Dec 26, 2008

Rechargeable 9 Volt Batteries

For years, in my work as a soundman, I would use and have to dispose of alkaline 9 volt batteries. When traveling on longer documentary projects I would have to budget for batteries and then pack according to my perceived needs. I almost always erred on the side of caution and usually added 30% to any estimate.
This resulted in more weight in the equipment cases.

Only once in the last few years did I actually run out of batteries in the field. That was in Southern China in 2007 and it was pretty scary as reliable alkaline 9 volt batteries were impossible to buy. Most merchants in electronic malls sold only zinc carbon batteries and some rechargeable lithium batteries that were better but had nowhere near the umph needed to power my Micron wirelesses.
This is a photo of some of the stuff bought in China that didn't work so well with my equipment. I was surprised at not being able to buy a decent 9 volt battery in China. The green ones are rechargeable lithium batteries while the Eveready is a zinc carbon 9 volt.

The zinc carbon 9 volt batteries would power my older 300 series Microns for around 10 minutes and last only 3 or 4 minutes with the diversity 700 series Microns. The Chinese lithiums lasted in the neighbourhood of 20 minutes with the 700 series. I somehow stumbled my way through the final 2 days of production by cabling into the camera instead of using a wireless link, thereby cutting down on my wireless use and also by saving the batteries for actual takes instead of having the talent wirelesses up all the time. It was not an experience I want to repeat!

Prior to this I had been experimenting with 9 volt batteries for some time as I was involved in several documentary medical series where we were filming surgery in hospitals. As a rule Micron transmitters only lasted 5 to 6 hours with an alkaline 9 volt battery and quite often the operations went on for a good deal longer. Since operating theatres are quite noisy with a lot of ambient clatter I would come to rely on pinning a lav or two on the principal surgeons and have them talk their way through the operation. Surgery being what it is I couldn’t very well tap a surgeon on the shoulder and tell him to stop for a second while I change the battery in his transmitter when it went down.

My experiments with all sorts of 9 volt batteries yielded nothing but frustration. No battery was as strong and reliable and long lasting in the Micron wirelesses as the Duracel alkaline 9 volt battery. Trouble was they were not good enough for what I wanted to do. While talking this problem over with Alex Bernardi, the proprietor of Audio Services (1545 The Queensway, Toronto, Ontario M8Z 1T8 – 416-251-5409), the possibility of rebuilding the Micron transmitter was broached. Alex had a machine shop cut down a 700 series receiver into which he inserted the electronics of the transmitter which now had a bay for 2 nine volt batteries. The resulting transmitter would go for 10 to 12 hours on the 2 batteries and was barely a half inch longer than the standard Micron 700 series transmitter.
This view shows the transmitter with the battery carriage slid open exposing the 2 battery compartment.

I have to salute Alex for his energy and resolve in finding solutions for vexing problems. Much successful work in sound relies on equipment that is custom built for a purpose rather than store bought generic products. That said, I must also state that while Micron (the British firm) puts out an incredible product in terms of quality, they are impossible when it comes to refining or upgrading or bringing out new products and accessories for their line of wirelesses. For years I have waited for a butt transmitter that can be attached to hand held microphones among a long list of other things. It’s like waiting for a corpse to pass wind. This state of affairs has made me start looking and adapting other wireless systems into my kit.

This is a view of 2 Micron transmitters. The one on the left has a battery compartment that holds 2 nine volt batteries. The one on the right is a regular sized 700 series Micron transmitter. Notice how worn the face plates of both wirelesses are. I have been trying for the better part of a year to get replacement face plates for these wirelesses from Micron so I can actually see what frequency I have these units tuned to. This is just another example of how unresponsive Micron can be when it comes to certain types of service. In fact, I will have waited so long that I won't need to replace these face plates as I have to send the units back to the factory to be reset to a new frequency band. As of February 17, 2009 these units will be illegal to use in the United States on the frequencies they currently occupy. Since I work in the U.S. fairly regularly I feel obliged to comply. Fortunately Audio Services in Toronto has a policy of supplying replacement units for Microns bought from them when they are in the shop. That was the kind of service that attracted me to Audio Services in the first place.

These are the new iPowerU.S. rechargeable 9 volt batteries. They come in plastic caddies which makes travelling and handling them very easy. On the bottom right you can see a partial view of the charger.

The rechargeable 9 volt batteries put out by iPowerU.S. ( are the first rechargeable batteries that have worked in my Micron wirelesses with any degree of satisfaction. They will power my Micron wirelesses approximately the same length of time as the Duracel alkaline batteries. That said, they are still not a perfect replacement. The Duracel alkalines when they were on the verge of being exhausted would trigger a warning of blinking lights in the LED display of the Micron wireless. This would allow me to change the battery in the unit during a break rather than having it crash during a take. The iPowerU.S. batteries do no such thing. They die suddenly, without warning, as do all lithiums. They are however, a reasonable solution for the moment, of powering wirelesses without the hassle of carrying extra boxes of alkaline batteries on trips and then dealing with their disposal.