[rollo]

   After hearing some battery powerd components at the recent RM event iIam curious to know the advantages and dis advantages of each method of powering our gear.
   Noise ? dynamics ? Cost ? Converting existing gear ? With the green thinking these days why would not all manfs be o the wagon ?



charles
   

[srb]

With the green thinking these days why would not all manfs be o[n] the wagon ?

Probably because a battery's life is limited to a finite number of recharge cycles and will require periodic replacement.  Although some get recycled (costly) due to non-enforcable regulations, the majority still get disposed of as toxic waste in landfills.
 
Batteries are one of the few good solutions to power portable devices, but for stationary devices they are the opposite of green thinking.
 
Steve

[JerryLove]

Agreed: Battery powered is about as far from green as you can get (perhaps when someone makes a gas-powered amp we can compare).

If you are worried about line problems from the grid: there are options to clean it up. The purpose of batteries is to make things portable (and to sit in reserve as aux power in brown-outs / black-outs).

[dBe]

Charles, what a can-o-worms you just opened up! 

Battery power is not for everyone.  Is a Chevy Volt green?  Uh, no... not really.  Same for the Prius and any other vehicle that uses batteries for go-power.  But we aren't talking cars here, we are talking audio so the animal is different.  Every power source has its' up and down sides.

DANGER!!! Gross Simplifications Ahead.

Grid power - becoming more and more polluted with grunge, dirt, crapola, noise - whatever you want to call it from all of the RFI floating around and the implementation of digital monitoring in smart grids and EMI from motors, heaters, coolers etc.....  I would personally like to thank all of the people that are putting this junk on the lines.  That is how I make a living....  Moving on > It can be spotty and there is always the possibility of surge issues from lightning, switching, etc.  Relatively low impedance to the input of gear and it has great reserves for for dynamics in our systems.  All around a pretty good source when cleaned well and handled properly.

Battery power - different noise components from the chemical reactions that are doing the work.  Not very efficient in a conversion context. Batteries can also have high output impedances that limit dynamics.  The BIG BUT is that it can be very quiet and very dynamic when properly massaged.  Most DACs and sources can/will run very happliy on 12VDC.  Pretty much battery power is immune to the EMI/RFI that is the bane of good audio.  It is a PITA to get the proper battery/charger setup.  I personally think that the best sounding batteries are the LiFePO4 batteries, but won't use them because of the potential for disaster when improperly implemented.  Remember the notebook computers that instantaneously ignited?  Bad ju-ju.  I use AGM batteries and Ctek chargers because they are safe and easy to use.  How many handicap scooter explosions have you heard of?

The sonic benefits of battery power is a dead silent noise floor when properly done.  The dynamics can be muted if there is not enough current capability.  This can be done several different ways:  High capacity batterys are the deal here.  There are other ways to improve the dynamics.  Car guys have been using stiffening capacitors for years.

It is all a trade-off.  AC and DC have their own strengths and weaknesses.  Tesla and Edison argued about it for years.  Being a power guy I fall on the side of silence.  I produce AC power products, yet my system is predominantly battery powered.  Go figure...   

Dave

[jtwrace]

The sonic benefits of battery AC power is a dead silent noise floor when properly done.

[HAL]

Dave,
The laptop fire was a Lithium Polymer battery with high output impedance.  Those have to be charged in a fire protective bag in a home environment.

The LiFePO4 chemistry is used in automobile applications as it does not catch on fire.  They do not need protective bags for recharging.  These are very low impedance devices like AGM batteries.

I have been using the A123 chemistry LiFePO4 batteries for a few years with audio gear.  Their lifetime is between 10-15 years from what I have seen.  Think that works for most product lifetimes.

To destroy a LiFePO4 battery, you put it in a bucket of salt water for a few days.  Passivated and ready for the land fill.  Less hazmat than AGM's.

[JerryLove]

Lifespan is usually in charge cycles not years.

Rechargeable batteries get their power from the grid: so cannot be more efficient than direct.

Dirty power on a line can be conditioned. A battery is kind of like a funny capacitor. Power goes in, waits, and comes out.

[dBe]

Dave,
The laptop fire was a Lithium Polymer battery with high output impedance.  Those have to be charged in a fire protective bag in a home environment.

The LiFePO4 chemistry is used in automobile applications as it does not catch on fire.  They do not need protective bags for recharging.  These are very low impedance devices like AGM batteries.

I have been using the A123 chemistry LiFePO4 batteries for a few years with audio gear.  Their lifetime is between 10-15 years from what I have seen.  Think that works for most product lifetimes.

To destroy a LiFePO4 battery, you put it in a bucket of salt water for a few days.  Passivated and ready for the land fill.  Less hazmat than AGM's.

I stand corrected on the LiFePO4 issue.  I get that part.  I was speaking too generally there.  My bad.     The potential for disaster that I was thinking (or not - way too many thoughts at that moment) about is the battery balance issues in charging and cells dying, money flying, etc, etc...  Battery management for many people is a PITA and I be one o dem guys.  That is why I am an AGM proponent for most applications.

Dave

[dBe]

A battery is kind of like a funny capacitor. Power goes in, waits, and comes out.

I love that comparison.   

Dave

[jules]

There's batteries and there's batteries ... The deep cycle acid/lead type traditionally used in stand alone solar installations can last up to thirty years [I'm using some that are past that age and still working perfectly]. At the end of their usable life the lead can all be recycled. If the power comes from the sun the "green" case gets more interesting though I guess the original post is directed more at the question of audio performance.

Battery v grid? I think it might depend on the quality of the grid supply where you live but there's some fantastic technology around these days to make battery systems as good as or better than the grid in terms of reliability, freedom from surges, voltage irregularities and the various other forms of  interference.

jules 

 

[silver_strings]

T-amps that are powered by batteries defintely sound better than with even a linear power supply

[HAL]

I stand corrected on the LiFePO4 issue.  I get that part.  I was speaking too generally there.  My bad.     The potential for disaster that I was thinking (or not - way too many thoughts at that moment) about is the battery balance issues in charging and cells dying, money flying, etc, etc...  Battery management for many people is a PITA and I be one o dem guys.  That is why I am an AGM proponent for most applications.

Dave

Dave,
I agree, but there is new technology to deal with that issue.  There is a per cell battery monitoring and charging system for LiFeYPO4 battieries that I have to install.  Just hook the pack up to a power supply and they monitor charge and balance for each cell individually.   This is used in the car systems, so that it is fully automatic.

I checked the 40Ah LiFeYPO4 4 cell battery that was fully charged in October 2011.  Even after some small uses, still at 80% charge in November 2012 without any recharges!  That is cool!

I just need to retire to have more time for fun projects! 

[mikeeastman]

Jules, what brand and type of batteries are you using that can last 30 yrs? I did solar installs for 18 yrs and the guy that taught me did them for over 40 yr and the longest any battery bank lasted ,we ever saw was 15-16 yrs and that was with forklift batteries that were used very lightly and that was very rare.

    Mike

[rollo]

  My main concern is sonics. I have zero issue with noise as we use one Uberbuss for Amps and one for all else. My concern was more related towards sonic differences, meaning PRAT, dynamics and tonality.
   If a battery stores waits and releases power it would make sense to use capacitors to feed the juice instead of from the battery. I guess that is where a Batterry Buss would enter the picture.
    After hearing the Dodd gear  the RM with GR speakers it was dynamic and so on however what would it sound like if fed from the grid ? I really like the idea for source and preamp, just not sure about amps or sub amps.
   Is using both the answer or just one over the other for all applications ??


charles

[JerryLove]

Someone remind me what the difference between the power conditioning done by a battery and the power-conditioning done by a capacitor (like the ones sitting in your power-supplies).

[werd]

The lithium in laptops make for great off grid isolation especially from the amps. Batteries in pre amps interest me.I see an isolation between the front end and amp. Sonic advantage in terms of noise. I would like to give the Dodd a whirl.

The best isolation I have experience is with using a TPV pre. The primary and secondary windings completely separate the front end from the Amps. Well so long as your amp is on a difference circuit.

[jules]

Mike, they're Exide 500Ah, 2V ex telco batteries. I think it's probably a case of survival of the fittest, in that these batteries were still passing their performance tests for the telco at twenty years when others of the same age had died. As a home power supply they are never discharged below 24V [12 X2] and even that low is quite rare. I guess it's not fair to claim these as a standard for performance in that they could well be the last of their breed still going.

Rollo, I don't know what the battery BUSS does but as I understand it, a battery bank, being a very big capacitor is also a low pass filter so it needs smaller caps in parallel with it to pass the higher frequencies if you're using the battery power supply direct to your equipment [and excluding the caps in a normal in-built power supply]. If you use an inverter to change your battery DC to the same voltage AC as your grid supply, the caps in any standard grid type piece of equipment should do the job.

jules

 

[dBe]

Mike, they're Exide 500Ah, 2V ex telco batteries. I think it's probably a case of survival of the fittest, in that these batteries were still passing their performance tests for the telco at twenty years when others of the same age had died. As a home power supply they are never discharged below 24V [12 X2] and even that low is quite rare. I guess it's not fair to claim these as a standard for performance in that they could well be the last of their breed still going.

Rollo, I don't know what the battery BUSS does but as I understand it, a battery bank, being a very big capacitor is also a low pass filter so it needs smaller caps in parallel with it to pass the higher frequencies if you're using the battery power supply direct to your equipment [and excluding the caps in a normal in-built power supply]. If you use an inverter to change your battery DC to the same voltage AC as your grid supply, the caps in any standard grid type piece of equipment should do the job.

jules

 

Jules,  the BatteryBUSS is more or less a 12V battery management/filter/impedance matching device that also provides 5A of regulated DC @ 5V.  There are 3 outlets standard on XLR and 2 - dual (5V&12V) voltage TinyXlr.

Batteries are inherently much quieter than AC, but still suffer from reaction noise.  I have a filter in there to eliminate that, a bank of selected VLESR capacitors with HQ PP bypasses and and a LT 1084 5V regulator.  There is also an On/Off switch and a circuit breaker protected reverse polarity safety for those of us that are RG colorblind.  Output impedance is < 0.01 ohms and it will dump current at about a 40A rate if someone gets dumb and shorts it.  There is no "uh-oh" protection.  Things have changed since the originals internally but the external configuration is basically the same as these prototype pics:





Dave

[HAL]

Just some math fun and battery specs.

A 12VDC, 100Ah AGM battery is the equivalent to a 30000 Farad capacitor.   The typical internal resistance of the same battery is 0.0025 ohms at full charge.

Discharge rate around 400 Amps.

Try finding an AC power supply with those ratings!

To check my math:

C = Q/V, where Q is 1A@1sec, C in Farads, V in Volts.

C = 100*3600/12 = 30000

[Vinnie R.]

Hal,

A 12VDC, 100Ah AGM battery is the equivalent to a 30000 Farad capacitor

It doesn't quite work like this because you have to keep in mind that the voltage will drop as the capacitor discharges. So half the charge is half voltage (12/2 = 6V).  With a battery (e.g. SLA) that's different because a battery that is half empty still has nearly the same voltage as it had fully charged (unlike a capacitor)...

If you are going to be storing that much charge, a battery is the way to go.  Capacitors are great at much higher voltages, though (where it's a bitch to build a high voltage battery and charge/equalize it)...

Cheers!

Vinnie