I need advice on a solar purchase please

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I need advice on a solar purchase please

Postby JoshInReno » Tue Aug 02, 2011 6:50 pm

Hello everyone.

Sometime this month, I will be buying a solar panel for my trailer. I am leaning toward something in the 50w range, but more is always better. So I came across this today, and am wondering if it is a decent deal:

http://reno.craigslist.org/mat/2515387183.html

My questions are:

1. Are they link-able? In other words, can I tie two of them together to get a 95w panel?

2. The specs are very faded, but I THINK each panel is capable of 1.22 amps if I read the label right. Does this sound correct?

3. How many amp hours can I reasonably expect, per day, to get out of a system like this?

Any help would be greatly appreciated!
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Postby Breezy13 » Wed Aug 03, 2011 8:26 am

If you get 5 hours of bright sunlight a day, with two panels, you could possible get 10 -15 Amp hours/day.

Have you looked into charge controllers yet?
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Postby bdosborn » Wed Aug 03, 2011 8:40 pm

It looks like they are 18 watt panels so the three of them would add up to around 54 watts. I can't tell what the peak voltage is but 16V in the sun without a load is a little on the low side. You might have a pretty low voltage on hot days. However, you could wire them in series with an MPPT controller and it wouldn't be an issue. But, an MPPT controller is $200.

A 45 watt solar panel on eBay is about $115 (with free shipping) or $2.55/watt.

The 54 watt craigslist panels are $135 or $2.50/watt.

I'd pass on the craigslist panels as I'd rather have a new, warranted panel with published performance parameters and being used, they aren't cheap enough to tempt me.

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Postby JoshInReno » Wed Aug 03, 2011 9:23 pm

bdosborn wrote:It looks like they are 18 watt panels so the three of them would add up to around 54 watts. I can't tell what the peak voltage is but 16V in the sun without a load is a little on the low side. You might have a pretty low voltage on hot days. However, you could wire them in series with an MPPT controller and it wouldn't be an issue. But, an MPPT controller is $200.

A 45 watt solar panel on eBay is about $115 (with free shipping) or $2.55/watt.

The 54 watt craigslist panels are $135 or $2.50/watt.

I'd pass on the craigslist panels as I'd rather have a new, warranted panel with published performance parameters and being used, they aren't cheap enough to tempt me.

Bruce


Thanks Bruce. The panels WERE listed as 45 watts apiece. It looks like the seller has now changed the ad.

At $45 and 45 watts, I was interested. But not at 18 watts. Thanks for catching that for me.
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Postby bdosborn » Wed Aug 03, 2011 9:38 pm

:thumbsup:
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