Customer Reviews

T-868 High Volume Automatic Charger with 16 Tenergy AA 2600mAh NiMH Batteries

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I've designed battery chargers for several years. Heat kills a battery (NiCD,NiMH,Lead Acid) faster than any other mistreatment. This charger is rated at 1200-1800 mA for AA size NiMH, 500-750mA for AAA. The AA battery sold with it is rated for 2600mA. If the charger switched to trickle after an hour or so, it could be considered a fast charger. Instead, this unit charges for 8 HOURS and heats the batteries >150ºF. But even as a fast charger it would dramatically shorten the life of the battery. The industry standard for rating/charging batteries is 1/10 the amp-hour rating of the cell or less. Above this the life of the cell begins to drop on an exponential curve. Switching the charger to NiCD does not reduce the charge current (AA 600-800mA/AAA 200-300mA) sufficiently and reduces the charge time to 5 hours. The unit also begins to smell within 20 minutes and the case gets warm all over. Whenever a charger gets warm enough to smell, internal transformers are heating up too 100ºC or higher, which can exceed insulation ratings causing failure of the transformer.

On the plus side, these are the first NiMH AA's that have powered my wife's 7MP camera without going dead within 15 minutes. However, some of them were in need of conditioning to get maximum power out of them. So you may need to discharge/recharge/trickle charge them a few times to get them performing. "Sulfation" is a natural chemical process and if the battery is left idle for a while the power capacity begins to drop. The only way to minimize this effect is to have a good charger that trickle charges at the proper cell voltage, keeping the battery in the charger at all times not in use.

The batteries are worth their advertised cost elsewhere, this charger is not (unless you know how to modify the internal electronics). Shop wisely on the charger and these batteries will give good life.

I am getting a good service from the product. I like how the charger is neat, and also the automatic function. I can put my batteries to charge confidently without worry, knowing that when charging is complete, it shuts off automatically.I would get an average of 3 days service on my grundig radio before the charged batteries are exhausted.Could be slighty longer, depending on how long one plays the radio.
It is truly saving me some dollars.