Northern Tool 45 Watt Solar Power Kit

[Dirtyfootcamper]

http://www.northerntool.com/shop/tools/ ... _200576739

Would this be sufficient enough to keep my battery charged when camping? I usually only run the fan at night for a bit, have a few LED lights, and charge the cell phone or DVD player. Is this deal too good to be true?

Bryce

P.S. Sorry, I don't know exactly what the fan draws, but I'm assuming it isn't much.

[MtnDon]

A Fantastic brand fan draws something like 1.5 to 3 amps depending on speed. Multiply the appropriate amperage by the hours of use = amp-hours used at the rated battery voltage. Let's say 8 hours use on medium speed, about 2.2 amps as a guess. 8 x 2.2 = 17.6 amp-hours. Call that 18 amp-hours. Multiply 18 x 12 (the battery nominal voltage) = 216 watts used.


Panel puts out 45 watts maximum. 216 / 45 = 4.8 hours time required for the 216 watts. BUT that assumes everything is ideal, not real. Add at least 20% to that to allow for battery inefficiencies in charge and discharge. 4.8 +20% = 5.76 hours of full sun. But there are few locations that have ideal sun on the PV panels for that length of time in a single day.


You can use that method to adjust for loads, sun-hours, etc and get a rough idea of how things will go.


I have used panels like that to keep batteries charged over the winter period of non use with great success (with a small cheap charge controller to ensure the batteries did not overcharge). One panel per pair of 6 volt golf cart batteries.

[absolutsnwbrdr]

If you search ebay, you can usually find a pretty good deal on kits. I think 100W kits start around $150 or $160.

I get my stuff from http://www.SolarBlvd.com, and they have an ebay store as well.

[Dirtyfootcamper]

A Fantastic brand fan draws something like 1.5 to 3 amps depending on speed. Multiply the appropriate amperage by the hours of use = amp-hours used at the rated battery voltage. Let's say 8 hours use on medium speed, about 2.2 amps as a guess. 8 x 2.2 = 17.6 amp-hours. Call that 18 amp-hours. Multiply 18 x 12 (the battery nominal voltage) = 216 watts used.


Panel puts out 45 watts maximum. 216 / 45 = 4.8 hours time required for the 216 watts. BUT that assumes everything is ideal, not real. Add at least 20% to that to allow for battery inefficiencies in charge and discharge. 4.8 +20% = 5.76 hours of full sun. But there are few locations that have ideal sun on the PV panels for that length of time in a single day.


You can use that method to adjust for loads, sun-hours, etc and get a rough idea of how things will go.


I have used panels like that to keep batteries charged over the winter period of non use with great success (with a small cheap charge controller to ensure the batteries did not overcharge). One panel per pair of 6 volt golf cart batteries.

Thanks Don!! A lot of good info you just said. I'm not well versed in electrical so that did clear up a few concerns I had. Take care!

[Dirtyfootcamper]

If you search ebay, you can usually find a pretty good deal on kits. I think 100W kits start around $150 or $160.

I get my stuff from http://www.SolarBlvd.com, and they have an ebay store as well.

Thanks Zach!! I haven't jumped the gun yet, still doing a little research on Solar vs. Generators or the combination of the two. Thanks for that advise. By the way I really love the work you did on the X-II!! That is one nice looking trailer. Hope you get a buyer for it soon.

[bdosborn]

A Fantastic brand fan draws something like 1.5 to 3 amps depending on speed. Multiply the appropriate amperage by the hours of use = amp-hours used at the rated battery voltage. Let's say 8 hours use on medium speed, about 2.2 amps as a guess. 8 x 2.2 = 17.6 amp-hours. Call that 18 amp-hours. Multiply 18 amp-hrs x 12 Volts (the battery nominal voltage) = 216 watt-hrs used. (watts=amps*volts)


Panel puts out 45 watts maximum. 216 watt-hrs / 45 watts = 4.8 hours time required for the 216 watt-hrs. BUT that assumes everything is ideal, not real. Add at least 20% to that to allow for battery inefficiencies in charge and discharge. 4.8 hours +20% = 5.76 hours of full sun. But there are few locations that have ideal sun on the PV panels for that length of time in a single day.

My high school physics teacher used to have a fit when I left the units off my calculations. I guess she made an impression on me after all.

The 20% losses is conservative IMHO, and assumes the panel is angled at the sun. Add another 10-20% if it's laying flat.

The NT Kit has a junky controller that's notorious for failing and fluorescent lights you probably won't want to use in your tear.

Here's an 80 watt panel:
Solar Blvd

And a good controller:
Morningstar

For about the same price. More power and a better controller.
Bruce

[MtnDon]

My high school physics teacher used to have a fit when I left the units off my calculations. I guess she made an impression on me after all.

Mine did too. Somehow I passed and graduated but also somehow I have regressed.

[Dirtyfootcamper]

A Fantastic brand fan draws something like 1.5 to 3 amps depending on speed. Multiply the appropriate amperage by the hours of use = amp-hours used at the rated battery voltage. Let's say 8 hours use on medium speed, about 2.2 amps as a guess. 8 x 2.2 = 17.6 amp-hours. Call that 18 amp-hours. Multiply 18 amp-hrs x 12 Volts (the battery nominal voltage) = 216 watt-hrs used. (watts=amps*volts)


Panel puts out 45 watts maximum. 216 watt-hrs / 45 watts = 4.8 hours time required for the 216 watt-hrs. BUT that assumes everything is ideal, not real. Add at least 20% to that to allow for battery inefficiencies in charge and discharge. 4.8 hours +20% = 5.76 hours of full sun. But there are few locations that have ideal sun on the PV panels for that length of time in a single day.

My high school physics teacher used to have a fit when I left the units off my calculations. I guess she made an impression on me after all.

The 20% losses is conservative IMHO, and assumes the panel is angled at the sun. Add another 10-20% if it's laying flat.

The NT Kit has a junky controller that's notorious for failing and fluorescent lights you probably won't want to use in your tear.

Here's an 80 watt panel:
Solar Blvd

And a good controller:
Morningstar

For about the same price. More power and a better controller.
Bruce

Bruce, since I'm new to the whole solar thing, would I need certain cords/wires to hook it all up to my battery? and how would I go about doing so? Sorry if this a dumb question, I'm not skilled in electrical things whatsoever.

[MtnDon]

Look at the image under the link to the controller. Four color coded wires with an explanation of what they connect to, + & - signs included. That's a very brief and simple description of the electrical connections. The connections, the principle, would be the same with different examples of the hardware.

[martymcfly]

I think the HF 45 watt panel is expandable. I read that you can hook up to 6 panels into the controller. It may be cheaper when you use the super coupon.

[MtnDon]

There is another thing to consider when comparing the NT and HF panels to the SolarBlvd panel Bruce linked to (as well as others). The physical dimensions.

The set of 3 NT panels that produce 45 watts are approximately 36 x 36 inches in size. The one 80 watt panel that Bruce picked is only 34" x 26.5" (got the measurements precisely noted that time : ). Almost twice the power in less space. Much better deal when working with small trailers.

[Dirtyfootcamper]

There is another thing to consider when comparing the NT and HF panels to the SolarBlvd panel Bruce linked to (as well as others). The physical dimensions.

The set of 3 NT panels that produce 45 watts are approximately 36 x 36 inches in size. The one 80 watt panel that Bruce picked is only 34" x 26.5" (got the measurements precisely noted that time : ). Almost twice the power in less space. Much better deal when working with small trailers.

You make a great point Don. I do like the SolarBlvd Panel that Bruce posted the link to a lot more than the Northern Tool one I first asked about. As for Harbor Freight, I personally don't trust their electrical stuff. I've heard too many horror stories of their products for my taste.

Bryce

[bdosborn]

The Sunguard is super easy to wire:



I'd use #12 wire and add a fuse on the red wire, right at the battery. There are larger controllers if you want to expand beyond 80W and we can help you size the system. But 80W is plenty for the typical teardrop. Me, I'm at 420 watts (I've kind of got a solar monkey on my back).
Bruce

[mikeschn]

Bruce,

At 420 watts, how long does it take you to recover from a half empty battery?

Mike...

[jonw]

For a little more money here's a folding 120w one from Solar Blvd that comes with a controller and case:

http://www.solarblvd.com/p2756/W-Solar-120-Watt-Foldable-12-Volt-Solar-Panel/product_info.html