This week on Digital Foundry, Linneman dropped the truthful reminder in this time of power-hungry GPUs that the Wonderswan used a 75hz refresh rate running on a single AA battery.
This week I was in correspondence with Flashmasta developers of the best Wonderswan flash cart on the market. They still recommend the use of name brand alkaline batteries, because the wonderswan, if not recently recapped, will have power draw issues, especially with a flash cart. This is especially true for the original B&W console, when unmodded and completely stock.
They also, of course recommend the use of their drop-in replacement battery. They even stated in this use case, the battery would last a very, very, very, long time. Yes, that is true, but I am not at all fond of that solution, it’s overkill, and ruins the form factor of the console, and the aesthetic.
I recently replaced all capacitors in my wonderswan and am using a rechargeable lithium, 1.5v regulated AA battery. There is no need to sacrifice the elegant form factor and convenience of the wonderswan, even when using a flash cart.
In my correspondence they were glad to hear that there are other means.
I basically told them an abridged version of what I said in this recently edited insert credit forum post.