UKH

Does anyone have any suggestions for a super lightweight USB C battery pack - something for emergencies to recharge a headtorch or phone?

It needs to be rugged - Anker and similar are not up to the job in this regard.

The closest I've seen is the rechargeable battery pack for the Petzl R1. Others in the lower price range seem to be micro-USB not USB C.

The standard answer is the Nitecore 10k.

https://www.nitecore.co.uk/products/nitecore-nb10000-gen-2-power-bank.html

I have one. I like it, it feels light but robust compared to the Anker equivalents we have in the house. Not cheap. It has worked whenever I have needed it. It lives in my sack in a very snug (made to measure) DCF pouch with a v. short iPhone cable. 

Nitecore 10k? USBC, seems rugged enough to me.

Looks good but not very cheap. Guess you get what you pay for.

If you want protection from knocks etc, then pop it in a neoprene pouch.

How have you managed to break a power pack?

I've got the medium sized Alpkit one, not too expensive and seems to work as well as my branded ones. Aluminium case that seems pretty robust. I think you can use the USB C as either in or out, but I might have misremembered that. 

I think that wireless charging is essential. Getting moisture in the port / cable causes the phone to block charging till dry....and my thought is that if I really need to top my phone up it will be wet, horrid and difficult to keep the connectors dry.

Isn't wireless charging typically pretty finicky about keeping the two devices in perfect alignment? I think I'd be more inclined to just stick the whole lot in a dry bag while it charged. Could probably find one with a see-through window if necessary.

Wireless charging has a significant efficiency cost that you probably don't want to pay when you have limited total charge available anyway. And I'm not sure it would work with any head-torches, or a lot of other devices you might want to charge.

I think that would be my solution to the whole problem really. Keep it simple. Buy a decent general-purpose power bank that gets good reviews (including for being modestly durable) and then protect it as needed for the activity you're doing i.e. in a dry bag if the activity you're doing is piss wet and wrapped up in something else if it requires your kit to take some knocks.

My phone (Samsung) really dislikes even a trace of water in the charging port, and even in a nice dry house can take an hour to stop grumbling (ie refusing to charge).

Obv it depends what you are doing and why you want a powerbank, but one of the main reasons I carry a powerbank is so I can be confident I'll have a working phone.  The critical window is connecting the cable to your phone. If it is wet then charging may fail. It depends where you envisage charging things (somewhere nice and dry) and if you are happy to risk not to be able to top your phone up.

Yes you need cables to charge alot of things and are simpler, but the technologies usually coexist in the same device (ie you have a choice of mode). If it is dry obv use a cable.

Alpkit looks like a really good choice. I would prefer the small one but it looks like it's not available

Another vote for the Nitecore 10k.

Nitecore 10k. 

A common fault appears to be the weakness of the USB sockets bonding to the PCB.  So you end up with either a dodgy connector to the device requiring power or else an inability to reliably charge/top up the power bank. I've seen this on quite a number of devices.  Either the solder breaks or possibly even the tracks/pad connectors to the socket on the PCB fracture.

I beefed up the powerbank I use by opening the case and using epoxy putty built up round the sockets to prevent any movement of the USB connectors caused by insertion or flexing of the USB lead.

I suspect you could also use a less sticky solution - polymorph - to do the same