Chosen Solution
I worked on a dead iPad today. The owner thought the battery was dead and so brought a replacement obtained from eBay (in fact, a complete rear shell with battery still glued in place). The original battery indeed read 0V - evidently it’d gone into protective hibernation, but the replacement read 2.5V - probably on the verge of going into hibernation. (Probably not a lot of life left in it, but that’s not my concern for the moment.) We replaced the battery and put it all back together, but still no sign of life. We tried with it plugged into a 1A powebank but still the same. I suspect either a faulty logic board or faulty screen. I’ll advise the owner to see if iTunes will recognise it. But first, my question: should an original iPod boot up when plugged in even with a dead or fully discharged battery (as an iPhone 4 does but not an iPhone 5, to my recollection)?
The battery has to have at least ~3V in order for the device to boot. The problem with using a smaller 1A charger is that that produces insufficient current to quickly charge the much larger iPad battery. So if you connect the small charger to a low-voltage battery like yours, no, the device will not boot. You could leave it charged overnight to see if that gets the voltage back to where it should be (~4.2V) and then try to boot. Or get a proper 2A charger :>).
