Disclaimer: Since I've written the firmware for another charger/analyzer, some may feel that I'm biased with the following. Feel free to take a truck load or 2 of salt with this:
I received one of these chargers only a day or so ago and so far I'm not very impressed!
Discharge accuracy seems to be very poor on the unit I've received. It appears that the charger doesn't measure the actual current when either charging or discharging. Running a refresh/analyze on a set of 4 Eneloops that I recently took out of the packet gave discharge capacities of:
1846
1831
1910
1711
Repeating the test with a different set of 4 Eneloops gave the following discharge capacities:
1850
1830
1912
1700
On the second test, slot 3 gave a capacity that was 12.5% higher than slot 4 - far more variation than I've ever seen between new Eneloops! There's an obvious pattern above - comparing slot to slot between the 2 tests gives variations ranging from 0.05% to 0.65% - what I'd expect with Eneloops.
The current shown on the display and in the Android app never varies from the set current. I also did a test charge on a known high resistance cell to see how it would handle it. The charger reported that it was charging at the set rate of 1 amp, but the voltage only went up extremely slowly (from about 1.28V to 1.30V over the whole time) so it appears that it simply wasn't actually charging the cell. I left it to see what would happen and it finally stopped charging at 5 hours and about 5Ah showing on the screen.
Given all of the above, I think it's reasonable to conclude that the charger doesn't measure actual current and is also not very accurate with its discharge currents and hence discharge capacity results.
The other major complaint that I've got is the fan noise. As reported by others here - it's really loud and doesn't seem to be achieving much - I can't feel any air coming out of the fan - it feels like it's trying to suck air into the charger, but I can't feel warm air coming out anywhere. Temperatures are fairly warm here, but not so high that I would expect that it should need to be running most of the time. Charging a set of 4 AAA Eneloops at 400mA, it had the fan running quite often - I think it's quite concerning that it can't handle 16% of its peak load without needing to have the fan running! What's more, I left 4 cells in the charger after the last refresh and analyze above and even after everything had stopped for quite a few hours, the fan was still coming on intermittently!
I've since set the temperature control to 70 degrees and it hasn't run the fan since which is good, but I haven't tried doing a charge yet.
The Android app is also quite buggy - besides a number of quirks, it has force closed on me numerous times. The Bluetooth range seems to be quite poor as well. If I walk out my office holding the phone, it loses the connection after moving only a few meters from the doorway - the Bluetooth connection actually has less range than the fan noise - that's how loud it is!!!
Being able to view the charge/discharge curves on the phone is certainly a nice feature. It would be even better if the data could be saved out to somewhere for more thorough analysis - this could of course be done with a future upgrade.
Overall, I think that the NC2500 is a good idea, but it's just poorly implemented. There are also a few other minor problems that I've noticed that I haven't mentioned above.
At the moment, I'm considering selling this charger on Ebay and taking a loss. I'd be willing to overlook most of these problems, except for the inaccurate discharge results - in my opinion, a 12.5% variation is just unforgivable!
For anyone contemplating purchasing this charger, I'd recommend going for the Maha C9000 instead until something better becomes available. The C9000 isn't perfect, but it has far less problems than this charger...
