Once good batteries were installed
922571
...package arrived before the trip only to find both included batteries were dead.

Once good batteries were installed, the scales seem to be fairly accurate.
1795232
After about two months, the batteries have settled down and have decent enough life, but seems to have dropped a little bit from the first time they are used.  I have two Neato's (upstairs and downstairs) and it seems it needs to charge at least once at the end to finish.  I'd say each one is doing 800 sq feet (have a 1800 sq ft house, but some rooms are closed off).

But so far the battery packs don't seem to be faulty.  Like any battery packs, sometimes you'll get one with a faulty cell and the performance drops like a rock (had this happen before with another vendor).

So again, decent battery life, but not really a big difference with the stock batteries it seems.

I did get a couple of responses from the seller to make things right and if I wanted to return or exchange the batteries.  I added a star because of their customer service and willingness to fix things if I though these batteries were shot.
2276114
To fix these, take out the inserts and there will be a small hole for the battery, there will also be small white connectors and all you have to do is put them back together and tape them together with electrical tape.
4428538
Took a little while to figure out how to get the batteries in. I had read some of these reviews before hand and knew to unscrew from the bottom, but even then it was a hassle.  One of the three springs for the AA batteries had fallen off during transport, and I had to stick it back in. Even then, the batteries BARELY fit in the slots.

Once I had it assembled it worked fine. You had to shine the light relatively close to the ground (mostly things in the inner purple circle of light would show up fine), but it showed everything I was looking for (dog urine) just fine.

Overall good for the price.
68712
I have installed and used one of the batteries, and it worked well on my phone. I am saving the other one for my second phone.
2979755
I bought the two Fenzer Replacement batteries for a pair of Motorola walkie talkies, and they work fine.  The secret to long life usage, however, is not let the batteries run down completely and then forget to recharge them in a timely manner. I did not do the recharge on the last set of batteries ordered from the same source and the batteries went dead within nine months. Other than this caveat, the batteries provide very good service.
425933
I found that it is hard to get the end screwed back on once removed to check out the battery.
1169626
Nice battery. We packed.  Terminals had to be soldered to connect. I wish it would have been easy plug in. Bit of work, but works well.
4384301
Took me emailing the company to find out there were batteries needed and where. Once I put batteries in. It worked fine. Thanks for resolving my issue
716650
One of the packs was fine but the other had to be manipulated in order to fit the battery.  A metal part was bent and prevented the battery from going all the way in.  Used a screwdriver to bend the piece out of the way, which then enabled the battery to fit.  Better than buying a new controller.
331597
When it arrived, I removed the battery-saver strip and tried to power it on, but the screen just kept flashing on and off. I thought the unit was defective, so I had Amazon send me a replacement. The second unit did the same thing. This time I went out and got new batteries for it. After swapping the batteries with new ones, the unit works fine. I'm not sure why the original batteries arrive dead, especially since they have a plastic strip to protect them from draining. No big deal though. I just wanted to leave this review for anyone else who purchases; plan on having to replace the batteries.

Once powered properly, the gauge works great!
194827
Batteries may have been old. Shorter live than ones purchased @ local stores.
3757979
The included batteries were no good - after I inserted them, the scale didn't work; when I inserted my own new batteries, it worked fine.  It seems to measure accurately.
2986570
These batteries work & do a good job. They gave my phone a longer battery life & didn't need to charge as often. The reason I only gave them 3 stars was that I had one of the batteries fail after about 6 months.
2554228
While the batteries may work getting them installed in the shaver is difficult. I've been a radio station engineer for years and gave up.
601997
The concept was good, however, one side of the batteries kept falling out, and the batteries had to be put in each time.
3844676
I installed a new battery, it worked once, after that it would not function any longer. Ive been working out of town so I haven't had a chance to return it.