I emailed Sun Electronics about the St1500's there selling on ebay , they are NOT upgraded units

The XR2500's they are selling ARE UPG's ... this is verified

DON"T directly connect to the Suntie , bad things might happen. If for grins and chuckles you want to see what happens , use a blocking dioide and if the output is no to varible , it might add a little to the panel output

This string is old but right up the alley I want to explore.
It seems the st1500 should not care what the input power comes from. Why could I not diode isolate my solar from a wind turbine/battery hook up? The battery will clamp the voltage of the wind turbine and smooth the output. If that does not seem like it would work how about charging the batteries during the day and with a photo, or timer switch have them connect to the st1500 in the evening to expend there power into the grid system? No problem over drawing the battery the st1500 shuts off at 48 volts and limits its intake to 1500 watt or about 31 amps.

What do you think?

The Suntie will kill the batterys for starters, the Suntie will work down to 40 volts before taking a low voltage fault.

Second, the mppt is not user adjustable and in a best case would do the above, IE, track down to 40 volts, worst case, the mppt would be hopelessly lost and NOT load the wind generator properly and exceed the input voltage spec (wind unit unloaded or lightly load will exceed 120V possibly)

Sorry, this won't work

Thanks

Not to beat a dead horse, how about the second option to charge batteries then dump into grid thru ST1500 at night. It seems the ST would see a fully charged battery as a source of more than 1500 watts solar and max out its output at 1500 watts and limits its input to 31 amps. Easy enough to disconnect with a voltage sensing circuit to shut down batteries at 45 volts.

The SunTie won't start as it needs a minimum wake-up voltage , I think its about 55 volts, been awhile since I have looked at that code

The Suntie is a Gridtie inverter and never will be anything BUT this

If you want to sell battery stored power, use a SW(Xantrex) or GTFX (Outback) which are designed for that application

mrasmussen,

According to this link:

http://www.dsireusa.org/library/includes/map2.cfm?CurrentPageID=1&State=TX&RE=1&EE=0

Texas does have net metering laws that only "pay" for avoided fuel costs, so there would probably not much reason to charge your batteries during the day and powering the grid at night...

I would suggest that you generate grid tie power when the batteries are full and the sun is bright. This way, you will have full batteries if there is a power outage and you will not cycle your batteries (probably extending their life and not adding the additional 10-20% losses of the charge/discharge electronics/battery cycle).

In California, I can use Time Of Use metering--That really encourages me to generate (and not consume) power during peak time (noon to 6pm, Mon-Fri). During the winter, my base rates are: Winter $0.09/kWh and peak $0.11--and for Summer: off-peak $0.09/kWh and peak is $0.29/kWr.

So, for every 1kWh generated during peak period, it gives me 3kWh worth of off-peak credit (during summer).

If you use the batteries only for emergency power, you probably would do well with a Grid-Tied inverter and run an AC battery charger too keep the batteries at full charge (saves the DC solar to DC Battery back to AC Inverter conversion).

The only missing link for my system is that I have a Xantrex GT 3.0 unit (works great) wired to 2 strings of 10 BP 4175 panels (20 panels total). This gives me around 300-320 VDC @9.8 amps and I would like to purchase a "back up" Solar to Battery Charger unit (or charger/inverter) to run a standby battery string/inverter--but so far, I have not found any Off-Grid type unit that will take the 320 VDC (through a DPST switch) from my arrays.

I know that Solar Guppy has wired his arrays for multiple voltage configuration support (to test various Solar Electronics)--but I would rather not do that to mine... Anything available yet, or in the near future?

-Bill

PS: Never mind Solar Guppy--I just saw in another thread your answer to somebody else with the same question your answer about the problems with FETs and current issues.... Thx. -BB