In 2010 I had surprising problems with replacement BLM-1 batteries for my Olympus E-30. Since then I've been keeping records aimed at understanding battery problems. In December 2013, I replaced the E-30 with an Olympus OM-D E-M1, and the original records for the E-30 are now here. This page relates to the BLN-1 batteries for the E-M1.

There's a difference in the market between the BLM-1 and BLN-1: the Olympus battery charger for the BLN-1 only supports coded batteries, and many of the replacements on the market can't be charged with that charger. Instead, they're supplied with their own charger. I don't know if this raises any quality issues, but it seems reasonable to assume that the suppliers of the coded batteries have gone to more trouble, and so are less likely to cause problems. Based on this and my experience with the E-30, I bought a set of three coded BLN-1 replacement batteries.

They lasted well, longer than the camera, which developed a fault not worth repairing in May 2024. Instead I replaced it with a “new” (used) E-M1, which came with two more batteries.

The batteries

My current batteries are

Number		Date		End date		Manufacture		Comment
						date
1		3 December 2013				25 September 2013		The original battery supplied with the E-M1.
2		17 December 2013		3 April 2022				One of the first set of three replacement batteries.
3		17 December 2013						One of the first set of three replacement batteries.
4		17 December 2013		15 July 2022				One of the first set of three replacement batteries.
5		27 July 2022		22 August 2022				Replacement for dying 1-3
6		26 August 2022						Replacement for dead 5
7		27 May 2024				31 August 2016		With “new” E-M1 Mark I
8		27 May 2024				23 June 2016		With “new” E-M1 Mark I