How to restore a screwdriver battery

I think that everyone is already familiar with this problem, when one fine day you take your screwdriver, turn it on, and it doesn’t work. Next, the first thing you do is try to charge it, assuming that the batteries are simply dead. But that’s not the case: charging doesn’t bring results.
This problem is as old as time. The thing is that inexpensive screwdrivers use relatively cheap nickel-cadmium (NiCd) batteries. They are quite whimsical and, if not used properly, they immediately fail.
I suggest you restore your screwdriver so that it is like new. To do this, we will simply replace the batteries with similar or better quality ones.
Although most people on the Internet recommend changing batteries to lithium-ion (Li-ion), I am not a fan of a complete redesign. After all, you can’t just replace them, due to the fact that lithium-ion batteries need to be charged differently, a charging controller must be introduced, a different power source must be used, etc. And the housing of the batteries themselves will undergo significant changes.No, I just recommend replacing the batteries with the same ones, it’s much cheaper and you don’t need to fuss or invent anything.

Will need

On AliExpress we purchase the required quantity nickel-cadmium (NiCd) batteries.

As you can see, the prices are quite reasonable. Search for your size and quantity. I ordered 12 pcs. The total voltage of the former unit is 14.4 V. One element is 1.2 V. Simple math 1.2 x 12 = 14.4 V.

Restoring a screwdriver battery

Well, now let’s move on directly to restoring the screwdriver. Remove the top cover of the battery pack.

Count your number of elements. It would also be a good idea to write off the brand of batteries used.


In order not to forget how the batteries are placed inside, I made a kind of map on paper with their location and poles. Do the same thing so you don’t have to rack your brains about what goes where.

Now you can disassemble this bundle to free the power terminals, which will be needed later.

Here is the complete circuit.

To connect the elements, I took a shielding wire from an old USB cable.

I cut it into even pieces.

Everyone tinned well.

Everything is ready to replace one with another.

We assemble the chain. We solder these battery segments together according to the previously drawn diagram.

In general, closed-type batteries are not soldered. The jumpers must be welded using resistance welding. But since it is not available, let’s take a powerful soldering iron and quickly solder it.

We coat the pole with flux, place a jumper and quickly solder it with a hot soldering iron, holding the tip for no more than 1-2 seconds.

At the end, we glue back the general insulating spacers on both sides and assemble the block in the reverse order. We measure the voltage at the output terminals.It should be around 14.4 V. If so, then the battery switching sequence is correct. Let's put it on charge.

So, simply, without unnecessary manipulations, you can return the screwdriver to work, which will last for a very long time if you look after it properly.