Low Quality Batteries
I've owned a few Telesin replacement batteries now, specifically for my GoPro Hero 9, so here's my review...
The first set of batteries I purchased were their 9 series. While they were a lot cheaper than the OEM batteries, I found the GoPro was much more susceptible to overheating when they were used. I also found they held about "15 minutes" less of a charge than the official GoPro branded batteries did. In less than a year the 9 series batteries started to bulge. Back then I tried to get them replaced, but was never able to.
I'm not new to Lithium batteries. I know how to properly charge them, what charge you should take them down to, how to store them, and how to avoid damage. I have a set of Lithium batteries (not Telesin) for my Snap-On impact gun, which get used daily and are still going strong after 5 years of proper use. So while I admit that overcharging is the most common cause of bulging, these batteries have always been treated like gold and have never been overcharged.
Truth be told, both of the batteries developed their bulges while they were being used, not while being charged. This indicates the use of either inferior-quality parts or inferior-quality metals in the battery. Not really surprising for batteries from China, which are likely made with Chinesium. I did some research, watched several YouTube videos, and found that early bulging actually seems to be a very common occurrence with these batteries.
That said, because I can't afford to drop $80-100 on official GoPro batteries, and am tired of watching my GoPro sitting here unused, I recently decided to give Telesin batteries another chance. I noticed their newer 12 series batteries (neon yellow ones) had rounded edges to them which might help with the overheating problem. I got the batteries, charged them using their charger (which came with the new batteries) and took them off the charger as soon as they indicated full. I did about a 30 minute motorbike trip, with no overheating, but when I checked the battery it was down below half. So, sadly, it looks like no real improvement in battery charge between the Telesin 9 and 12 series batteries. Not really shocked by this result.
While these batteries work, and I seem to not be having the overheating issues I had with the 9 series, I really don't know if I trust them that much. I figure I'll be treating them as a "charge only when you're gonna use them" batteries and, when I'm not using them, store them at room temperature with around a 50% charge. Hopefully that will make these ones last longer than a year. I have my doubts though.
2 August 2025
Unprompted review