Battery driven gear - where does it end?

[microstrip]

Are you sure you had the proper Nagra approved batteries in the proper condition? How long could you operate it on batteries before shutting down?

I also owned the PLP and at one time the NiCd batteries were exhausted - it could not play for more than a few minutes without mains. As the distributor was on holiday, I got a 8 D cheap chargeable D cells from a shop. I could use the PLP for a few hours between charges but the sound was clearly of inferior quality even when played with the mains. Later I got the proper cells and the good sound come back. Perhaps if the PLP had a remote I would still own it ...

Edit - re-reading my my post it does not seem not clear. Please notice that the PLP should not be operated without mains - it was not designed to be operated that way. The batteries were used as filter, not to supply energy to the PLP. But if they could not stand for a about 4 - 5 alone hours they should have been replaced.

 

[untangle]

All about batteries (DIY audiophile perspective)

I have experimented extensively with batteries in line-level analog and digital components. My projects included a tube-based phono stage, a word clock, an RME Fireface AD/DA, and a highly-modified BADA Alpha DAC. I "progressed" in battery chemistries from lead-acid to ni-cad to lithium.

For background, the AC in my home is decent. I typically run line level components through some kind of P/C (e.g., isolation transformer) and my power amps from the wall - all on a dedicated 20a circuit.

Here are some of the things that I learned along the way:

• All batteries had a sonic signature, based on chemistry, state-of-charge, and capacity (all three matter)
• While lead-acid theoretically has the quietest chemistry, ni-cad/NiMH or Li often sounded "best"
• Charging is a pain, and differing strategies are req'd for each chemistry (I used outboard chargers for my experiments)
• Some components actually sounded cleaner at voltages well under nominal
• A well-designed AC power supply yields cleaner DC than a battery
• Was I hearing tube-like colorations from the batteries (i.e., less accurate but better-sounding)

I seldom use batteries in my audio gear these days, but now use them daily in my e-bike commute. So I continue to educate myself on chemistries and usage.

I would suggest that today's LiFePO4 batteries are the most advanced and versatile for power amps.

Here are links for 3 providers (DIY interest):

http://www.hobbyking.com/hobbyking/store/lithium_polymer_battery_configuration.asp

http://www.all-battery.com/144vnimhpackseries.aspx

http://www.pingbattery.com/servlet/the-12/48V-15AH-V2.5-LiFePO4/Detail

Bob

 

[Daveski]

... but now use them daily in my e-bike commute.

I'm an e-biker as well. Have been for a few years now. I don't use LiPo, NiMh, or LiOn though, as I find them way too expensive and finicky. I lug around 36V/7AH SLAs. They are cheap, durable, and very recyclable at EOL.

 

[Mosin]

I agree with untangle. Not all batteries sound the same.

Awhile back, I obtained a battery powered drive for a strain gauge cartridge. Like everything I own, I set about modifying it, this time by upgrading the batteries to ones with more current that would go longer between charges. Also, I increased the voltage, which was found acceptable by the units designer, Dave Slagle. Around that time, I learned that Frank Schroeder also owned one of the units, and that he also changed the battery scheme. I phoned him, and was told that batteries do not produce power as clean as one would imagine, and that adding a bypass capacitor to each one was a good idea. I added small high quality bypass caps, and I noticed a remarkable difference in performance.

Filtration of the battery itself may be why untangle heard differences between the battery types he has tried, and why different people hear different things when the mains are connected. That may be the missing link that explains the inconsistent results between different pieces from different manufacturers that you guys have been talking about. If you aren't getting what you expected, try some decent bypass caps. I believe you will notice a difference for the better. The brand Frank and I used is Roederstein.



Be aware that the lifespan of LiOn batteries is only two years. They aren't ready for prime time, in my opinion, whether you are using them for audio, or even to run a power drill. I'll stick with lead acid or nicads just for the cost and reliability, if for no other reason.

 

[egidius]

Many thanks for your extensive replies! Ill answer next week. Away on tour now, and not on my bike !
Egidius

 

[untangle]

I'm an e-biker as well. ... I lug around 36V/7AH SLAs.

You are hard-core, man.

Bob

 

[untangle]

This article is one of the better data sources for those interested in comparing battery and PS noise characteristics. (The whole article is interesting.)

But batt performance for audio isn't just about noise signatures. Voltage sag, output impedance, and heat buildup are all relevant too. No free lunch.

Bob

 

[garylkoh]

Thanks, Bob.

That link puts some solid measurements behind a listening test I did some 20 years ago with batteries and a battery-powered phono stage, and found that even different sizes of batteries sounded different. At that time, the best sounding turned out to be D-size EverReady Heavy Duty. NiCads sounded less dynamic and Alkalines sounded more grainy. DonH50 explained it to me with NiCads having a lower voltage than Alkalines.

 

[jkeny]

I use LiFePO4 batteries in my digital devices for which they are eminently suited - internal impedance ~ 8mOhm, low noise, 3.3V steady voltage output, 2.3A current output, easy to charge & 25 years lifetime according to manufacturers (A123) usage in electric vehicles.
There are some noise measurements from labs that I found a long time ago but I can't find them now. I would like to see LiFePO4 technology tested in that TNT report - I was always of the opinion that the battery noise under load was directly related to it's internal impedance. When powering an amplifier this becomes critical - the best sounding SLA batteries seem to have low internal impedance in the low mOhms.

 

[untangle]

More on battery types

I was always of the opinion that the battery noise under load was directly related to it's internal impedance

I believe that this is so, and the easiest way to lower impedance (other than chemistry) is to increase capacity (more parallel cells). This will also significantly increase longevity. but it adds cost and weight.

You can compare internal impedances - and a whole lot more - by perusing these charts. Note the terrific current delivery that NiCads delivery. Perhaps that's why my favorite audio battery was a NiCad pack from a vacuum cleaner!

Bob

 

[jkeny]

Interesting charts, Bob but I see the impedances are all above 100mOhm (includes the peripheral circuit?) - the A123 are specified as 8mOhm (I know this is better than most capacitors & also the impedance of any wiring has to be accounted for). This low internal impedances is probablt due to the nano-phosphate structure of the cells giving a very large reactive surface for the internal chemical reaction. The continuous current output is 70Amps with instantaneous of 120A. I reckon these should sound as good as the NiCds that you liked

 

[untangle]

Yep, I agree. And the A123 cells are the so good in other ways that they are clearly "what's best" IMO. (For e-bikes too.)

Bob

 

[egidius]

Thanks!

Yep, I agree. And the A123 cells are the so good in other ways that they are clearly "what's best" IMO. (For e-bikes too.)

Bob

Hi Guys,

I am back and was fascinated reading your staples of informations - thank you so much, especially untangle, to get this thread going.
When using the MIPA amp, I really went with the recommendations of Serge Schmidlin, nothing wrong in that at all. But then I got interested, what other peoples experiences are, and they seem to move away from lead batteries, where I still am, having first used Sonnenschein, but now CSB from the EVX series, using two 75Ah creates an extremely good sound.

I was interested to read about RWA developments into LiFePO4 batteries - but aren't those the ones that made the dreamliner get grounded ??

thanks, Egidius

 

[jkeny]

Hi Guys,

I am back and was fascinated reading your staples of informations - thank you so much, especially untangle, to get this thread going.
When using the MIPA amp, I really went with the recommendations of Serge Schmidlin, nothing wrong in that at all. But then I got interested, what other peoples experiences are, and they seem to move away from lead batteries, where I still am, having first used Sonnenschein, but now CSB from the EVX series, using two 75Ah creates an extremely good sound.

I was interested to read about RWA developments into LiFePO4 batteries - but aren't those the ones that made the dreamliner get grounded ??

thanks, Egidius

I hadn't heard about this so I looked it up & found this here http://translogic.aolautos.com/2013...n-batteries-ground-boeings-dreamliner-should/
"At the time, only lithium-ion cells made of cobalt oxide (CoO2) were deemed air-worthy. Since then, the FAA has approved additional cathodes, including the safer lithium iron phosphate compound (LiFePO4). LiFePO4 batteries are being used by some EV manufacturers like Chinese automaker BYD, who claim their Fe batteries offer "excellent safety performance" because of the material."

I knew that the LiFePO4 battery formulation was safe & not prone to explosion or fire, like other LiOn formulations. Charging is safe & can't create fires. Approval by FAA seems to confirm this.

 

[untangle]

I don't think that Dreamliner issues have much to do with the audio use case.

If you can tolerate weight and bulk (low energy density), SLA batts can do just fine.

Bob

 

[microstrip]

I don't think that Dreamliner issues have much to do with the audio use case.

If you can tolerate weight and bulk (low energy density), SLA batts can do just fine.

Bob

DartZeel uses four standard SLA batteries in their NHB18NS preamplifier. They should be changed every three year, but are inexpensive and easy to locate.

 

[untangle]

"At the time, only lithium-ion cells made of cobalt oxide (CoO2) were deemed air-worthy...."

Huh. Didn't know that. Lots of cobalt chem in laptops too. Times have changed. Phosphate is the new cobalt.

Bob

 

[jkeny]

Huh. Didn't know that. Lots of cobalt chem in laptops too. Times have changed. Phosphate is the new cobalt.

Bob

Well phosphorous is a very reactive element but the Ferrous Phosphate (FePO4) molecular compound conveys the stability. Making nano particles of FePo4 probably makes the reactive surface area much greater & is undoubtedly the reason for the high power density of the A123 cells?

 

[HAL]

About ready to try a 4 cell 40AH LiFeYPO4 cell pack with individual cell charging curcuit with my Dodd Audio tube buffer and shortly with the Dodd Audio stereo battery PA. I use a PI Audio Group BatteryBUSS for noise suppression. Will also work with my HAL MS-2 music server as it runs at 12VDC-19VDC.

Once I get the cell chargers setup will give it a go. Should be interesting.

Storage for the battery nice as it is at 80% charge after 16 months without a charge.

 

[HiFive]

Hal, welcome to WBF.
I have 100Ah AGM battery to power my battery gear:
Mac Mini, External hard drive.
Dodd Audio preamp.
Dodd Audio 2A3 PA.
And Pi Audio BatteryBuss.
I might give a HAL MS-2 a try.