Rechargeable batteries.

[steve payne]

I work at several small community theatres. They would like to start
using rechargeable batteries on their wirelass usits. The problem I
see is that they are only used once every month or two. We only use
100 or so batteries per year. Is this feasible or should we just stick
to regular batteries.

Steve

[Rhys Dawson]

Hi Steve,

Provided you have enough time to cycle the cells up before each use you should be fine. While NIMH like to be stored charged, they lose that charge as they sit. You'll get the best mileage if you cycle them, then charge them up and use them as freshly charged as possible( and by that I mean take them out of the chargers and put them straight into the packs.) . Also it depends on the transmitter, as some don't like rechargeable batteries (The Sony WRT 802/820's in particular).

That being said, with the amount you use on a yearly basis, it could be awhile before you recoup the cost of the batteries and chargers.

- Rhys

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[Nick Farwell]

We use a bunch of the Maha 2700mah AA rechargeables in our wireless clear-com and the 9.6v NiMH Maha rechargeables in our Sennheiser wireless mics.  They have paid for themselves at least twice a season so far.  We keep the AAs on trickle in 3 8-bay Maha chargers (http://www.thomasdistributing.com/shop/chargers-by-model--maha-mhc801d-c-147_148_244.html?osCsid=e532k64qaffaqj6m3c1abuk7p3) and do a refresh cycle before a run.  The 9v NiMH are a little less reliable - we use alkalines in tech rehearsals and then switch to the rechargeables for the run - they last half as long.  Our sound engineer built some homemade devices to drain them to 5v so we can approximate a refresh cycle.

We are quite happy with the Maha gear, only 5 9v out of 20 and 3 AA out of 48 have died in three years.

Nick Farwell

-----

ACT Theatre

[Mike Benonis]

I moved over to rechargeable batteries a year and a half ago (with Lectro SMDa transmitters). We originally bought the Sanyo 2700mAh batteries, and they worked great until we let them sit for a few months...then about half of them refused to come back up. We replaced them with Sanyo's eneloop line of batteries, and they have been fantastic--especially in terms of shelf life. I had zero problems after about six months of sitting on the shelf. THey are available in AA and AAA sizes; I'm not sure if you can get a 9V.

<http://www.eneloop.info/>
<http://www.thomasdistributing.com/shop/sanyo-eneloop-aa-2000-mah-4-battery-pack-brultra-low-discharge-nimhbr1-free-4-cell-battery-case-p-287.html?SP_id=50&osCsid=a98rm8a91donrsllit8gi3gna7>

We use the Lacrosse BC-900 battery charger, and not only allows you charge/trickle charge the battery, but also drain it and bring it up, and also drain it and bring it up repeatedly until the battery capacity levels off. You may need to use this feature prior to using the batteries for a show.

<http://www.thomasdistributing.com/shop/la-crosse-bc9009-alphapower-aaaaa-nicd-nimh-battery-chargerbrincludes-4-c-size-and-4-d-size-battery-adapters-4-aa-and-4-aaa-batteries-and-durable-travel-bag-p-1762.html?SP_id=&osCsid=a98rm8a91donrsllit8gi3gna7>

Hope this helps.

Mike



Best regards,

Mike Benonis
mi...@benonis.net
KI4RIX

[Rhys Dawson]

I use the MAHA powerex line as well (same charger even).

when nimh and nicad batteries drop like that and won't come back in the charger, you can "zap" them back. what has happened is that the cell voltage has dropped too low for the charger to "See" the battery (usually somewhere between .75 and .9 volts per cell). if you hook some test leads up to a dewalt battery and zap the  dead cell for a couple seconds, it'll pulse charge the battery enough that your charger should see it. this also helps to increase capacity of aging batteries (at least with nicads). I have done this with motorola radio batteries as well, with a 75% success rate.

-Rhys

[Ken Newman]

NiMH?

Not Li-Ion?

Interesting!

Can anyone tell me more about why the preference for NiMH?

Thanks!

Ken Newman
snd...@watamix.com

[Rhys Dawson]

we use NIMH for much the same reason the Prius does. also, not a lot of lithium ion aa's around. Lithium ion batteries are "chipped", they have power management circuitry built in (that's what keeps them from exploding). I'm not sure they've managed to create a protected AA-size lithium ion cell.

Nimh and nicad/nizn are "dumb", you use just the cell, no ifs ands or buts. and much less risk of fire.

[david avery]

Rhys Dawson wrote:
> we use NIMH for much the same reason the Prius does. also, not a lot
> of lithium ion aa's around. Lithium ion batteries are "chipped", they
> have power management circuitry built in (that's what keeps them from
> exploding). I'm not sure they've managed to create a protected AA-size
> lithium ion cell.
>
> Nimh and nicad/nizn are "dumb", you use just the cell, no ifs ands or
> buts. and much less risk of fire.

the problem is Li cells are roughly 3V per cell - great for 9V
impossible for 1.5V.

dave

[steve payne]

Thanks everyone. We are going to try the eneloop batteries for a year.
We can always find a use for them if they don't work out for the
wireless.
Steve Payne

[Mike Benonis]

Let us know how they work out for you.

Best regards,

Mike Benonis
mi...@benonis.net
KI4RIX

[steve payne]

On Dec 13, 2:05 pm, Rhys Dawson <rhysfeez...@gmail.com> wrote:
> I use the MAHA powerex line as well (same charger even).
>
> when nimh and nicad batteries drop like that and won't come back in the
> charger, you can "zap" them back. what has happened is that the cell voltage
> has dropped too low for the charger to "See" the battery (usually somewhere
> between .75 and .9 volts per cell). if you hook some test leads up to a
> dewalt battery and zap the dead cell for a couple seconds, it'll pulse
> charge the battery enough that your charger should see it. this also helps
> to increase capacity of aging batteries (at least with nicads). I have done
> this with motorola radio batteries as well, with a 75% success rate.
>
> -Rhys
>

I tried this and it did work!
They do get pretty hot though.
Thanks

> On Sun, Dec 13, 2009 at 1:36 PM, Mike Benonis <mailingli...@benonis.net>wrote:
>
>
>
> > I moved over to rechargeable batteries a year and a half ago (with Lectro
> > SMDa transmitters). We originally bought the Sanyo 2700mAh batteries, and
> > they worked great until we let them sit for a few months...then about half
> > of them refused to come back up. We replaced them with Sanyo's eneloop line
> > of batteries, and they have been fantastic--especially in terms of shelf
> > life. I had zero problems after about six months of sitting on the shelf.
> > THey are available in AA and AAA sizes; I'm not sure if you can get a 9V.
>
> > <http://www.eneloop.info/>
> > <

> >http://www.thomasdistributing.com/shop/sanyo-eneloop-aa-2000-mah-4-ba...

>
> > We use the Lacrosse BC-900 battery charger, and not only allows you
> > charge/trickle charge the battery, but also drain it and bring it up, and
> > also drain it and bring it up repeatedly until the battery capacity levels
> > off. You may need to use this feature prior to using the batteries for a
> > show.
>
> > <

> >http://www.thomasdistributing.com/shop/la-crosse-bc9009-alphapower-aa...

>
> > Hope this helps.
>
> > Mike
>
> > Best regards,
>
> > Mike Benonis

> > m...@benonis.net