Running Old Trace 5548 without Battery?

I am really reaching back to school here--I think I got this roughly correct now (I pulled an earlier post where I got it completely wrong doing the capacitor size calculations).

Energy = 1/2 * C * V²

Less say we want the capacitor to store enough energy to supply 5.5 kWatts @ ~52 volts for one cycle with a 0.5 volt swing in voltage (ripple voltage) and the inverter is running at 60 Hz (technically, should be a sine squared wave form running at 120 Hz--Just wanted factor of 2x safety factor).

E = Watt * Seconds = 5,500 Watt * 1/60 second = 92 Watt*Seconds of energy

C = E * 2 / (delta V²) = 92 WS * 2 * 1/[(52 volts)² - (51.5 volts)²] = 3.6 Farads

It has been a long time since I ran these sorts of equations... But this sort of gives you an idea of how large of capacitor you may need. I took some guesses--Like 0.5 Volt ripple current is acceptable (may not be for the Super Cap or the Trace's internal capacitors).

A Visia 4 F super cap @ 8.4 volts (useful life ~2,800 hours at 55C). Also note that this is probably not the right capacitor--Really intended to be a "battery" that discharges over minutes to days--Not 120x per seond:

http://www.mouser.com/ProductDetail/Vishay-BC-Components/MAL219691126E3/?qs=sGAEpiMZZMsCu9HefNWqpofZ%252b8Ak8%2fFpHwEcD6pUNMd2U4eUJxF65A%3d%3d

Maybe around $1,400 each--Need ~7x $14 each or ~$100 worth of capacitors (nominal guesstimate) plus cost to mount them (these are 24 week delivery--Not sure you can use 8 in series):

http://www.findchips.com/search/bmod0165

Also, the Trace will need ~48 VDC from the capacitor bank to "turn on" (I would guess to "boot strap" the inverter--Assumes a working 48 volt battery bank).

Or you can buy a 5 kW GT inverter:

Fronius Primo 5.0-1 5,000 Watt Grid-Tie Inverter

For about $1,850... And you can get rid of the Solar Charge Controller (you probably would need to re-wire the solar array to run the Fronius).

Note, the existing solar array may not fit (Vmp-array / Imp-array) with the requirements of the Fronius--Matching solar array configuration to the GT inverter's input requirements can be a pain.

Of course, you could look at using Micro Inverters for similar costs (and other panel wiring/selection issues).

Not saying the above is the exact/correct or even a workable answer (I would tend to think it is not a good idea to try and use the Trace in this way, the charge controller+inverter may be wildly unstable with a 4 Farad capacitor bank)--However, it does give you an indication of what the costs could be like with in a factor of 2x / or 0.5x to try and "re-purpose" the Trace.

-Bill "my second guess" B.