Now... How do I use this thing? And what batteries can I use to replace the NiCads?
@thelastpsion if you can't find matching nicads, NiMH batteries work too
@vxo @thelastpsion +1. NiCd and NiMh work with same voltages and ostensibly both can charge with same chargers
@thelastpsion @mavica_again that is absolutely an option if you want to go that route! you'll just need to keep the builtin charge circuit off it - a Schottky barrier diode in series with the battery cell should work fine. I'd recommend using a protected cell. You can get a little thumbnail sized board containing a proper Li-ion charge controller and sneak it in the chassis wherever it fits :)
@vxo @mavica_again See, now I'm wondering about replacing the centre-negative barrel socket with USB-C and PD... To be honest there's a fair amount of space in the box.
@thelastpsion @mavica_again yep! I don't think this actually uses any of the advanced capabilities of PD but it'll work with it. https://www.sparkfun.com/products/15217
You should have no problem finding a place to mount it and a battery in that big thick enclosure.
@thelastpsion @mavica_again that being said, how many NiCd cells were in series originally? if it's 3, that should work straight up; tiny boost and buck converters can be had easily if you need to go one of those routes
@vxo @mavica_again It was 4 in series.
@thelastpsion @mavica_again ah yeah, depending on how much voltage the device actually needs you might be able to get away with feeding it the 3.6-4.2vdc battery voltage straight up. If it complains the batteries are too low though you might want one of these too https://www.amazon.com/QEBIDUM-XL6009-Adjustable-Synchronous-Non-Isolated/dp/B0C81RQ4CN
@mavica_again @vxo I take it it's not worth trying with Li Ion and a new charging circuit? Happy to give NMH a go, I'm just interested in all the options.