I’ll preface this by saying that this power-meter is well out of warranty and has had a good innings, being bought new in 2017.
However as I was warming up for a race late last year I noticed it was cutting in and out on my head unit, checked the battery and the negative terminal fell out onto the ground 
Has anyone experienced this and would you say it’s fixable? I was thinking just some epoxy over the top, making sure there’s still metal contact, but maybe there’s a better way?
Get in touch with 4iiii. I can’t say what the response or outcome will be but they’ve always been great when I’ve had to contact them. I’d guess they’ll ask for you to send it in for repair/replace. Whether it’ll cost is the mystery you’ll find out as this was something that never happened to me.
Hard to tell from the pic.
Were the electrical connections soldered, or spring-loaded contacts that relied on pressure (from a cap that is presumably missing from the pic?) to maintain the electrical connection?
If the former, you’ll likely need to re-solder them to get a secure connection.
If the latter, you’ll need to figure out a way to maintain appropriate pressure on the contacts to maintain the electrical connection. Possible epoxy might work for this - just need to figure out how to glue things together in the right way to maintain this pressure, while keeping the epoxy away from the electrical contact points. This could get messy.
If you’re not the tinkering type, see if 4iiii will replace.
This is the problem, I am the tinkering type! I think it was soldered on and I have a soldering iron so I’m tempted. I’m a little worried about heat dissipation, but I might just try and take it very easy first… Though I’m wondering about contacting 4iiii first for advice.
Or you could try something like this:
But I’d test it out first to see if it actually conducts
A drop of silicone caulk will fix this. I can testify.
Thanks for suggestions! I ended up soldering it back on this morning. Got it powered up, calibrated and seemed to have normal numbers on commute to work. Will see how long the fix lasts.
