Thread: Makita 24 volt drill failure

Something is limiting the current available to the motor. I suspect that it being caused by a couple of weak or dead cells in each battery pack. These can be partially charged and show their nominal voltage soon after charging, but once placed under load discharge very quickly, and ultimately are forced to reverse polarity by the load current provided by the viable cells. If this happens it often gives the charger a false full charge indication, preventing the viable cells from fully charging. In this case, while the battery might manage 24V at the top of the charge, under load it could concievably drop to 12 to 14V.

Another possibility would be a defective or incorrect charger, causing the batteries to not be properly charged in the first place, so you are essentially trying to operate the unit with flat batteries even though you have attempted to charge them.

The next possible issue with batteries is corrosion of the ties linking the cells together, probably caused by leakage due to overheating during charging. You could open the packs if they are screwed together and visibly check for signs of corrosion and leakage.

The next thing to consider is terminal erosion/corrosion where the battery pack connects to the drill body. The terminals are generally silver or tin plated, and wipe against each other each time a batery is connected or disconnected to/from the charger or drill. Eventually the contacts start to develop significant series resistance which limits their ability to pass significant currents.

I doubt that the trigger/controller is failing and causing the problem, as they tend to either work properly or fail totally.

The motor could have a damaged winding, but if it did visible smoke and obvious odour would be present, particularly if you lock the chuck as you outlined.

Reasonable electonic knowledge and test equipment would help to isolate the problem.

Assuming the electrics are working as they seem to be by your description, I think problem may be mechanical.

On one of my drills, when I switch from low ratio to high ratio, I sometimes don't quite push the little lever home, this means the gears aren't meshed correctly, I then have exactly the same problem you describe.

Mick.

Thanks gentlemen for your assistance. I think Malb has identified the problem. The Makita battery cannot be opened, so I will take both to the dealer and see if they can test them. The gears are meshing ok Optimark, it is just that there is so little torque I can stop the chuck in my hand with the trigger fully depressed. Great drill and tons of power when working, so if the batteries test faulty, I will just buy new ones.
Thanks for your input and help. I have heard that the Li-lion batteries only have about 4 year life and die without any early indications.

Regards Ian

You can give the batteries a quick zap with an arc welder set at it's lowest current, no idea how or why it works but a bloke told me about it a few years ago and I revived an almost dead DeWalt battery.
It's got to be a quick zap, like momentary, positive to positive, negative to negative.
If it doesn't work you've lost nothing.

Thanks for the advice. Both batteries have dead cells and will not hold a charge. The production date on them was Jan 2001, so not too bad to get 10 years out of a battery used 5 days a week.

Regards

There may be an issue here other than the batteries too, as it's not too likely that after 10 years both failed at spot on the same time, could be a coincidence but there may be an underlying cause. Such as the batteries were shorted by something or overcharged or something along those lines and given their ripe old age it finally did them in.

I think you should check if the battery has died or the charger can not work first.