Xiaomi Wiha Zu Hause Electric Power Screwdriver (Arrived)

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tatasal
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Well, this is the ‘exploded’ view of the screwdriver.
I won’t know if the OEM cell was crap, or was damaged by the extremely high parasitic draw since I don’t think this thing has low-voltage protection.
But what is certain is that its electronics has extremely high leakage and it certainly left the OEM cell at 0 voltage after only 3 days.

Barkuti
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tatasal wrote:

But what is certain is that its electronics has extremely high leakage and it certainly left the OEM cell at 0 voltage after only 3 days.

Into the trashcan time, then. Amazing to see a company like that allowing a clanger like that.

The Light Innocent I am

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tatasal
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Barkuti wrote:

tatasal wrote:

But what is certain is that its electronics has extremely high leakage and it certainly left the OEM cell at 0 voltage after only 3 days.


Into the trashcan time, then. Amazing to see a company like that allowing a clanger like that.

Not so fast, my friend…

Tomorrow you will see my (rudimentary) solution. Beer

Barkuti
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Well, yeah, you seem like one of those DIYelvers, like me in fact LoL. Determined to make it work the way it should work.

At times I've wondered if it was worth it… 

P.S.: installing some MOSFET switch to cut-off power from the cell when not in use?

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tatasal
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Barkuti wrote:


P.S.: installing some MOSFET switch to cut-off power from the cell when not in use?

That’s too high-tech for me! It will be the most traditional way, mind you.
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I remembered this Latching power switch uses momentary pushbutton @ EDN circuit tatasal, which shouldn't work right without blocking diode given the electric motor load. But there are many other “MOSFET as switch” tutorials and articles, like this one @ ElectronicTutorials. You could use a small latching switch to control any MOSFET gate drive(s), and so you would be able to connect and disconnect the battery triggering a small switch which would drive the MOSFET(s) gate(s).

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tatasal
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Well, pending Mr. Barkuti’s more high-tech suggestions, this is my primitive solution to the problem:

Since I took out the OEM 1500mAh cell that was utterly ruined by over-discharging while in storage due to (I believe) parasitic draw or leakege, I put in a brand-new Samsung INR18650-25R cell..soldered wires in place of the original cold-soldered metal strips, installed a long wire connected to the (-) side of the circuit and put a connector to interrupt the electrical flow when not in use…talk about a true mechanical for electrical lock-out haha.. I tested the unconnected wire with my DMM and it showed 10.54mA.

So, if the new 25R cell will have a net output capacity of 2350mAh, it will drain the cell completely in less than 10 days! (as explained to me by my friend, TA)


I welcome members’ suggestion for a ‘sleeker’ solution.

MtnDon
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Buy a different brand of tool?

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