Topic: Rechargable batteries for wireless mics?

[runonce]

Is there any reason not to use rechargeable batteries in handheld wireless mics?

We have 2 Shure rigs we use for every show - I hate throwing out half good batteries.

I go 2 shows with the 9V - and change the AAs every show.

The mics end up being on for 3-4 hours per gig.

[John Willett]

Is there any reason not to use rechargeable batteries in handheld wireless mics?

We have 2 Shure rigs we use for every show - I hate throwing out half good batteries.

I go 2 shows with the 9V - and change the AAs every show.

The mics end up being on for 3-4 hours per gig.

If it's a 9V - stay with alkalines.

The old Sennheiser transmitters that took a 9V battery did about 5-hours with an alkaline, but only about one hour with a rechargeable.

So I would say "no".

[notlance]

"Discharge rate in wireless mics is pretty high, so you won't get the runtime you do with alkalines because of the higher internal resistance of NiMHs."

I always thought that alkalines had higher internal resistance than NiMH, especially at higher discharge rates.  Here's a reference: http://batteryuniversity.com/learn/article/primary_batteries


You might want to try a 9V Li-ion rechargeable.  I have talked to people that have had good luck with them in wireless mics, but I do not have any experience with them myself.

[ScoobieKW]

We chew through AA batteries like mad with our Shure UHR wireless, but the cost of replacing batteries is nothing compared to the cost of having a corporate client's mic cut out during a presentation.

It's a "Penny wise, pound foolish" decision.

[notlance]

The problem with rechargeable 9V NiMH batteries is that many are not 9 Volts even when fully charged since they are made up from 1.2 V cells. Alkaline cells are 1.5 V so 6 cells = 9 V.  NiMH cells are 1.2 V so 6 * 1.2 = 7.2 V.  If you use 8 1.2 V cells you get 9.6 V, but since the cells have a round cross section and you are trying to put them in a rectangular box (the 9 V battery case) there is a lot of wasted space.  So "9 V" NiMH batteries don't work so well.  With Li-ion 9 V batteries it's a different story.  Here is a page on 9 V batteries that explains quite a bit.

http://michaelbluejay.com/batteries/9v.html

I don't know who the page author "Michael Bluejay" is, but after a quick read of this page I didn't see anything that appeared obviously wrong.