Can anyone help me with my Gridtie SB 2500- 240v/50Hz Sunny Boy System. Could I temperarily power up the PV module line ( inverter DC input) in the evening, with something greater than 80vdc to take it off night time standby to read energy today? If so would I need a blocking diode at the modules (10 X BP3160) to stop back feed? Could I use a 240v to say 120v transformer with a high voltage bridge bridge rectifier to have DC output? How much current would I need? Would it have to be filtered for spikes etc? I would only need it for a minute, to read the data, as I don't get home till dark in the winter. I could put it on a timer or use a momentry push button so it didn't get left switched on. I could buy the Poobah software & a PDA but it seems a lot of expense just to get the current day's output reading. Thanks for your help Leigh

I don't understand your issue ..

If you have the lcd display, you just knock on the LCD and it will show the releveant production numbers, day or night

If there is no display on the SB2500 , you can add a RS232 card (about 100US) and connect to a PC and use the free SunnyData program from SMA.

In either case , DC power is not required as the CPU runs of the AC mains or so I seem to remember, Its been 3 years since I have used the SB2500's

You should alos post this to the sma-america discussion board as they can give you a more up todate answer

Hello Solar Guppy
Once the voltage on the solar DC line drops in the evening the Sunnyboy inverter goes to sleep & doesn't wake up till the next morning when the sun hits the panels. The daily E Total is logged but cannot be retrieved. My inverter is in the attic in the roof space & I run Sunny Data program on my laptop via a serial RS232 cable. I don't want to leave my laptop going all day long as I am at work during daylight hours. SMA America suggest running Sunny Buddy software & a PDA but then you have to charge the batteries in that too. I will email SMA AG in Germany maybe they can help me. Thanks for your help - Leigh

Leigh is correct, the SB goes to sleep when the sun sets. It doesn't wake up until after sunrise and the panels are producing about 7-10w to get the inverter past startup mode.

I would say a transfer switch on the DC input side that cut over to a 250vdc low current supply might do it for you. I say might because the SB's MPPT algorithm will try to extract a maximum voltage/current ratio out the supply you choose, so choose wisely. However, what I would really like to say is :

Rig up a low power computer to a line timer, have it come on an hour before sunset and grab the SB data using the free SunnyData software (like Gup suggested). I'm sure you or someone you know can get the computer to automatically run the SunnyData program for a given set time and then shut down the computer (simple batch or script program should do it). Worse case (or plan B) the line timer cuts the power.

BTW - A SB running in a hot attic area may not be the best place for your inverter, as it will heat derate and possibly decrease the operating life of your unit.

-- Larry

If you just want KWH for the day, just buy a cheap Edison type meter and put it on the output of the SB2500 before it goes to the breaker on your panel. They are only about $35 to $50. I have that, but never use it anymore since I went the RS485 route and the SMA SunnyData program to store the results all day long. I have 3 inverters, so I needed the multidrop RS485.