If you have been working under a rock, then you would be excused for not knowing about the powerhouse that is Makita. They have successfully dominated the market especially since Battery operated tools were first introduced to the market in 1969. In particular, The Makita 18v battery has revolutionalised the construction industry but they do have their faults. For example, I'm sure you have asked your self "why has my Makita battery stopped working?" Don't worry, you're not alone. This blog post will teach you how to fix your Makita battery and, above all, prevent it from happening.

What causes my battery to die?

There seems to be two main causes as to why your Makita 18v batteries die. The first is overheating which is due to several reasons. The second main cause is that the first two cells fail due to them being used to power the circuity of the battery management chip. Which causes the battery to slowly discharge while it’s not in use.

What causes my battery to overheat?

There are several reasons as to why your batteries overheat. I’ll start with the obvious one which is the environment that you are storing/using your batteries in. For example, are they cooking in your toolbox due to a lack of ventilation? Or are they in the back of your car which consequently acts an oven on a hot day? Do you work outside, therefore, you have to charge your batteries in direct sunlight? These are all factors as to why your battery would “overheat” in the general sense of the word.

Excessive heat exposure:

Exposing your batteries to such heat could lead to Thermal Runaway, which is the technical term for explosion. This is due to an accelerated increased temperature. In turn, releasing energy that further increases temperature. This can lead to the battery no longer working, budging, corrosion and in some extreme cases explosion. Here is more on “why is heat bad for batteries?”

A general rule of thumb is to try and charge your batteries at room temperature (20 – 22°C). However, living in a hot and temperamental climate like Australia makes this is somewhat impossible. According to this article from Battery University, it’s safe to charge your batteries in any environment between 0 – 45°C. It’s been deemed safe to use your batteries between -20 – 60°C.

Damaged cells

The most common way for a cell to die would have to be from external damage! Think of all the times you have dropped a battery or dropped other heavy tools onto your battery? Don’t worry I’m guilty too… This could lead to battery damage.

The screenshot below is from a YouTube channel called Well Done Tips. In this video, he takes apart a dead Makita 18v battery and teaches you how to fix your Makita battery. Highlighted by the orange circle is the damaged cell. It’s unclear as to how this happened but as you can see in the photos below it’s a rather delicate system. If you don’t protect your batteries they could break down and corrode like the one shown in this video. 

This is a photo of a damaged battery cell from a Makita 18v battery. there is noticeable cell damage on the second cell from the bottom.
In this brilliant video, you see the YouTuber @welldonetips take two bad Makita BL1830 lithium batteries and make one good operating battery. Plus he will show you two tips, how to solve protection circuit problem when it was triggered and when the regular Makita charger isn’t charging battery any more.

How tough are my Makita 18v batteries?

Below is another example of how fragile the inner workings of a Makita 18v battery is. The only thing protecting the cells and chip is the plastic casing that surrounds the battery. For more information about the chip please scroll down.

here is a photo of a Makita 18v battery that has been opened up for inspection. you can see the memory board and battery cells powering it underneath.
This Is a photo of the contents of a Makita 18v Battery from the Makita Battery Repair Blog.
Yes, the Batteries can take a beating but after seeing this it has made me realise how fragile they can be! After all, the cells and chip are only protected by the 3mm polycarbonate casing. Hopefully, now you think twice before you start chucking them to each other... Haha, I defiantly will!

The batteries we use for power tools are generally more rugged than those in consumer products. Largely because we use Power Cells instead of energy cells. They have a lower Ah rating than Energy Cells and are in general more tolerant and safer if abused. This doesn’t mean they are indestructible so you should protect your batteries as best as you possibly can! Here is a video on Reviving battery cells. Please note only attempt this if your battery is no longer under warranty and if you are confident with electrical goods and possess the right equipment.

Damaged batteries due to metallic particles and dust:

Another main reason why your batteries overheat is due to unwanted metallic particles and dust. Outlined in this brilliant article from the Battery University, that is to say, you can see that manufacturers go to great lengths trying to minimise the exposure of metallic particles. As pointed out by the Battery Association of Japan in this article, metal objects may short-circuit the positive and negative terminals of the battery, as a result, this provokes a large electrical current, which may result in overheating, explosion or fire of the battery, or overheating of the metal object.

Here are a few tips to protect your batteries:

  • Don’t charge your batteries in direct sunlight.
  • Don’t leave your battery and charger inside your car! Especially during the warmer months.
  • Try not to leave your toolbox exposed to sunlight as a result, it will heat up the contents of the box which could lead to damage.
  • Try to be cautious when it comes handling your batteries. For example, you should think twice before you chuck them to your mate on the floor below so he can put it on charge. 
  • When storing your batteries you should use the plastic cap to prevent any unwanted particles from entering the battery. However, doing this every time you store your batteries seems unpractical, alternatively, you could keep your batteries locked into your tools or place them in a 48tools Battery Holder.
  • Don’t charge your battery on the floor as it will be susceptible to water and dust etc.. but If you have to, you should consider using the Batloc Box for additional protection.
  • Try not to carry your batteries around in a tool bag full of metallic particles and dust, as a result, this could enter the battery leading to permanent damage. 
  • If you feel that your battery is roaring hot due to overuse, Most importantly you need to give it a rest and use a different one. (Let the battery cool down before you place it on charge!)
  • Ideally, you should charge your batteries at room temperature!

Your Battery might not be working because of the faulty memory chip

Inside of every Makita 18v battery is a memory chip or control board. This chip is a crucial feature of the battery because this is how the battery can communicate with the charger and other tools. This is a brilliant safety feature, however, they can be faulty. If a chip in the battery is saying it's overheated or has a damaged cell then the charger will deem the battery unsafe. Once you get the red and green lights flashing simultaneously three times then your charger will deem your battery unsafe locking out the management chip on the battery. This will essentially turn the battery into a brick. 🙁

It only takes one damaged battery cell to notify your memory chip of the problem to consequently disable the battery.  There are countless tutorials on YouTube I suggest you start with either Well Done Tips or Vuaeco. Most of the time, however, the chip is correct by notifying the battery charger the battery is no longer safe to use.

How can I fix my Makita battery?

Too often good batteries are ending up in landfill because of a chip’s faulty reading or something that could have easily been fixed! For more tips on replacing the memory chip and how to fix your Makita battery click on the photo below. You will certainly void the warranty if you attempt this. So please only try this if you feel confident have the right tools and past warranty.

In this photo you see the insides of a Makita 18v battery. the link will take you to a blog post where he will teach you how to fix your Makita battery
This is a photo that I sourced from a Makita 18v Battery repair blog written by Ryan Flint. In this post, he shows you how to properly repair the fusible link for the battery chip. This problem seems to be quite common for these Makita batteries. (The numbers reflect the steps in the blog post above.)

In Summary

I know batteries feel strong and robust, but they are delicate, impressive pieces of technology which need to be treated accordingly. We take this science and technology for granted because it's apart of our everyday lives. We need to know how to work with these technologies and respect them at the same time! Hopefully, now you realise how intricate inner workings of a lithium-ion battery can be and now you know how to fix your Makita battery!. Which will make you more careful when it comes to this impressive technology.

Please let me know if there is anything you think I should add to this. You can reach out to me on my Email: [email protected]batloc.com.au Because I'd love to hear your thoughts.