I always believed the cheapest way for your battery mate was to buy it seperately ,i picked up a
17ah sealed battery for £35 from a local distributor ,its perfect for the striker ,not overly heavy
and lasts long enough for a decent nights lamping ,i remember 20 yrs ago running with 24ah golf trolley
batteries ,great for the job but by god you,d some bruises next day ,good luck mate ,hope you get it sorted .