I haven't read all of the replies, but I have to imagine that since no current camera uses the BLN-1 battery, that Olympus may have shutdown the production line. I don't know for certain, but a similar thing happened several years after the E-5 was announced where the official BLM-1 and BLM-5 batteries became hard to find.
I've gone through several cell phones where each phone had a unique battery, and when the manufacturer moves on to newer models, you generally have to switch phones to something more modern. However, now many cell phones don't have a user replaceable battery, so it isn't an issue about finding replacement batteries because there aren't any. But of course every 2-3 years, you now likely have to upgrade your phone.
I have read that in general for lithium-ion batteries, you want to consider retiring them after 4-5 years after being made, as they start losing capacity. Note, it doesn't matter whether you use the batteries or not, the battery starts to degrade once the battery is made. Of course if the manufacturer no longer makes the battery you use, then you have look at 3rd party battery suppliers.
I've used Watson batteries (sold mostly at B&H photo) for some time now. Since I have accumulated several different cameras over the years, I like that I can just use a different Watson charging plate to charge different batteries. I used Watson because of some posts on dpreview by somebody named airmel that tore down various BLN-1 clones, and the Watson batteries were better made than most of the other BLN-1 clones (
2016 DPreview post on BLN-1 batteries).
One thing to know is that Olympus BLN-1 batteries use a slightly different chemistry from the standard lithium-ion cells used elsewhere. This means it has a higher voltage when the battery is freshly charged. I imagine that the camera will signal batteries with standard li-on cells as being empty quicker than the official Olympus BLN-1 battery.
In the case of BLN-1, you should use a charger that is designed for the battery. Ii.e. for the official Olympus BLN-1, I use the BCN-1 charger and I use the Watson charger for my Watson batteries.
I recently had to retire two of my Watson BLN-1 batteries because they started swelling. I think I got them after I read airmel's post, so figure they were about 5 years ago. Before switching to Watson, I had used Wasabi batteries, and they didn't last a year. Some other people posted about Wasabi batteries starting to swell up. Perhaps Wasabi had a bad batch of BLN-1 clones, or perhaps mixing the Olympus charger with the Watson BLN-1 clone caused i to swell.
Though since the E-m5 mark III is now my main camera, I need to get a few more BLS-50 batteries or clones. But I will need to get at least 1 BLN-1 battery or clone to replace the two that I retired.
When I retire the batteries, I take them to the town transfer station, and they have a shed to hold lithium-ion batteries, florescent lights, etc. Do not throw litium-ions into the normal trash.
) stated they were expecting delivery in June; which suggests OEM may become available.
