May have to re-do the wiring slightly then to adapt for the new packs

anyone know of any good chargers that are not £100 each, bit steep for £420 in total for a conversion so want too bring that cost down a bit really

How viable would it be to use 8.4v nimh packs of the same 3000mah? would need 3 packs of 3 so 9 packs in total, but comes out at under £200?

http://www.wheelspinmodels.co.uk/i/70479/

Just exploring different ideas here, dont want to run SLA's forever