Mr. Beams produces an inexpensive line of autonomous outdoor lights. Coming in at 25$ each and 47$ or so for a pair they’re decent bang for your lighting buck.
But what if you’re not satisfied with the product out of the box? What if you’d like to completely void any warranty provided with the product? Possibly break it horribly?
We’ve got some design ideas that might fit the bill! Note that these could reduce your once functional light to a paperweight or flaming pile of goo. We are in no way suggesting, implying, or instructing you to do anything similar and would caution strongly against it if you value your device, health, property, or safety.
Now that you’re duly notified here’s what we’ve made the little lights do!
Lithium-Ion Rechargeable Battery Swap
Alkaline batteries work well. They have done for a long time. But they’ve got a couple of characteristics that make them less desirable as a lights power source for a low power draw system.
Size is one complaint. D Cell batteries are huge and three of them add up to quite a bit of bulk.
Second, and more importantly in our case, is that they’re not rechargeable. Which means we’re unable to hack a solar bank into the mix for charging. Or just take the battery out every six months and charge it.
Fortunately for us the power handling in this little light accepts a narrow range of voltages and steps them down to 3v to power the Mr. Beam light, its processor, and its wireless support. Four alkaline batteries puts out 4.5v and has a declining power output over the life of the battery.
So that all makes sense. 3v minimum input gets the most life out of your Alkalines.
What that means in this case is that we can substitute in a single rechargeable Li battery to take the place of the Alkalines. Or a set in parallel for a longer time between charge.
Do realize that there may be safety issues with running batteries in parallel. If you’re unfamiliar with batteries research safety issues with whatever type you’re using prior to implementing any sort of device using them.