Can I connect the output from three [solar] panels..

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Old 01-11-17, 10:40 AM
J
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Can I connect the output from three [solar] panels..

..to get more amperage? I have a shipping container far from 120v that sweats badly inside and bought a 12v fan that you place in from of your car radiator for extra cooling.. it's 12v x 80w.

I have three small panels of unknown power.. one gets the blades moving at about 10rpm (other two Nada - but will light a test lamp) ..could I simply pigtail all three and connect it directly to the fan? ..and/or - would a single 100w overspeed the motor? Thanks.

Jim
 
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Old 01-11-17, 11:59 AM
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would a single 100w overspeed the motor?
Motor speed is determined by volts not watts. You need to be running the fan off a 12 volt car or if you can afford it marine battery. The solar cells would be just for charging. Gut says the solar cells won't keep the batteries charged if the fan runs contentiously. Maybe a timer to run the fan only occasionally.
 
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Old 01-11-17, 03:15 PM
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Are all three your solar panels the same size?

If one panel spins your fan but the other two do not maybe those two panels are bad.

Since you said "small" panels I'll just guess that they are way too small to power your 80w motor. I have a solar powered boat that has a 5 watt panel that keeps the battery charged and that panel is about a foot square. Unless you've got about 8 square feet of panel area I'd guess you don't have enough to fully power your fan. Also keep in mind that the rating of a solar panel is under optimal conditions when the sun is directly overhead, something that never happens in the mainland US, so your output will always be less.

I would install passive, non powered vents. They have no moving parts and can work 24/7. A solar powered fan will only run when the sun is out which is generally the time you don't need a fan to prevent sweating. It's when the sun goes down and things cool that condensation forms.
 
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Old 01-12-17, 05:58 AM
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Thanks guys...

Ray - That's a good solution but I didn't need a timer; I figured the Sun would be the timer.... Good to know about RPM.

P-D - No three sizes.. mostly unidentified. I'll simply wire them together, then to the motor and report back. Pictures included...


Jim
 
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Old 01-12-17, 06:48 AM
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Solar panels have varying output, both voltage and amperage, depending on how much sun is striking the panel. To increase the voltage you need to wire the panels in series and to increase the amperage you need to wire the panels in parallel. Even then the voltage and amperage will vary so it is best to have both a load controller and a battery (load) connected to give a constant voltage to the item being powered.

This way the battery supplies the load a fairly constant voltage, the load takes the amperage it requires and the load controller charges the battery with the output from the solar panels.
 
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Old 01-12-17, 08:48 AM
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One danger with using a battery though is over discharging the battery. Most batteries are damaged by being drained too low so some type of low voltage cutoff would be a good idea.
 
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Old 01-15-17, 10:32 AM
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Guys... It didn't work. I hooked them in series and did not get enough 'poop' to move the blades. (I did get the 12v test lamp to light)

A 120v to 9v DC - 700mA, computer accessory power source drives it just fine. I have to run about a 50' line to add 120v near the container. Then I'll just let it run.... Cheers.

Jim
 
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Old 01-15-17, 01:28 PM
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It is possible that the two panels that won't even cause your test light to glow are simply not working. It is also possible that the amperage of the three panels in series is too low to run the fan.

Have you tested for voltage output of each panel with a meter?
 
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