Solar battery charger

Anyone use them?

like this: http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=44768

How long does it take to charge a battery that's drained (let's say) half way?

 

It won't. It's only to keep the battery from going dead while the car is sitting.

 

spend $300-400 on a big solar panel, and another $50-100 on a charge controller, and you can charge a half run down car battery in a day.

 

The magic of solar power. Just buy a good battery.

 

There are times/places where solar charging is worth the money to buy the equipment....not many, though.

 

It's for a project.

Building an electic vehicle and need a way to charge the battery with renewable energy.

 

.... then you need the big panel and the controller like Squirrel said......

 

just how big is your electric vehicle? We used one of those big solar panels to recharge the batteries for our underwater ROV this summer, it took a few hours to bring them back up...4 each 7 amp hour 12v lead acid batteries. And the ROV weighs about 25 lbs, and moves at a couple feet per second max (underwater)...and could run for about half an hour on a charge.

 

I use these
I have many ol cars,

these chargers give me the knowledge that a battery wont go dead if one of my cars isnt driven enough

I let one car sit for 8 months, splashed some gas down the carb and the well charged battery fired it right off

RECOMMENDED

 

I use one on my boat, but the battery needs to be up for it to do the job. It's really nothing more than a trickle charger...

 

That thing is rated at 1.5watts. That is about 100mA of current in a 12 volt battery. If you have a half dead 60 amp-hour battery, it will take 300 hours to charge. I assume that is the output at full direct sunlight, which you can hope for for maybe 6 hours per day at most. It might maintain a battery, but it is not going to charge one.

Large scale solar systems cost a few dollars per watt of output. As a guess say you have 4 batteries, 12 volts each and 60 amp-hours. If you have a 1,000 watt solar system you could charge the pack in about 3 hours. You are maybe looking at $5,000 for this system.

Those 4 batteries will give you about 3 hours of run time at 1hp of output. Let the good times roll!

 

We don't know how big his electric vehicle is, it could be something pretty small...but if it's a full size car type thing, it ain't gonna work with any kind of affordable solar array.

 

We have a solar panel on the roof of our engineering trailer at work. Runs more than just a battery charger. When parked out in the Imperial Dunes, it keeps a couple of laptops, 18V tool battery chargers, radio, and a small fridge humming all day long.

 

there are specific batteries for solar aplications.

 

I'm taking some PV and alternative energy classes. I really want to move into this industry.

We have a class project to turn junk into energy. Most evryone is doing simple stupid stuff like making a magnet out of battery and some copper wire.

I figure I could make an electric vehicle (ok it's a motorized bar stool). I can use either an old 13v battery drill for the motor or go bigger with a motor from a home cieling fan. I'm going to run it with an extra 12v car battery that I have laying around. It's not a deep cycle .. but good enough for the project.

All I want to do is be able to recharge the battery with out having to plug it into the grid.

I don't have a full solar array yet. Just starting out.

IDEA: Could I hook up extra cables in my car and charge a secondary battery while I drive? It wouldn't be completely energy independent but it would charge during my regular driving.

 

A motorized bar stool, with battery and driver, would weigh somewhere around 200-300 lbs (depending on the amount of time the driver has spent on barstools, obviously). That's 1.5 to 2 x as much as the "big" robots we play with...they run pretty much continously during a 2 minute match, with a 18 ah battery, and run the battery down about halfway during a match. This I have experience with. Recharging that battery would take about 10 amp hours...you'll get about 5 amps peak out of a "75 watt" solar panel....so it would take a few hours to recharge with that solar panel after driving your barstool around for say 5 minutes or so.

If you bought a 20w panel you could probably do what you want. You'd either want a charge controller to go with it, or you have to keep a very close eye on the charging voltage, so it does not overcharge....so, plan on getting a charge controller. exploding batteries are not pretty.

You could also just charge it from your car as you drive, and pretend that you're not using any extra gas to power the alternator.

 

your starting to scare me................using terms like "the grid"

 

You need to look into using the brakes as a generator as well. Braking causes resistance. Not sure if the act of the wheels turning couldn't be utilized as a generator as well. Like a windmill.

Just thinking outloud. Maybe not.

 

for what he's doing, regenerative braking is probably way too involved and not worth the effort.

 

I was sceptical about solar panels until I bought a small one for my caravan earlier this year,
It was only a $50 ebay panel but it charges a car battery enough during a day to run the 12V lights and water pumps at night. Made my noisy generator redundant.
In the winter I have it connected to my Rod battery to keep it topped up.
Rich

 

These are to offset the constant tiny loss of an ECU in a modern car that sits unused for a month or three. Don't expect them to actually power anything bigger than RC cars.

 

Thanks guys.

I'm a tree hugger at heart. Not one of the "the tree is crying people"... just one of the "I'd rather look at a tree than a billboard" type of guys. I have always recycled and I compost.

On the energy side. It's an economic and security issue for our country.

(Peak Oil: http://en.wikipedia.org/wiki/Peak_oil)

I don't mind driving old cars on oil annd gas... but no reason that my 3 cell phones, 4 computers, 4 TVs, and every other "modern" piece of electrical equipment has to run on coal or natural gas when we have perfect sunlight 10months a year.

 

I can see getting into the PV field for another reason...there might be money to be made, what with the current legislative attitude.

When we were using solar power to charge up the ROV batteries last summer, it sure was neat to just plug the battery box into the panel in the morning, by noon it was all charged up. Since my brother owns the solar panel, it was all free energy for me

 

Keep an eye on what they're doing at the U of A labs on solar. I'm gonna wait and see what develops before I buy a PV setup, they predict $1 per watt soon. Thats cheap!
Probably do a Google search on the progress, guy's name is Angel or something like that...

 

roger angel the telescope mirror guy? or someone else?

(my brother works at Steward)