Battery Power

[Kingrex]

@Kingrex

I have a Victron off-grid battery based system with solar charging. It is setup for the entire office, which just happens to be where the system also resides. It is certainly better sounding during the day even when solar charging is concurrently occuring, when compared to running off the grid power, but is better at night when the sun is below the horizon. Our grid here in Australia is likely much more consisent than in the US.

There is a huge balanced isolation transformer not yet connected to the circuit which I expect will reduce or eliminate the sound disparity that occius when the sun is out. Others experience with this custom transformer has been transformative (pun intended). It uses inductive and capacitive filtering post the transformer to further attenuate any noise, and I would not be surprised if it also improves sound at night.

LiFePO4 batteries 19.2kW @ 80% DOD
9.36kW solar, mostly using microinverters
Victron 48/10000 10kW inverter
Completely off-grid
When balanced isolation transformer is connected a separate earthing rod will also be connected.

System is mostly tubes and horns and draws a consistent almost 2kW mainly due to the pair of six channel SET amps that (of course) run in Class A, not to mention the tube dac, tube phono, DHT preamp and all the other solid-state electronics. On work days the off-grid system also runs six computers and the air-conditioning.

It's now been raining here for two days straight and the system is down to about 60% battery remaining. There have been a few patches of sunlight but not many, and the audio system runs about 15 hours every day.

Great feedback acg.
Couple questions if I may.

Currently, do you have any filters at the wall feeding the audio equipment. A Shunyata or Puritan or anything.

How far is the inverter from the room it serves.

Did you ground the inverter frame as well as the battery negstive terminal.

I assume you have 5 x 100 AH batteries. Are they rack mount. Victron? What brand.

Your 230 volt 50 hert. So about 40A output from the inverter.
Do you have a dedicated panel to provide branch circuit protection.
Did you go through a RCB and all the normal overcurrent protection?. In other words, is the panel from the inverter feeding the room the same as the panel feeding circuits to the room from utility power.

Did you do anything special for the branch wires from the inverter to the room like oversizing them? Again, are they the same as what wires are coming from the utility power?
Or, by utility power, do you mean the utility passes through the Victron to the room and your using software to tell the inverter to disconnect from the utility and only use the battery when listening.

Thanks
Rex

 

[Kingrex]

So, no need for central heating then? What about air conditioning in summer?

It still seems rather counter-intuitive to start with DC (from the battery, however it is charged), then convert it to AC, and then back to the DC that the amps require.

A few amp brands (Naim for example) have a choice of power supply options. As they stand, the house AC is connected and the internal power supply converts to the DC voltage required by the electronics. At a big extra cost, an extra box can be added that is effectively an external power supply that does the AC-DC conversion away from the amp's electronics. There is a cable between the power supply and the amp to carry this DC. Why shouldn't one mimic this arrangement by sending DC from a battery directly to the electronics, this avoiding DC > AC > DC conversion?

I appreciate that tube amps require more than a single DC voltage so this sort of power supply wouldn't work, but with ss it should be a preferred method if hum and RFI--free sound is the reason for looking at alternatives to house AC.

Please don't derail the thread. No one is breaking open their VAC, CH Precision, Gryphon, preamps, phono stages etc and bypassing the input power supply. Start a thread on hot rodding your equipment with DC power to pursue this. Thanks.

 

[acg]

So, no need for central heating then? What about air conditioning in summer?

It still seems rather counter-intuitive to start with DC (from the battery, however it is charged), then convert it to AC, and then back to the DC that the amps require.

A few amp brands (Naim for example) have a choice of power supply options. As they stand, the house AC is connected and the internal power supply converts to the DC voltage required by the electronics. At a big extra cost, an extra box can be added that is effectively an external power supply that does the AC-DC conversion away from the amp's electronics. There is a cable between the power supply and the amp to carry this DC. Why shouldn't one mimic this arrangement by sending DC from a battery directly to the electronics, this avoiding DC > AC > DC conversion?

I appreciate that tube amps require more than a single DC voltage so this sort of power supply wouldn't work, but with ss it should be a preferred method if hum and RFI--free sound is the reason for looking at alternatives to house AC.

Does not get cold here, so no central heating. The only reason an air-con is needed in the office is the six computers and 50 odd vacuum tubes radiating heat, and even then it is really only spring and autumn when the sun is low enough to beam directly into the room. In summer, most days, air-con is not required.

I built my tube gear from scratch and have thought a lot about doing away with the power transformers but when you get into the detail power transformers are useful noise filters, particularly the EI type, and are not a hindrance to sound quality. Lowish voltage DC kills people, think 50 volts, and I would not want that distributed through my room at say the 440vdc that my tube gear needs or even 48v that some of my SS gear needs. Great way to start fires and it gets you nowhere because that 48V has to be changed to 5v, 12v, 15v, 36v or whatever the other parts of the gear requires at specific parts of the circuit, which is potentially more harmful to sound than an AC power transformer especially if regulated converters are used.

Anyway, that is all I will say about it as @Kingrex has asked.

 

[acg]

Great feedback acg.
Couple questions if I may.

Currently, do you have any filters at the wall feeding the audio equipment. A Shunyata or Puritan or anything.

No filtration from the wall feeding the audio equipment, but the power supplies of my gear are very well designed and are well filtered. The balanced isolation transformer and subsequent AC filtration should, on paper, remove AC noise from the inverter.

When I first installed the dedicated circuit to the office years ago the new wires had to push up through a narrow space bunched in parallel with all the wiring for the house...think a bunch of wires 200mm/8inch in diameter running parallel for a few metres. Without connecting my dedicated line at either of the ends, I could measure 16V of inducted power in that line, which is a huge amount. It varied and jumped higher and lower but 16V was about the middle. This is probably an a problem in many houses and is the reason that when the off-grid system was installed the dedicated line was re-routed such that it is not in proximity to any other wires for any distance.

How far is the inverter from the room it serves.

It would be about 25m or 80 feet.

Did you ground the inverter frame as well as the battery negstive terminal.

Not sure. The installation was done by a certified electrician to meet all the state and federal regulations. I did not install it myself.

I assume you have 5 x 100 AH batteries. Are they rack mount. Victron? What brand.

Installed are 6 x PowerPlus Energy 4.0kW batteries in a rack

Your 230 volt 50 hert. So about 40A output from the inverter.
Do you have a dedicated panel to provide branch circuit protection.
Did you go through a RCB and all the normal overcurrent protection?. In other words, is the panel from the inverter feeding the room the same as the panel feeding circuits to the room from utility power.

The inverter is set to output exactly 240v as this was the standard mains voltage in my area when I started building my amplifiers. With more people in the area and a huge uptake in rooftop solar power the nominal voltage here was dropped to 230V (it was supposed to be 230V all along, but never was) which negatively impacted the unregulated power supplies in much of my gear. Having the voltage always at 240V means my operating points are always hit perfectly and tube bias does not wander like it started to with lower mains voltage then highe mains voltage when everybodies rooftop solar was piling into the grid and then falling again when the clouds came over.

The entire off grid system including batteries, inverters, chargers, safety and circuit protection are in the one cabinet which is physically and electrically separated from the remainder of the house wiring apart from, at the moment, sharing the same ground rod. Once the balanced isolation transformer is included in the off-grid circuit, the off-grid will shift to its own ground rod. The balanced isolation transformer sits in its own cabinet adjacent to the off-grid cabinet and the ac filtration in another cabinet adjacent to the iso-trans cabinet.

Did you do anything special for the branch wires from the inverter to the room like oversizing them? Again, are they the same as what wires are coming from the utility power?
Or, by utility power, do you mean the utility passes through the Victron to the room and your using software to tell the inverter to disconnect from the utility and only use the battery when listening.

Thanks
Rex

The wires between the inverter and room are a normal variant used to wire every home, just the largest gauge wires I could find so that resistance losses are minimised. I think they are 6mm2.

Just to be clear, the Victron is run entirely off-grid and has no connection to the mains power other than sharing a ground rod. The Victron inverter receives solar generated power whenever the sun is out so the batteries remain charged.

 

[Kingrex]

Personal musings here.

I was engaged in some brain drain TV watching. A concept was presented where a character was saying how their creative nature leads them to seek new challenges.

It hit me as to why I'm so spun up on battery/Inverters. I proved to myself how valuable good power is. How important shedding aluminum from the power supply is. I'm satisfied. I get it. It's been resolved in my mind. But where to go from here

A new to focus . But what is it. I love electricity and powering stereos. But what else is there for me. Where is the new challenge.

Ahhh, battery and Inverter. I'm convinced utility power is flawed on many levels. Noise from loads on the grid. Noise from RF attaching to power lines. Noise from low quality load centers. There is only so much an all copper power supply can do. Copper does not fix dirty utility power. You have to break away from it. The how has perplexed me for some time. I did spend energy researching a electric belt driven generator. Basically a 5 to 10 hp electric motor spinning a high mass flywheel attached to a generator motor. Too difficult. No industry support and development.

Now the path is clear to me. Inverters are maturing and only getting better. The market and products are expanding as the world turns to solar. Batteries are improving and getting safer every day. Its a logical direction. And more and more anecdotal reports are saying it can be better than the wall. But how good was their wall. Well heck. A guy with a $1200 Goal Zero compared it to my wire and proper installation into a stock loadcenter. Pretty much the pinnacle of NEC code compliant residential grade installations. And everything I hear says there are 2 levels of improvement from where he's at. I actually think its 3 as I have ways to step beyond what is stock using Benjamin products.

I have to prove it, but I have a very strong feeling grid power will go to the sidelines for the best stereo out there. Really any stereo. But its not inexpensive. And it takes room to achieve the pinnacle for high power systems. Low power, 250 watt and less will be much less expensive and much smaller.

 

[Kingrex]

For example. This needs a second 5000 watt inverter. Ditch the Autoformer. Use better battery cables and busbar. You don't need so many batteries. Add a Benjamin distribution panel. This is roughly what it takes.

 

[Chrisl]

Yikes. That's a lot of equipment and space. Strong argument for battery power though...

 

[Kingrex]

Yes Chrisl.
These setup can be beefy. ungodly amounts of.power. But its space. And a large out of the room setup requires a plaquard at the electrical meter as well as a remote shutoff in case the house is on fire and the fire department wants to shut of power to spray water and not be electrocuted.

This next picture is much more compact and good for a 250 watt amp and front end gear. A bit of a sloppy install. But hard to make look neat. Thats part of what I am trying to work out. Article 90 of the NEC. Neat and workman like maner. This should not need a plaquard or remote shutoff.

I don't like these type high frequency inverters. But it can fit in the room. And it needs a fused AC cord of required length to get a power strip behind the rack with the inverter off to the side.

Only needs 1 x 48 volt battery. Thats twice the stored power of the 2 batteries on the floor in the picure. And a 48 volt battery will discharge a higher instant current to the inverter.

 

[adyc]

How much battery capacity are you thinking of? 5, 10 or 20kwh?

 

[Kingrex]

For a small in room system, or even on a rack, I would start with 1 x 48 volt 100AH battery per 5000 watt inverter. That is 4.8KW per 5000 watt inverter. 48v x 100AH.

If your exhausting 400 watts static power and you take the battery down to 20% before shutoff, thats 9.6 hours play time. Technically this is not true due to inverter losses. Lets say the inverter looses 10%.. You still have about 8.6 hours per battery.

If you started with 2 batteries, you would actually extend the life of the batteries as you would only draw them down about 40% with 8 hours play. They generally will recharge 5000 times. A 5000 cycle life battery, deep discharge to 20% remaining, are supposed to still charge to 80% of new. If you had 2 and only took them down to 60% charge remaining, you would probably get 10,000 to 15 000 cycles. And they would still be recharging to 80% of new.

10,000 cycles divided by 365 days is 27 years. And they are still recharging to 80%. Honestly, you will burn through 2 to 3 inverter in that time depending on how hard you drive them.

 

[adyc]

4.8kwh is not enough for class A gryphon amps. Maybe it is enough for SET amps. High power Gryphon class A monoblock can draw 1kw at idle. If I listen to music for 10 hours, the battery at least must have 20kwh.

 

[Kingrex]

4.8kwh is not enough for class A gryphon amps. Maybe it is enough for SET amps. High power Gryphon class A monoblock can draw 1kw at idle. If I listen to music for 10 hours, the battery at least must have 20kwh.

Parallel up to 6 inverters for 30,000 watts. Lets say you get 3 inverters x 5000 watts each for 15,000 watts. At 120 volts thats 125A on the panel bus. A 20A CB for each mono and 2 for the front end. 3 batteries is 4.8 x 3 = 14.4kw. X .7 for inverter loss and 20% remaining in charge is 10.8kw.
2 x 1000 per mono and 400 for the front end is 2400 watts dissipating power. So 10,800/2400 = 4.5 hours play. Each additional battery gives roughly 1.5 hours additional play.

You can build any size system you want. You can parallel 6. But you can parallel 2 sets of 6 at 240 volt so you could have 240 volts of 250A per phase. Thats more power than my industrial SQD NQ all copper panel is rated for. That panel is 225A MLO. And it is used to power large motors, drives, pumps, data centers.

You can't build a stereo a battery system can't power. There is intense growth in the industry designed around off grid use for residential and commercial use. Solar is much larger outside the USA. Were not really aware whats going on. Victron looks at the USA as a small market. Most of their equipment is 230 volt 50 hertz.

If your gonna go that large, you can put a solar array on your roof and get the government credits, charge the batteries for free and sell back excess power. Costs a lot more. Maybe adds $20k to $30k. The government seems to keep it so the payback is around 25 years. Just about the time your system needs to be replaced. Sort of like putting $30k up front and 25 years later you got your money back. Of course. $30k in the market for 25 years would be $80k in the bank. So its not really a gain. Its just doing good because your wealthy and you can.

 

[Hear Here]

I have a very strong feeling grid power will go to the sidelines for the best stereo out there. Really any stereo. But its not inexpensive

Batteries have been around since single-DC-voltage transistor-powered audio gear overtook tubes.

You have to ask yourself why (apart from one or two companies such as Red Wine), no major brand has decided to go the battery route. As I mentioned before (and you scoffed at me for doing so), a few top brands have gone part way in that they offer external power supplies usually as an option, but they still start with grid AC.

Like you, I can't understand why battery power isn't favoured over mains power and conventional (normally built-in) power supplies. I think you really need to do more research and establish why the top brands, where price is no object, still choose to do the AC-DA conversion within the enclosure, or occasionally in an external enclosure. No one uses batteries - so you need to find out why, before extoling the theoretical virtues (and I agree with you 100% on this) of battery power. I've accepted that I must be wrong (as I think Red Wine has) as otherwise top brands would be using them - wouldn't they?

Perhaps have a conversation with Vinni Rossi as he has taken that route in the past and abandoned it. Ask him why. I'd be interested too as a former owner of one of his amps and an advocate of the aparent advantage of DC from start to finish. But I would be dead against AC > DC > AC as one of your ideas seem to suggest. Good luck.

 

[Kingrex]

Batteries have been around since single-DC-voltage transistor-powered audio gear overtook tubes.

You have to ask yourself why (apart from one or two companies such as Red Wine), no major brand has decided to go the battery route. As I mentioned before (and you scoffed at me for doing so), a few top brands have gone part way in that they offer external power supplies usually as an option, but they still start with grid AC.

Like you, I can't understand why battery power isn't favoured over mains power and conventional (normally built-in) power supplies. I think you really need to do more research and establish why the top brands, where price is no object, still choose to do the AC-DA conversion within the enclosure, or occasionally in an external enclosure. No one uses batteries - so you need to find out why, before extoling the theoretical virtues (and I agree with you 100% on this) of battery power. I've accepted that I must be wrong (as I think Red Wine has) as otherwise top brands would be using them - wouldn't they?

Perhaps have a conversation with Vinni Rossi as he has taken that route in the past and abandoned it. Ask him why. I'd be interested too as a former owner of one of his amps and an advocate of the aparent advantage of DC from start to finish. But I would be dead against AC > DC > AC as one of your ideas seem to suggest. Good luck.

Inverters provide AC power. I am not changing anything ouside altering the mix of sources the AC is derived from. I am using a single very clean source.

 

[wil]

Batteries have been around since single-DC-voltage transistor-powered audio gear overtook tubes.

You have to ask yourself why (apart from one or two companies such as Red Wine), no major brand has decided to go the battery route. As I mentioned before (and you scoffed at me for doing so), a few top brands have gone part way in that they offer external power supplies usually as an option, but they still start with grid AC.

Like you, I can't understand why battery power isn't favoured over mains power and conventional (normally built-in) power supplies. I think you really need to do more research and establish why the top brands, where price is no object, still choose to do the AC-DA conversion within the enclosure, or occasionally in an external enclosure. No one uses batteries - so you need to find out why, before extoling the theoretical virtues (and I agree with you 100% on this) of battery power. I've accepted that I must be wrong (as I think Red Wine has) as otherwise top brands would be using them - wouldn't they?

Perhaps have a conversation with Vinni Rossi as he has taken that route in the past and abandoned it. Ask him why. I'd be interested too as a former owner of one of his amps and an advocate of the aparent advantage of DC from start to finish. But I would be dead against AC > DC > AC as one of your ideas seem to suggest. Good luck.

I use the Taiko Olympus battery powered server.
The positive impact of this battery supply on the sound quality is very apparent.

Perhaps there are some insights to be gain by looking at their application?

From what I’ve read, they are using lithium titanate oxide batteries that can supply 1000++ amps of instantaneous current.

 

[Kingrex]

@Hear Here
Are we on the same page now per my post #74?
Additionally, the reason we don't see a lot af audio systems using a single dedicated AC source derived from a inverter that is using a battery as a storage medium has many reasons.
First is that batteties and invertets like everything have a signature that can be heard through audio equipment. Lithium batteries I am told sound much bettet than led acid. The inverter has a signiture too and those have improved wih much lower distortion and reliability.

Second they take room. Look at Stromtank. People love it. But its big.
And while on Stromtank, third is cost. They ask $32,000 for something that can't power an amp. But they have shown a cheap Chinese inverter in a fancy box with a lithium battery sounds very good on front end gear.

I am focused on powering amps and the front end.

 

[Rumpole]

Perhaps have a conversation with Vinni Rossi as he has taken that route in the past and abandoned it. Ask him why. I'd be interested too as a former owner of one of his amps and an advocate of the aparent advantage of DC from start to finish.

Yes, it would be interesting to here from the people who build the amps why they don't use batteries. I wonder if Nelson Pass has explored this. He might say that AC power is good enough, so there is no need to add to the cost with a battery power source? darTZeel uses a battery power supply for their preamp, so there is one example.

You could easily run your Atma-sphere Class D amps on a battery. I have an Ecoflow Delta 2 Max and a GrowWat 1300, both are LiFePO4 pure sine wave solar generators. I used them for a day With my AGD Duet Class D amps (that used about 13 watts each) and PBD streamer and DAC (about 50 watts). It was an experiment to see how long I could run my system during power outage (30 hours), and I did not notice any change in sound quality. I need to try this again for a longer test.

 

[Lagonda]

Batteries have been around since single-DC-voltage transistor-powered audio gear overtook tubes.

You have to ask yourself why (apart from one or two companies such as Red Wine), no major brand has decided to go the battery route. As I mentioned before (and you scoffed at me for doing so), a few top brands have gone part way in that they offer external power supplies usually as an option, but they still start with grid AC.

Like you, I can't understand why battery power isn't favoured over mains power and conventional (normally built-in) power supplies. I think you really need to do more research and establish why the top brands, where price is no object, still choose to do the AC-DA conversion within the enclosure, or occasionally in an external enclosure. No one uses batteries - so you need to find out why, before extoling the theoretical virtues (and I agree with you 100% on this) of battery power. I've accepted that I must be wrong (as I think Red Wine has) as otherwise top brands would be using them - wouldn't they?

Perhaps have a conversation with Vinni Rossi as he has taken that route in the past and abandoned it. Ask him why. I'd be interested too as a former owner of one of his amps and an advocate of the aparent advantage of DC from start to finish. But I would be dead against AC > DC > AC as one of your ideas seem to suggest. Good luck.

Rowland dabbled in battery power supplies too .

 

[Kingrex]

Imagine telling your customers its up to them to buy a big a$$ battery to power their amp. Where do they put them. DC cables should be measured in inches. Not feet. And each battery is $2000. And at 12 volts, you need 4 for any play time.

Have you read what I'm posting? Wire them wrong and they will charge incorrectly. Might even catch one on fire if you do something stupid. Ever seen an electric car fire. Behind your audio rack!!!! I was actually talking to 2 consultant today about enclosures and about fire proof boxes for batteries. Burn bags. Aluminun cases. Battery Management Systems (BMS). You have to buy the right battery with the right BMS to have a high level of safety. You think Jeff or anyone else wants to take that responsibility. And do you think Jeffs customers want to pay an additional $9000 for batteries and chargers as well as having to give up 18" x 30" x 10" rack space with 250 lbs of weight. Think an added stromtank S5000 of space per amp and S2000 for front end components. Busy rack.

 

[Hear Here]

Yes, it would be interesting to here from the people who build the amps why they don't use batteries. I wonder if Nelson Pass has explored this. He might say that AC power is good enough, so there is no need to add to the cost with a battery power source? darTZeel uses a battery power supply for their preamp, so there is one example.

You could easily run your Atma-sphere Class D amps on a battery. I have an Ecoflow Delta 2 Max and a GrowWat 1300, both are LiFePO4 pure sine wave solar generators. I used them for a day With my AGD Duet Class D amps (that used about 13 watts each) and PBD streamer and DAC (about 50 watts). It was an experiment to see how long I could run my system during power outage (30 hours), and I did not notice any change in sound quality. I need to try this again for a longer test.

Yes, Red Wine amps used internally-located 12V batteries to power their amps. I had their Signature 30 Mk II for a while. The amp had a conventional power supply that was used to charge the batteries or could be used to power the amp directly, but the recommendation was to turn off the power supply while listening and leave pure battery-supplied 12 V DC to power the amp for optimal listening. The batteries provided several hours of listening. If Nelson's amps used such a system the batteries would run flat in no time because his amps are mostly Class A - very greedy for juice! Better for preamps, DACs, streamers, Class D amps, etc that require low current.

Yes, my Alma-Sphere amps could easily be driven by batteries, but it would mean an extra box as the case is already pretty full, so no room for a battery. Also the idea of messing with the amp doesn't attract me and would jeopodise the warranty. If Ralph was to consider a battery option for his amps, that may be a good thing, but I guess that, as he has installed a very high quality power supply with massive transformer, he is satisfied that the use of AC from the mains doesn't adversely affect the sound.

As I have said before, there seem no point at all in using batteries only to convert their DC to AC before the amp's power supply converts back to DC. If using DC, then use batteries of the voltage that the circuit needs and avoid DC to AC to DC conversions.