Can you charge a T23/T30/T40 battery in a T60?

[RealBlackStuff]

Saw this on Reddit and it is exactly what I'm looking for.

Charge a T40 battery in a T60 possible?

5-pin Battery from T40 is charged using a 16V charger.
7-pin Battery from T60 is charged using a 20V charger.
5-pin layout: plus-clock-data-temp-minus
7-pin layout: plus/plus-clock-data-temp-minus/minus
Now make an adapter: female 7-pin to male 5-pin, where you connect all matching pins.
IMHO you should now be able to put a 5-pin T40 battery -via that adapter- in the 7-pin T60 battery bay and charge it in there.
The charging circuits for both T40 and T60 series provide around 10.8-11.1 Volts.
Do you think this works?
(same applies to T2x/T30/T6x/T400 and many more).

PS: I'm not trying to put the T40 battery in the T60 bay, just connecting their charging pins.

I have a few interposers for T4x and T6x machines, so I cut the battery part off from both of them and managed to squeeze the male 7-pin side into the female 5-pin side, ignoring the 2nd +/- contacts on the 7-pin.
Literally fits like a glove and gives me the required female 7-pin to male 5-pin.

I have a T30 battery which still shows ~11V in my multimeter and has very few cycles.
And I also have a T60 which I used for my LED-mod testing.

I looked at the schematics from T23, T30, T40 and T60 and they all are very much lookalikes in their battery charging circuits.
Big question now: can I hook up that T30 battery via my "adapter" to the T60 battery-connector and thus check/charge the battery?

This is my concoction:

[RealBlackStuff]

No comments/ideas?

[astral]

if the charging voltage is the same then you shouldn't light anything on fire in theory but it would almost certainly not work, if I had to guess. Battery BMS boards are usually very strict and unless it identifies properly as the correct battery, my guess would be that the computer would at best report a battery-related error, or likely just not detect one at all.

[RealBlackStuff]

Yesterday I had a bright idea, dug out my external Lenovo battery-charger 40Y7625 (7-pin) and connected that (5-pin) T30-battery to it, using my contraption.
The charger started blinking yellow every 5 seconds or so, so I figured I'll leave it in overnight.
This morning a miracle!
The charger control led had turned a solid green, meaning it must have charged the battery!

I plugged the T30-battery into the T60 with T2500 CPU, booted into 32-bit W7 with Lenovo Power Manager 3 and kept my fingers crossed.
Tried "cmd/powercfg -energy" but the battery readout was also empty.
After about 30 seconds it said ERROR and that it was not a Lenovo battery, so no results.
Tried another HDD with Vista, no dice.
Tried Linux, but that told me I need a 32-bit version because of the old CPU without PAE(?).
Downloaded 32-bit MX-Linux, put the ISO on a USB-stick with Rufus, then booted it.
Unfortunately Linux was also not capable to do any battery readout.

However, with my multimeter I measure a steady 12.55V DC, so the battery is charged!
I no longer have a T23/T30 so can't do a proper test.

Any other suggestions?

[kfzhu1229]

Well I guess I do know that a ThinkPad A2x/T20/21/22 battery is not going to charge here.
I learnt this the hard way that even if I put my rebuilt A22m battery in my thinkpad T42 with the same connector, the communication do not work, although the battery will discharge okay. (My A30 battery works fine on the T42) And if I put my T42 or A30 battery in my A22m it would actually work perfectly okay
I am not surprised if T6x are more picky with their batteries with the whole not a lenovo battery thing. I know the T6x batteries themselves have much more evil BMS than the T4x counterparts, all of my T6x/R6x came with dead batteries that sometimes aren't even dead with all cells holding charge.