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Hi George,
some weeks ago I visited the fair in munich and have seen some interesting battery solutions:
* Salt water battery – uses only salty water, which isn’t dangerous. Deep cycle discharge up to 100% is possible. Livecycle minimum 15 years with 80% power.
* Crystal battery – unfortunately a special charging electronic is necessary
* Redox flow – actually in size of a refrigerator with 6 kwh storage.
My favorite is the salt water battery, because it is easy in installation.
As I wrote weeks ago in this forum I am working on independency solutions with a friend and some engineers. My personal conclusion is:
The costs for energy storage in Germany is actually between 650 € and 1000 € per kwh. Even if you calculate a livecycle of 15 years and an average use of 60% your costs per kwh is in the same range as from the common suppliers. And your 24 Kw PV Generator will produce much more energy as a normal house would use – but not to the right time. With a total off-grid installation you cannot sell the energy that cannot be used in the moment and batteries are charged.
I don’t know your special situation weather about energy usage in your house (heating with electricity) nor about your energy production. The following proposal is only if your situation is normal ( consumption of 5000 kwh / year, Sunshine-hours around 1000 per year, warm water and heating with solar water panels and in additional electric heating combined with oil or gas.
I would think about a storage to get an independence of maybe 1-2 days but actually with grid connection. You can get some cash with selling energy and this can be invested in better storage technology. This could bring an independency of more something around 90% over the year.
But maybe in your case it can be different.
HD
Von: [email protected] <[email protected]>
Gesendet: Donnerstag, 5. Juli 2018 02:06
An: george gray [email protected] [EVGRAY] <[email protected]>
Betreff: Re: [EVGRAY] Modifying an SMA Tripower 15kw grid tied inverter to stand alone
Good on you George, keep us posted on your progress, here is a link for a search on Vanadium redox batteries, they were invented in Au. the Howard Gov. failed to promote them but they are still around.
cheers
Eduardo
On Wednesday, 4 July 2018, 10:02:01 pm AEST, george gray [email protected] <mailto:[email protected]> [EVGRAY] <[email protected] <mailto:[email protected]> > wrote:
Eduardo,
Thanks for the advice mate. I have 2 of these 15 kw 3 phase inverters in parallel and I'm looking to get off the grid altogether. I don't want to switch back to the grid. I have 24 kws of solar panels, 96 panels in all and I have a couple of generators and I want to get a battery bank etc.
George
On Tuesday, 3 July 2018, 7:01:18 pm AEST, Eduardo Codina [email protected] <mailto:[email protected]> [EVGRAY] <[email protected] <mailto:[email protected]> > wrote:
I think that grid tie inverters use the grid to chop up the DC so that the frequency is synchronized and doesn't clash with the grid, so to stand alone they would require added circuits to create the alternating frequency, may be it would be easier to use a stand alone inverter for off grid use and switch to the grid tie one when you want to export surplus to the grid.
cheers
Eduardo
On Tuesday, 3 July 2018, 5:18:11 pm AEST, george gray [email protected] <mailto:[email protected]> [EVGRAY] <[email protected] <mailto:[email protected]> > wrote:
Anyone got any experience of modifying SMA Tripower 15kw grid tied inverters to stand alone off the grid?
Thanks in advance for any advice.
George