Olympus BLH-1 1720mAh Rechargeable Lithium-Ion Battery for E-M1 Mark II Camera (Replacement)

I have had these batteries for six months and they are great. They charge very fast and keep the charge.

My previous Olympus cameras used BLN-1 batteries, and third-party options had always worked almost as good as the Olympus batteries, and getting two replacement batteries for less than half the price of one original is a bargain that was hard to pass up.But finding good BLH-1 batteries for my EM1-II has proven to be a challenge. I tried several different third party brands and none of them last even half as long as the originals, and one swelled up so badly that it could no longer fit in the camera. Not sure why that's the case with the BLH-1 clones, but after my third set of crappy replacements, I finally gave in an bought the Olympus brand.The good thing I can say about this battery is that it will give you the longest lasting and most stable performance for your EM1-II. The downside is the price and the charger that comes with it. Third-party chargers are way better since they offer options like multiple battery charging and/or the ability to be plugged directly into a socket instead of dealing with wires.

I conducted two tests with the Olympus BLH-1 and the Wasabi and Power2000 fully decoded clones. The first test was a controlled-lighting tripod-mount time lapse on an E-M1.2 at 1 minute intervals with the screen active. The second test was a constant current discharge to 7.2V at a rate which resulted in discharge time roughly matching the number of pictures taken in the first test. The 7.2V cut-off point was chosen as that appears to be when the E-M1.2 powers off - batteries consistently measured around 7.4V after shut-off, which at a 500mA current drops to around 7.2V.As is to be expected, the Olympus BLH-1 matched the best of the two clones that I tested in terms of capacity at around 1500mAh. The Wasabi 2 pack had one battery also measure around 1500mAh while the other was only around 1200mAh. Meanwhile both Power2000 batteries only measured around 800mAh.So why would I recommend the Olympus BLH-1 for most when the Wasabi 2 pack costs the same and provides anywhere from 80% to 100% the capacity? Well, the variability is one mark against the Wasabi - it's clear they're not using a single supplier/specification for their 18500 cells given the variance I observed. Second is that the circuitry within the battery isn't quite on par with the Olympus as there's no mechanism for charge-balancing between the two cells. Charge-balancing circuitry ensures that both cells are always fully charged by effectively charging each cell individually. The BLH-1 clones lack this circuitry and instead charge the two cells serially, which over many charge-discharge cycles invariably results in one cell having a higher state of charge than the other due to minute differences in charge rate between them. This results in a much faster reduction in usable battery capacity as the battery will stop charging soon as one cell is fully charged even if the other is only half charged, while on the discharge side the camera will turn off soon after one cell is mostly 'discharged'.

Not much to say about a battery. I have tried 3rd party batteries in the past due to price, but sometimes they swell and don’t fit properly. I decided to stick with OEM to protect my camera investment. This battery works as it should and is consistent with the other Olympus batteries I own.

The only thing to dislike is the price of the Olympus batteries. I also have some non-OEM batteries, but they don't have anywhere near the life of the Olympus batteries, and the meter on my OM-D EM-1 Mark II will not accurately gauge the percentage of battery life left in the generic batteries. Yeah, the generics were cheap, but at least they came with an awesome compact charger, which works great with the genuine Olympus batteries.Seriously, pay the $60 for the Oly batteries, two of them outlast 4 of the generics, and they hold on to their charge when not in use much longer, and you will know when to swap a depleted one out before your camera shuts off.

Over the years I have cheaped out from time to time, and it's usually not worth it. My off-brand batteries (though, presumably from an OK supplier) have all expanded and won't fit any longer. Now that my batteries can be charged with USB-C in-camera I would not trust third party batteries any longer.OEM batteries cost an arm and a leg, but for longer trips I now take two/three OEM bateres and a big USB-C power bank, and recharge in the field.

This is a massive upgrade over the batteries the EM-1 Mk 1, although they're definitely not cheap. They last far longer than the old batteries. I shot a couple Spartan Race events with these and they held up very well through hundreds on hundreds of photos. Seeing battery life in a term of percentage as well as the little battery logo indicator is very nice as well. One of these in the body plus another in a battery grip is going to keep you covered for quite a while.

Having learned the hard way about 3rd party battery 'replacements', I didnt even bother with my new Olympus EM1 MkIII, went straight to the vendor.It fits perfectly in the camera, slides in and out easily. 3rd party batteries frequently dont fit 'quite' right - i've had more than one get stuck in the camera requiring some tool work to remove.Holds a charge well. Lasts long. (these are other faults of 3rd party batteries, not holding a charge, or having a sudden drop off in charge - i.e., one moment the battery shows full, the next youre getting battery empty notice)So, for professional phtographers, I always recommend spending more and going with the OEM battery.