Allright. I got it all figured out. I'm trying to convince my girlfriend to spend more time with me in the mountains. I bought a pickup and am going to find a futon mattress to fill the truckbed (maybe on a loft if I can find/build one...help?).

Today at the hardware store, I saw the answer.... 12V electric blanket. If I can build a super comfy bed with an e-blanket, no reason not to go.

However, I got to thinking how bad it would suck if I drained my battery during the night. But then I thought back to when I scored a solar car battery charger on Ebay. So now all I have to do is find the best spot to sleep that isn't too tree covered and will get plenty of sun the next day while mtn biking or climbing or hiking.

It's always kind of baffled me how plugging 17V into the cigarette lighter charges a battery. Has anyone else charged their battery this way while leaving your vehicle at the airport or whatever?

 

that sounds pretty cool! maybe bring a second batter just for the purpose of draining it? like buy a deep cycle battery.

and that's how all battery chargers work, they charge batteries with 15-17 volts... kinda like osmosis... going from an area of higher concentration (higher voltage) to an area of lower concentration (lower voltage).

 

You would probably have better luck going with an isolated dual battery system with the second battery being a deep cycle. That way you are not up the creek when the next day is too cloudy to get your rig started again. Also, unless you have a deep cycle replacement for your starting battery, it's not going to like being drained very much.

Do a search and you will find a bunch of different ideas about the best way to set up dual batteries.

Then, you can always use your solar charger to maintain the batteries and as a backup.

 

Don't count on any ammount of solar cells you can fit on a pickup to compensate for an electric blanket, extra batteries is the only way to go.

Lamm

 

Here ya be man:









The frame was built with 1x10 supports and i used 5/8's plywood for the top of it

 

yeah that would be perfect!

 

Well, shoot me a PM if you want to know any more info.

 

Worked thru the math a little. An electric blanket is about 80 watts. The solar panel claims max power to be 3.2 watts. That means for every hour using the blanket, I'd need 25 hours of perfect sunlight shining directly on the panel to replenish.

Might be worth getting a deep cycle marine or golf cart battery and not connecting to my alternator. They are actually really expensive, though. Maybe someday I'll run across a used one. Just charge it all week and it should work for several nights. (Colorado = endless sunshine) Keeping it away from the alt is a lot easier than dealing with the dual charging and mounting issues.
I still have the 25:1 charging to use ratio with the Solar panel.

Quoting L33T35T 4runner:
"and that's how all battery chargers work, they charge batteries with 15-17 volts... kinda like osmosis... going from an area of higher concentration (higher voltage) to an area of lower concentration (lower voltage)."

The part I don't get is what happens once the battery is fully charged? Then I have 15-17 volts going somewhere and assume it goes to heat but what heats up? There's no safety switch turning this thing off.

 

well it matters what amps your charger is putting out. if you have it on HIGH charge, its probably putting out 30-40 amps at 15 volts. this is really hard on batterys. what your actually doing is pushing the acid back into solution inside the battery. once all the acid that is back into solution and no more will go, it simply wont charge anymore. if this is done for a while, batteries can heat up quite a bit and if gone for too long, explode. i was charging an 8D battery (huge battery) at school once, and the timer stuck. i put it on the charger for 30 minutes, it ended up charging (we got caught up with class and what not) for 3 hours. there was acid all over the floor, and you could hear air trying it escape from the vents on the battery. as soon as i found this out i put it outside to let the gases vent, becuase those gases are highly explosive (hydrogen gases, kinda like the hindenburg)

 

http://hyperphysics.phy-astr.gsu.edu.../leadacid.html

i like this second link:
http://www.batterycouncil.org/works.html

 

Gotta remember this is a solar charger. At max sun, it puts out like 0.25 Amps at 15 Volts.

 

exactly. i never made a reference to the low charge. you could probably leave that charger on a 12v battery indefinately and not have a problem. i know at my Diesel Tech school in the USMC we have these small trickle chargers on all our batterys for our learning trucks. we have 2 rows 10 trucks. each truck has its own trickle charger that is permanitly hooked up, since the trucks arent moving. the chargers are on 24/7, so i dont see any problems with a 24/7 solar charger... especially since the sun is only out for half the day.

 

More than half the day as of now.... WOOO HOOO.
Come on summer.

 

the solor battery charger will only work if your cig lighter works with the truck in the off position. Ant then they take forever.

 

the blanket would use 80 watts per hour (of operation ON time) choose a battery that would be rated (W=V x A) to run for the amount of time needed. car batteries are usually only described in CCA. when using a dual battery system, both batteries should be identical. higher rating will last longer or run more stuff for the same time. maybe a generator would be a good choice if you have to run all that stuff, and a hair dryer too???

the 3.2 watts is probably a charge rate and is independent of battery usage, but is a measure of how long it will take to fully charge a discharged battery.

 

I'm looking for a reliable solar float charger for my 95 4Runner, which gets little use (once a month or so). The battery has gone dead a few times and I'd like to avoid having to disconnect it and take it to the local parts house for charging/replacement. The truck is parked outside, so a solar panel is a must.

1. Can anyone recommend a good one they are using?

2. What power output solar float battery charger should I buy?

The only info in my owners manual that is remotely relevant is the spec page: "charging rate, 5 amp max."

FYI, "trickle chargers" continually charge a battery and can cause damage if not disconnected once the battery is fully charged. "Float chargers" have a charge controller that shuts off the juice going to the battery when it is fully charged, and turns the juice on when charging is needed again. As such, float chargers can be connected to a vehicle for months with no overcharging issues.