I was just wondering if there's any reason that I shouldn't use a backpack battery on my trolley? I realise it won't last as long as a big juicy one, but then I only get 5 hours from the one I have at the mo anyway and could just change over.its basically a weight thing as to why Im thinking this way. And would I have to have a specific charger or would I be ok rigging it to the car charger like I have with this one?