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Cheap solar panels at Harbor Freight
By whatsnext, Section Classifieds Posted on Thu May 25, 2006 at 09:09:01 PM MST
cheap solar panels

I just got emailed a coupon for a 5 watt panel with the final price being $24.99 with a lilit of five. $5/watt is not too bad for someone wanting a 5-25 watt solar array.
You need to sign up for email offers to get the emails which can be a bit much after a while but this one looks good.
John..

Cheap solar panels at Harbor Freight | 17 comments (17 topical)

Re: Cheap solar panels at Harbor Freight (3.00 / 0) (#1)
by ghurd on Thu May 25, 2006 at 03:39:01 PM MST

Not a bad price right now. Good price.
The quality is not very high.
G-

Re: Cheap solar panels at Harbor Freight (3.00 / 0) (#2)
by DanG on Thu May 25, 2006 at 05:57:09 PM MST

http://www.billt.com/harborfreight.htm

Link is a website just for passing on Harbour Freight coupons..

Don't know how many you can tack onto an order but it's worth a try...
-

Re: Cheap solar panels at Harbor Freight (3.00 / 0) (#4)
by whatsnext on Fri May 26, 2006 at 06:54:58 AM MST

I went by my HF and got five. Not sure yet what I'll do with a 25 watt panel but I'll think of something.
John..

[ Parent ]

Re: Cheap solar panels at Harbor Freight (3.00 / 0) (#3)
by terry5732 on Thu May 25, 2006 at 10:30:05 PM MST

I hate coupons and sales. I'll bet it's just a bait and switch gimmick and they charge $10.00/Watt for the sunshine.

Re: Cheap solar panels at Harbor Freight (3.00 / 0) (#5)
by asheets on Fri May 26, 2006 at 09:59:22 AM MST

Most of the time I'd agree with you, but HF in Ft Collins does do a decent job honoring their coupons and rainchecks. They redeemed a 40% off flyer ad for a compressor 3 months after the actual sale. Of course, the thing was barely worth what I paid for it, as noisy as it turned out to be.

I had, at one point, bought a bunch of these -- http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=44768 -- at the sale price and then threw in a 50% off coupon. But HF sells out of these fairly quickly when this combo of events comes up.
_____________________________

Alan Sheets
[ Parent ]

Re: Cheap solar panels at Harbor Freight (3.00 / 0) (#6)
by rottingspinalcord on Fri May 26, 2006 at 01:33:38 PM MST

alan where did u get the coupons? i kinda want to get one of those 45w sets, nits only 4.44$/watt!
dont ever get stuck in the sky when your high-soad
[ Parent ]

Re: Cheap solar panels at Harbor Freight (3.00 / 0) (#7)
by asheets on Fri May 26, 2006 at 02:06:43 PM MST

I have coupons sent to me every week by signing up at harborfreight.com...
_____________________________

Alan Sheets
[ Parent ]

Re: Cheap solar panels at Harbor Freight (3.00 / 0) (#8)
by cjdock on Fri May 26, 2006 at 05:27:06 PM MST

I have that 45w 3 panel kit. Yes it was cheap but I never get more than 2.4 amps from the panels, and usually it's under 2 amps. This is with me up on the roof, placing the panels in the best position, and with perfect sun conditions. I have a very acurate amp meter in series with the power cable going to the batteries. 45w/12v=3.75 amps...not with these panels. I checked each one out seperatly to make sure none were bad. They were very consistant with each other...
Cheap panels....never again

[ Parent ]

Re: Cheap solar panels at Harbor Freight (3.00 / 0) (#9)
by dinges on Fri May 26, 2006 at 05:37:44 PM MST

Not sure, but probably these panels put out 17-18V @ 2.4A = 43W.

However, when you connect it to a battery for charging you only get the 13.8V x 2.4A= 33W. For the remaining power (the 18-13.8V times 2.4A) to be useful you need to have a MPPT (maximum power point tracker) connected, basically a switchmode PSU.

Maybe that's the reason why you're not seeing expected power output. And yes, marketing has a lot to do with it, I'm afraid. On the other side, you could harvest that power, if you take care: installing a MPPT, installing a solar tracker.

Sometimes I suspect the datasheets are made by marketeers and not the engineers.

Peter.

[ Parent ]

Re: Cheap solar panels at Harbor Freight (3.00 / 0) (#10)
by BrianK on Fri May 26, 2006 at 06:24:18 PM MST

I have 10 of those hf 5 watt solor panels and 1 set of the 45 watt panels they all seem to work good the only part that i think is really cheap is the charge controler that came with the 45 watt kit

Re: Cheap solar panels at Harbor Freight (3.00 / 0) (#11)
by fungus on Sat May 27, 2006 at 03:22:52 AM MST

Hi,
for a switching regulator, have a look at http://www.ortodoxism.ro/datasheets/fairchild/KA7805.pdf, the datasheet for the KA7805 chip. it's only 1 amp but could be expanded. Go to page 24 a nd it's got a switching regulator schematic.

'Two things are infinite: the universe and human stupidity; and I'm not sure about the universe.'-Albert Einstein
Fungus - www.reenergy.co.uk

Re: Cheap solar panels at Harbor Freight (3.00 / 0) (#12)
by fungus on Sat May 27, 2006 at 03:29:47 AM MST

sorry the link is http://www.ortodoxism.ro/datasheets/fairchild/KA7805.pdf (a comma was put in)

'Two things are infinite: the universe and human stupidity; and I'm not sure about the universe.'-Albert Einstein
Fungus - www.reenergy.co.uk

Re: Cheap solar panels at Harbor Freight (3.00 / 0) (#13)
by justjimmy on Thu Jun 08, 2006 at 06:35:43 PM MST

i live in arlington texas i have 12 of the harbor panels i get about 1.5 amps per
set of 3.they are cheap, but if a tree branch goes thur one i trash it .not like a
125 watt $600.00 in the trash.while i am crying.if you sign up whit harbor to receive emails i get 20% off on one item last 45 watt set was like 178.00 with tax.
no a bad deal.

thanks jimmy

Re: Cheap solar panels at Harbor Freight (3.00 / 0) (#14)
by jerryg on Sat Dec 15, 2007 at 12:20:18 PM MST

>For a switching regulator, have a look at >http://www.ortodoxism.ro/datasheets/fairchild/KA7805.pdf

The 7805 is a linear regulator, probably no more efficient than
what came with the Harbor Freight kit. Perhaps try the
National LM2679, available from digikey.com as LM2679T-ADJ-ND.
Could also be used to efficiently convert 12v from battery down to
something less (5 volts?) needed to replace a wall wart DC adapter.

Re: Cheap solar panels at Harbor Freight (3.00 / 0) (#15)
by fungus on Sat Dec 15, 2007 at 02:50:55 PM MST

jerryg - if you had read the rest of the comment and looked in the datasheet there is a circuit to make it a switching regulator using the 7805 as a 'driving module' so it can be used as a switching regulator.

'Two things are infinite: the universe and human stupidity; and I'm not sure about the universe.'-Albert Einstein
Fungus - www.reenergy.co.uk
[ Parent ]

Re: Cheap solar panels at Harbor Freight (3.00 / 0) (#16)
by jerryg on Sun Dec 16, 2007 at 10:38:34 AM MST

Wow, that's a novel circuit!
You're right, I didn't read your post thoroughly.
Fairchild data sheet now here, switcher on page 26:
http://www.fairchildsemi.com/ds/KA/KA7805E.pdf
They're pretty common in consumer electronics of
the last 20 years, so should be free. But I would
probably spend the $5 on something like the National
part, if only for the more complete design notes.
Thinking of getting a few of those HF 44768's,
1.5w at $11.99 without a coupon. Price per watt
within 2x of the 100w panels I see, rather amazing.
jerryg

[ Parent ]

Re: Cheap solar panels at Harbor Freight (3.00 / 0) (#17)
by ghurd on Sun Dec 16, 2007 at 11:37:29 AM MST

I like these... About $12, but ready to use!
http://www.cd4power.com/data/meters/dms-78xxsr.pdf

G-

[ Parent ]

Cheap solar panels at Harbor Freight | 17 comments (17 topical)

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