Solar Chargers

How long would it take a 7 or 13.5 watt solar panel to charge a 5AH battery?  (12v)

.... Till July
Unless you move.

Good Question Lee.

And, where do I find the electronics to make it a switching trickle charger?

-Spot-

I have a feeling pole^2 is about to spray a metric ton of assbeat all over this question.

I'll spray later.  At Lambert Bridge drinking some of their tasty merlots.

-Allen

Beuller?

Maybe rawkfish will chime in he's and electrical engineer. Me thinks he should have the answer. Mr Rooney is looking for Beuller also.

Beuller?

A 12 volt, 5 A/H battery delivers a total of 12 x 5 = 60 watts.
So, the time a 12 volt, 7 watt charger will take to deliver 60w  is 60w / 7w  = 8.57 hours.

And the time a 13.5 watt charger will take to deliver 60w  is 60w / 13.5w  = 4.44 hours.
This assumes the battery is really discharged...when fully charged, the battery open circuit voltage will be on the order of 13.5 volts DC

Thanks! 

Spot.....Linear Technology is only one of the sources of "smart" charging chips.....you might be able to wrangle a "sample" from them if you ask.

Thanks Doc!

A 12 volt, 5 A/H battery delivers a total of 12 x 5 = 60 watts.
So, the time a 12 volt, 7 watt charger will take to deliver 60w  is 60w / 7w  = 8.57 hours.

And the time a 13.5 watt charger will take to deliver 60w  is 60w / 13.5w  = 4.44 hours.
This assumes the battery is really discharged...when fully charged, the battery open circuit voltage will be on the order of 13.5 volts DC

This also assumes 100% efficiency from the sun exposure as well. 

I too am considering a solar charger for my phone, and or FF/GPS during a week or more float trip.

The reviews I read on the Goal 0 products look really good.  Small, light, not too expensive, and they work.

I just got a goal zero guide 10 to charge my cell phone for a 4 day hunting trip.  I would charge the phone directly from the solar cells when I could, but I could also charge the 4AA battery pack and then charge my phone from that. 

I just got a goal zero guide 10 to charge my cell phone for a 4 day hunting trip.  I would charge the phone directly from the solar cells when I could, but I could also charge the 4AA battery pack and then charge my phone from that. 

Not a bad thing to keep in your emergency preparedness kit at home for those long power outages.