I think, but don't quote me, that there are 'plug in' models. Though all the ones I've seen have 5-year lithium batteries.

No idea about refurbishes.

They're supposed to be checked daily, and theoretically run through an internal QA during the check. So theoretically there's no external calibration needed.

Training???? You don't need it - push the button that says start and follow the voice prompts.

The big thing with them is the pads have a shelf life. And even in that shelf life, you probably need extra. We went through 2 pairs on a 10 minute ambulance ride after the first pair literally burned through and developed a hole after repeated shocks.

Don't think that they're the be-all&end-all. In something like a trauma, they're not going to be much use (ie, you can't shock a heart that's bled out). So even if you use one and it works, there's a good chance that the person will re-arrest, if you truly are that far from some medical care. Simply b/c you haven't reversed the cause of whatever precipitated their arrest initially.

Have fun dishing out $3000. Wonder if your job will partially reimburse.