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Is a toggle switch necessary for this USB Solar Charger? Answered

Hi all! I am a newbie with a simple question. In the instructable below, is the toggle switch necessary or just a design feature? I thought the circuit would only be complete once the USB device is plugged in, acting as the switch so to speak? It is a 6V solar panel to 3 AA rechargeable batteries, then to a DC boosting converter with a 5V USB output.

Also, a big thanks to Joshua Zimmerman. Love your instructables!

www.instructables.com/id/Solar-USB-Charger-20-21/?ALLSTEPS

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steveastrouk

Best Answer 4 years ago

His circuit is incorrect. The item at the right hand side is a USB charger MODULE, not a USB connector. So unless you have the switch, its always "on", it may not draw much current if the load USB isn't connected, but it may draw SOME.

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Stevemills04steveastrouk

Answer 4 years ago

Thanks for your reply Steve. So the item I have is a "Step Up DC-DC Boost Converter 3V to 5V 1A USB Charger", the same as the red one in his instructable. Are you saying the switch is a good idea to prevent the USB module from having a current draw when not plugged in? Is there an alternate way to avoid the loss without using a switch? Thanks again for your help, is it appreciated.

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steveastroukStevemills04

Answer 4 years ago

You could try it without the switch, and measure the current draw when there's nothing being charged - I may be wrong, it might be microamps, and ignorable. Otherwise, unless the step up wotsit you have actually has a shutdown or sleep pin, you'll need a switch,