Getting the Modified batteries to work on the tools!

Ok so I had one oversight in the battery modifications... The newer tools require the 3rd pin on the tool that is switched by the onboard chip and has to have voltage on it to enable the tool to be switched.  This is done so the tool is electrically isolated when the batteries parameters such as over current, temperature and under voltage.  

So as I have modified the batteries without using the onboard chip but the batteries fail to work in these tools! 

There were multiple solutions to this!

Solution #1

The first solution was to link the Positive rail and the control pin so that there is voltage on the pin so it will work in the tool.  The only problem in my case was some of the chips had the small pin and still did not work as they were not making connection!

Solution #2

Modifying the tool. This was something i didn't want to do but in the end became the easier method. Because i had several batteries that had the older style board with the shorter control pin it seemed to be the logical method.  However i will look into fixing the board so that my batteries will work in everyone's tools not just my own modified ones.

This picture shows the modification of the tool.

Aftermarket Charger

After a lot of research, time and effort there was found to be no EASY fix for the Makita 18v battery pack repair.  I am sure however it is possible to crack the on board chip design and reproduce it but the cost of which would require a full scale operation.   There are aftermarket batteries on the market and it would be nice to be able to source these aftermarket chips because I am sure that Makita did not release these to the companies!   So if any one knows how to get a hold of these chips please let me know!!!

Once again they have to be at the right price to make these repairs cost effective.

The Idea

So after trying to repair the batteries I ended up with all these BL 1830's hanging around and I knew there had to be something I could do with them.  So I decided to customise the batteries to and build my own custom charger using a spare Makita charging base I had laying around. 

The Batteries

Most of the time the batteries fail it is one cell or one cell pack.  By taking these dead cell packs out and replacing them with ones from a donor pack the balance charger was able to get the packs up and going. Some of the donated batteries were as low as 4 volts and got the batteries up and about!

As I do not afford a spot welder i had to solder then new batteries into the packs they are pretty tight to get in and out of the pack i used solder wick to stitch them all together which is narrow but should have the current carrying capacity for this project.

It was hard to get the heat into the batteries without getting them to hot.. so i apologise for the soldering job but it has stuck!  Just not pretty!  I think if you were going to build a pack from scratch again I would purchase the 18650 batteries that have the battery tabs spot welded on.  I used to use these batteries with the tabs when building the NiCd batteries for my old 12 volt stuff.  

The Charger

The charger that I decided on was the IMAX B6 balance charger.  There are many different chargers on the market and as I was trying to reduce my costs (because I was still unsure if it would work!).  Aftermarket balance chargers range from $40 to over $500! I am sure that if you are willing to spend that kind of money they would be great chargers with many having USB interface etc

The charger runs off a 5A 12v power supply (not connected in the picture above) similar to the power supply of a laptop.  The Red and Black banna plugs connect the battery while the smaller coloured cables are the balance leads connected to each of the individual cells inside the battery (connections shown later).

The charge time of the battery is going to be affected from the standard charger.  This charger has the capability of charging at 4.5 amp hours which theoretically should give a charge time of under and hour. The way in which the chargers automatic function works is that it slows the charge rate down after the battery is up to 80% gives a total charging time of around an hour.  With this many batteries it is hardly going to be a problem but for the tradey etc this could be a problem..

The Battery Modification

The primary function of the battery was to be connected to the tool so the modification of the actual battery connections was out of the question.  However as I wasn't going to be using the yellow control pins and I decided to use these pins on the charger and the battery to connect to the charger.

The chip itself was cut away and the individual cell voltages taken back to the yellow control pins.  The balance charger requires the connections as below.  As there are 7 pins on the control pin I separated the cell voltages by a pin for isolation and connected the + and - terminals inside the charger itself.

So this enabled the battery to be used in all the tools but due to the modification these batteries can NEVER be put back into the normal charger!  To avoid this ever happening i decided to paint the batteries to give a visual reminder each time you go to put a battery on a charger.  Below shows a picture of my pretty blue batteries!

The Custom Charger

So now it needed to be put together into the old charging base.  Due to my current living arrangement my workbench is my computer bench so I need to bend some aluminum plate etc to finish the job completely but you get the idea! 

Testing

So now it is time to test these batteries out.  I will report back in the next few months to see how these "repaired" batteries turn out and last.  I think this charger will keep these batteries optimized and running to their full capacity.  And if another cell was to die it would simply be replaced and the battery put back into service.

Feedback

So if anyone out there has any questions or some feedback on the design please let me know!  I am far from an expert in this field just trying things and measuring the results!  Happy drilling!

Ryan

Throwing the Towel in!

Throwing the towel in!

So unfortunately the previously posted article has turned out to be a mislead.  I was able to get the three batteries repaired using this method but..................

The next few repairs have not been so successful.  It has really bugged me to.  I have spoken to more people and read more articles and all lead to one final outcome.  Unless some smart cookie with more time than me can find out the protocol and re program the chip it is not a "viable" option.

As a tradey myself i have spoken with others in the industry and they are quite happy to fork out $50-$70 bucks to get a battery going (as long as it lasts a little while) but with no guarantees and the fact that with my cost in labour it is not a option.

However there is a market out there I know it but i may not be the one to tap into it as I don't have the time!

BUT!

Please keep an eye out on this Blog as due to the amount of batteries in my possession i have been able to build 5 batteries to date and am in the progress of building an after market charging station.  Once i have finished it i will post it!

Fusible Link Repair

18v LXT Battery Repair – Chip Reset

By Ryan Flint – April 2013

Introduction

The Makita range of battery power tools are undoubtedly the best tools on the market, with the range and availability unparalleled by any other brand.  Unfortunately in the 18v LXT range for the general user the batteries have a tendency to fail and become useless.  As an Electrician/Engineer I thought there would be plenty of solutions to this problem….. 

I have searched the internet in hope that I could find a solution to my faulty batteries, I have contacted Makita agents and supposed repair centres all giving me the same advice.  Throwing them away and buy new ones...

I decided to ignore their advice and to have a play around with them and think I have a solution to some of the problems.  Please note that this solution is not for all problems and that this will void all warranty.  If your battery is less than 12 months old and you have a proof of purchase I advise you to go through the proper channels and have your battery replaced by Makita.

The common red/green flashing fault on the 18v Makita Charger

Some basic electronic skills and tools such as a soldering iron, multi-meter and basic hand tools are required for this procedure.   

Opening the battery

To open the battery you will require a small flat head screw driver and a T10 long torx bit.  Firstly you will notice a white tamper proof bung in one of the screw holes.  Flick this out with a screw driver and toss it, this will no longer be required.  The 4 screws are all that hold the top of the battery in place.  Remove the top and the white clip (Be careful of the spring under the clip, it could cause a possible short).  You now should see a similar view to Figure 1.

Figure 1

Testing the Cells

To test the voltage of each cell use a multi meter and test the voltage between the 6 points shown in Figure 2.  Each cell when fully charged should have close to 4 volts in it (point 1 to 2) but in most cases we will see much less.  Check between points to make sure none of the cells have gone to zero.  If one of the cells has gone to zero, the cell will need to be replaced before any further repair can be done.  You may have several batteries with a faulty cell and my advice is to create a battery from the spares. (Example: make 3 from 4)

Figure 2

Removing the Circuit Board

To remove the board several joints need to be un-soldered and parts removed.  Listed below are the items that need attention.

                                  1.       Positive Terminal - unsolder from the board 

                                       2.       Negative Terminal – unsolder from the board

                                       3.       Temp Sensor – glued in (need to lever out, be careful not to damage)

                                       4.       Ribbon Cable – remove

                                 5.       Screw – removed

Once these parts have been attended to the board should be able to be removed from the battery pack.  The temperature sensor (point 3 in Figure 3) is glued into place and becomes the hardest part to remove, be careful not to snap the probe from the board.  The ribbon cable (point 4) is very delicate and also needs careful attention.  At all times be careful not to short any parts of the board or cell pack while removing the board.

Figure 3

Repairing the Fusible Link

The fusible link being blown has been the cause of the problem on three of my batteries to date.  I have not been able to find any circuit diagrams online to actually understand what the fuse supplies but I assume it is the supply to the chip itself. 

The fusible link has a black cap (noted F03 on my board) that can be flicked off with a screwdriver showing the metal parts.  A solder blob was the applied to the top of the chip to bridge out the blown section.  This should have hopefully of fixed the problem.   

By bypassing the fuse (shown in Figure 6) we have supplied the chip with power again and in my case it solved the problem.  However as you are bypassing a fuse the next time such fault occurs there will probably be irreversible damage to the electronics, so far all is running well in the repaired battery!

Figure 4 - Underneath the board

Figure 5 - Cap flicked off

Figure 6 - Soldered repair of the fuse

Re-Installing the board

The board can now be reinstalled into the cell pack and the pack put back together and placed into a charger.  A handy hint on reinstalling the circuit board is installing the ribbon cable first as it is quite difficult once soldered and screwed back in.  Hopefully your battery pack comes back up to full voltage and runs for many more cycles giving the Makita tools the customer satisfaction they deserve!

Ryan Flint 31/03/2013