Solar Panels size

[arizonatruck]

What would you prefer and why? One large capacity (say 300), or multiple lower capacity solar panels.

Now that I think about it, I would like multiple 100 watt panels versus one 300 watt panel. Although, if I could, I would have multiple 300 watt panels. But at the high price of one panel, it's hard to afford. Today in the phoenix area, it's cloudy, on days like this, it's relying more on battery power.

 

[AltTransBikes]

Good question, this is all new to me and I'm real interested in what users have experienced for the particular power needs they have.

 

[WheelEstate USA]

I like having multiple panels. Having had mine out as portables, there were some days I only needed one.
And, as someone said on another thread, if one takes a crap you still have the rest.

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Also, on limited funds a person can always upgrade as they can afford it.
At first we had no charge controller, so I would monitor with my meter and hooking and unhooking as needed. I got pretty good at "feeling" our system. Kind of a hassle, but camped on BLM it worked till we scored a nice charge controller from a buddy.

 

[Mac J]

The main point I'm trying to make here is that once the batteries are fully charged having one large (300 watt) solar panels or even multiple large solar panels is moot as they are only topping up any use the battery bank is using. On a cloudy day you will be relying on stored energy in your batteries not your panels (no mater how many or how large they are). As I mentioned before 2 six volt Trojan T105 batteries will hold 550 amp hours. More or larger solar panels will not change that.

 

[Willy]

I'll take issue with the 'cloudy day' bit cuz the panels will still charge your batteries.. just at a reduced rate. Believe me, got lotsa cloudy days up here in the winter, just had a week of 'em (with rainrainrainrainrain) and my batteries were charging up. More watts can definitely help, in that scenario, though more batts doesn't hurt. ..Willy.

 

[Mac J]

You are quite correct Willy, cloudy days do still charge the batteries but at a reduced rate which is why the end user will most likely be relying on the battery bank.

 

[Willy]

I can see that being the case for shorter periods of time but.. weeks/months of cloudy weather (with shorter days), on the other hand, would be a different story. That's why I bumped my solar up from roughly 100W to 185W, and might add another 100W. ..Willy.

 

[Mac J]

Yes Willie, but you are operating a fridge on your system and you need as much trickle charge as you can get. In the case of those that have their solar system in/on their primary vehicle and keep their heaters and fridges on propane extra panels are just extra panels. A trip to the store or to refill LP would most likely recharge the drain that may accumulate over a 5 day period and a 2 x 6 volt battery system would carry the needed energy if used moderately.

 

[Willy]

I got sneaky with my fridge, actually a CF-50 cooler, and stuck it in the cab of my pickup. This way, I let nature do the cooling for me (below freezing weather last night and STILL around that now) and use considerably less power. Where I find the most power draw occurs is from increased lighting needs and just plain entertainment. Yup, got a laptop, and it's reasonably thrifty with power, but kicking back for hours on end watching movies (or surfing the net w. free Wi-Fi when in town) can use a surprising amount of power. Drawing an average of, let's say, 35W of power (pulled that number outta my butt, though it's probably something around there) and' given the various inefficiencies (inverter, power brick, copper losses), can add up to quite a bit. There's also my radio and various batteries that need charging (metal detector, cell phone, heap 'o AA/AAA's, ebook reader). Others might need less power but, judging from some of the posts I've read, some 'need' considerably more; diff'rent strokes 'n all. ..Willy.

 

[Mark Andrews]

I've got 2 x 80 watt solar panels up on the roof of my stealth camper van which I live in full time. A third one I keep inside to aim it straight at the sun, ideal for when the sun is low in the sky at this time of the year or when it's particularly cloudy or overcast.

By and large, I find this set up is ideal for my needs.

The TV draws 22 watts an hour.

The netbook (laptop) also draws 22 watts an hour.

The fridge (which doesn't need to be plugged in at this time of the year) draws 35 watts an hour.

The LED lighting is minimal, 5 watts maximum an hour depending on how many I use.

The pure sine wave inverter, I must admit I don't know how many watts it uses, not off the top of my head.

By and large I just use old 'duff' 12 volt car batteries picked up at the scrapyard for £15 each, typically 100amps. There's 3 of those onboard plus the main battery under the bonnet (hood) which I don't like to use for anything but starting the engine.

The solar panels on the roof btw are fixed in place using bolts and aluminium 4" angle and on those brackets which are not bolted through the roof I've used marine grade Sikaflex which is like an industrial strength super glue. It has immensely strong adhesive properties and will bind anything to almost anything as long as the surfaces are clean and dry to begin with.

The solar panels on the roof, I've been out in 100mph winds and they ain't going nowhere, they're well and truly stuck down solid.

 

[WheelEstate USA]

By and large I just use old 'duff' 12 volt car batteries picked up at the scrapyard for £15 each

Used to do the same in my old van until I was told what I was supposed to have. Damn, I was a happy camper back then.

 

[Mark Andrews]

Might be different in North America but I doubt it. There is actually no difference at all between ordinary 12V car batteries and leisure / marine batteries.

The latter tend to simply have fancy stickers on the side denoting that it's a leisure or marine battery, as the case may be. All the while the price suddenly jumps right up far in excess of what you'd pay for exactly the same item, which normally you would pay a lot less for. It's just another marketing con.

In fact, on this side of the pond, there are only two manufacturers that i'm aware of that do actually make real leisure / marine batteries. The rest are all fakes.

 

[Willy]

It quite possibly IS different here in N. America. Got 3 deep cycle batteries and they are significantly heavier than the same sized starter battery (thicker plates) and have both post and stud connectors. ..Willy.