29Mar Blatantly miss labeled Generic DOT-01 Sony NP-FW50 batteries
First of all, I’d like to point out that most generic battery claims are dubious at best. If you look at the labeling for any type of generic battery out there, the Watt-hour (Wh) and milliamp hour (mAh) ratings are almost always higher than their name brand counterparts.
It is easy to assume that a larger mAh (corresponds with Wh rating which is a factor of voltage x current over time) number on the back of your battery automatically means a better battery. There for any generic battery that has a larger mAh number than the OEM battery will last longer, right? The problem with this thinking is how that number is calculated.
I’m not going to work through a lot of math here because this site is not dedicated to engineering. So let’s do this the easy way. A battery’s mAh rating is derived from a calculation of the rate of discharge over time and the time limit is reached when a minimum voltage is hit as the battery discharges.
So, let’s say your camera needs an absolute minimum of 3.8 volts to operate. With that number in mind, your mAh rating comes out to a certain number. If you are a manufacturer of batteries, your marketing team says “We could sell a lot more of these if that mAh number was higher.” so what do you do? Simple, you lower the minimum voltage for your rating and suddenly your mAh rating jumps up. Now instead of 1020mAh your battery is 1860mAh. Good job team, you’ve made a better battery, on paper. The problem is that your camera can’t actually run at a voltage that low. Which means this new higher number is basically useless to the end user.
Now, let’s take a look at this generic Sony NP-FW50 from DOT-01. Somehow DOT-01 managed to fit a 2200mAh into this tiny form factor. On top of that, this battery weighs about 5 grams less than Sony’s official NP-FW50 battery which is rated at 1020mAh. How can this lightweight DOT-01 battery have double the capacity in the same form factor? Is that even possible?
The answer is, it’s not. Either DOT-01 is fudging the numbers, or they are outright lying in their advertising. In testing, the performance results are consistent with a mislabeled battery. They seem to last a little over 25 min v.s. 50 min from the Sony and Wasabi brand.
Is it false advertising? That’s hard to say thanks to the way these numbers can be calculated and because of that, Manufactures like DOT-01 can posit claims of 2200mAh without much issue. They aren’t the only offender, just scroll through page after page of batteries on amazon for every type of camera. There isn’t really much of a solution. Be mindful of the reviews and stick to brands you’ve had good luck with in the past.
March 29th, 2016 at 5:49 pm
That’s why when I buy a camera, I buy a spare OEM battery at the same time. Only later will I try another brand to add to the mix, ONLY as a backup to the other two.
March 29th, 2016 at 6:03 pm
Sony does provide two batteries with the a7s II which is nice.
April 30th, 2016 at 7:14 pm
I have found that BM Premium (also known as Big Mike’s Electronics) work extremely well in every camera I have owned. They are the only ones I have had that have not had at least one battery that failed faster than the name brands (except for one that accidentally got wet, but that’s my fault) and I have used them a lot over the years.
I am also not kind to my batteries, they get a workout like you wouldn’t believe.
I have also found that they typically take a at leat 25% more pictures and 20% more video than the name brand batteries on a full charge.
I only came looking for information about Dot01 because they had a good deal on Amazon for four batteries for my camera (I just lost my existing ones by leaving them somewhere…grr), but after reading this, I am going to stick with Big Mike’s (make sure they are sold directly by Big Mike’s Electronics, there are people out there who fake the BM Premium brand of batteries).