As is typically the case here, an OP again leaves out specific information - what type of batteries?? (6v, 12v, group, etc), drip, drip, drip...So I have to assume the replies as generalized...
I purchased two WM 6v's recently (about 7-8 mos ago) and so far no problems, even runs the 11.5btu AC for over 30 minutes without a hitch... At time of purchase I called Interstate and was told that they are rated at 208 a/hrs each (or 208 total when in series)... I'll keep everyone advised as they progress...In my view, for $85 per, If I get even 3yrs out of them (properly maintained...), I'll be glad to swap 'em out for another brand new set....Time will tell...