Below 10V is actually the kill zone, 8V is a promise.
Thing is, you might get another 3 months use out of it... and depending on your warranty, you might get a new one.
Yup, think Jaycar have 'em, my old work has em (12 Volt Shop), charge rate of 1 amp or greater would be ideal.
Be cautious about any electronic gear that Bunnings spews out.