i think u will need 3 amps to charge it as the current is split into two arms...but to be on the safer side jus check the reference manual or something of the device.
what is suppose to be the charging rate of your battery? let us suppose that you have a 800maH battery and you wish to fully charge that batt in 2 hours, it means that that your charging rate will be 400ma per hour. the ampere rating of your transformer should be about twice the batt capacity.
but if you wish to fully charge after 8 hrs then you will need to charge at 100ma per hr. and transfo should be rated at least 500ma.
it is the charging rate that dictates what current rating you need.
a M hydride batt charger can charge a Lith I. as long as it can support your charging need.l