Tips to repair your Makita 18v or 14.4v Li-Ion battery yourself
Update May 2019: Unfortunately, it appears that more and more batteries are defective beyond just the PCB. We have therefore stopped selling PCBs. We recommend ordering a new replacement battery for your Makita machine.
Looking for a Makita 14.4V battery? Click here!
Looking for a Makita 18V battery? Click here!
Makita is known for its powerful tools and complete range. These tools are high-quality and often only need replacing after years. Despite the quality of Makita tools, the Li-ion batteries often have a shorter lifespan than the tools themselves. These defects are often outside the warranty period and are not repaired by Makita. In most cases, the battery defect is caused by a faulty motherboard inside the battery. In this tutorial, we explain step-by-step how to replace this motherboard.
What problems can you solve with this repair?
Makita Li-ion battery failures can be divided into two causes. The first is battery overheating, and the second is a lack of current to supply power to the motherboard. This leads to an unbalanced voltage in the battery cells. If you see the red/green/white light on your charger flash three times, the motherboard is blocking the battery and charging is no longer possible. This manual discusses how to resolve or repair the second defect. To fix this error, a new motherboard (PCB) must be installed on the battery.
Before you can start replacing the PCB, you should be aware that the cells in the battery may still contain residual voltage!
Disassembling the battery
To disassemble the PCB, the battery must be removed. Unscrewing the Torx 10 screws will remove the Makita battery housing. Newer batteries have a rubber cap on these screws. This cap can be removed with a screwdriver.
Once the screws are removed, the case can be opened. While opening, the spring under the push button may slip out; be careful not to lose this spring. When opening the battery, you may find a lot of dust inside. If this is the case, avoid charging batteries in dusty environments or charging them with the charger on a dusty surface. The charger blows air through the battery to regulate its temperature, and this air can suck in a lot of dust. This will negatively impact the battery's lifespan!
Testing the cells in the battery
To determine with certainty that the PCB is defective, the cells must be tested individually. This can be done with a multimeter. The cell voltage must be measured between the six indicated points. Each cell, when charged, should provide 4V, but this is often not achieved. The minimum voltage should be 3.2 volts. If one of the cells does not provide any voltage or the voltage is too low, it can be replaced. Replacing an individual cell is more expensive than simply replacing the PCB. We recommend replacing the battery, not the individual cells.
Disassembling PCB from Makita battery
In order to disassemble the PCB, some solder points need to be loosened.
- 2x red wire from PCB -> desoldering of cell pack
- 1x black from PCB -> desoldering of cell pack
- Temperature sensor -> remove from cell pack
Mounting the new PCB
The new PCB should be assembled in the reverse order of disassembly. Ensure that the solder joints are strong and not too fragile.
- Thin red wire is soldered to the side of the battery cells
- Thick red wire is soldered on top of the lip of the battery cells
- Black wire is also soldered to the lip of the battery cells
- Temperature sensor -> insert back between the cells for correct temperature measurement
Replacing the housing
When replacing the housing, follow the reverse steps of removing the battery.
Would you like to order a PCB for a Makita battery?
Unfortunately, it appears that more and more batteries are defective beyond just the PCB. Therefore, we have stopped selling PCBs. We recommend ordering a new replacement battery for your Makita machine.
Looking for a Makita 14.4V battery? Click here!
Looking for a Makita 18V battery? Click here!
