Topic: How reliable are Energizer Lithium AAs?

[DSatz]

Hi. I've just bought a small Sound Devices preamp that can run on a pair of internal AA cells, which I think could be very convenient. The preamp has a 15-Volt setting for phantom powering, which nearly doubles its battery life as compared with the 48-Volt setting, and that setting should work well with my Schoeps CMC 6-- or MSTC 3-- microphones.

I'll test the preamp's running time with alkalines, and meanwhile I'm told that a pair of Energizer Lithium cells (particularly the "Ultimate" line) could last for 10+ hours in the 48-Volt setting--and I think, with the 15-Volt setting, could maybe even last for three or four whole concerts.

But I have two concerns. One is the relative lack of advance warning when Lithium cells are about to run down. For that reason alone, if the battery life of alkaline cells is adequate, then that's what I'll most likely use; I don't wish to gamble and lose.

My other concern is that http://www.energizer.com/batteries/performance-lithium/ultimate-lithium/Pages/aa.aspx and http://www.energizer.com/batteries/performance-lithium/advanced-lithium/Pages/aa.aspx carry large numbers of user complaints of failed batteries. Now, I realize that any manufacturer who sells to the public and dares to let the public comment on their products will get complaint postings. And I haven't noticed similar postings on this board about Energizer Lithium cells.

So I'd like to ask directly: Have people here had failures with Energizer Lithium batteries? And if so, did they fail right away, i.e. could a few minutes' testing beforehand have detected the ones that were going to fail?

--best regards

[yousef]

I used them during my final DAT days when they were good for four shows whereas the best alkalines were only reliably giving me a full show (plus maybe another support set).

Never had anything unexpected happen but I would change them as soon as the battery indicator showed anything other than completely full.

Expensive though. And hardly environmentally friendly...

[kleiner Rainer]

Hi DSatz,

sounds like you bought a Mixpre D. I use rechargeables, in this case "Kodak" brand precharged ones for camera use. My reasoning is as follows:

- generating phantom power and power for the preamp means that the 2.4V to 3V of the pair of AAs must be stepped up.
- maximum phantom power requirement (two mics) is abt 1.5W (DC/DC losses included)
- I would estimate preamp power with another 1.5W (including LED meter and headphone)

This gives 1.25A, rather high for alkalines. NiMHs have typically a lower voltage, but also a lower internal resistance.
Energizer lists an internal resistance for its Ultimate Lithium of 90 to 160mOhm. For 1.25A, this gives a worst case loss of half a watt in the batteries alone!

For comparison: the Energizer NiMH 2300mAh cell is listed with an internal resistance of 30 to 40mOhm (3 to 4 times less than the Lithium...)
http://data.energizer.com/PDFs/nh15-2300.pdf


The Energizer alkalines are listed with 150 to 300mOhm per cell when fresh. The discharge curves end at 1A. I suspect Battery life is abysmal with 48V phantom power...

So my conclusion is: use NiMHs with as low an internal resistance as possible, especially with phantom power on. For the price of a pair of Lithium AAs you should be able to buy a set of quality rechargeables.

My 2 ct.

Greetings,

Rainer

who at the moment is listening to Bachs Toccata in F BWV540 played on the Silbermann organ in Dresden cathedral with a Mixpre D as audio interface and Sennheiser headphones