solar panel for charge car battery in woods

Does anyone have a recommendation for a solar panel for charging a car battery in the woods?

 

Assuming you JUST want a trickle charge to keep the battery up, 40-50 watts will do. Here is a 40w (about 70 bucks) I use on the corner of my sawmill building to keep the battery topped off when I go for long periods I don't run the mill. I use a cheap (like 15 bucks) charge controller so it doesn't over charge the battery.



Wire to the right goes to plug connector on the mill.




Here is a 50 watt I use on the roof of one of my chicken coops....it keeps a 12v battery up that runs the automatic door open/closer on the coop....two cycles/day of a small 12v motor.



Battery connected to that 50w panel, and same charge controller as at the mill.....cheap.....I buy them in bulk.....ahahhaaaa. White thing on the door is a DC timer that tells the door when to open and close.


Here is a 100w panel on one of my green houses.....no battery in this deal, wire directly to a DC fan.....suns shines, fan runs. I ran it thru a breaker and a thermostat so it doesn't run on bright sunny WINTER days when cooling the greenhouse isn't needed.



IF you want more power than just a trickle charger, you're gonna have to step up to larger panels, better charge controller, etc.

Here is a 6,000w stand alone system on my shop:

 

wow. That's quite a setup you've got there. I'm jealous of your saw mill. So cool!

I was talking to a guy tonight at Advanced Auto Parts and he said that he has a solar panel for his van and he'll trickle charge the battery via solar panel. He said he got his panel from Harbor Freight.

I'm totally new to all this. This will be my first experiment with solar panels. I think I just need a trickle charger for my battery and that unit that prevents the battery from getting over-charged. Do you have a recommendation on where to get one of those?

I might also want something to charge my phone and run a computer. Not sure if I can do that off of the same unit or if it's better to have separate ones.

 

How are you going to mount the panel ? On a vehicle, or something else ?

And what is your budget ?

 

In the woods? You'll need a sunny spot to set the panel, the roof of the car may well be not the best place.

 

You might consider a separate deep cycle battery for your solar, for lights and play, and the vehicle battery remains exclusive to the vehicle.

 

I don't have a huge budget for this. I just wanted something to get me out of a sticky situation if I was in the woods with my camper. Maybe a couple hundred dollars. Not sure how much these things run.

Ya, maybe I'd need to cut down some trees to get a sunny spot. Hadn't thought about it too far to be honest.

 

The

The guy at Adv Auto Parts was talking about deep cycle batteries. I think he said he had a marine battery?

I know my camper has two batteries. One is for the vehicle and I guess the other one is for lights in the camper (which don't work currently). There's also a converter in the vehicle. I never really understood what that was or how it worked. I think it worked when I first got it, but it doesn't seem to work anymore. Maybe it's because the other battery died. Not sure.

But maybe I should swap out the other battery and put in a deep cycle battery?

When I was at Adv Auto, I got a new "Platinum" battery for the main battery. The guy said it has more oomph when you're trying to start it in the cold or in the woods, so I figured it was worth the extra cost. It was like 200 bucks or so.

 

As a side note, one other interesting thing the guy at Adv Auto told me, is you can take a tin can, fill it with sand, heat it in a fire, and put it in your tent and it will provide heat throughout the night. I never heard of that before. Kind of interesting.

 

It's an old Toyota camper from the 70s.

 

Not sure I even want to admit to my solar setup I had at my cabin for years. We're talking low/no budget. I used 2 old car batteries. Not good enough for vehicle use but they still would hold a charge. I kept one hooked up to a 5 (maybe 10) watt harbor freight solar panel with just clips. When I went up to the cabin I would use the unconnected one. Only used it for a little DVD player or to charge my phone. Occasionally I would hook up a radio to it or an inverter to use the vacuum for a few minutes. When I left after a day or 2 I would connect that battery to the panel. That left the other charged battery ready for the next visit. Not kidding when I say I used it like that for almost 8 years. I was careful to never allow the voltage to drop too much. If it did I would pull out a larger panel and top it off. Or just stop using it. I kept a cheap multimeter hooked up to them when I was up there so I could monitor. I bet it was more like 10 years now that I think about it. One visit I found both batteries dead and the alligator clips corroded apart. Haven't gotten around to installing a (real) system yet. Have all the components. Just not the batteries. One day. Just not really necessary up there. I fire up the generator when I run the vacuum.

 

I like the generator idea. That would be a good thing to have as a fail-safe.

 

I picked up the generator and battery charger. I also picked up a cheapy solar panel from Harbor Freight to experiment with:
25 Watt Solar Panel

 

Harbor Freight stuff is junk, and a 25w panel is barely enough to keep a battery topped off with zero draw on the battery.

 

What would you recommend instead?

 

That you go to at least a 100w panel with some kind of charge controller if you plan to actually use the battery, not just maintain it's internal loss.

Go to Amazon, enter the words "100 watt solar panel". They run 80-100 bucks. Then look up "charge controller".....get a 20-30amp one, they run about a buck/amp. 20 amp will let you add a second 100w panel down the road if you find you need it. 30 amp will let you add up to 3 or 4. Personally, I'd allow for expansion, because it will surprise you how little real world production even a 100w panel does. This is the bare intro stage that will provide some small amount of solar power......IMHO.

If you decide to go beyond that, you get into far better charge controllers (MPPT) and far higher watt panels, more/better batteries and so on.

 

The idea of watts is also sort of confusing (it was to me at the start) I like to convert to Amp to calculate my charging. I have a 40 amp/hour battery on my ham radio for backup, 25watt solar panel at 12volts is ~2amps (everyone feel free to correct my math if i go sideways) so 2 amps per hour means I need 20 hours of full sun at 100% efficiency in order to charge that battery from empty to full with your solar panel (well, maybe 16 as you should only use %80 of a deep cycle)
Most deep cycle batteries people use are in the 75 to 100ah range.. so.. 100ah battery.. 80ah usage, 2 amps would be 40 hours of charging. FWIW.
Of course your load requirements will factor in to all this (you can have 1,000,000ah of battery, but if you only use 2amp worth a day then no big system needed)
The generator is a good move, you could probably charge the battery and use the power from the gene at the same time. I think definitely look into a bigger panel. Last I looked (over a year ago) about a dollar a watt was a good price, maybe someone else can chime in on what the current rate is.

-JW

 

During the winter while living in the desert the sun was very low on the horizon so the solar we had was not working. in place of that, I assembled a small 5 Hp Briggs and Stratton engine with an automotive alternator and voltage regulator, to charge my battery bank. It worked out very well and only needed to fire it up for an hour or so in the evening unless we had something special going on. and this before LED lighting we used automotive lights.