I have an Sakay external power pack BP1800. The package says fits Canon etc. The pack includes a 6 volt rechargeable lead acid battery (3 cells in a plastic case). The input receptical on my Powershot A70 says 4.3 volts DC. Four alkaline cells internally makes 6 volts. Can I use the 6 volt pack externally. I asked Canon and they said we do not support that configuration. Unless they have done something very strange internally it should work. On the other hand I don't want to damage my A70.