rickj
New Member
Posts: 3
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Post by rickj on Jan 20, 2017 22:20:08 GMT
Bought a solar ventilation package a few years ago to ventilate my house when I'm not there for longer periods. Idea is that the fan is powered only when the sun shines, so the air is dry, so the house is kept dry. This works fine! Specs: "blue" cells panel 12V/5W , fan 12-17 V 0.8W
As that package costs a lot more than its parts, and is no longer available, I decided to assemble my own, using an amorphous gray panel, 12V/4W (actually: 230 mA @ 17.5V) and a Panasonic 24 V fan (90mA @ 24V, allowed is 10 .. 27 V). This does not work well. It does make the fan turn, but it has no power. And, it starts later and stops far earlier than the blue panel, with the same sun exposure.
Measured the voltage across the terminals with the fan connected: 7.5 V instead of the promised 17 V. That same fan connected to the other "blue" panel runs absolutely fine: the voltage is 17 V, with the fan running fine.
Do you know of a reason why that gray 4W (230 mA @ 17.5 V) panel cannot power a 90 mA @ 10-27 V fan, and the voltage across collapses?
Many thanks for ideas!
rick
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Dave Simmo
Junior Member
Recovering from Surgery. Shoulders had to be rebuilt. End Stage joint damage
Posts: 76
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Post by Dave Simmo on Jan 21, 2017 13:05:21 GMT
Hi Can you post a link to the product. or a pic of the box it came in some of the old Timers here have bought Fans Ventilators ect. Many of us have bought just junk on wonderful recommendations of sellers. Just to have it sent back.
Lets take a look at make and model???
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rickj
New Member
Posts: 3
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Post by rickj on Jan 22, 2017 17:18:53 GMT
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Post by dennis461 on Jan 22, 2017 18:35:11 GMT
I suspect you received a defective solar panel, call for a replacement under warranty.
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usernameinvalid
New Member
Even if you're on the right track if you stand still you'll get run over.
Posts: 16
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Post by usernameinvalid on Jan 22, 2017 19:49:45 GMT
I'm not an electrician but I noticed your fan is 24 volts and your pannel is 12. Or am I missing something?
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rickj
New Member
Posts: 3
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Post by rickj on Jan 22, 2017 23:40:54 GMT
Yes, the fan is a 24 V version, on purpose. These solar panels don't give you 12 V, but something between 17 V and 21 V, depending on the load. The fan is specified for 10 to 27 V; I chose it so it does not get fried. Anyway, this 24 V fan runs ABSOLUTELY FINE on the blue panel, and the voltage across then still is 17 V, and not 7.5 V.
I suspect the panel is defective, too, but I want to be sure I'm not missing something. I'm discussing with the dealer, but they try wriggling out of their responsibilities with nonsensical arguments. For example: "as you know the specs say the panel is only 7% effective so it cannot drive this fan".
Yeah right.
I do understand that 7%: the energy in sun light here is ca 600 W per m2. This panel is .315 x .315 = 0.1 m2, so it catches 60 W; 7% of 60 W is 4.2 W, which is precisely the spec for this panel, and should be more than sufficient for this fan. (I think.)
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usernameinvalid
New Member
Even if you're on the right track if you stand still you'll get run over.
Posts: 16
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Post by usernameinvalid on Jan 23, 2017 0:42:25 GMT
That makes sense. I'm still new to this solar thing. Thanks for taking the time to explain it to me.
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