Battery Power Our Systems?

I've been thinking....Dangerous I know! On another forum a fellow was reporting that he was using a Portable Power Supply (A LiPo battery in a box with a Pure Sine Wave Inverter) to power his system. He suggested that it got him totally away from the "Grid" and all its noise and distortion. I've done a lot of work and built a number of these +Solar Generators" for the Overlanding RV crowd and I know the best of the best still has issues with the inverter phase of the operation when used with delicate electronic equipment. This morning I'm reading a review in Stereophile about the "FE - HYPSOS"....A stand alone power supply to be used in place of supplied outboard power supplies. Very interesting article, BTW. So...I was thinking, with Li battery technology exploding as to amp-hours and limited voltage drop over its discharge cycle, would it be practical to build HiFi equipment that runs on 12, 24 or 48V DC and do away with the whole AC to DC conversion in the equipment. You would charge up your LiPo battery at night from the grid, or during the day while at work off solar, and run your system for hours when needed. Pure, Clean, Voltage stable DC power...No grid connection during play. Wouldn't this drastically reduce the cost of components if they didn't need elaborate power supply filtering etc? LiPo batteries are relatively light weight, have huge amperage discharge available and have life spans of 20+ years with the ability to be recharged thousands of times. Current Lithium batteries don't catch on fire like older batteries did...So don't go there. One LiPo power supply unit could run the entire system rather than multiple power supplies in each unit. Yes-No.....Go back to bed?

I'm looking at it as not only a noise/performance issue (as many folks have really horrible grid electricity or live in apartments with outdated infrastructure)......But also as a manufacturing cost savings and weight saving for shipping. No heavy toroidal transformer and extra heat sinks. Shipping cost have become a huge part of the cost of manufactured goods.
 

Pano

diyAudio Moderator
Paid Member
2004-10-07 6:05 am
SW Florida
Yes, I understand. Re-reading your makes that clear, you want pure battery power.
Of course this has been done for over 140 years, as the first audio (telephone) systems were battery powered. Mains power is just more convenient.

It's true that batteries have gotten much better recently which makes log run times of audio gear from batteries easier. I suppose many of us here have built high performance systems that run on battery. Or at least parts of systems. I've done mostly DACs and small power amps powered by battery or by solar cell.
 
When you say "Our Systems", that's a pretty wide swath. Some like class A, others like heating up a quad of 6550s and burning a lot of quiescent current. Run time will be an issue for those demanding that level of performance.

For those of us that can tolerate Class D throughout the audio range, that's more doable. I can run mine off batteries - still, not indefinitely, but more like at a comfortable listening level for as long as I probably ought to be listening in a single session.

Performance. I recently read in another forum "I'll never buy an EV until they can hit 700 miles and recharge like a regular fill-up". Someone will always need to listen for another hour longer than any battery can do.
 

Pano

diyAudio Moderator
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2004-10-07 6:05 am
SW Florida
Yeah, with today's batteries it should not be much of a constraint for line level devices and digital sources (or radio). It's those pesky power amps that pose a challenge.

This makes me wonder what sort of audio noise problems there were back in the 1870s and 80s before AC was everywhere in everything. Was hum and buzz just not a problem?
 

rif

Member
Paid Member
2003-01-27 2:36 am
South NJ
I've used batteries on phono preamps, low current draw. Figure when you're under 1mv everything counts.

Do Pass ACA builders try it? Isn't it DC input already, right?

@koda- never thought of that, wonder if telegraphs in the 1800s sent full DC voltage for miles of wire to power an electromagnet.
 

kodabmx

Member
Paid Member
2011-10-31 1:00 am
Toronto
I assume they sent DC across the wire but it was pulsed (Morse code) and low enough voltage to be "safe". As long as there was enough current to run the magnet, it would work. There were probably mechanical repeaters for long runs, too. There are many members on here that are older than I am and might know the technical specs...
 
@kodabmx - there were repeaters for Morse code. I used to have one when I was a kid, just as a shelf display. Worked just like a SPST relay, but totally steam-era construction; brass parts, mahogany platform, cast iron base. I imagine it sat in a box with several dry cell batteries, to kick the, er, digital signal on down the line. I've no idea how often they needed one of these - nor what factors you had to consider in designing a system that went for, say, 50 miles. Maybe how often some guy had to ride out into the middle of nowhere and change the batteries!
 

Pano

diyAudio Moderator
Paid Member
2004-10-07 6:05 am
SW Florida
Before there were vacuum tubes and triodes, there were audio amplifiers! To amplify a telephone signal they used a sort of speaker coupled to a microphone. Or an earpiece coupled to a carbon mic. It can not have sounded good, but it did amplify current.
 

Arez

Member
2020-10-16 10:16 pm
With the EXCELLENT power supplies we can build today, I find it nonsense reverting to batteries based on supposed advantages.

And including inverters or any kind of switching in the equation even more.
With the emphasis on CAN maybe.
Because most products you buy will have a noisy, badly designed SMPS's from China. Also theyre "floating zero points' can cause headaches as noise, and induced voltages if circuit design is improper etc.
The general trend in electronics and electrical equip, is to mfg it as cheap as possible for max profit and skimp down on everything possible enough that it survives its warranty by a small margin.
And Switch Mode Power Supplies are not used because they are excellent in any way except for low weight/size/price for the power delivered and cheap to mfg.
And to make good power supplies has been done for a very long time.

Batteries are a good source for signal handling and will exclude noise from the general power grid, which is a issue some places. Even locally in some places because of fluorescent lights, cheap 1$ power supplies etc.

As for the use of inverters i agree completely, but it can be done in a proper way too.

Batteries of course has it's usual drawback of maintenance cost, replacing batteries, checking theyre conditions etc. Takes up a lot of space and weight anywhere theyre used if any real capacity or voltage is needed.


Fx: ASR Audio Emitter Exclusive amplifiers, that use battery power for the signal handling in the amp. Very well engineered and made example of a commercial high end amp using battery power, although just for part of the product.
The separate battery supply unit is an extra 33 kgs or so though, to just supply the 'preamp' part of it.
 

PRR

Member
Paid Member
2003-06-12 7:04 pm
Maine USA
1870s and 80s before AC was everywhere in everything. Was hum and buzz just not a problem?
Audio amplification didn't exist yet. The first triode didn't come until 1906, right?
There were amplifiers long before triodes. A telephone is almost impossible to use without amplifiers. Practical telephony came with carbon transmitters (microphones), which take sound and DC to make strong audio. Acoustic To Electric amplification. As Pano says, combining this with a receiver makes Electric To Electric amplification. Which I suppose makes hum/buzz a lot worse.

But even with just carbon mikes, the racket of lighting static on long lines could spoil communication. Even in teleGRAPH! Run a line across New Jersey, or Kansas, in-season, the code clacker will jump non-stop until the storm passes. This is when Balanced Lines were discovered.

With the rise of electric power, even DC (typically dirty with commutator hash and starting surges) but also AC, balanced became essential and pair transposition became a Big Deal.
 

Pano

diyAudio Moderator
Paid Member
2004-10-07 6:05 am
SW Florida
Lightening - of course!! for sure that will cause big noise in long lines.

Speaking of the telegraph circuits, some years ago I was watching the John Sayles film Amigo in which there is a scene of stringing telegraph lines across the Philippines. I noticed they were stringing just one wire. I thought "that can't be right, one wire? How's the current going to flow?" So I looked it up, and by golly, return current flowed thru the earth! Just one wire and earth. Battery power. Of course I had to try with audio. It works! And that led to my infamous experiments running audio thru mud, potatoes, bananas and so on.

FWIW, there seems to be a whole lot of 60 cycle and harmonic noise in the ground. Hard to get away from, batteries or not.