I'm building a project based on something like one of those Elegoo Arduino based smart robocar kits.
These kits usually come with LiIon 18650 battery holders but I don't have such batteries and I'm not sure if I want to mess with LiIon batteries, considering that they require special care when using and charging and how many fakes there are on the market.
So, I'm considering my options to power my hobby project based on what I currently have on hands:
Anker Astro3 10000mAh USB External Battery Pack and Charger (Power Bank) - I have it for a year or so and I have been using it when traveling by train and watching movies on my smartphone. I guess, it's also LiIon but at least I know it's good quality. Still, it's somewhat bulky and might be too heavy for the small-ish robocar. I'll have to modify the kit to make the powerbank fit firmly and still be removable when I need to use it.
I have 8 of NiMh AA batteries and I can buy more. They are so versatile. Also I have Duracell CEF22 NiMh Multi-Charger which works great. The only thing I don't have is a battery case to make a pack of 6 batteries to make 7.2 volts. But I've heard that it would be a good idea to power the motors from a different source to prevent Arduino from brownouts when the motors are under stress while fighting against some obstacle. Still, it seems NiMh AA is great to mix and match as I wish, but I just have to buy appropriate cases and think how to fit them on the chassis of the car.
I have also an old pack of 5 NiCd batteries wrapped in a pack and with just two wires going out. I could use them alone, but I think 5 might not be enough for both motors and Arduino, so again - I might mix them with NiMh AA batteries.
But one more huge problem with the last option - I don't have a charger for this 5 NiCd pack! How do I charge them? Can I use my Duracell Multicharger also for NiCd battery pack?
I know, this is NiMh charger and it might not be appropriate for NiCd, but at least I hope they won't explode? And how do I attach them to the charger? I don't want to disassemble the pack because the batteries are soldered together in series. Can I charge the entire pack by attaching the wires to a single battery slot on the charger (observing the polarity, of course) or it might be bad idea for the charger or the batteries?