Some battery test data

Started Jun 7, 2012 | Discussions thread
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Some battery test data
Jun 7, 2012

I posted a while back about batteries to take with my on a Mt. Kilimanjaro climb next week. Now that I have all my batteries, I've been working on cycling them so they perform better and display more accurate percentages. I also decided to run some tests. I have three types of batteries in my collection of nine: 2 NP-FW50 from the Nex-5 era, 5 NP-FW50 from the current generation, and two Wasabi batteries from Blue Nook.

The difference between the old and new NP-FW5s is that the ones from my Nex-5 are 7.3Wh (1020 mHh) and the ones from my Nex-7 and current purchases are 7.7 Wh (1080mAh). They both work fine in the camera, but the older ones have a lower capacity, confirmed by my test. The Wasabi claim to be 1300 mHh. I call BS on that, as seen below. You can tell they don't have the capacity by how light they are. Cells = weight.

After making sure that each battery cycled down to 50% and went through a full recharge three times or more (using video in 3 cameras to get it done), I set up a test in the Nex-7. I put the Nex-7 on a tripod with the lens in manual focus mode. It remained focused on a single scene. After putting in a fully charged battery, I turned on the camera and hit movie record as soon as I could. I let it record it's maximum movie of a 2GB 1080 file which equals 29:50 of video, and I recorded the battery percentage as soon as the video stopped for each battery. I used the same SDHC card each time, but always freshly formatted (not using power of the battery in the test though). I ran the test through twice on each battery, and got exactly the same results for each battery each time with one small exception. I also let the camera cool down fully between each test. The heat warning is usually flashing by the end of the video.

So how did they do? Here are the battery percentages remaining at the end of the test for each battery:

NPFW (1020)-1 79%
NPFW (1020)-2 79%
NPFW (108)-1 80%
NPFW (108)-2 84%
NPFW (108)-3 81%
NPFW (108)-4 81%
NPFW (108)-5 80%
Wasabi-1 71%
Wasabi-2 70%

The only variance between tests is that Wasabi-1 ended test 2 at 72%, but it flipped to 71% before I could even pick up the camera and format the card, so it was right on the edge.

My new battery #2 is clearly a good battery, hitting 84% on both tests and this shows there is some variance in the capacity of the Sony batteries. My sample size is small for all of these categories though and I bet the standard deviation is small overall.

The Wasabi batteries are clearly inferior, or I got two duds. They both work fine in the Nex-7, but they run down faster on this test and during regular shooting too. Sure, two batteries cost less than 1 Sony and the two should have more capacity, but that's two batteries to carry. I wish I had gotten another Sony instead, but I couldn't find any data like this to support my decision.

Now I know this test isn't perfect, but it does have a decent control of a 2GB video file. I don't know how that translates to still shots. I also realize that a percentage on the meter is an area with a significant variance, but I'm ok with it for ballpark, especially since two tests yielded the same results. This was the best I could do without actually measuring the batteries with complex instruments before and after.

I hope this helps some others out there. I know it is a long post.


 dark13star's gear list:dark13star's gear list
Fujifilm X100S Fujifilm X-E1 Nikon D600 Fujifilm X-E2 Fujifilm X-T1 +10 more
Sony Alpha NEX-5 Sony Alpha NEX-7
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