Explorer
Still waiting to see the first

I wish I had bought less

Post

CincyGus
Explorer II
Explorer II
From what I have learned about solar, The main benefit of having additional panels is for those days you are not getting full sun or only getting sun for part of the day.

Say you have a day where the morning was cloudy and you were getting zero to minimal output from the panels. Then during the afternoon, you get about 3-4 hours of bright sun giving you near maximum output from your panels. Obviously if you have a third (all equally rated panels) panel vs. two, you are going to recover about 50% more AH's than you would with just the two. So it's a matter of better recoverability in less than ideal conditions.

On good sunny days, you may recover to near full on your batteries and have "overkill" solar. So it's a case of how much recoverability do you want and how much do you hate running the genny. If that aggravates you, add the extra panel. If it's not a big deal to run the genny on cloudy days if you need to, save the hundred and change to spend on something else.
2015 GMC 2500 Denali Crewcab 4x4
2019 Forest River Wolfpack 23pack15

Hope your travels are safe and the friendships made camping are lasting.

3TV
Explorer
Explorer
I like what was said earlier about one panel per battery. The truck camper will come with dual batteries, and I have asked for the biggest that will fit in the space allowed. So two panels sounds like a good idea.
2019 Ram 3500 Crew Cab Laramie SWB 4x4
2020 Lance 825
2021 Grand Design Momentum 350G

Joel_T
Explorer
Explorer
We have two 160w panels feeding two 6v 260a batteries. With just a fair amount of sun we have no problems recovering around 40 or 50a a day. Hit and miss sun and we might get a week before needing to use our 2200w westinghouse to recharge although we'd probably run it sooner. No sun and we can go 3 days before a charge is necessary. Just our example...a lot of variables to consider.
Lance 15.5 2285 w/rockers Ram2500 4x4 CC 6.4 hemi 6spd w/3.71
Two 6v Crown 260ah / TM-2030 monitor / SC-2030 controller / Two 160w panels / EMSHW30C surge protector / 2000w inverter / TST507 TPMS

jplante4
Explorer II
Explorer II
Moved from General RVing
Jerry & Jeanne
1996 Safari Sahara 3530 - 'White Tiger'
CAT 3126/Allison 6 speed/Magnum Chassis
2014 Equinox AWD / Blue Ox

fitznj
Explorer
Explorer
Summer and winter will place differing demands on the solar/batteries;
14 hours of sunlight in summer and 10 of cloud in winter;
Light electric demand in summer and heavy usage in winter;

I have 200W and 2 Walmart batteries which work great in summer but I need
generator boost in winter; I keep the solar plugged in during storage and
keeps the batteries topped up till the next camping trip.

As others have said - you can never have enough solar panels.....
Gerry

Lwiddis
Explorer II
Explorer II
“you can choose to run things like the water pump (showers or dishwashing) or watch TV, while the sun is high.”

Good point, bpounds. I shower, recharge phone, iPad and tire air pump etc. too.
Winnebago 2101DS TT & 2022 Chevy Silverado 1500 LTZ Z71, WindyNation 300 watt solar-Lossigy 200 AH Lithium battery. Prefer boondocking, USFS, COE, BLM, NPS, TVA, state camps. Bicyclist. 14 yr. Army -11B40 then 11A - (MOS 1542 & 1560) IOBC & IOAC grad

bpounds
Nomad
Nomad
Yeah, you didn't tell us how much battery capacity you have.

But I'm so far very happy with 400w handling 230ah of battery.

I'm not sure there is overkill as far as panel size. Unless you consider spending a nickel more than necessary as overkill.

Consider this...the best way to charge your battery is to not discharge it to begin with. So with a lot of panel capacity, you can choose to run things like the water pump (showers or dishwashing) or watch TV, while the sun is high. Use that excess panel output instead of battery supply.

We did the same thing with our generator. Try to do water pump things while it was running, and at the time we had to run it to watch TV anyway. We have carried those habits over to our solar life.
2006 F250 Diesel
2011 Keystone Cougar 278RKSWE Fiver

garyhaupt
Explorer
Explorer
I have 250 and 3 12v Deep Cycle and have never ever run out of power. I don't have a microwave or TV. Lights are the normal ones and I don't let the furnace run all night. I's go for one more panel. There is an overkill..you aren't there quite yet.


Gary Haupt
I have a Blog..about stuff, some of which is RV'ing.

http://mrgwh.blogspot.ca/

doc_brown
Explorer
Explorer
I have 400W and 6 batteries. Boondock for a week at a time, assuming full sun I let the inverter/auto gen start dance take over. I have a residential fridge, all lights changed to LED as well as the tv’s. Gen typically goes on once early morning or if I need AC’s. Be sure to get an appropriate controller and gauge wire based upon your distances.
Steve,Kathy and Josh
Morpheus(Basenji)at Rainbow Bridge
2004 40' TSDP Country Coach Inspire DaVinci
350 Cummins, 3000 Allison
2014 Jeep Wrangler Unlimited Sport S, Air Force One Braking, Blue Ox

time2roll
Nomad
Nomad
100 to 200 watts per battery should be fine. Two panels is probably good unless you have a crazy usage pattern. Many get by on less. Less than ideal conditions may still have you wanting more. Find your middle.

2oldman
Explorer II
Explorer II
Forum members solar
Solar basics
Why solar? 2016
"If I'm wearing long pants, I'm too far north" - 2oldman

donn0128
Explorer II
Explorer II
Where are you going to put all the batteries?
Solar is useless unless you have the storage capacity to support it.

Lwiddis
Explorer II
Explorer II
The number of solar watts is usually determined by battery amp hours...one to one for us southern US RVers. If living in Colorado I’d go more...1.25 or 1.5 watts per AH. And, yes, the goal is not to need the generator except for AC. The key is to wire for more than you anticipate needing so that adding a panel is easy. When my TT is at rest the solar panels are too. I use a 25 watt panel and weather proof WindyNation controller to keep the batteries charged. Start with an energy use survey. That determines necessary battery AHs and that determines solar watts.
Winnebago 2101DS TT & 2022 Chevy Silverado 1500 LTZ Z71, WindyNation 300 watt solar-Lossigy 200 AH Lithium battery. Prefer boondocking, USFS, COE, BLM, NPS, TVA, state camps. Bicyclist. 14 yr. Army -11B40 then 11A - (MOS 1542 & 1560) IOBC & IOAC grad