How big of a solar system is enough?

[Fireballsocal]

While planning out the addition of solar to my 2009 Lance 1880, I gravitated to the 160 watt systems right off the bat. It's what the new trailers come with and seems to be a common wattage available. Now I am questioning whether I need that much and if I would be better off saving a few bucks. I generally am a spend now, cry later consumer but more opinions are welcome.

Current camping is boondocking but I hope to start hitting more National and state parks, with or without hookups. I have a Yamaha 3000 generator for running the air conditioner but look forward to not having to lug it around when it's cool. Basically, I need the solar to keep the batteries topped off in storage. When I am out camping sans generator, I'd like the panel to provide enough juice to extend my camping for a few days off grid. Say, my 2 12V batteries last me a 2 day weekend in the winter running the heater etc., I'd like to extend that to 4 days roughly.

Again, I am more inclined to spend the money on the bigger system if justifiable but don't have a benchmark to hold that 160 watt system against.

[MikeInOregon]

We have a 150 watt panel on the roof and a 100 watt portable panel that is handy for those times when you are parked under a tree that is shading the roof panel. The portable panel can be moved around on the ground to capture direct sunlight.

When in full sun its nice to have both panels providing power.

[Fireballsocal]

It's gonna take me forever to clean!

[Jayco-noslide]

The solar system we live in is really really big. Sorry, just couldn't resist that opportunity.

[time2roll]

Kits are generally over priced, very rarely have the exact items you need and the controller is usually low end.

Panels are a commodity, shop by price per watt for best value.

Controller is where you should not skimp. More expensive units are more reliable, have better charging algorithm, adjustable voltage, temperature compensation etc. Do fully read the manual before you click and buy.

Matching the components (panels, controller, wire, etc)so they work together is very important to get the value you expect.

[Fireballsocal]

Wow, thanks for the great information. I am now planning the other way. Have the 160 watt setup installed along with a second set of brackets for a second panel should I need it in the future. Plug and play. My usage is about the same as everyone else I guess. I might watch TV a bit more but not all day. I sleep early and wake early and don't have kids.

Now that I have the system settled, what about cost? I work in the automotive parts business. OEM parts are as good as you'll get in general but you pay a premium and there is lots of markup involved. No name aftermarket parts are a **** shoot. You might end up with junk that you need to replace again, you might end up with a solid part that gives lots of value for the money. I see $800 160 watt kits and I see stuff on ebay for a couple hundred.

My goal is to put up the solar system and forget about it, other than to clean it.

[mike-s]

1stgenfarmboy wrote:
I just talked to our friends who are full time in a 26ft TT, he said they can run there 2 batteries almost down and the 160w system will have them topped off in 2 hours in the southern CA sun, 6 hours on a cloudy day.

It doesn't take much to charge a couple of nicad D cells. 😉

In a real system, 2 deep cycle lead-acid batteries would be in the 150-230 Ah range. Let's say 200 Ah. Recommended draw down is no more than 50% for good battery life. So, the need is about 100 Ah of charging after a "full" discharge. Ignoring charging system inefficiencies and the need to put more back in than you take out, 160W will provide a charging voltage of 14.4 V @ ~11 A, in peak sun. So it would take over 9 hours (9 hours x 11 A ~= 100 Ah) of directly overhead, noontime sun to recharge them. And actually much more than that, since the current tapers off as the battery gets full. It's hard to fully recharge a battery which has been drawn down by 50% in 12 hours, even with unlimited power available.

Either they're not discharging as much as they say, or their battery isn't getting fully charged. Probably a combo of both.

[FLY_4_FUN]

When I was planning my system for 2 x 6v I was convinced 200W was plenty. My buddy convinced me that for an extra $200 and a few brackets I could get a second 200W panel. Glad I did as now I can get 4 x 6v or just have my twin GC batts charged up that much faster. I still have room to expand if I want to. For sure everybody's needs will differ but few on here ever complain about too much solar.

[1stgenfarmboy]

I just talked to our friends who are full time in a 26ft TT, he said they can run there 2 batteries almost down and the 160w system will have them topped off in 2 hours in the southern CA sun, 6 hours on a cloudy day.

We had 50w on our Lance TC and it kept the 1 battery full unless it was dark and rainy for 3-4 days in a row, we only used it for water pump, and WH,fridge control power, we used portable lights and no tv, we have camped for 9 days off grid and only ran out of water.

[mikakuja]

We currently have 200 watts with a 30A controller and will be adding 200w more.
We love our solar and have not looked back once... Sure we still have to break out the gen every now and then, but that's ok as it's not that often.
I wouldn't go for less than the 160w that you were looking at.

[BizmarksMom]

What are your actual needs?
I use water pump, lights, charge phone via 12v plug, and furnace. 120w of solar works just fine for me.
If your power needs are higher, you'll need more solar panels.

[4aSong]

Everyone solar requirement will be different based on usage. We manage to get by nicely with a Renogy 100 portable suitcase unit which keeps both batteries sufficiently charged, our main usage is water pump, lights and the occasional inverter to keep our phones charged.

[time2roll]

While in use 160 watts is just barely there. Don't get less.

160w panel $125 10 amp controller $50 https://www.solarblvd.com/ (Norco)

You will not save much by going smaller. Price per watt for all things goes up as the system shrinks.

[pianotuna]

It truly depends on the camping style. When I was part time 256 watts was enough. Now I'm considering going to over 1000 watts.

For my further thoughts on solar, surf here: https://freecampsites.net/adding-solar/

[KD4UPL]

160 watts, in my opinion, is probably enough for moderate needs. I have 100 watts on my truck camper and it meets our needs quite well. We just use it for lights, pump, furnace, etc. We don't watch TV or have a big inverter in use normally.
Typically the larger a solar panel the less expensive it is on a dollar / watt basis. You can get a smaller panel but you won't be saving much money. In fact, you may be able to get a larger one for almost the same price.
You can't have too much. There's no downside to going larger other than cost.