[RE-wrenches] Low voltage DC v. higher voltage DC

[Jeff Clearwater]

Hi Dave and All. 

Reasons for HV batteries off grid? 

1) Smaller cable size (I just did an 18 Kw off grid with 4 SIs and the cable costs alone were in the order of $400) and increased flexibility locating batteries and inverter.  10 AWG plug and play. 

2) Higher efficiencies.  Easy integration on the DC bus.

3) Integration with GTBB battery tech and systems. Why have two standards and two sets of equipment?  The line between Off Grid and GTBB will blur as more GT customers want more storage and more Off-grid customers want the option of grid hookup at some point.   For developing countries as off grid micro grids grow they can merge. 

4). Integration with Electric Vehicles as  storage for either GTBB or Off-Grid - can integrate on the DC bus seamlessly.

These are the reasons that seem obvious to me. I’d be surprised if the manufacturers are not thinking this way. Though you may be right as I was surprised that Outback went 48V with the Skybox. And it’s been a hard sell to get SMA to support US off-grid. If the equipment could do both seamlessly they would have more market. 

And High Voltage safety is not really an issue with proper (standard electrician) training and as the only electrician or customer interface is a plug or set of small non-energized terminals. Having high voltage DC in you car is more dangerous. House fires are caused by amperage leaks (much higher in Low V) (and shorted PB-acid) way more than voltage leaks. 

I’m off to SPI. I’ll ask them . . From what I understand Pika is heading that direction.  I imagine Powerwall too if they ever decide to support off-grid. 

Best

Jeff











Sent from my iPhone

On Sep 25, 2018, at 7:32 AM, Dave Angelini Offgrid Solar <offgridsolar at sti.net> wrote:

> I do not see the need for high voltage battery systems offgrid. Neither does Schneider, Outback or Magnum. I was involved with electronic field testing with a 400vdc model (all in one) that was not released. There was not a significant market for it. The new Outback Skybox (all in one) is going to be 48Vdc.
> 
> There also are plenty of choices for 48V and 24V Lithium batteries and more technologies out there. The great lead acid batteries are plentiful. Why would you want high voltage DC batteries in your home?
> 
>  
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> Dave Angelini Offgrid Solar "we go where powerlines don't" http://members.sti.net/offgridsolar/ e-mail  offgridsolar at sti.net text 209 813 0060
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<blocked.gif>they’d have more market penetration. 

I’m off to SPI. I’ll ask them . . From what I understand Pika is heading that direction.  I imagine Powerwall too.

Best

Jeff











Sent from my iPhone

> On Sep 25, 2018, at 7:32 AM, Dave Angelini Offgrid Solar <offgridsolar at sti.net> wrote:
> 
> I do not see the need for high voltage battery systems offgrid. Neither does Schneider, Outback or Magnum. I was involved with electronic field testing with a 400vdc model (all in one) that was not released. There was not a significant market for it. The new Outback Skybox (all in one) is going to be 48Vdc.
> 
> There also are plenty of choices for 48V and 24V Lithium batteries and more technologies out there. The great lead acid batteries are plentiful. Why would you want high voltage DC batteries in your home?
> 
>  
> 
> Dave Angelini Offgrid Solar
> "we go where powerlines don't"
> http://members.sti.net/offgridsolar/
> e-mail  offgridsolar at sti.net
> text 209 813 0060
> <image.jpg>
> <image.jpg>
> <image.jpg>
> <image.jpg>
> <image.png>
> <image.jpg>
> <blocked.gif>
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