I've never had an active bass before , I've just snapped up a Lodestone 5 string from Ashdown ..these were £1800 .there is about 4 left on their site for £425 ..They bought them out before the T bass , I'd really recommend getting one ….anyway how long are these batteries likely to last & do they suddenly cut out or do you get some sort of warning when they are on the way out ? cheers .