Opus Battery Charger Analyzer Tester for Li-ion NiMH NiCd Rechargeable Batteries C3400 BT-C3400 AA AAA C 18650

This charger appears to work well and the instructions are good. I used this charger on 25 NiMH batteries to charge them up and then I used the "Quick Test" function to determine the internal resistance. The "Quick Test" identified three bad batteries (all three were Enercell batteries) with internal resistance of 2.5 ohms to 4.0 ohms (should be no more than 0.2 ohms or less). I then performed the "Discharge-Refresh" function to attempt to reclaim these three bad batteries; it did not work on them. I tried the "Charge Test" function on good batteries and according to the User Guide I should see "FULL" flashing alternately with the mAH number. However, I only saw the mAH remaining statically on the LCD. This means, I am unsure if the charger completed the charging part of this function. ALERT: This charger prevents exceeding the 4000mA charging current limit, which means you can only charge 2 batteries at a time using the 1500mA or 2000mA setting. If you attempt to charge three or more batteries at these higher settings, the charger automatically reduces current to 1000mA to prevent exceeding the 4000mA limit. This information is in the User Guide under "Current Selection." CONCLUSION: This is a nice charger and I recommend it.

This unit works very well. In addition, the customer service is excellent. I had an issue with the display on my unit and despite that it was out of warranty, customer service promptly responded (on a Sunday, no less) and offered to make it right.

Great, versatile charger. Good/informative display that actually shows the charge rate. It also allows you to preset the initial intended rough charge rate (200ma - 1000ma). I seriously like the 'conditioning' mode, which automatically does three charge/discharge cycles ending with a full charge, giving you an excellent capacity status on the cells. Nice to know. I subsequently label my cells with that capacity. Knowing that capacity helps you match your cells (with near-same capacity cells) when powering any multi-cell device. That way the chances of ever driving any single cell into reverse polarity (and harming that cell) are minimized. EXCELLENT little charger. 5-stars.

I got this as an update to my old my old Powerex MH-C9000, but it's way more than an upgrade. It can charge each battery with a different program, or all four with the same settings. Charge/discharge current goes down to 200ma, which I think is best for AAAs. It will charge both button top and flat top lithiums, which is a big plus. Some have complained about the fan noise; it's more of a rushing sound than a buzz or hum, and I just keep it in another room and it's no bother. The fan does help keep the unit, and the batteries, cool. Really nice unit, worth the money if you do a lot of charging.

I rate this suitable for amateur DIY enthusiasts. I give it 4 stars because the internal resistance measurement results differ significantly from those of a professional internal resistance meter.

I have nimh and lithium ion batteries that are up to 12 years old. Wanted to test them and see how much capacity is left and wanted to test new batteries I was purchasing. I have used this for about a month now and am very happy with this product. It takes awhile to test capacity because it charges to full, discharges and then recharges. Some of my batteries have dropped about 30 percent capacity but many of the five year old batteries are at 90 percent. Pros it is easy to use, good instructions and reasonable price. All of the new batteries I have tested have been +/- 100 milliamp hours so seems pretty accurate. Cons I have not found any yet. Some complained of noisy fan but mine is ok and I use in a room that wouldn’t matter if louder. In the end I am glad I bought this Opus charger and would buy another.

This is a great tester/charger. I saw it in a video about batteries. My other tester/charger just went in the donation box.

Has worked perfectly