Battery level meters for 9V batteries? at DVinfo.net

Myron Iwankewich · May 28th, 2006, 09:03 AM

My wireless mic uses 9v batteries. I don't want to risk losing power during a crucial shoot, so I generally use fresh batteries each time. It's such a waste (Even though I do save them for smoke detectors, toys...)
Is there an accurate little meter that would give me confidence in what might be left in a battery.

Thanks, Myron

Dean Sensui · May 28th, 2006, 05:39 PM

I started using rechargeable NiMH 9v batteries Sept 2003. I set the countdown timer on my watch for 3 hours to make sure I replace them in time (250 mAh).

Just switched to Lithium Polymer 9v batteries and they seem to run for 5.5 hours now (400 mAh).

It's running an ATW-101 transmitter. The receivers run off a 12-volt pack consisting of 10 AA batteries with a total of 2.5 AH capacity.

Considering 9v alkalines are about $1.75 each from Costco, the rechargeables have more than paid for themselves, and I'm assured a predictable run time.

Myron Iwankewich · May 29th, 2006, 06:30 AM

I used to use rechargeables but found that when they started to lose power they dropped like a rock. Without warning the mics just stopped working. The shoot before these batteries worked fine, this time they only held charge for twenty minutes!!

David Ennis · May 29th, 2006, 06:58 AM

I use this little battery checker. With a little experience you learn to adapt the reading to your purposes. For instance, I've found tha a 9V battey that tests "good" is good enough to be trusted to power my BeachTek DXA-8 for a two act play with phantom power on only if the needle reaches the middle of the second "O" in "GOOD." If it only reaches the "G" it's starting to tank, but it will still power my Rode VideoMic for several hours.
http://www.radioshack.com/product/in...entPage=search

Myron Iwankewich · May 29th, 2006, 02:34 PM

Just the answer I was looking for. Thanks Fred.

Myron.

David Ennis · May 29th, 2006, 03:48 PM

Battery drain is an interesting topic. As with a lot of things, there's a lot more to it than meets the eye. There are three basic types of circuitry designed to use battery power; constant resistance, constant current and constant power. Constant resistance is the worst and constant power the best in terms of efficient use of the energy stored in a battery. Info courtesy of Duracell's website. I checked it out a while back when I was studying the power consumption behavior of my DXA-8 (http://www.dvinfo.net/conf/showthrea...ghlight=DXA-8).

Hart Boyd · May 30th, 2006, 05:20 AM

I use the following and like it a lot as it places a load on the batteries and I never had any problems or false readings plus you can test more that just 9v batteries.

ZTS Mini-MBT Multi Battery Tester

http://www.bhphotovideo.com/bnh/cont...ughType=search

Myron Iwankewich · May 31st, 2006, 07:22 AM

Hmmm. looks good Hart. Thanks for the reply.

Myron

May 28th, 2006, 09:03 AM	#1
Myron Iwankewich New Boot Join Date: May 2004 Location: Toronto, Ontario, Canada Posts: 20	Battery level meters for 9V batteries? My wireless mic uses 9v batteries. I don't want to risk losing power during a crucial shoot, so I generally use fresh batteries each time. It's such a waste (Even though I do save them for smoke detectors, toys...) Is there an accurate little meter that would give me confidence in what might be left in a battery. Thanks, Myron

May 28th, 2006, 05:39 PM	#2
Dean Sensui Inner Circle Join Date: Oct 2001 Location: Honolulu, HI Posts: 2,054	I started using rechargeable NiMH 9v batteries Sept 2003. I set the countdown timer on my watch for 3 hours to make sure I replace them in time (250 mAh). Just switched to Lithium Polymer 9v batteries and they seem to run for 5.5 hours now (400 mAh). It's running an ATW-101 transmitter. The receivers run off a 12-volt pack consisting of 10 AA batteries with a total of 2.5 AH capacity. Considering 9v alkalines are about $1.75 each from Costco, the rechargeables have more than paid for themselves, and I'm assured a predictable run time. __________________ Dean Sensui Exec Producer, Hawaii Goes Fishing

May 29th, 2006, 06:58 AM	#4
David Ennis Fred Retread Join Date: Jul 2004 Location: Hartford, CT Posts: 1,227	I use this little battery checker. With a little experience you learn to adapt the reading to your purposes. For instance, I've found tha a 9V battey that tests "good" is good enough to be trusted to power my BeachTek DXA-8 for a two act play with phantom power on only if the needle reaches the middle of the second "O" in "GOOD." If it only reaches the "G" it's starting to tank, but it will still power my Rode VideoMic for several hours. http://www.radioshack.com/product/in...entPage=search __________________ "Nothing in the world can take the place of persistence..." - Calvin Coolidge "My brain is wired to want to know how other things are wired." - Me

May 29th, 2006, 03:48 PM	#6
David Ennis Fred Retread Join Date: Jul 2004 Location: Hartford, CT Posts: 1,227	Battery drain is an interesting topic. As with a lot of things, there's a lot more to it than meets the eye. There are three basic types of circuitry designed to use battery power; constant resistance, constant current and constant power. Constant resistance is the worst and constant power the best in terms of efficient use of the energy stored in a battery. Info courtesy of Duracell's website. I checked it out a while back when I was studying the power consumption behavior of my DXA-8 (http://www.dvinfo.net/conf/showthrea...ghlight=DXA-8). __________________ "Nothing in the world can take the place of persistence..." - Calvin Coolidge "My brain is wired to want to know how other things are wired." - Me

May 29th, 2006, 06:30 AM	#3
Myron Iwankewich New Boot Join Date: May 2004 Location: Toronto, Ontario, Canada Posts: 20	I used to use rechargeables but found that when they started to lose power they dropped like a rock. Without warning the mics just stopped working. The shoot before these batteries worked fine, this time they only held charge for twenty minutes!!

May 29th, 2006, 02:34 PM	#5
Myron Iwankewich New Boot Join Date: May 2004 Location: Toronto, Ontario, Canada Posts: 20	Just the answer I was looking for. Thanks Fred. Myron.

May 30th, 2006, 05:20 AM	#7
Hart Boyd Regular Crew Join Date: Jan 2004 Location: Atlanta, GA Posts: 148	I use the following and like it a lot as it places a load on the batteries and I never had any problems or false readings plus you can test more that just 9v batteries. ZTS Mini-MBT Multi Battery Tester http://www.bhphotovideo.com/bnh/cont...ughType=search

May 31st, 2006, 07:22 AM	#8
Myron Iwankewich New Boot Join Date: May 2004 Location: Toronto, Ontario, Canada Posts: 20	Hmmm. looks good Hart. Thanks for the reply. Myron