No, I guess I have to host images on the web elsewhere to post them here? I think that's too much of a hassle. I'll email it to you if you want. Since it doesn't show the IC's that are on the back side, I'm not sure it's very useful to you.
Makita 18V LXT batteries....
- Thread starter maverick
- Start date
Help Support Candle Power Flashlight Forum
Bullzeyebill
Flashaholic
Firedog91902
Newly Enlightened
- Joined
- Oct 11, 2013
- Messages
- 1
I've been able to repair Makita 18V Lithium batteries; use and charge them safely. I've found most bad Makita batteries, don't have bad cells. They have, for some reason gone out of Makita's safety range (usually voltage too low) and the battery's circuit blocks them from recharging . To Makita's credit, it's not easy to do, since most or all tools turn off at a set minimum voltage. So far, no one has found away to reset the battery's circuit failure mode.
A few bricked Makita batteries will have a bad cell or pair. There is a plethora of similarly failed laptop batteries with perfectly good, 18650 cells available for donor replacement cells. Usually, they are free or almost.
The 18650 cells used in tools are a slightly different design than used in laptops. Laptop batteries discharge over 4 hours. Tools require higher currents for short bursts and faster charging. In addition, the older Makita batteries, for safety, are never fully charged (to 4.2 v/cell). Since the cells are charge in series and each cell's voltage is not monitored, it would be too risky. It's rare, but if the cells become unbalanced one might reach 4.5v while it's neighbor is only 3.9v and the circuit wouldn't know it. Because of this, each Makita cell is rated 1.5AH while 18650's harvested from old laptop batteries are rated 1.8 to 2.8 AH.
When ever possible, I use good Makita cells to replace bad Makita cells. But, I've also picked strong cells from laptop batteries and they seem to work fine. My favorite solution is to use all laptop cells in a Makita case but wire 3 cells in parallel instead of 1 or 2. That's 15 cells total so the battery is slightly taller and heavier, but the current load is now shared by 3 cells and the capacity is about double a 3.0AH Makita. Saws and grinders work much better than with genuine Makita 10 cell batteries. Converting a 5 or 10 cell case to 15 is simple. Screw 4, 4-40 circuit board standoffs into the top screw holes. Use long, 4-40 machine screws cut to the required length to assemble the bottom to the rest of the battery. This leaves a gap which can be wrapped with tape. The critical edges are still protected by the case and the battery is very sturdy.
To monitor and balance each of the 5 series wired cells or parallel cell sets, a connection is needed to the cell's positive and negative. That requires 6 wires. RC batteries use in line female connectors with .1" spacing between pins. These connectors are cheap and very common. Glue a 6 pin connector to the outside of the battery, holes pointing down (towards the label) on the end opposite the white release button. Then solder a 28 gauge insulated wire to the 1st pin of the connector and the other end to the battery negative. The 2 pin gets wired to the common connection of cell 1 and 2 and so on down the line until the 6th pin gets wired to the positive of the battery.
It is best to balance and test cells before assembly, but you can also test cells in an assembled battery if you add the above discussed 6 pin connector. Or, simply use alligator clips to test the suspect cell(s). Use care, short are easy to do and the resulting sparks unpleasant.
I use 3 steps to test cells.
1. Charge the cell(s) with a single cell Li-ion charger. I use one from DealExtreme.com, Item # 132558, $5.40. These are designed to charge a bare cells to 4.2volts, but it is a simple matter to open them and solder 2 wires; one to the positive and one to the negative. On the other end solder to a 2 pin male that will plug into the 6 pin female connector. Each time you shift the charger pins one space, you are charging a different cell in the battery. Try to keep positive and negative straight, but if you get it reversed the charger senses the problem stops any damage.
If the cell voltage below 2.5 v, the charger won't start the charge. If the low voltage is caused by an internal short, it's toast. More likely the cell was stored with an external load and it might still recover. Here's a safe method to find out. Connect a small Ni-MH cell (1.2 v) to the cell (positive to positive) and see if the voltage starts to recover. The internal resistance of the NI-MH cell will prevent very high current if the Li cell is internally shorted, but if the voltage doesn't start up in a few seconds it's bad. If the Li cell charges to 1 volt, switch to 2 Ni-MH cells in series. If it reaches 2 volts the charger should now work and charge the cell.
2. Store the charged cell 24 hours to see if the open circuit voltage drops below 4 v. If it does there is likely an internal short or other problem and the cell won't hold a charge.
3. Connect a 2 ohm resistor capable of 2 amps to the cell and note the voltage after 60 seconds. If it stays above 3.7 v it will probably work fine in a tool battery. If it's less, use it in a flashlight or other low drain device.
If all goes well, you now have a full charged, balance and tested battery with an added 6 pin connector. Purchase a RC voltage monitor (DealExtreme.com, Item #20024, $3.26). It comes with 7 pins on .1" centers (to monitor 6 cell batteries) but we use only the first 6 pins for our 5 cell, 18v system. Plug it into the added 6 pin socket and it will report cell 1, it's voltage, and so on through cell 5. Finally, it reports the total battery voltage.
Test the battery on various tools with the V monitor plugged in to see how the cells are doing under various loads. If one is especially weak then consider replacing it.
To recharge the battery after use, one could theoretically use the single cell charger 5 times. Of course that is ridiculously slow and time consuming. An RC balanced chargers is the preferred solution and it should plug into the 6 pin connector and charge the complete battery in one shot, carefully monitoring the voltage of each cell. They are a bit expensive and I don't have one so I don't have a purchase suggestion.
Another way is to use a 19v or 20v DC laptop charger to charge all 5 cells wired in series. If the cutoff voltage maximum is 4.2v/cell then 21volts is the absolute maximum for safety. Connect the laptop charger to the battery's main + & - and monitor each cell's voltage. 20 volts works out to be 4.0V/cell which although not a full 4.2v charge, it is substantial and you probably wouldn't notice the difference in days work.
I use a Kensington Universal Power adapter which can be set to any voltage from 0 to 24 volts, by changing the value of one 1 resistor. I set the voltage of the Power adapter to 1 volt above the battery's discharged voltage and increase it gradually during the first few minutes of charge. I then leave it over night with the charger at 20.5 v (4.1 v/cell) and get excellent performance.
If the cells become out of balance, as shown by the V monitor, charge all 5 to 4.2V, in turn, using the single cell charger.
One final consideration. Makita's chargers are fast. If an overnight charge isn't fast enough, then your are pretty much stuck frequently buying new batteries from Makita and using their chargers.
A few bricked Makita batteries will have a bad cell or pair. There is a plethora of similarly failed laptop batteries with perfectly good, 18650 cells available for donor replacement cells. Usually, they are free or almost.
The 18650 cells used in tools are a slightly different design than used in laptops. Laptop batteries discharge over 4 hours. Tools require higher currents for short bursts and faster charging. In addition, the older Makita batteries, for safety, are never fully charged (to 4.2 v/cell). Since the cells are charge in series and each cell's voltage is not monitored, it would be too risky. It's rare, but if the cells become unbalanced one might reach 4.5v while it's neighbor is only 3.9v and the circuit wouldn't know it. Because of this, each Makita cell is rated 1.5AH while 18650's harvested from old laptop batteries are rated 1.8 to 2.8 AH.
When ever possible, I use good Makita cells to replace bad Makita cells. But, I've also picked strong cells from laptop batteries and they seem to work fine. My favorite solution is to use all laptop cells in a Makita case but wire 3 cells in parallel instead of 1 or 2. That's 15 cells total so the battery is slightly taller and heavier, but the current load is now shared by 3 cells and the capacity is about double a 3.0AH Makita. Saws and grinders work much better than with genuine Makita 10 cell batteries. Converting a 5 or 10 cell case to 15 is simple. Screw 4, 4-40 circuit board standoffs into the top screw holes. Use long, 4-40 machine screws cut to the required length to assemble the bottom to the rest of the battery. This leaves a gap which can be wrapped with tape. The critical edges are still protected by the case and the battery is very sturdy.
To monitor and balance each of the 5 series wired cells or parallel cell sets, a connection is needed to the cell's positive and negative. That requires 6 wires. RC batteries use in line female connectors with .1" spacing between pins. These connectors are cheap and very common. Glue a 6 pin connector to the outside of the battery, holes pointing down (towards the label) on the end opposite the white release button. Then solder a 28 gauge insulated wire to the 1st pin of the connector and the other end to the battery negative. The 2 pin gets wired to the common connection of cell 1 and 2 and so on down the line until the 6th pin gets wired to the positive of the battery.
It is best to balance and test cells before assembly, but you can also test cells in an assembled battery if you add the above discussed 6 pin connector. Or, simply use alligator clips to test the suspect cell(s). Use care, short are easy to do and the resulting sparks unpleasant.
I use 3 steps to test cells.
1. Charge the cell(s) with a single cell Li-ion charger. I use one from DealExtreme.com, Item # 132558, $5.40. These are designed to charge a bare cells to 4.2volts, but it is a simple matter to open them and solder 2 wires; one to the positive and one to the negative. On the other end solder to a 2 pin male that will plug into the 6 pin female connector. Each time you shift the charger pins one space, you are charging a different cell in the battery. Try to keep positive and negative straight, but if you get it reversed the charger senses the problem stops any damage.
If the cell voltage below 2.5 v, the charger won't start the charge. If the low voltage is caused by an internal short, it's toast. More likely the cell was stored with an external load and it might still recover. Here's a safe method to find out. Connect a small Ni-MH cell (1.2 v) to the cell (positive to positive) and see if the voltage starts to recover. The internal resistance of the NI-MH cell will prevent very high current if the Li cell is internally shorted, but if the voltage doesn't start up in a few seconds it's bad. If the Li cell charges to 1 volt, switch to 2 Ni-MH cells in series. If it reaches 2 volts the charger should now work and charge the cell.
2. Store the charged cell 24 hours to see if the open circuit voltage drops below 4 v. If it does there is likely an internal short or other problem and the cell won't hold a charge.
3. Connect a 2 ohm resistor capable of 2 amps to the cell and note the voltage after 60 seconds. If it stays above 3.7 v it will probably work fine in a tool battery. If it's less, use it in a flashlight or other low drain device.
If all goes well, you now have a full charged, balance and tested battery with an added 6 pin connector. Purchase a RC voltage monitor (DealExtreme.com, Item #20024, $3.26). It comes with 7 pins on .1" centers (to monitor 6 cell batteries) but we use only the first 6 pins for our 5 cell, 18v system. Plug it into the added 6 pin socket and it will report cell 1, it's voltage, and so on through cell 5. Finally, it reports the total battery voltage.
Test the battery on various tools with the V monitor plugged in to see how the cells are doing under various loads. If one is especially weak then consider replacing it.
To recharge the battery after use, one could theoretically use the single cell charger 5 times. Of course that is ridiculously slow and time consuming. An RC balanced chargers is the preferred solution and it should plug into the 6 pin connector and charge the complete battery in one shot, carefully monitoring the voltage of each cell. They are a bit expensive and I don't have one so I don't have a purchase suggestion.
Another way is to use a 19v or 20v DC laptop charger to charge all 5 cells wired in series. If the cutoff voltage maximum is 4.2v/cell then 21volts is the absolute maximum for safety. Connect the laptop charger to the battery's main + & - and monitor each cell's voltage. 20 volts works out to be 4.0V/cell which although not a full 4.2v charge, it is substantial and you probably wouldn't notice the difference in days work.
I use a Kensington Universal Power adapter which can be set to any voltage from 0 to 24 volts, by changing the value of one 1 resistor. I set the voltage of the Power adapter to 1 volt above the battery's discharged voltage and increase it gradually during the first few minutes of charge. I then leave it over night with the charger at 20.5 v (4.1 v/cell) and get excellent performance.
If the cells become out of balance, as shown by the V monitor, charge all 5 to 4.2V, in turn, using the single cell charger.
One final consideration. Makita's chargers are fast. If an overnight charge isn't fast enough, then your are pretty much stuck frequently buying new batteries from Makita and using their chargers.
elduderino970
Newly Enlightened
- Joined
- Sep 28, 2013
- Messages
- 7
Thanks for the detailed info Firedog!
I recently replaced a bad pair from my 3.0ah pack with 2 Samsung INR-18650-15M (Knowingly against advice posted here). I matched the charge carefully and the pack was stable for a few days. However, with just a few minutes of use in a reciprocating saw, the whole pack was hot and the Samsungs were 10 degrees hotter at 115F.
I have been scrounging for a failed Makita pack but I can't seem to find one. Right now, the only type of identical cells I have 15 of are IMR-18650BB from two 5s2p Graco packs. I already have the RC charger and voltage monitor.
I recently replaced a bad pair from my 3.0ah pack with 2 Samsung INR-18650-15M (Knowingly against advice posted here). I matched the charge carefully and the pack was stable for a few days. However, with just a few minutes of use in a reciprocating saw, the whole pack was hot and the Samsungs were 10 degrees hotter at 115F.
I have been scrounging for a failed Makita pack but I can't seem to find one. Right now, the only type of identical cells I have 15 of are IMR-18650BB from two 5s2p Graco packs. I already have the RC charger and voltage monitor.
Charging 5 LiIon cells in series without supervising each cell voltage can be dangerous!!! Either use BMS circuit, which monitors the cells or AT LEAST put a 4V2 1W zener diode over each cell (reverse polarity), which may take some power instead of cells. Because especially when mixing old and new cells (or - even worse - hi power cells (machines) with low power cells (laptops etc)), there may be pretty great differencies between cells within single packet. Or - perhaps the simplest solution - use a charger with built in balancing circuit (hobbyking.com sells them for real small price!). This way you can also quick charge the cells ... (depends on a charger and cells offcourse).
Regards,
Gregor
ginbot86
Newly Enlightened
I just did some research into the bq77PL900, and it appears to only be an analog front-end for the microcontroller in the battery pack. Although the bq chip has support for standalone protection, the use of a microcontroller in the battery tells me that it's being used in "host-control" or non-standalone mode. The bq chip also doesn't appear to have any sort of permanent fault shutdown like many laptop batteries have; this tells me that all the charge-disabling functions are done inside the microcontroller. I have the PC interface and software that Texas Instruments provides, but don't have any batteries around that I can test out with the software.
Long story short, the bq77PL900 chip is not one of the droids that we are looking for.
Long story short, the bq77PL900 chip is not one of the droids that we are looking for.
elduderino970
Newly Enlightened
- Joined
- Sep 28, 2013
- Messages
- 7
I have three separate topics within this post.
1.
So my other 3.0ah battery gave me the red/green flashing lights once. Now that I know about the "3 strikes and your battery is bricked" rule, I don't want to try it again until I ask the experts. On this occasion, I connected the battery to the charger and then plugged the charger into the wall instead of connecting to the wall THEN connecting the battery. Would that cause the red/green flashing lights? I checked each cell with a volt meter and they are all reading around 3.95. My only other guess is maybe some of the cells have developed high internal resistance. Is there a specific list of conditions that cause the red/green flashing lights? Any ideas for saving this pack?
2.
Thanks to Firedog91902's suggestion, I made a super pack out of two rescued recycled Graco packs! It seems to work well and hasn't disintegrated in the reciprocating saw. pic1. pic2.
3. After I spent way too much time tinkering on my super battery, I found that Amazon and eBay sell non-genuine replacement packs in several varieties - just the cells and circuit, a fully assembled 3.0ah pack and a fully assembled 4.0ah pack. Search "Makita Replacement Battery" on either site, do check reviews, warranties etc.
John
1.
So my other 3.0ah battery gave me the red/green flashing lights once. Now that I know about the "3 strikes and your battery is bricked" rule, I don't want to try it again until I ask the experts. On this occasion, I connected the battery to the charger and then plugged the charger into the wall instead of connecting to the wall THEN connecting the battery. Would that cause the red/green flashing lights? I checked each cell with a volt meter and they are all reading around 3.95. My only other guess is maybe some of the cells have developed high internal resistance. Is there a specific list of conditions that cause the red/green flashing lights? Any ideas for saving this pack?
2.
Thanks to Firedog91902's suggestion, I made a super pack out of two rescued recycled Graco packs! It seems to work well and hasn't disintegrated in the reciprocating saw.
pic1. pic2.3. After I spent way too much time tinkering on my super battery, I found that Amazon and eBay sell non-genuine replacement packs in several varieties - just the cells and circuit, a fully assembled 3.0ah pack and a fully assembled 4.0ah pack. Search "Makita Replacement Battery" on either site, do check reviews, warranties etc.
John
torukmakto4
Newly Enlightened
- Joined
- Aug 4, 2013
- Messages
- 112
Nice super pack.
I have built a number of packs from these high power 18650 cells (bought new, not scavenged) which I use in place of lipos for various purposes and I really like these sort of batteries. Sooner or later I am going to build a big 6S (possibly 6s2p) pack for an old drill of mine and make a custom hard case with the original slide adapter for the drill. I am thinking 6s2p with Samsung INR18650-20R, 22.2V 4.0Ah 44A continuous, should beat the old 20s 4/5SC nicad pack and garbage charger hands down.
What firedog suggests, I would say falls into the "not recommended" category. That is about how RC Lipo was handled in the early 2000s when it was new and everyone wanted to be a LiPo cowboy and use the latest tech, and what do you know, there were a ton of preventable fires caused by what we now know as stupidity.
Improvised chargers (I'm not talking about homebrew or adapted CC/CV chargers, I am talking about using a wallwart power supply to charge) are dangerous. You have no proper current limiting and no termination. Going only to 4.1 is safer but that type of rig to charge Li-ion is just not worth it, hobby chargers are about $20 now, get one! Plus with a hobby charger you can charge as fast or faster than Makita does with the OEM charger, up to the charge current limit published by the cell manufacturer, and that will be a balancing charger that is aware of cell voltages and much safer. Unbalanced Li-ion chargers belong with the dinosaurs, dead and buried.
Laptop cells, let's generalize as 2000mAh 2C = 4A continuous discharge rating. 3p is 12 amps. I've seen worse misapplications I guess, but still exceeding cell manufacturer's specs, I would not run that on a tool that can generate huge current transients. The stock packs have high power, low IR cells in them for a reason. Don't put LiCos in them, that's just scary.
I have built a number of packs from these high power 18650 cells (bought new, not scavenged) which I use in place of lipos for various purposes and I really like these sort of batteries. Sooner or later I am going to build a big 6S (possibly 6s2p) pack for an old drill of mine and make a custom hard case with the original slide adapter for the drill. I am thinking 6s2p with Samsung INR18650-20R, 22.2V 4.0Ah 44A continuous, should beat the old 20s 4/5SC nicad pack and garbage charger hands down.
What firedog suggests, I would say falls into the "not recommended" category. That is about how RC Lipo was handled in the early 2000s when it was new and everyone wanted to be a LiPo cowboy and use the latest tech, and what do you know, there were a ton of preventable fires caused by what we now know as stupidity.
Improvised chargers (I'm not talking about homebrew or adapted CC/CV chargers, I am talking about using a wallwart power supply to charge) are dangerous. You have no proper current limiting and no termination. Going only to 4.1 is safer but that type of rig to charge Li-ion is just not worth it, hobby chargers are about $20 now, get one! Plus with a hobby charger you can charge as fast or faster than Makita does with the OEM charger, up to the charge current limit published by the cell manufacturer, and that will be a balancing charger that is aware of cell voltages and much safer. Unbalanced Li-ion chargers belong with the dinosaurs, dead and buried.
Laptop cells, let's generalize as 2000mAh 2C = 4A continuous discharge rating. 3p is 12 amps. I've seen worse misapplications I guess, but still exceeding cell manufacturer's specs, I would not run that on a tool that can generate huge current transients. The stock packs have high power, low IR cells in them for a reason. Don't put LiCos in them, that's just scary.
elduderino970
Newly Enlightened
- Joined
- Sep 28, 2013
- Messages
- 7
Thanks for the quick reply torukmakto4! Btw, I am using an Accucell 6 and I have a voltage monitor to use to watch the pack. The cells in the two Graco packs are these: Model Number IMR18650BB, Nominal Capacity 1200mAh,Nominal Voltage 3.8V, Weight 45g, Size(diameter×Height) 18mm×65mm, Charging Temperature 0~45°C, Discharging Temperature -20~80°C, Storage Temperature -20~35°C, Cathode Material LiMn2O4.
If any cells start to go bad, I can try to reconfigure them as 3s instead of 4s. But that might not cut it with these cells. Which model of loose cells do you recommend for purchasing new and replacing all at once? The Samsung INR18650-20R you mentioned? I don't use this too often but I do like knowing it will work when I need it.
Any thoughts on the red/green flashing from my other pack that appears healthy from my volt meter? My dad is using this pack so I will probably have to replace it with the 'best' knock off pack I can find instead of switching to hobby charging. I have asked one seller what type of cells are used in his packs but I don't think he wants to open one up to find out.
John
If any cells start to go bad, I can try to reconfigure them as 3s instead of 4s. But that might not cut it with these cells. Which model of loose cells do you recommend for purchasing new and replacing all at once? The Samsung INR18650-20R you mentioned? I don't use this too often but I do like knowing it will work when I need it.
Any thoughts on the red/green flashing from my other pack that appears healthy from my volt meter? My dad is using this pack so I will probably have to replace it with the 'best' knock off pack I can find instead of switching to hobby charging. I have asked one seller what type of cells are used in his packs but I don't think he wants to open one up to find out.
John
Last edited:
I guess, the original cells are Konion 18650 - they were used in RC hobby world as well and were very reliable, but expensive. DO MIND, that you must not mix old cells with new one ... Not good idea at all: if you do built a new pack, then use only new cells (same type, if possible same series).
About your "flashing battery": try to load the battery with some load (i.e. car bulbs - do mind, that you connect them in parallel to get enough voltage, otherwise they won't light for a long time ) and then measure the cell's voltage. If one of cells has significantly different internal resistance, this will be clearly shown, as this battery (under load) will have lower voltage.
I would also try to do a cycle with those batteries using RC charger with balancer (but only charge to 4,00 V/cell and discharge to 3,30 V/cell). It might be, that cells are too unbalanced (Makita balancing circuit isn't really a powerful one ...).
Regards,
Gregor
About your "flashing battery": try to load the battery with some load (i.e. car bulbs - do mind, that you connect them in parallel to get enough voltage, otherwise they won't light for a long time
) and then measure the cell's voltage. If one of cells has significantly different internal resistance, this will be clearly shown, as this battery (under load) will have lower voltage.I would also try to do a cycle with those batteries using RC charger with balancer (but only charge to 4,00 V/cell and discharge to 3,30 V/cell). It might be, that cells are too unbalanced (Makita balancing circuit isn't really a powerful one ...).
Regards,
Gregor
Huh, and some more words about hacking the Makita's BMS unit ...
Currently I am so busy, that I didn't make any significant improvement in the protocol decoding. However, I have designed a programmable 6S BMS with proper data output, which will be (later) able to replace (locked) original Makita's BMS in 18 V batteries. Basic BMS functions are already working, but I have to dig deeper in order to persuade Makita charger to give me some power ...
Regards,
Gregor
Currently I am so busy, that I didn't make any significant improvement in the protocol decoding. However, I have designed a programmable 6S BMS with proper data output, which will be (later) able to replace (locked) original Makita's BMS in 18 V batteries. Basic BMS functions are already working, but I have to dig deeper in order to persuade Makita charger to give me some power ...
Regards,
Gregor
torukmakto4
Newly Enlightened
- Joined
- Aug 4, 2013
- Messages
- 112
Lishen IMR18650BB. Chinese made LiMn (IMR) cell, kind of cheap and not top notch, probably not as long lived as the name brand hybrid cells, but a stock cell in many tool packs. If you look at the Dewalt Owners Forum you will see them show up in a lot of teardowns.
The pack should be good for current capability, even if you cut it down to 3p. I googled and am seeing a lot of 2p tool packs with them.
For making a "super pack" and using a hobby charger and other commonplace Li-ion management tools: Use whatever is appropriate, and you like. There are tons of cells out there.
I use quite a number of Sanyo UR18650SAX. Only 1300mAh, but 25A continuous rated and cheap, they make good robust high performance RC-type packs for low cost. Sanyo also has the successor WX and RX, 1500 and 2000mAh 20A cont.
Sony is a serious contender. You can't go wrong with the US18650VTC3, 1600mAh 30A cont. or the US18650VTC4, same rating and more capacity. I wouldn't mess with the older V and VT, 4.1 charge voltage, less than 20A and less than 1500mAh, Konions anymore for a DIY pack.
Samsung, has the 20R and a new 24R, 2000/2400mAh 22A cont.
LG apparently has a 2500mAh 30A cell!
If you are recelling a stock pack to use the stock BMS? I dunno, I will just note that some makita and other packs do not balance or monitor individual cells, and I would not use anything but the original (proven safe and balance-maintaining) Sony Konion V/VT.
Also I would not assemble by soldering. I made myself a tab welder.
jackbombay
Newly Enlightened
- Joined
- Jul 31, 2011
- Messages
- 39
I disassembled my makita pack and remoed the electrical connectors from the circuit board, then used a 5" grinder with a 36 grit sanding disc to removed everything from the circuit board, then put the connectors back on the circuit board with JB weld, and used the 6 connectors on the yellow plastic fitting on the pack as balance charge leads. Now, I can balance charge my packs every time I charge them, I use the fitting from the makita charger and an aftermarket Lion charger to charge the packs.
The makita packs are designed to fail, the circuit board only pulls power from one of the cells in the pack, thats why the dead cell is always the 1st one, once that cell gets discharged disproportionately compared to the rest of the cells the makita charger will no longer charge the pack. The makia charger does not balance charge the pack, it is a truly terrible design.
I really like the 18v tools or I would have quit using makita long ago, the cordless concrete vibrator and the 6.5" circular saw are so nice, and the the vibe was expensive enough that I "need" to keep it. I hope that by eliminating the curcuit board from the battery and them getting a proper balance charge each time they are charged I will get 2-3 times the life from the pack. I don;t use my cordless tools as much as I used to, but I was always quite concious about not discharging my batterys too far, kepping them inside during winter/freezing weather/etc... and the batteries never lasted long for me, 4 batteries in 3 years is not acceptable IMO.
delus
Newly Enlightened
One of my 18V LXT batteries went dead. At least it will not charge on a factory charger. I lined them all up, and it turns out I have exactly 11 of them, and all the rest take a charge. Then I noticed they all have a little star on the sticker, except for two. The dead one does not have a star. Next i looked at the makita website and found this.
http://www.makitatools.com/en-us/Modules/Tools/LXTAdvantage/StarProtection.aspx This star identifies the "new" type of battery.
Makita does not mention anything about cell balancing, but looking at clues in this thread, I'm 90% sure that the star means it includes balancing.
Most of my tools also have a star where the battery is attached.
I also have five chargers, four of the older green ones, and one of the new smaller black-plastic design. They all have a star except for my oldest green charger.
I had a couple of drills before i got into Makita in a big way, at Xmas 2010. So i think these star batteries started to become available around the same time this thread started, late 2010.
In any case, I still want to get that one dead battery working again. I'm drawn to the quick and easy, but dirty way. Quote from "JCSSJ2". (A lot of people with low post counts in this thread.)
If my other non-star battery is wasted it's not a giant loss, i figure it doesn't have much time left anyway.
My question is.. I reverse the polarities right? I'll use the two non-star batteries and wire them positive on the good battery - to negative on the bad battery, is this correct?
I'll wear a full face shield and some other rubber protective equipment designed for working with acid. And I'll do it outdoors on concrete, with a fire extinguisher ready.
http://www.makitatools.com/en-us/Modules/Tools/LXTAdvantage/StarProtection.aspx This star identifies the "new" type of battery.
Makita does not mention anything about cell balancing, but looking at clues in this thread, I'm 90% sure that the star means it includes balancing.
Most of my tools also have a star where the battery is attached.
I also have five chargers, four of the older green ones, and one of the new smaller black-plastic design. They all have a star except for my oldest green charger.
I had a couple of drills before i got into Makita in a big way, at Xmas 2010. So i think these star batteries started to become available around the same time this thread started, late 2010.
In any case, I still want to get that one dead battery working again. I'm drawn to the quick and easy, but dirty way. Quote from "JCSSJ2". (A lot of people with low post counts in this thread.)
If my other non-star battery is wasted it's not a giant loss, i figure it doesn't have much time left anyway.
My question is.. I reverse the polarities right? I'll use the two non-star batteries and wire them positive on the good battery - to negative on the bad battery, is this correct?
I'll wear a full face shield and some other rubber protective equipment designed for working with acid. And I'll do it outdoors on concrete, with a fire extinguisher ready.
Last edited by a moderator:
ginbot86
Newly Enlightened
No! You don't want to reverse the polarity as you'll get a short circuit.
If you want to charge this way, connect all + to +, and all - to -.
Last edited:
woodworking
Newly Enlightened
- Joined
- Jan 11, 2014
- Messages
- 1
hey everyone. I came across his forum when looking to replace 2 old 18v li-ion batteries, these are about 5 yrs old and age has gotten the better of them. I'm wondering if these have the chip in them, I don't think they do. I believe Milwaukee has a battery that is inter changeable, although I don't know how good it is for the battery. The way I see it, instead of spending $180 on new batteries, I'm going to buy a new tool set probably Milwaukee, replacing the 3 Makita tools I have. Any thoughts on a good replacement brand? Has anyone tried switching battery brands?
Hi all I'm new to all this,my query is that I rebuilt 1 of my batteries replacing some dead cells and fitted a new pcb board now when I put it on the charger it just flashes red as though the battery temp is to high sadly not charging but when I put the battery in one of my tools it runs fine I'm stumped
I use Dewalt cordless tools, with NiCad batteries. LiIon have never served me well when it comes to longevity. When I can avoid them, I do.
elduderino970
Newly Enlightened
- Joined
- Sep 28, 2013
- Messages
- 7
I'm no expert but here are my thoughts on your question.
I assume that you have read that the pcb will brick itself on the third occurence if you try to charge when in error condition.
You might try checking the voltage of each set of cells in the pack to make sure they are close. If not, try charging just that set to get them close to the rest. This process would take some sort of li ion or lipo charger.
If all else fails, you can use a hobby charger, a voltage monitor, and make a balance connector to attach to the pack. See my posts above for more info.
HTH
John
Latest posts
-
-
-
Thrunite rocks !!! Whats your favorite brand ?!?
- Latest: CarpentryHero
-
-
-
-