I have a Hanger 9 voltmeter, that applies a 400 mA load @ 9.6 volts. This one:

http://horizon.hobbyshopnow.com/prod...sp?prod=HAN111

It measures 9.4 volts - that is loaded (~400 mA). So there is current flowing. However, the 9c tells me 9.9 volts.

So, I will step out on a limb here and assume the poly-switch has a resistance of (9.9-9.4)/.4 = 1.25 ohms.

Perhaps that is giving the alpha 4 some problems. To charge it at 400 maH you have to supply .5 volts more than would be required in the absence of the fuse.

.... just a guess.

Perhaps someone can dig up the specs on the poly switch. That might help.