Metabo cordless tool 18V, battery adapter Makita, compatibility problem

[jff]

Hello all,

Sorry for my bad english! (I'm from Belgium)

I would like to run a 18V Metabo SCV18LTXBL16 shear with a 18V Makita battery.

Why? Because all my machines and battery are Makita. Unfortunately, Makita doesn't make shears like this.
So I had to buy a Metabo. (without charger and battery)

I bought a battery adapter from china but it is not fully compatible. The machine runs 4 seconds and stops. After that it is no longer possible to restart it with the ON/OFF button.
I have to remove the battery and put it back to it to work again for 4s...

On a Metabo 18V battery there are 5 pins:
- = 0V
T- = battery temperature sensor (variable resistor)
T+ = battery temperature sensor (variable resistor)
D = ??  numerical communication
+ = +18V

My adapter have a resistor between T+ and T- pins to simulate the temperature sensor and send 18V between the + and - pins.

I tried with a Makita 18V 4Ah battery fully charged. The voltage is just over 20V.
This is the same voltage as a fully charged Metabo 18V 3Ah battery with which the shear works.

the problem is on pin D. Because when I connect all the pins of the Metabo battery except the D, the motor runs for 4s then stops.

On a Metabo battery, I measure:
between + and -: 23V
between + and D: 22.9v
between - and D: 0v

in ohmmeter:
59.8 kohm between D and - (with the - of the multimeter on pin D)
60 kohm between D and - (with the + of the multimeter on pin D)

I don't know what this resistance measurement is worth but we can conclude that it is not a simple resistance.

When I add a diode between battery and machine on wire D (in direction that lets the current flow from the machine to the battery), the machine works normally.
It confirm the machine sends signals to the battery.


With an oscilloscope between pin + and D, we see the signal which varies between -16V and -20V when the machine is running and again for 10s after stopping the machine.
After that, the voltage is stable at -20V:

I tested with a 60 kohm resistor between pin D and - of the battery. It still does not work. the voltages measured are between -13 and -18V.

It can be seen that voltages are different with the 60k resistor. That would be the explanation?

I conclude that it is a digital communication, only from the machine to the battery. And the machine would measure the current on the pin D based on the voltage. When this current is outside limits, the machine goes into safety mode after 4s.

Does anyone have an idea to try to "trick" the machine?

Thank you in advance for your help.

[abdulbadii]

When I add a diode between battery and machine on wire D (in direction that lets the current flow from the machine to the battery), the machine works normally

So confused by which real question is when there's no unsolved which is said above

[jff]

Hello,

Sorry for the bad explanation.

When I add a diode between battery and machine on wire D (in direction that lets the current flow from the machine to the battery), the machine works normally

It's with the original battery Metabo, Not with adapter.

Regards

[connectTek]

https://a.aliexpress.com/_m03GErk
Should solve the problem

[jff]

It's what I bought but not working.
This converter don't manage serial communication between tool and battery.
Without serial communication, tool go to error mode after 4s and stop.

Thanks.

[bastl_r]

Metabo addet a digital conversation between machine and battery some years years ago.
This problem was in dicussion some time ago in germany too with no solve.

bastl_r

[jff]

Hello,

Happy new year!

Thanks for the link in Germany.
It seem to be too much difficult for me! I will spend a lot of time without success warranty.

I have no other choice to buy an original Metabo battery and charger.
I go to the shop...

Thanks for your help!