PV storage array

[toplessHO]

thinking of going to solar for electricity only(have a geothermal heat pump and heat recovery for domestic water heating).
I have a 48vdc to 120AC inverter and a rectifier to keep 48v battery array charged up. How could any of this be used to store excess and use on cloudy days or nights.
Or is a better choice to sell excess back at wholesale and use POCO for the lean times.

 

[toplessHO]

so Tesla just unveiled the powerwall
just a fancy looking battery pack
but the idea is to sell to everyone
http://eattomorrow.com/blog/2015/09/tesla-unveils-a-battery-to-power-your-home-completely-off-grid/

 

[kd3pc]

Tesla announced this earlier this year and the pack still needs the appropriate inverter (and likely a home charger, as the car system is quite different). From what I have read, the pack produces 350-420 vDC...your inverter would then need to handle that on one side and produce 120vAC on the other to tie in to your home panel. If it is like the one in the car, (heard that it is either 1/4 or 1/2 of an S battery pack) it uses a DC to DC charger to replenish the battery....

It needs to be engineered, if you plan to run an entire "home" DC system...large currents and small wires (like one uses for AC) are not a good mix in the home...the cost of running #4 to a room and it's inverter will get quite costly, fast....there is a reason our homes are served by AC distribution. Google tesla and westinghouse and the whole AC v DC distribution thing, back then....and why.

small (300-500 watt) DC to DC chargers and/or 350vDC to 120vAC inverters are available - but to the tune of $2-3K EACH... Ideally this is set up to accept the 200vDC PV string most systems now support.

Tesla has been less than forthcoming about these key details, unless you are one of their accredited "installer partners"...Based on information since the spring announcement, you can easily spend $10K to get it installed and working in your home. The 7Kw unit would barely cover the needs of small home, so plan on the 10Kw unit for an extra $500.

 

[theoldwizard1]

Or is a better choice to sell excess back at wholesale and use POCO for the lean times.

I have a buddy who is an electrical engineer and has a house in FL with a PV array. He sells it back to the POCO. The hook up is still expensive but it is SO MUCH EASIER !

 

[toplessHO]

I have a buddy who is an electrical engineer and has a house in FL with a PV array. He sells it back to the POCO. The hook up is still expensive but it is SO MUCH EASIER !

there was a fight for a while that POCO could charge retail but would pay wholesale.
I guess this is just big buisness,gotta pay for all the generation stations and supporting infrastructure .
We currently have a 40% surcharge for a nuke unit that wont be built
add to that the fuel surcharges(which have NEVER gone down),inspite of lowest
fuel costs in 10 yrs.

Would be interested to know more about the details of your buddys system

 

[theoldwizard1]

there was a fight for a while that POCO could charge retail but would pay wholesale.

Yeah, common. But I think my friend said that was resolved a few years ago and they will pay retail up to when you "break even". After that, they pay wholesale.

Would be interested to know more about the details of your buddys system

Sorry, no details and I don't see him very often since I retired.

I do know he is an excellent EE, but his expertise is in lower power "control" systems. There are several "good" brands out there now for feeding power back to the grid.

 

[toplessHO]

not sure how the payback or buy back from POCO works here
we are currently on a 40% increase(said its 5 yrs temporary but we know how that goes)
and have fuel"adjustments" totaling about the same.
Im betting those items are not part of the payback on making surplus power.

 

[theoldwizard1]

I found my friends email. I will try to get more details.

 

[toplessHO]

thanks
what part of Fla is he and what POCO?

 

[rsanter]

I guess it depends on where you are, but here when you are backfeeding the grid because the PV system is generating more than you are using at the time, you get full value for the electricity you are putting onto the grid.
they will not send you a check but they credit your account and you can use that later that day, later that week, or later that year

bob

 

[toplessHO]

I guess it depends on where you are, but here when you are backfeeding the grid because the PV system is generating more than you are using at the time, you get full value for the electricity you are putting onto the grid.
they will not send you a check but they credit your account and you can use that later that day, later that week, or later that year

bob

yes and I can understand this
gotta pay for the equipment some how
Would be like me saying to my neighbor
hey I ll size the infrastructure for both of our requirements
and take care of it all
but you just pay me wholesale.