Works after cleaning the battery contacts
341535
Works fine.  Charged to 100% in a few hours.  When first putting it in, the phone still indicated that the battery was not installed.  I thought the battery was defective.  The battery contacts looked a bit dirty. After cleaning the contacts, it started working.
2359826
The terminal went onto my battery just as expected, but I had to get a smaller terminal to attach to this disconnect. Wasn't a big deal, but kind of a headache to go get more parts.  I wasn't too happy with the connection anyhow, so it gave me a chance to clean it up.
439986
Used the grease after installing a new battery. Cleaned up the battery posts using&nbsp;<a data-hook="product-link-linked" class="a-link-normal" href="/NOCO-D420S-Battery-Post-and-Terminal-Cleaner/dp/B00DTLOKQ2/ref=cm_cr_arp_d_rvw_txt?ie=UTF8">NOCO D420S Battery Post and Terminal Cleaner</a>, inserted the battery terminal protectors&nbsp;<a data-hook="product-link-linked" class="a-link-normal" href="/NOCO-NCP2-MC303S-Oil-Based-Battery-Corrosion-Terminal-Protectors-Pack-of-2/dp/B001DKUTR0/ref=cm_cr_arp_d_rvw_txt?ie=UTF8">NOCO NCP2 MC303S Oil Based Battery Corrosion Terminal Protectors (Pack of 2)</a>, attached the cables and finally applied the grease liberally around the exposed areas. Hopefully it will all last until the next battery replacement. It's been a few months, everything looks like I installed the battery yesterday. So far, so good.
3420173
The battery has to be carefully positioned on the bump in the metal contact, or you get a false red ("dead battery") reading. But it's great to be able to check if the batteries I find here and there in the house are used or new.
3924676
The contact on the power stick was different from the one I needed. I had to dismantle the new power stick and install the contact from the old power stick to make it work.
1369887
These work fine, but the plastic label on the battery interferes with the contacts on my charger on many of the batteries causing them not to charge. I have used a razor to remove the offending portion of the labels.
485483
I had been using acetone to keep the battery contacts acid-free, but for some reason, it was a never-ending issue. Eventually, it became unfixable. I started shopping for new controllers and stumbled upon this. I am so glad that I found this before I bought a new one! Made my controller work like new again!
2835898
Had a severely discharged battery in my Olympus camera, it would not charge nor turn on. This solved the problem, kick started the battery back  up and charged.
3540747
I had the same issue as another customer .... the connector doesn't fit my phones but the batteries (I needed 5 of them) work very well. So I used a soldering gun to switch the cables from the old batteries to the contacts on the new batteries (rather than perform micro-connector surgery on the connector). Not a big deal. Good price. Shipping took longer than I expected but I am happy if all 5 batteries give the life back to my phones what I need. Thanks.
3392435
I love it . It is very useful. If it doesn't work, disconnect battery and connect it again.
1671666
Yeseree !  This one works much better than the old one that quit charging the battery.  All electrics are good now.
1161873
A few weeks ago I used this on my dead battery after someone (maybe even me) left the ceiling light on in my car. I had to override the fail safe feature with the "!" button because the battery was completely dead but to my surprise it worked and turned the engine over. The fact that this charges via USB-in is kinda unique among these things and means I can charge this from the cigarette port, an outlet, or even a solar panel in the middle of nowhere.
638314
Took it out of the packaging and plugged it into my camera and it started shooting off pics at random as if the button was held down.

Took it apart, tightened a screw which put a bit more separation between the contacts and then it started functioning.

Works great after fixing it :)

For the price, I can deal with the quality control issues :)

Works great with a k3II
3455761
Fixed the issue where my phone was turning off randomly. I think my old battery had some bad cells.
2159989
Found my house battery not charging from the alternator or the converter at random times.  This device is supposed to make a semi loud 'CLUNK' sound when switching between power sources, and mine was not.  I understand the mechanical solenoid inside wears out after some time.  After replacement, no more charging issues.
1010202
I have used this on a couple of batteries that I have been restoring with a Desulfator.  It provides feedback on the progress of the recovery and the battery condition.
4734056
I originally purchased this product for use with digital camera electrical contacts and audio/visual equipment.  It has worked very well.  One advantage of the kit is the different types of applicators and solutions.  When using any product on digital camera contacts the application of the cleaner must be done very carefully so as not to get fluid on the sensor.  The kit simplified that.  I had another and very unusual application occur.  A friend of mine has a left ventrical assist device, i.e., a heart pump, and it is powered by expensive lithium ion batteries.  One of the batteries refused to charge sufficiently and he thought he might have to replace it.  We decided to try the DeoxlTKit on the batteries contacts and the battery was able to take on a full charge and work normally.