Solar Panel Wiring to power/charge 3V light?

[Nathan_wertz]

Howdy everybody! a little project i'm working on is a red dot sight for my rifle. i love it, but it burns up a lot of juice, and its useless to turn it on and off all the time. i got the idea today to rig up a solar panel to it (just a small one).
Some background information: the sight uses a 3V circular flat battery.

http://www.google.com/imgres?q=Sun+...&ndsp=32&ved=1t:429,r:25,s:0&biw=1440&bih=730


I want the sight to be on all day, and for the battery to act as a backup power source at night when there's no solar power being created. The solar panel should recharge the battery the next day.

Would i need a rechargeable battery?
What would i need to do to accomplish this?
Does anybody have any suggestions?

Thanks a bunch for ANY help you can offer.

 

[davenn]

hi welcome to the forums

one has to wonder why you want it running contineously ? I put a laser sight onto my rifle some years back and just switched it on as needed. worked a treat, no big deal
and a hell of a lot safer than having a laser swing all over the place all the time and the eye danger it poses.
Yeah cool fun, the targets didnt stand a chance!! ya didnt even have to bring the rifle up to eyeline, just "shoot from the hip" etc

yes a rechargable battery
there are rechargable versions of the CR2032 button battery available dunno if they would have the current capacity tho to power a laser contineously for long periods.
You may need to go to a more substantial power source. The one I used was multiple cells that in total were the diameter and length of a standard AA battery.

cheers
Dave

 

[Nathan_wertz]

Thanks for the welcome davenn .

Just for clarification it isn't a laser, its holographic, but thats neither here nor there... I would just prefer to let it run while im walking around, since it will shave that 2-5 seconds off of target acquisition time...

Would it work if i hooked up the solar panel to, say, a rechargeable AA battery and hooked that up to the sight, with a 3V capacitor in between?

I dont know a dang thing about electronics, so any help would be great..
Thanks

 

[davenn]

Thanks for the welcome davenn .

Just for clarification it isn't a laser, its holographic, but thats neither here nor there... I would just prefer to let it run while im walking around, since it will shave that 2-5 seconds off of target acquisition time...

Would it work if i hooked up the solar panel to, say, a rechargeable AA battery and hooked that up to the sight, with a 3V capacitor in between?

I dont know a dang thing about electronics, so any help would be great..
Thanks

a 1.5 volt battery isnt going to charge a cap to 3volts if the unit requires 3 volts then thats what it needs. does it state its current drain?
3V at xx mA ?

 

[Nathan_wertz]

I've only found one source online about the battery's drain rate, "0.4 mA".

What other batteries have 3V or greater charge that I could use? How would the circuit be set up?