TenergyTN136 4 Bay 9V Smart Charger with 8 Pieces 9V Tenergy Centura (Low Self Discharge) NiMH 200mah Rechargeable Batteries

The smart charger works great for charging both my Tenergy Centura and Tenergy Premium 9V NiMH batteries. Way better than the dumb charger I was using.I used an electronic load to measure the capacity of a freshly charged (taken off charger 1 hour prior to testing) battery vs one that had been charged a month prior.I set the cutoff voltage at 7 volts, based on a datasheet I found for a different Tenergy 9V NiMH battery.I set the discharge current to 100mA. The same datasheet I found suggested the rated capacity is based on 36mA discharge current, but also gave data for 90mA and 180mA. It stated the 250mAh battery should last for 108 minutes at 90mA discharge current.I did NOT allow the battery to recover and discharge further.The freshly charged battery had a voltage of 9.92 volts and a capacity of 176mAh after 106 minutes.The one month old battery had a voltage of 9.29 volts and a capacity of 159mAh after 96 minutes.While the capacity measured is less than the advertised 200mAh, it's important to remember that I could've got some additional energy out of the batteries had I let them recover and re-run the test and that I was testing at three times the current that Tenergy rated them for. I could've also taken them down to around 6.3 volts, but I prefer to not drain them that far.Overall, I'm happy with the capacity and self discharge rate after a month long test.I'll update this review after a year to further test the self discharge rate.

After fully charging using the included charger and following the directions to connect the batteries before plugging in the charger, I got 4 batteries that had a charge of 9.5, 2 had 9.4, and 2 had 9.3. I recharged the 2 at 9.3 and they went up to 9.5. I will have to update after a few months to determine longevity in smoke detectors, but so far, an excellent start.

Just what I was looking for. Our 2 metal detectors need rotating batteries and this is perfect. Buying batteries constantly is horrible. This is the solution

I have used this charger and these batteries for several months now.Only time will prove this for sure, but everything looks excellent sofar.The batteries appear to be really slow discharge, suitable for fire alarms, guitar tuners,microphones etc etc. And the battery really provides 9 volts (not just 7V or 8V like others do)The charger does exactly what is needed.What is specially welcome is the price, about half of what I used to see advertised.At this price, it makes sense for individuals to replace all existing 9V conventional batteries !I'm not in charge of this at a church, but if I was, I sure would experiment with this productand probably save a lot of money every year !True progress in technology at a COMPETITIVE PRICE.

No issue so far after 3 months. I'll continue posting if there is any changes...

Our church purchased these because we were eating through 9V batteries every week to power our Sennheiser wireless handheld mics. After ever rehearsal and Sunday service, the batteries all go back on the chargers and are ready for the next event. We typically see a 3-4 hour life in these power-draining mics. We used the first set we purchased for 2 years before we noticed the life on them dropping enough to where we felt uncomfortable relying on them. We used to have to budget some $250 or more for batteries every year. This has saved us gobs of money. Highly recommend them.

The convenience and practicality of these rechargeable batteries is a must for all households. Especially if you have smoke detectors throughout the home and other electronic devices such as remote controls for toys and electronics.

For a short time, these batteries are useful and hold an adequate charge. But, only used once a week in church microphones, they faulted out and could not be charged (the dreaded blinking red light) before we'd had them one year. The return on investment was not what I would have liked.