View Full Version : Rechargable 9 Volt and Wireless Mic


Richard Zlamany
August 15th, 2006, 02:43 PM
Hi, a photographer told me that rechargabe batteries are not 100% reliable when used to power a flash so he doesn't use them. He said the voltage is weak and can cause problems.

But, he said I should be okay using rechargeable batteries with a mic.

However, when I used the wireless with the rechargeable batteries that were brand new, I had numerous drop outs. I never had this problem before. I checked everything and ran tests. Everything is working well. The only thing I did different was use these rechargeable batteries.

Is it possible that rechargeable batteries caused the drop outs? Does anyone use rechargeable batteries with a wireless lav system with success?

I was capturing a wedding in Catholic church and was about ten feet away from the transmitter.


edit: the odd thing is the 9v NIMH says only 7.2V That doesn't sound right. Maybe that is the problem.

Sam Gates
August 15th, 2006, 05:41 PM
That sounds about right for some NiMH batteries. A few are rated at 9.4 volts but none have the capacity of alkalines. I think NiMH batteries are 150mAh to 200mAh while alkalines run 550mAh to 650mAh.

I don't use rechargeable batteries but a lot of people do. You have to pick the right batteries and stay on top of charging them. Too much trouble for me. I just buy new alkalines and do not take a chance.

Sam

Richard Zlamany
August 15th, 2006, 05:47 PM
I'm with you. I returned everything.

Pete Cofrancesco
August 15th, 2006, 05:55 PM
I'm surprised they worked at all. Your wireless mic manual should have warned you. Repeat after me "Never use rechargeable batteries with wireless mics" and "Always use fresh batteries for each event"

Richard Zlamany
August 15th, 2006, 06:25 PM
I was very stupid and feel like a heel.

I will never use rechargeable batteries with wireless mics and I always will use fresh batteries for each event.

Sometimes, I have to learn the hard way.

Pete Cofrancesco
August 15th, 2006, 11:23 PM
I was very stupid and feel like a heel.

I will never use rechargeable batteries with wireless mics and I always will use fresh batteries for each event.

Sometimes, I have to learn the hard way.dont feel bad i made the same mistake except my wireless setup wouldn't work, i was ready to ship it back as defective when i tried alkalines for the heck of it.

The real lesson to be learned is never use equipment you're unfamiliar with or haven't used before for something important. You should always wear headphones to monitor the audio especially with wireless. you could be getting interference, batteries could be dieing, lavalier fell off or rubbing against the persons shirt... The key thing is to catch the problem and react to quickly.

Danny Fye
August 20th, 2006, 03:36 PM
I was very stupid and feel like a heel.

I will never use rechargeable batteries with wireless mics and I always will use fresh batteries for each event.

Sometimes, I have to learn the hard way.

Well, you are neither stupid or a heel! The problem is not you. It is the batteries that you got. I read somewhere that batteries that have 7.2 volts actually are Ni-Cad (Ni-CD) instead of NIMH. The batteries you got may have been misrepresented.

I bought two Tenergy batteries that are 9.6 volts when fully charged. They are rated at 250 mah and are labelled 'Nickel-Metal Hydride Battery'. Before I used them for a project I tested them and they went 4.5 hours before the low battery indicator came on. Which is plenty for me.

What is interesting is that just after the low battery indicator came on I took the battery out and tested the voltage and it was 7.2 volts.

I put the batteries to the real test today with a video project and got perfect results.

I bought these batteries and chargers from, http://www.all-battery.com/index.asp. Note, the highest price charger they sell is a 'smart' charger for aaa aa c and d batteries and a timer type for the 9 volt types. The 9 volt batteries are trickle charged so this is not a big problem.

I've seen threads on other forums about rechargeable batteries and people using them with success.

The problem is not in using rechargeable batteries, it is making sure you get the correct ones.

This is one of those situations where you don't want to throw the baby out with the bath water. Just because you had problms with one brand/type of rechargeable battery doesn't mean you should condemn them all.

There is a lot of money to be saved by using rechargeable batteries and a lot of waste avoided.

I strongly suggest that you shop around some more and give it another try. Makes sure the batteries are 9 volts or better and get the highest mah rated ones you can find.

Note: I have two transmitters. One is fairly easy on the batteries and the other one uses a lot more power. I got 4.5 hours on the unit that uses more power.

Danny Fye
www.dannyfye.com

Vito DeFilippo
August 26th, 2006, 08:14 PM
I second the rechargeable recommendation, along with making sure you get the right ones. Most rechargeables have lower voltage than the equivalent alkalines, which causes trouble.

My particular wireless uses AA, but the batteries I got work great. The same company (PowerEx) makes 9v that have been recommended as well.

In Canada, I got them here:

http://www.paulsfinest.com/batts_maha_price_list.php#aaa

I've seen them online in the US as well.

Richard Zlamany
August 26th, 2006, 11:34 PM
Thanks for helping. If I buy them I'll make sure to give them a complete test with my wireless system.

Glenn Davidson
August 27th, 2006, 12:16 AM
I use Duracell 9V batteries. I get them in 10 packs from Costco. I put in a fresh battery in the morning and change them at lunch (about 4.5 hours). Then I throw them away at the end of the day. I have never had a transmitter go down. California now treats batteries as hazarous waste, so you are not supposed to throw them in the trash , so I put them in the recycle bin.