Let's imagine that you need a new battery set for your Neato robot. Usually, we would like to install a new battery with maximum capacity, which means longer run time and better overall performance. Capacity is measured in mAh with the greatest the number, the better. All Neato robots, for example, originally have the batteries with capacity 3200 mAh.
But if you was looking for new batteries, you would see that there are numerous offers on the Internet that claim that their battery capacity is much higher - up to 4500 mAh. That's looking odd and we decided to conduct few tests to find out if these batteries are really so good.
Measuring capacity is not too difficult: there are many smart chargers around, especially in the remote-controlled models world that will show you the numbers. It must be taken into account that new batteries of this particular type (NiMH) might temporarily loose their performance if stored for awhile due to a "memory" effect. To overcome this phenomenon, we just need to do full charge-discharge cycle few times (we did it three times).
Initially we have measured the original Neato battery from a new robot to make sure that there is nothing wrong with our method. Not surprisingly, the capacity engraved on the battery is exactly as we have measured - 3200 mAh (within few per sent of error, which is unavoidable).
Next, we have tested batteries from a Chinese manufacturer that is known to produce batteries of good quality. A label sticked to the battery claimed the capacity of 3500 mAh, which is slightly better than the original Neato ones. The measured capacity, however, was 3200 mAh.
Finally, we have tested the batteries with a really suspicious label 4500mAh. As you may guess, of course there is no free launch here :) . The measured capacity was only 3300 mAh, which is slightly better than the previous battery, but is still far away from the claimed value.
We could only guess where these labels came from, possibly a middle-man trading company. However, I should notice that there is nothing wrong with the engineering or fabrication process as long as the quality of the batteries is really good - we have sold tones of them and had only about 0.1% of returns so far!
The bottom-line: there are definitely good generic batteries on the market and it might worth purchasing them over the genuine ones as long as the price is more attractive. However, they are often (always?) labeled unfairly. So, please be cautious choosing the place where you going to buy them from!
p.s. A little hint. There is an easy way to compare the capacity of the batteries of the same type. Just weight them! Batteries of the same capacity must have roughly the same weight. The more is capacity, the heavier the battery will be. For the reference, the weight of the genuine Neato battery 3200 mAh with the connector is about 296g.
This article was published on Tuesday 01 April, 2014.