Solar - 2 panels better than 1?

[OuttaHere]

Good day all!

I am starting to gather items for my build as I see them. There are some 100w (5.6A) panels under $200CAD on sale here in Ontario and wondering if wiring two would be beneficial or just a waste if money. The amps seem low for a single panel. The description states they are crystalline, but thinking they may not specifically be the more efficient “mono-crystalline”.

Thank you for for your input.

 

[smritte]

I have a single 120 watt crystalline panel with a decent controller. The panel's a bit big. I set it up in the sun on a homemade stand and have 10 gauge wire from it to my controller mounted in my trailer. Due to the fact nothing is perfect I get about 7-8 amps out of it. If you do the math I should get 10 amps. I found this output to be average. The panel is more than enough to run my fridge and keep my trailer battery charged. I'm thinking of going with 2 smaller ones due to ease of handling.

I did some searching and found a place that sells surplus panels. https://www.solarblvd.com/.
Here is link to their 12 volt panels https://www.solarblvd.com/product-category/solar-panels-systems/12-volt-solar-panels/
It seems some of these solar farms replace their panels every couple of years. This place is about 5 miles from me. The guys there are great, the panels come with the remainder of the factory warranty and are discounted pretty well.

As for what you should run, figure out how much power you need. The panel only puts out max when pointed at the sun directly. Figure in a bit of loss unless you want to move your panel once or twice during the day (I center mine so the sun sweeps across it and call it good). Next look at the panel dimensions, use solar blvd web site to do your size and output calculations. Now go shopping for panel and controller. Look at the controller types also. With only one panel I run a cheaper controller. The loss isn't significant and I payed $60 instead of $150 for the real good one.

Scott

 

[Jason Harris]

Take a look at overland solar they sell sun power celled mono crystalline panels they are very effective. I’ve been running them for quit some time with 100 percent satisfaction and a very reasonable price

 

[bendts]

2 is 1, 1 is none. If you have 2 panels and one dies, at least you can still get something from the other . With 1 panel, it dies and your sol.

 

[Jason Harris]

2 is 1, 1 is none. If you have 2 panels and one dies, at least you can still get something from the other . With 1 panel, it dies and your sol.

 

[Jason Harris]

We ran two 100 watt panels on this build and used two into one mc4 connectors that could be easily removed to run just one panel IF one got killed without any hassle.

 

[Kelso]

Depends on your power requirements and available space (if mounting to rig). Obviously 2 are advantageous for redundancy as well as higher output IF you have the electrical demand. Are you staying stationary for days at at a time or driving every day where your alternator is primarily keeping things charged? If you buy 2 but don't have the power draw and never have a failure then the second one was 100% unnecessary. Also shop around more, panels can be had for closer to $1CAD per watt these days (250W mono-crystaline for $280 for example)

 

[DK_XV]

You would likely want at least 100w per house battery. 150w would be good for just one battery as that's a little bigger in a pannel, but will give you more capacity. About 50 amps per day you would collect.
When I had my camper I had 400w to two batteries. I live in the NW so not all sunny days are full sun days. So added in more pannels to keep up demand. never needed to plug in or run the Genny with that setup.
For my build, I'd like a 150w mounted to a roof rack, then a house battery out back. But for the moment I have a 25w portable pannel, and a 40k mah lithium pack that charges my lanterns, batteries, phone etc without much trouble. Once I get a fridge, then I'll get the solar as thats the only high drain device I'd have.

To find the right size for your needs you'll want to chart how many amps you will need per day, then find a suitable battery that can discharge the right amp hours (lead acid can only discharge about half of it's rating and maintain good life) and then add solar that will recharge the battery depending on the amount of sun you get in your area (we get a good 5 hours here in the NW, more equitorial will see 7-8+) as for the pannel makeup (poly vs mono) if you find you really only need a few amps, and don't really need the extra effiencies, you can save a few bucks. But charting your "worst case day" bad sun, lots of recharges and lighting use, fridge warm to start, you can build a system you will be confident will perform well.

Some power examples:
Laptop (3-5amps per charge)
Tablets and phones (1-3amps per charge)
Fridge (30-50 amps)
Lights and accessories (1-5+ amps per hour used)

@DK_XV | PNW | '17 Colorado Diesel