Piss poor Trace SW preformance in "sell" mode. [RE-wrenches]

[Travis Creswell, Ozark Solar]

I got bored while waiting for a fax and worked this up... I think the
results will surprise you

Why don't we use a DR or a PS for the backup power and a ST for selling
power back?  A ST2500 is a lot more efficient than any modifications that
can be done to the SW plus it comes with the array combiner, GFP,and MPPT
all built in.  The DR is a still great machine that is very efficient and
can out surge the SW.  I have put several DR's in for back up purposes and
they have just amazed the customers with their strength.

Comparing the list price of a 

DR3624 Power Panel $2,529  (I am using this price so we have all the
necessary goodies)
ST2500 $2500

Total $5029 

SW4048 Power Panel   $4,995
GFP                  $275
TCB10 Combiner Box   $229
C40 with DVM         $285

$5784

2400 (20 AP1206's) watts of solar assuming an annual average of 5 sun
hours/day would produce....
I'm not bothering to de-rate for heat on the roof or other factors as I am
using the same array and battery bank for both systems.

ST2500 and the DR

2400 watts x 90% eff (a guess) x 5 x 365 = 3942 kWh's per year
But we need take the idle losses from the DR away from that
Using Doug's number of 750 watt hours per day of idle and float losses. 
Although I think the DR wouldn't be as bad as the SW.

The net would be 3668 kWh's per year with a ST2500 and a DR


SW4048 with C40
 
35.5 amps x 53.6 volts x 90% eff. x 5 x 365 = 3125 kWh's per year
subtract the idle and float losses of 273 kWh's per year

for a net of 2852 kWh's per year

the winner, producing nearly 30% more kWh's annually and costing 13% less,
the envelope please
The ST2500 with a DR for back up power!


Travis Creswell









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