Posted by: @marvin-1989

- Very little circuit, at the top and TL431, MC908JK3E, fusable link 15AH3 as main components at the bottom.

I already have the binary code of MC908JK3E used in Makita. It is an 8 bit microcontroller, with a schematic, maybe we can try to reverse engineer the hex image. But this is an old battery, I don't know how much it is worth.

Posted by: @marvin-1989

My idea was to make use of the 'intellegance' of the Chinese copy and add balacing and safety (fuse, thermal fuse). To create a good working replacement board for the Makita batteries. But the problem is time..

I have never compared Chinese copy BMS with a genuine BMS in terms of performance. What do you want to improve for Chinese copy ? It looks like you are interested in balancing and safety. I don't know if this BMS has active balancing, it could be that only cells voltage monitoring is implemented.

@azzido 

My idea was, since the Chinese is faking the charger, to tread the PCB as blackbox, measure the output and also fake to the charger that "my" BMS needs to be charged.

The Chinese BMS is not really a BMS, just a PCB that makes the Makita charger charge the battery. This will be stopped by the temperature fuse/switch, otherwise the battery will be charged. There is no balacing, check of voltages or anything. Second, this board is much simpler compared to the MC908 board.

I was thinking of designing a BMS board my self, to make sure the cells are monitored and corretly charged by a BMS chip. At a ATmega or some arduino MCU to fake the communication to the charger; since Im more into hardware than software.

But maybe you can help with faking the communication to the charger when we link the firmware to the schematic.

I can create a schematic of the simple Chinese board or MC908 board.

I have 4 of this PCB to rapair or reset but no succes - many videos on yt says it must be used specific charger - Makita DC18RC - and after plugin/plugout it should restore.

Also found some info on the web :

If the charge count on the batteries is under 300, Makita will replace them. Makita has a known defect in this battery that causes the battery to shut down before it is dead. So as of now they are exchanging ones with low use.

So, if anyone need a pcb for testing, will give a try to help 🙁 i have nlba device and ev2300

@marsotica 

Makita is using one wire protocol communication between the battery and the charger. This protocol could be HDQ and EV2300 interface has this protocol. 

You can download this demo software that works with EV2300 and supports HDQ: http://wwv.regeditvn.com/download/TEST-BATTERY-VER-5.20.msi

Can you try to establish the communication ?

Here are my investigation results I have done 2 years ago:

no. don't know how, can you help with the pinout ? i've installed the program

makita conector side

and ev2300

edit: ok, will try tomorrow, thank you for help

@marsotica 

GND from Ev2300 to the first pin from the right side of Makita.

HDQ from EV2300 to the second pin from the right side of Makita.

Is this a working battery ?

The battery is locked like dead, not charging and the tool is not spinning if it is fully connected (with all 3 pins)

If it don't get fully in place, it's spining, but once the TH terminal is joining the tool(drilling machine) pin, it will stop spinning.

Posted by: @azzido

@marsotica 

GND from Ev2300 to the first pin from the right side of Makita.

HDQ from EV2300 to the second pin from the right side of Makita.

Is this a working battery ?

it's not working, sorry

i have no readings in the program

i have 4 pcb of makita bl1830, replaced the cells but now i will buy another compatible pcb with balancing

@marsotica 

I think you did not connect the wires correctly. Please check again my suggested wiring.

Still nothing

just draw a line.....how is correct ?

In my analysis, there was another signal that was driven by the charger, a kind of enable pin for starting the communication. Can you try it with any other Makita battery that is good and has output voltage ?

@azzido 
I put it back in the charger, flash red/green and then reconnected to ev2300 but still no signal

The cells are brand new sony vtc5, balanced and charghed. on output power pins it has around 20 volts

@marsotica 

When I will have time I will check on my battery.

Another dead PCB...

It can be repaired, with new cells only of the battery is still working. I think it must be fail by 3 times in the charger to get locked.