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Need new batteries? Going from 12V to 18V or 6V to 12V? Wiring Questions?
By glassputan
#20954
Okay, my daughter inherited an old Barbie Jeep from my neighbor. The car takes two 6v batteries. I was working outside and I got an idea, I was wondering if anyone else has tried this... solar panels! :D There are a few 6 & 12v panels on the market today. Has anyone tried this yet? Do you think it would work? If you have, and had success, please share the details!

Thank you!
User avatar
By ElectricRay
#20987
I think it would work as a recharging device. To generate enough juice to power the vehicle in real time, you would need a very large mounting surface. The cost will increase accordingly as well. Here is a panel I saw earlier this week that is somewhat interesting for this type of application.

http://www.harborfreight.com/45-watt-solar-panel-kit-90599.html
Last edited by ElectricRay on Sun May 08, 2011 9:57 pm, edited 2 times in total.
By glassputan
#21013
Okay, I aced physics back in college a few years ago but unfortunately have forgotten most if it.
So admittedly I'm quite the "ignorant fool" at this point. What does the 6v battery offer that a 6v panel misses?

Hypo, I've included the link to the panel I was thinking about.
From what I understand, "output" is measured in volts, but I'm probably wrong, is it amps? :?



Please enlighten me. I'm very interested in this... and thank you again for your replies!
Last edited by glassputan on Mon May 09, 2011 5:42 am, edited 1 time in total.
By treebeme
#21054
You couldn't fit large enough panels to power the vehicle in real-time.

As for a recharging, I looked up that specific charger. Moultrie didn't say how many amps it puts out, but I'm guessing it's far less than a hundred milliamps. That's not enough to recharge a PW battery which has twice the AH that the bird feeders that are designed to use. In fact, I found this in Moultrie's FAQ section.

"Will my solar panel keep my battery charged?

Answer: Not completely. It will extend periods between charges significantly, but has a very low amperage output and will not completely recharge a battery."
By treebeme
#21084
Think of it this way, voltage is how "fast" the electricity can be used and "amps" is how long it can be used. Though that's still not a great description. Let me put it another way, if you had a 12v battery with 10ah it has the same amount of energy as a 6v battery with 20ah. But the 12v battery is going to deliver twice as much power for only half the amount of time.

To recharge the battery you must connect it to a source that has a higher voltage than it so that the battery will accept energy rather than outputting it. So a 6v charger can not charge a 12v battery. A 12v charger really puts out between 13 and 15 volts. The rate at which it charges depends on how many amps the battery charger puts out. The higher the amps the faster it charges. A stock PW battery has 9.5ah (which is really amp hours, not just plain amps) so if you have a charger rated at 2ah, it will take somewhere around 4-5 hours to charge a completely dead battery. If you have a charger that only puts out 0.08ah (which is what I believe that solar panel puts out) it would have to charge between 110 and 120 hours to charge a completely dead battery. With only 12 hours of sunlight a day it would take 10 days to charge.
User avatar
By chozian
#21091
I like to visualize a pipe with water going through it when describing watts, volts, and amps. Watts (power) is the equivalent of the water. Volts (force) is the equivalent of the diameter of the pipe. The speed at which the water is flowing through the pipe is the amps (current). Let's say that 6V is the equivalent of a pipe that is 6 inches in diameter, and 12V is the equivalent of a pipe that is 12 inches in diameter. If both pipes have water passing through them at the same speed (amps) and over the same period of time, you'll end up with twice as much water (watts) out of the end of the pipe that has a 12 inch diameter (volts).

If this is incorrect, please feel free to correct me. Thanks!
Last edited by chozian on Mon May 09, 2011 2:45 pm, edited 1 time in total.
User avatar
By jparthum
#21183
treebeme wrote:...With only 12 hours of sunlight a day it would take 10 days to charge.
And that would also be assuming that the manufacturer's output rating is being achieved. From what I've gathered in solar panel forums, around half of the manufacturer's (maximum) rating is a pretty typical result. :(

I had considered adding some solar panels to my shed for maintaining batteries, and since we live in a hurricane prone area (sometimes without power for weeks at a time), I thought they might also come in handy for emergencies. But the cost/benefit just didn't (currently) add up for me after doing more research. :?

chozian wrote:I like to visualize a pipe with water going through it when describing watts, volts, and amps.
Me too ;) :) ...

http://forum.modifiedpowerwheels.com/viewtopic.php?f=33&t=207
Last edited by jparthum on Tue May 10, 2011 12:15 am, edited 1 time in total.
User avatar
By dozer
#21192
chozian wrote:I like to visualize a pipe with water going through it when describing watts, volts, and amps. Watts (power) is the equivalent of the water. Volts (force) is the equivalent of the diameter of the pipe. The speed at which the water is flowing through the pipe is the amps (current). Let's say that 6V is the equivalent of a pipe that is 6 inches in diameter, and 12V is the equivalent of a pipe that is 12 inches in diameter. If both pipes have water passing through them at the same speed (amps) and over the same period of time, you'll end up with twice as much water (watts) out of the end of the pipe that has a 12 inch diameter (volts).

If this is incorrect, please feel free to correct me. Thanks!


Close
The pipe would be the same for 6 or 12v but would change for more current/amps.
20 amps at 12v is under more pressure than 10amps at 6v so the pipe would be the same size.
When you start getting to 30 000 volts you would need a thicker pipe which is why sparkplug wires have so much insulation.
The math for hydraulics and dc power is the same.
Volts would be pressure.
Amps is volume. There is actually a number for how many electrons pass a certain point in a given time frame, 100 000 or something.
Resistance is your load : light bulb. hose nozzle. the less restricted the pipe the more current you have.
By celinaaniston86
#51285
I have used one but before more than one year though I remember how I did it. Get a voltmeter and a solar panel. Be connected the panel to your battery & check out the voltage rise. When it gets near 14 v your battery is energized. Disconnect your solar panel to keep it from overcharging your battery.
User avatar
By sea_stork
#51296
The charge controller will also regulate the charging voltage, as most panels put out 17 to 20 volts. Not really good for your battery.

And for gosh sakes don't buy those harbor freight garbage panels, the specs say 3A of output, but the reality is more like 1A. I would imagine the life span of the panel is about a third of what is stated too, if you're lucky...

It can be done though with the right stuff. The panel in this vid looks to be about 175-210 watts...
Last edited by sea_stork on Fri Jan 20, 2012 8:52 am, edited 1 time in total.
By bennelson
#71009
I just did this a couple of weekends ago.

I had a Power Wheels Jeep I got for free because it didn't have a battery or charger. I already had a Harbor Freight solar panel kit that I bought a while back to learn about solar energy and experiment with.

I put in a used 20AH battery in the Jeep, and made a rack for two of the solar panels from some 1/2" conduit welded together.

Those panels are rated at 15 watts (which isn't a lot) but that's basically one amp of charging power per panel. You typically charge a battery at 1/10 of it's capacity. So, I have 2 amps of charging for my 20 AH battery.

I've had the Jeep set up like this for a couple weeks. My little girl uses it every day, and we haven't yet plugged it into the wall to recharge even once.

It works great!


Image
Image

http://300mpg.org/2012/07/solar-powered-power-wheels/
User avatar
By sea_stork
#71031
Very nicely done. Kudos for using a sealed battery! I guess you already know I don't care much for those Harbor Freight panels...

Can you give us any numbers? How much longer than the typical 1.5 hour run time (continuous) that battery would last, do the panels add. How long do they take to recharge to full charge? What is the typical voltage and current output of the panels in the sun, at the flat angle?
Last edited by sea_stork on Tue Jul 24, 2012 2:23 pm, edited 1 time in total.
By bennelson
#71034
I haven't been taking before and after voltage numbers or anything like that.

The battery that is in there IS USED, and I can tell. You can see the voltage drop on Harbor Freight charge controller as the vehicle is driving. It drops quicker than it ought to for the small amount of amps the vehicles pull.

My daughter is pretty small, so she maybe plays with the car for 20 minutes at the most, and then just leaves it in the yard. It's always totally recharged by next time she plays with it.

According to the numbers on the battery, the solar panels, and charge controller, 10 hours of daylight should top off the battery from completely discharged.

As for "extending run time" - if the car could run for 1.5 hours per charge, that would be adding 2 amps for an hour and a half, or 3AH. Adding 3AH to a 20AH battery isn't much. You could extend driving time by about 15%. Not enough to make it worth while JUST for extending drive time.

Since I didn't have a pair of PW batteries or the matching charger, and I already owned a used battery, the solar panels, and solar charge controller, it all made perfect sense as a fun experiment that's been working great so far!

As an added bonus, the solar panels act as a shade! Little kids keep from getting sun-burned, and the panels make electricity. That's a WIN/WIN in my book!
Last edited by bennelson on Tue Jul 24, 2012 2:54 pm, edited 1 time in total.
By bennelson
#127418
UPDATE:
My Solar PowerWheels has been running for about two and a half years since it was last plugged into the wall.

I did replace that old used battery. A friend of mine gave me one of his old PowerWheels batteries, which while used is still much better than the one I had. The 9.5ah battery is always topped off by the solar panels.

Also, I can charge my smart phone off the 12v out on solar charge controller.

I often take this project to "Eco-Events", as people really seem to understand the concepts of both solar energy and electric vehicles when displayed this way.. I have an electric car that I built myself, and it never seems to get as much attention as the Solar PowerWheels!
By Jasonroush
#127681
I thought this was an awesome project too.
Video of what I did.


Where do you find echo events at? I would love to take the car and show it off.

Sorry I don't know how to add pictures yet.
User avatar
By TH1RTE3N
#148350
If i have a 12V/20W solar panel with a 9.5Ah 12V PW AGM battery, would a 10A charge controller be correct?

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