Charge adapter D batteries

I found 2 rechargeable NiMH D batteries for a project, but all I had is a small AA - AAA charger. I wondered if this Rayovac AA charger would charge the big Ds. Yes it will.

My Energizer batteries are rated 1.2 V and 2,200 mAh. In storage for a year, the battery voltages began at 1.20 and 1.21 V.

Plugged it in for a couple hours. Voltage is now 1.42 V.. Batteries are not even warm. I think a D has 8 times the capacity of an AA, so charging this way might take some time. (Came back in 6 hours and the light was off. Cooled, finished voltage 1.41)

Wondering how to do it, I designed the adapter in two parts to give me options. The upper and lower parts were eventually hot-melt glued together, but might be friction welded (link) or glued, or perhaps modified and printed as a single piece?
https://www.thingiverse.com/thing:1807093 (welding)

As for electrical connections, I chose stranded wire, and poked holes where needed. A touch of solder here and there can help make electri