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[Stephen Swaffer]

I still say using a DC battery to create a "pure" sine wave so that gear can convert it back to DC which causes ineffeciencies both in the DC to AC and in the AC to DC conversion AND requires filtering to remove noise is counterproductive.  Audio gear powered directly by DC should be inherently very low noise.

[Tim McCulloch]

I still say using a DC battery to create a "pure" sine wave so that gear can convert it back to DC which causes ineffeciencies both in the DC to AC and in the AC to DC conversion AND requires filtering to remove noise is counterproductive.  Audio gear powered directly by DC should be inherently very low noise.

"The wonderful thing about standards is having so many to choose from."  - Ivan B.

So what will the "standard" be for DC distribution to end user devices?  Mr Edison, I presume, is spinning in his grave having previously lost the generation/transmission biz to George Westinghouse/Nicola Tesla.

Who's old enough to remember "You can be sure, when it's Westinghouse"?

[Roland Clarke]

To give an idea of what's possible, the (now 4 year old) battery in my car is nominally 85 kWh and weighs ~1500 lbs. It could power an event with an AVERAGE consumption of 4 kW for 16 hours without breaking a sweat. Purpose-built in reasonable quantity I would expect the cost to be comparable to that of a 20 kVA diesel generator, which is about the size you would rent for a 4 kW average event.

Another advantage is that a battery pack could supply low-power loads, such as security lights and mobile device battery chargers, during standby portions of the event without noise, stink, and potential for wet stacking.

--Frank

Potentially Frank, if you had an output, you could just roll your car in there, power the event and as long as you have enough power that you can reach a charge point, job done! 😉

[Riley Casey]

So what are you thinking here, run everything from 5Vdc USB ports?

I still say using a DC battery to create a "pure" sine wave so that gear can convert it back to DC which causes ineffeciencies both in the DC to AC and in the AC to DC conversion AND requires filtering to remove noise is counterproductive.  Audio gear powered directly by DC should be inherently very low noise.

[Stephen Swaffer]

Pick a voltage.  24 VDC is very common in industry, 48 V is just below the 50 V threshold for shock potential.  Our forklifts run on 36 volts-but they are lead acid cells, so you can tap off any voltage you want-say to run 12 volts lights/radios (probably shouldn't admit we did that?)-though I am sure there are downsides to doing so.  Getting 5 volts from a combination of 2 volt cells might be a problem though!

[Frank Koenig]

Potentially Frank, if you had an output, you could just roll your car in there, power the event and as long as you have enough power that you can reach a charge point, job done! 😉

Indeed, you are not the first to lust after this option Unfortunately, Tesla does not make it easy. They don't even provide a low-power 120 AC output. I'm guessing one reason is that they don't want people with unlimited charging contracts harvesting power from Tesla's chargers and bringing it home. Hacking into the system would not be easy either. Warranty issues aside, the battery is part of a complex and highly integrated system involving charge management, thermal management (freon heat pump, 3 circulating pumps, several heat exchangers with motorized louvers and fans, lots of valves) and safety devices. The pack operates at around 380V (depending on state of charge) and can put out a peak current of ~1000 A. Not for the faint of heart. If you could find or build a 380 DC to 120/240 AC inverter it would still be difficult to integrate. I think it would be far easier to buy a Powerwall, or one of the commercial power storage products and put it on a trailer. Or, if you're ambitious, buy a pack from a wrecked Tesla and go to town.

I'm guessing that in a few years we'll see a lot of mobile battery/inverter systems from various manufactures. Multiquip, are you listening?

--Frank

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