Solid charger. 3A is great. Being able to measure internal resistance is great. The capacity test sometimes leaves the cells at 3V instead of charging them back up. Maybe 1/4 of the time. That's a bug and runs counter to the docs. I would really like a "storage" mode which would set the cells to 3.7V.

I just actually went to go use this product again today and it is defective the lights are flashing and it is not properly charging. I bought two of these.

This battery charger is very sophisticated for the price. It handles LiIon, Nicad, NiMh etc. and can charge different types simultaneously. It can also discharge LiIon batteies to a safe level of about 80% to avoid possible instability, overheating and fire. It checks for undercharge too which can also cause dangerous instability.

Like this charger a lot. It does the basic functions most would want out of a multi chemistry charger. In my opinion most of us just want information on a screen that tells us about our cells like do they really have that capacity advertised for, are they really rated at the voltage they should or is it time for the recycle bin. It's advertised as an upgraded newer version but still has that problem I'm seeing on other reviews with #4 bay where if you are running a capacity test it will not recharge on the last cycle of test. This is intermittent and does not happen every time. Not a big deal. When you hear the tone that it's done way before the other three cells you just set that #4 bay to charge. This charger can be fast if it wants to be but heat will creep up if you're pumping too much too quickly. Putting a fan close by can help with this. Fits protected button top 21700 cells perfectly. Will not charge those 1.5v controlled rechargeable lithiums which is the only other oddball cells I have lying around. Have run the repair function on some old NiMH cells and recovered some more life out if them. Overall this charger fits my needs & charges a wide variety of cells that I use for different flashlights.

Unable to complete a capacity test. It will charge and discharge the battery but then it in a matter of 30 to 40 seconds the percentage just counts up to 100% and the charger stops. This was a reported problem when the charger was first released and the "upgraded" version still has the same problem. Plus the charger chooses the discharge rate, not you. As you see in the photo it chose 500mA to discharge this new freshly charged Molicel P42A that shows a 20ohm resistance value even though I selected 1 amp in manual mode. The low capacity reading seems legit because my Opus had an even slightly lower reading. I left the charger sit for over two and a half hours and the voltage only rose by 0.2v during that time. Both the slots 1 and 4 have this problem. I did not try slots 2 and 3 because those 2 slots are have a maximum 500mA discharge rate. But it is capable of charging 4 cells simultaneously at 1.5 - 2 amps without breaking a sweat, even though it can charge 4 cells at 3 amps, I'm not comfortable pumping 3 amps into my cells. And it has very long slots for protected 21700 cells. Just be sure you can live with its bugs and limitations.