G'day Matilda,

The solar panel has a charge output of 360mAh, and the capacity of the battery itself is 16000mAh.  This means that charging it up exclusively from the solar panel alone would take 44 hours, assuming all those hours are with optimal sunlight.
Ideally, you'd have this power pack fully charged by 12/240v, and use the solar panel to keep it topped up.

G'day Nemi,

I don't believe the battery in this power bank is user-replaceable.

Lithium-ion batteries of this size generally have 500 lifecycles if you discharge to empty - meaning you'd get 2000 full charges of an average mobile phone before battery performance started to deteriorate.
For optimal battery health, if best to keep the power pack topped up, and not dropping much below 30%.

G'day Betty,

Companion doesn't provide any advice on this one, so our only real option here is to look at generic Li-Ion battery advice.
It seems this type of battery chemistry can be used down to -20ºc, however ideally should remain between 5/10ºc - 40/45ºc for ultimate battery health, and longevity.  Based on this info I'd suggest -5ºc would be ok for the odd or once off use, but anything consistent at these temperatures will shorten the units life span.
Hope that gives abit of info for you.

G'day Stephen,

That depends on the size of your phone battery, which you can find with a quick google if you are unsure.
My phone battery is around 4200mAH so I'd get about 4 charges out of the Companion Solar Powerbank 16000mAh.

G'day Matt,

Yeah, absolutely.  There's no guaranteed specs but we estimate the lights only use around 1-1.5Ah, which means you'll probably get 10hrs of runtime from this power bank.

Hi Dan,

Sorry about the delayed reply, we've been waiting for some verification from Companion on this one, but they've not come back to us yet. We assume that the charge time is based on USB charging as the solar input is only 0.36Ah.

G'day Phil,

This is such a great compact charger, however, the batteries are unfortunately not replaceable.