Replacing a Battery Contact on a 4iiii Power Meter (Single-Sided)

Hey all,

I’m hoping someone here has experience with a 4iiii single-sided power meter — specifically when it comes to dealing with internal battery contacts.

Here’s what happened:

During a recent race, my power meter started acting up — displaying wildly inaccurate power numbers. I figured it was just a dying battery, so I tried replacing it with a few fresh ones. I also attempted a reboot, just to rule out any software hiccups. Unfortunately, nothing helped — the readings were still way off.

While inspecting the internals a bit more closely (and maybe rushing it), I accidentally dislodged one of the battery contacts. It wasn’t a clean break, but it’s no longer in the proper position and the connection is spotty at best.

Now, here’s the catch:
My unit is just past the 3-year warranty period, so unfortunately it’s not covered anymore. I did contact 4iiii support, and while they were helpful, the best they could offer was a swap for a new unit at half price — which is fair, but still a chunk of change.

Before I go that route, I’m wondering if anyone here has successfully reattached or repaired the battery contact on one of these units? Is it solderable? Or does it require special tools, epoxy, or maybe a complete teardown?

Any tips, success stories, or photos of similar repairs would be hugely appreciated.

Thanks in advance — and here’s to hoping someone’s fixed this before I start poking around with a soldering iron and a prayer.

If you post a few pictures it will be way more useful to judge how repairable it is.

If you can’t get to the solder point through the battery opening, then it will greatly simplify the repair

I had been lightly lifting the battery contacts on my gen 2 4iiii until the start of this year, each time it started giving , Then I managed to have it pop off the base board. Amazingly since I stuck it back in place with a tiny piece of electrical tape its been reading solid ! It might be the most stable it has been in a while.