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Achieving The Most From Rechargeable Batteries

Successful use of a rechargeable system for Pro AV applications revolve around three basic principles:

1. Using the right batteries for your wireless units.
2. Using the right charger for your batteries.
3. Understanding your run-time requirements.

Utilizing Ansmann and Fischer Amps chargers and rechargeable batteries take care of the first two.

Understanding Run-time

Determine how long you will need to use the wireless unit. Depending on your set-up and run-time requirements, use these recommendations as a starting point:

9V Wireless Systems:

Run-time Requirement Part # Description Recycles Discharge
Up to 3.5 -4 hours, 5035453 Ansmann 9V 300 mah Low Self Discharge 300-500 recycles No self-discharge, only 15% per year
Up to 12 hours 960-00097 HiTech 9V 600mah Lithium Ion Up to 200 recycles About 10% per week

** When using HiTech 9V Lithium Ion Battery, these batteries can ONLY be charged on the HiTech Lithium Battery Charger. Any attempt to use a standard NiMH battery charger will result in explosion or leakage of cell.

AA Wireless Systems

Run-time Part # Description Recycles Discharge
Up to 3 hours 5030842 Ansmann AA 2700mah up to 450 recycles About 2% per day
Up to 11 hours 5035212 Ansmann AA 2850mah up to 1000 recycles About 2% per day
Up to 11 hours. Slimline for older Shure models or dimension sensitive 5035212-US Ansmann AA 2850mah SLIMLINE up to 1000 recycles About 2% per day

The efficiency of the wireless unit and how hard you drive it, will determine actual run-time with high-capacity cells. For example, Shure ULX wireless units were tested with the Ansmann 300mah 9V cell and found to deliver 4.5 hours continuous use.

Discharge Curve

There has been much discussion regarding the differences in discharge curve between alkaline cells and NiMH rechargeable cells. Much of the concern is placed on the fact that with an alkaline battery there is a gradual decrease in voltage drop as opposed to a dramatic cut-off with the NiMH cells. A common mis-statement is "There is no warning signal with a rechargeable battery, so therefore a rechargeable cannot be trusted."

Simply not true.

In actuality, the reverse is true. A rechargeable battery's run-time is quite predictable. Once you determine the length of your run-time application, you can determine how much "spare time" you have with a rechargeable. With an alkaline, you're guessing or hoping the gradual voltage decrease still has enough juice to power the wireless.

Also, for those wireless units that include a battery life display, please note that with rechargeables, the meter may show slightly less than full. This is not an indication of a battery not acheiving a full charge. It is due to the calibration of the battery life display set to alkaline battery voltages. A rechargeable will stay "good" longer than the alkaline (except for 9V NiMH) on the battery life meter, but it may start slightly lower.

Stretching the 1x use.

Some of us have been trained to squeeze the most use of of each alkaline battery, but this is NOT the way to approach rechargeable usage. Because there is no memory effect with the Ansmann rechargeable, it does not matter if you use a 9V for 1 hour or 6 hours. When the show or church service is completed, the use of the rechargeable is too. Do not try to use the same rechargeable for Sunday and then again on Wednesday, like you may normally try to acheive with an alkaline.

Fail-safe procedure.

  • Charge the batteries in the appropriate charger to full charge. The charger will automatically switch to trickle charge and keep the batteries topped off.

  • Leave the batteries in the charger until ready to use,

  • Just before use, check the remaining capacity in the battery utilizing the Energy Check

  • Load the batteries into the wireless units.

  • After use, remove batteries from wireless unit, and return to the charger until ready for the next use.

  • As your battery enter their 2nd year of life or after 100 cycles, we recommend measuring the remaining capacity of the cell. We recomment the Powerline 4 Pro for this

Follow these simple procedures and you will have no issues.

Spare Rechargeable Batteries

We recommend having several spare rechargeable batteries charged and ready to go. Some venues insist on having 2 sets of batteries for each wireless unit. As a minimum, we suggest at least 2-3 spares. If you are swapping batteries between shows or church services, then of course you should have two batteries per wireless.

What about Refresh - Reconditioning?

Ansmann rechargeable batteries are designed for high recycles -- up to 300-400 times for high-drain devices that require near full capacity. To acheive the most recycles from your batteries, they need to be refreshed. The Fischer Amps Rack-Mount Chargers and the Ansmann Energy 8+ or Energy 16+ Chargers will automatically analyze each cell and perform refresh/deep cycling on the battery as needed. This becomes extremely important as the battery ages -- particularly after 150-200 uses. Over time, the cell's chemistry can become imbalanced and crystal formation can occur. This will diminish run-time of the battery and additional recycles. Refreshing the cells periodically helps to restore chemistry to a balanced state. The refresh function is a proprietary algorithim of charge and discharge cycles at various voltage levels. Only Ansmann Energy Series chargers have this function. The Fischer Amps Rackmount chargers acheive this through deep pulse charging cycles which help to optimize battery life as well.