Repurposing Makita 9.6V Tool Battery

[Elektrishun]

I have some devices that are designed to run off of a nominal 9V DC power supply. The type of devices that need the 9V will perform better on a battery source.
The 2 basic battery requirements I was looking for:

- long life battery relative to the power demand (devices have small power demands).
- rechargeable

Standard rechargeable 9V batteries, even two in parallel, didn't have the greatest life for what I wanted. After considering some options I recalled seeing the occasional Makita 9.6V drill and charger combo for sale. I began watching for a drill/battery with charger that looked and sounded like it was well cared for and CHEAP. Found it.

Charged the battery up, put it in the drill, clamped the trigger to run it, and timed how long it ran. Gave the motor a brief rest about every 5-10 mins. Ran for at least 35 minutes total time. Not under load but good enough for my needs.

Next, came up with a design and put it all together. Here's the result without the final polish:



Little circuit board off to the side should OPEN the circuit at about 8V but needs to be tested. I plan on using the old Makita metal case to store this power supply along with the charger.



Roughly 10.54V when fully charged. Devices have their own voltage regulation and can tolerate the range that this power source will provide.

Now, I will need to keep my eyes open for more of these vanishing batteries.🙂

 

[Elektrishun]

Got a line on two more batteries. I think I can strap them in under the lid...

 

[YotaBota]

Makita also does a 10.8v lion battery if that voltage would work. A lot shorter, a bit bigger around and uses 3 AAish sized cells.


I've had a drilldriver/hammer set for around 15 years and only replaced one of three batteries.

 

[Dan Dubeau]

I remember those stick tools and batteries well. Dad used to have a couple of them when they first came out in the late 80's, and they also used them at his work. When a battery would "die" they'd toss it, and buy new ones. He'd bring them home, find the dead cell or two, and rebuild the packs scavenging good cells together. It's one of the earliest, if not first things I learned to solder. He tossed the last of them a few years ago when he moved. I still see them once in a while at thrift stores and have so far resisted the urge to buy them 😀.

Makita also does a 10.8v lion battery if that voltage would work. A lot shorter, a bit bigger around and uses 3 AAish sized cells.
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I've had a drilldriver/hammer set for around 15 years and only replaced one of three batteries.

I have a couple of those tools. I like those much better than the new 12v cxt ones they replaced them with. Batteries are tough to find for them, but I grab them when I can. When those go, I'll probably replace them with m12 versions.