Good for LiPo, but not LiFePO.
594567
Works well for LiPo batteries, but the capacity measurement for LiFePOs are really far off.
1222253
These cables aren't good for high-amperage applications. Using a 2.1A port along with my PortaPow USB Power Monitor, I couldn't pull more than 800-900mAh on my phone. In contrast, I purchase some of those "dayglo" inexpensive Monoprice cables and was able to pull about 1200mAh on my phone which was the same as the OEM cable. So while these aren't as bad as the worst cables (that can't pull more than 500mAh's), they're not as good as the Monoprices.
4685564
The description on here was not very detailed to say the least. I assumed it would balance Lipo cells like my other meter, but unless I'm missing something it doesn't. Also can't figure out how to discharge batteries. I think it's because you need another part with resistors or light bulbs to soak up the energy. Still it is pretty accurate as a cell checker.
3680251
I bought this charger after having a disappointing experience with the MAHA MH-C9000. Let me talk about that for a moment to provide some background.

I wanted a charger that would charge an Eneloop or similar LSD battery to full capacity as well as perform a proper discharge test to measure that capacity. If for instance a battery is specified to have a 2000 mAh capacity, I want to be able to compare the actual condition and performance of the battery to that spec. The problem with the MAHA is that the firmware has a poor charging algorithm that will terminate charging well before the battery is full. To compound the problem, the discharge is so conservative that it will produce an unrealistically low measurement of the battery's charge. I didn't find it acceptable that my charged batteries would not perform to their full capacity and that I couldn't get a useful measurement of their capacity.

So how does the Opus BT-C2000 perform in these respects? The good news is that it fully charges on an Eneloop battery and appears to terminate on negative delta v rather than on some arbitrarily low terminal voltage. The bad news is that the discharge algorithm is, like the MAHA, too conservative. Lets say you have a 2000 mAh battery with an actual capacity of 2050 mAh. The Opus will charge the battery to the 2050 mAh level, but it will return a discharge test result of less than 2000 mAh. Maybe 1950 to 1980 or so.

Close but no cigar. This one is getting returned. It's a shame too. I like the physical design of the MAHA and the Opus. The size is nice, with ample spacing to dissipate heat around the batteries, and I like the backlights. Unfortunately, even though I like it less in those respects, I'm ultimately going with the La Crosse BC1000. My BC700 is the only advanced charger I've owned so far that would both fully charge batteries and return good test numbers. I assume the BC1000 will work similarly.
3610965
The Lumia 1020 has a pretty good battery life so long as you're not a heavy game player, so this is far from essential. I bought it because I thought it would be helpful with all the photos I take; in practice, the bulk it adds makes the phone a little unwieldy and awkward to carry, so I rarely actually bring it out with me unless I know I'm in a heavy-duty situation where an extended battery is worth the extra weight. It's a shame that it doesn't include the Qi wireless charger, also.

To the phone, this seems to appear as an external power source rather than a battery - so when you attach it, the phone switches into power charging mode, drawing from the extra battery, rather than simply switching to use the other battery. That seems like an inefficient way to make the most of the battery, but perhaps I'm not fully understanding how the phone recognizes it.

In summary, it's a nice-to-have, but the phone is more than adequate as it stands. Go ahead and buy it, but the Lumia 1020 is a perfect phone on its own without the extra baggage.
466199
I tested this as a charger with my Galaxy S4 and Battery Monitor Widget. I also used a USB battery bank (capable of 2.1A charging) with a power meter for additional testing. Peak charging to the galaxy S4 at 50% battery was around 1.4A, average around 1.2A. An excellent charger would be 1.6-1.8A in the same circumstances.

The voltage started at 4.91V with no load, but dropped to 4.85V under load. That is on the low side for the spec - it is allowed to drop as low as 4.75V, but charge speed is typically significantly reduced well before then. In this case in particular that was evident.

Charge rate to the USB battery bank was around 1A with the power meter hooked up - but with the relatively low voltage, I have seen issues with charging slowdowns when I add the power meter to the circuit. In this case, that meant it was charging at 1A when the battery is capable of drawing two.

I tested that QC 2 did work on a friends new Moto X, but did not get detailed speed measurements.

The listing states that the charger should provide 2A @ 5V; in practice I never got that high or even close. However, the actual product stats 1.5A @ 5V, which was closer to reality. The product information on the charger actually lists lower numbers for the current at all three voltages than the product listing, it is even visible in the companies pictures. It isn't a massive difference, but enough to matter, and not nice to see when you get the product.

The charger is 1" tall x 1 3/8" wide x 1 3/4" long (2 3/8" with prongs). The cable is as advertised, just over 3. Fairly small and light.

Overall, I like it as a lower speed charger for non-QC phones. It is not the one to use when you want to get a quick boost on those. If you have a QC phone, performance should be better. I dislike the discrepancy from product listing to the information on the product.

The product was provided to me at a discount in exchange for a review. The review is my own.
3619870
The battery I purchased was for an RC airplane and not for an Airsoft gun. It arrived on time and was packaged nicely with a good instruction sheet. Unfortunately, the polarity on the Dean's plug was reversed and I nearly destroyed my ESC.

I contacted the company and they sent me a new replacement and told me I didn't have to ship back the defective one. The replacement arrived two days later.

The battery itself didn't last as long as I expected.

This purchase was made when Lipo batteries of this type were first on the market so I don't know if their product was poorly made or if the technology wasn't where it is today.

For the above reasons I give the manufacturer 5 stars for customer service and 2 stars for the quality of that particular battery.
188435
I am only giving this a 3 star due to the fact that it burns out easily. When it is running it is a great motor and its water proof like the rest of the Traxxas vehicle so that is a big plus. It says it can handle up to a 2s lipo but honestly i recommend not using lipos unless you only plan on doing it occasionally and for very short periods of time. two have burned out and one came to me defective and would not run. After issue with third motor i just decided to buy a brushless for 20.00 and a brushless esc for 25.00 small investment for huge difference in speed. Even the 20-30 GoolRC or Hobbywing, hobbyfan, whatever generic brushless blue motor that has 50 different names and brands but looks like the exact motor is a pretty solid decent performer and much better then this. So do yourself a favor and skip the headache of trying to figure out why your car won't turn on and just upgrade to brushless. I ran my car using one 2200mah 2s lipo and it ran fine until LV warning appeared and i packed it up for the day went home. Next day pulled truck out to go run and it wouldn't arm and I received no response when throttle applied. Replaced with different brushed motor and it worked so i ruled out the ESC and so i bought a new motor and installed and it worked fine. Brushed motors are not practical if you want to run lipos. If you only us NIMh then your fine and this is a pretty good motor especially with a hump 7 cell nimh it is pretty quick
3998145
I've been using this charger and battery for almost a year now. The charger seems to work fine with the OAproda battery, as well as Olympus-brand Li-50B and other off brand Li-50B-replacement batteries.

With a simple but hard to describe test, I've convinced myself this charger terminates at about the same point as the in-camera charger. (That's good.) All Li-50 batteries I've tried click into the correct location fairly easily, but I snug a rubber band around the charger and battery so the battery can't jostle out of place.

The battery fits my Olympus TG-870 and makes it run. But it has never run my camera as long as the original, Olympus-brand battery. Recently I tried some other off-brand batteries and devised a run-down test shooting time-lapse video at various frame rates, lasting about 2-4 hours per test. In equivalent tests, none of the off-brand batteries ran as long as the original.

This OAproda battery performed worst, supplying less than 700mAh, unless the Olympus greatly exceeded its nominal 925mAh rating. (I have also obtained a second Olympus-brand battery that performs almost identically to the first one.)

I've noticed the Olympus-brand cells are about 0.27 inch thick, whereas the off-brand batteries I've tried are only about 0.25 inch. Perhaps the off-brands under-size their cells to fit more camera types? But I don't know how they justify marking a smaller battery 925, 1500, or even 1800mAh, as the brands I've tested did.
799100
As a battery charger, this case is fantastic.  It has a large battery capacity that I think is as slim of a design as you could expect.  But it is heavy (that's really just something you have to live with if you buy a battery case - not a negative for this particular case vs. other battery cases).  The three stars and I'd maybe even say it should only have 2.5 is because it only does 1/2 of what I feel like was the "sell" of the product.  It is NOT protective.  With even the slightest drop (6 inches), the face plate will pop off and the phone can come flying out.  I am glad that I experienced this with a small drop so I had no damage to the phone.  But my hands are full a lot so drops are just something I know will happen - therefore, I'm returning it for the LifeProof battery case.  If you don't drop your phone or aren't looking for the "protection" aspect of the case, it could be a good case for you.  I use my phone for email, internet, calls and texts regularly throughout the day for work and I was able to keep it charged all day without plugging in and not even running it down to close to nothing by the end of the day.
3101805
I used this power supply to charge my Lipo batteries for my RC planes.  This power supply worked fine when I was charging at 3A continuous.  However, the Voltage dropped to an unacceptable level when I tried to charge at 5A.  Even 4A did not work very well.
4915579
Buying a second battery just to put it in this grip is fine if you like the extra heft the grip offers.
But other than heft, it doesn't do too much; the main benefit is the additional AE-L/AF-L button on the grip can be assigned a different function to that on the camera - handy for a specific AF-ON assignment.

You have to carry the second "cradle" if you want to use 6 AA batteries.

Having said this, it fits flush to the camera and looks the part. The main drawback is that the second battery cannot be "manually" switched on or off, so if you leave the camera on, say by accident as I did, then both batteries will eventually  be drawn down.

Cheaper to buy a spare and keep it in your pocket.
3056347
HQRP 2200mAh Battery for Canon NP-E3 seems to have decent performance and life, but the fit is not great. The locking mechanism is substandard and hard to work with, but satisfactory given the price point.
1595701
I feel like it was a great charger but after about 6 months of use the battery just wasn't holding it's charge as much. Overtime the LIPO battery started to inflate with gas, causing the structure to expand, and thus is now unsafe to use.
3083995
The build isn't bad, fits well on my light stand, but it was a loose fit on my Youngo 685. I'll have to ghetto rig this thing, if I want to even use it with my flash.
3670258
The zerolemon battery looks like everything it was described as. I'm noticing a longer life, however it doesn't seem too much longer. I'm only gaining a couple extra hours of life, rather than another half a day or even a full day. There also seems to be an issue. The phone literally cuts off while using the flash during a picture capture. After trying several things (different camera apps, different roms, using the charger, using the stock battery), I have seen countless times where the zerolemon battery is not able to handle the flash. This doesn't happen eventide I take a photo, but it is often enough to ruin the opportunity of a night shot the might take a few tries. I'm hoping this is just a bad battery, and zerolemon can replace this one so I can test it again.

As for now, the functionality has not met my expectations. A battery that is 3x the power capacity of the stock battery should not have such as a similar life span during discharge, or cut out during a basic phone operation. I literally have to pull the battery, or plug in the charger, to get the phone to come back on once the battery cuts put, which is annoying to go through removing the case multiple times and wasting several minutes just to get one photo.
4008366
A nice small lipstick charger, very similar if not exactly the same like the ravpower. I like this one just a bit more, but they appear to be from the same factory. Keep in mind this unit doesn't charge at more than 1amp, so you won't be charging your phone like as if it were plugged into a wall charger or a 2amp charger. It came with a nice little bag, good to have in an emergency when you are tight on space, but not that great for everyday charging unless you just need that little bit of extra juice and can let it sit and charge for awhile like during class.