Funnily enough it went completely dead about ten minutes ago! I left it switched on without using if but not sure for how long... so charging up again. the one worrying thing is it just stopped - there one moment, next moment sound off, light out!
Not worried about latency - if I can hear anything it's barely audible. All my digital effects are old-school use the dry signal (chorus, flange, delay) as well as the digitised one so they won't add latency.
I understand it's when you use fully digital processing that the latency starts to add up.