| I recently purchased two remote control cars for my nephews from a dollar store. The cars came with three rechargeable AA batteries and also a cheap AC charger that connects to the car, but unfortunately grew hot when plugged in (a classic wall wart). So I’m giving them the cars with a solar panel and withholding the AC chargers. The best part is how easy it was to make it all work as I piggy-backed on the car’s built-in charging circuit. |
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| Step 1: Parts and Tools Toy with 2-3 AA or AAA batteries and a recharge feature 1 6 Volt Solar Panel ($25) 1 Circuit Box Set ($3) – optional 1 Universal Adapter Set ($4) – optional |
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| Step 2: Determine Connection from Panel to ToyIn this case, I was lucky as the car’s AC charger was the same size as our panel, 3.5mm x 1.3mm. If it didn’t fit, it is quite easy to connect the panel to the circuit box and the circuit box to one of our 4 standard sized universal adapters.
There is a blocking diode in the circuit box, so using the circuit box will prevent charge from flowing backwards out of the battery. I’m giving this to youngsters so I wanted to make it as simple as possible and left it out. |
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| Step 3: Do a Test Run On a bright day, I put 3 flat, rechargeable batteries in the car and connected the car to the panels. I pointed the panel at the sun for an hour and then ran the car for 15 minutes. Success. A single 6 Volt, 1.5 Watt panel would charge all three batteries (700mah) in about 4.6 hours of direct sun. |
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Solar Charge Battery Powered Toys
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Congratulations on your solar charger and I wondered if you could help me with a small problem.
I have a home weather station. the wind speed gauge is, of course on the roof but runs off 2 AA batteries.they last for about a year but of course are difficult to replace.
I have a small solar panel(about 2×2 inches)which I got from a motorised toy. can I install this with a diode to charge my batteries. I do not know the voltage of the panel or whether this is important.
I live in Cyprus so have no shortage of sun! but equally don’t know anyone here to ask.
Thanking you in advance.
Robert
Hi Robert,
It could work. A couple of thoughts – make sure the batteries are NiMh. We haven’t done a lot of work with direct charging of AAs, but one rule of thumb is that you don’t need a charge controller between the battery and the panel as long as the panel in Wattage is < 10% of the Battery Capacity in Watt hours. If higher than that, you risk overcharging. A quick guess is that your panel is about 0.5 Watts. If your batteries are 2500mA, 1.2V, than the Watt hours of your batteries should be 6 in total. Second, the Voltage of the panel should probably be in the 3.5-5V range. Check with a multimeter to be sure...finally, yes you would need to have a blocking diode.