Tenergy makes high quality cells. I've used their products in micro flying RC to heavy duty applications for several years. Three years ago I purchased four of these cells to replace a set for an outdoor power tool (electric hand shears for lawn work) and they've been through two seasons and now into their third season as I type out this review. By comparison, the other no brand cells would last a season with diminishing returns after every charge cycle. These Tenergy cells continue to perform with no noticeable degradation in performance as we move into our third spring/summer cycle of lawn care. These are a great value.

I've used these batteries for rebuilding name brand hand drills and a hand held wet/dry vac. They have excellent charge and discharge characteristics! I don't have any metrics to share on performance, but they charge fast and pack the punch necessary to operate the device they're installed in. None of the batteries in the packs I've created have failed so maintenance is basically just applying proper charge cycles. I opted to have tabs installed so I didn't damage the battery directly when heating with solder. Not having tabs is helpful for clearance needs.

These Folks apparently sell very fresh stock. I'd purchased these same batteries before from another source and tested their capacity with my fancy battery analyzer to find them around 3250 to 3400 mAh. I just received these batteries and ran the same load test. They ranged from 4094 to 4214 mAh. Fantastic.

Very pleased with the seller and their products. Give them a try as you will not be sorry.

Bought these batteries in April 2017 and installed them into the battery pack for my HP97 calculator. I have replaced many batteries in the pack over the years but these batteries have excelled in power and has very low self discharge. (November 2017) I use the calculator on battery all the time and only connect the HP charger through a timer for charge to avoid overcharging. You do have to modify the battery pack plastic body and cut out some of the plastic to get the batteries to fit. I tape everything together with electrical tape.

I purchased these Tenergy cells to rebuild a rechargeable battery pack for an electric impact tool used in the automotive industry. These cells were the right size and fit the plastic battery case very well. Impact not only has a longer run time but has more power now. I would recommend using these cells to rebuild other types of drill / impact batteries. Just be sure your charger is NiMh capable.