Converting Motion Detecting security light to solar?

[TrpnBils]

I have a motion-sensing security light that currently runs off of four C-cell batteries. We have quite a few stray cats in our neighborhood that tend to set it off at night, and as a result I'm replacing batteries about once per month. I know they sell solar versions of these lights, but they're quite expensive, and I'd like to see if it can be converted using a 12v "RV battery charger" type panel. I'm also a teacher, and one of the reasons I'd like to see if I could convert this is because it could potentially lead to additional projects within my classroom next year.

If I got rechargeable C-cell batteries (or whatever equivalent I might be able to use), does it sound like something that could be a viable project? A very greenhorn question, sure, but help me out here....

[inetdog]

I have a motion-sensing security light that currently runs off of four C-cell batteries. We have quite a few stray cats in our neighborhood that tend to set it off at night, and as a result I'm replacing batteries about once per month. I know they sell solar versions of these lights, but they're quite expensive, and I'd like to see if it can be converted using a 12v "RV battery charger" type panel. I'm also a teacher, and one of the reasons I'd like to see if I could convert this is because it could potentially lead to additional projects within my classroom next year.

If I got rechargeable C-cell batteries (or whatever equivalent I might be able to use), does it sound like something that could be a viable project? A very greenhorn question, sure, but help me out here....

Since you have a roughly 6volt battery in the form of 5 C cells, you can use a 12v battery maintainer panel if its current output is small enough that it will not overcharge you batteries. If the panel is rated 12 watts, for example, it will deliver about 1 amp at 12 volts. But it will also deliver only one amp at 6 volts.

This is a use for which a very small panel without a controller may be the simplest way to go, provided you choose rechargeable batteries such as NiCad which can tolerate continuous overcharge at a low current. Typically a 2000 milliamp hour NiCad can tolerate up to a 100 milliamp overcharge, but you need to check the battery specifications carefully.

If you use a more sophisticated battery, you will need to use a charge controller which is designed for that specific battery type between the panel and the batteries.