Sunny Boy 1100 Inverter

[billi]

guy thats not my point .... i ordered a waterturbine  and its here ... is it still providing 240 V AC   when  water is only flowing half  of the required flow ?  i doubt that


billi

[guydewdney]

then you ordered a turbine too big! You need to size the turbine like a wind turbine - for the 90% of the time flow rate...




anyway - wheres Allan?

[AllanMcDonald]

anyway - wheres Allan?

I am here in South west Scotland.
Allan

[roys]

So am I, are you near Stranraer?
Cheers Steve

[AllanMcDonald]

I am near Dalbeattie.
Allan

[qeipl]

Allan,

I'm trying to do the same as you (but in NW Scotland) and have bought the following kit:

Navitron 750W high head turbine
REUK 600V bridge rectifier
SMA Windy Boy grid tie inverter

As Ivan says the DC out of the rectifier isn't smooth enough so you need a smoothing capacitor between the rectifier and the Windy Boy.
According to the reading that I've done an electrolytic capacitor rated at least 400V and 1200 microFarads will do the job for me. You might need more Farads as you are generating 1kW (see http://www.kpsec.freeuk.com/powersup.htm#bridgerectifier - scroll down for the 'Smoothing' bit).

You might have to consider going for the 1700W inverter.
The 1100W model recommends a maximum generator output of 800W for 5000 hours/year. I hope to be generating 750W for 70% of the year, which is 6000 hours.
The 1700W model is 1240W for 5000 hrs/yr, which is probably more suitable for your 1kW machine.


Ivan,
You talk about 'a bank of capacitors' - can you explain why more than one and how we should be sizing them (or it)?

Cheers,

Malcolm

[northern installer]

A bank of capacitors is just a means of assembling the required capacitance from what is available;ie 12 x 100 microfarad connected in parallel = 1200 microfarad.Make sure that the voltage rating is well above the highest peak to peak voltage;nothing finishes a capacitor quicker than over voltage !

[Ivan]

perhaps someone with greater electronics knowledge than me can work out the required capacity for you. I did it a few years ago for a 1.5kW water turbine and worked out, at Farnell prices, it required about £200 worth of capactors. The Sunny Boy needs ripple voltage to be below 10%. If you're rectifying single phase, the 'ripple current' ie what flows to/from the capacitor to keep things smooth, will at times reach much higher levels than the current flowing. So if you have a 1Amp current from the water turbine, you'll see 8 (I think) Amps at times to/from the caps. As a result, you need to over-rate the capacitors to prevent over-heating. Large caps have a ripple current rating, and like batteries, I think it reaps dividends to over-spec the caps if you want them to last a long time. If you're running them at temperatures of 70C, you can't expect them to last more than a couple of years.

Anyone care to do the calculations? I think you'll need a lot more than 1200uF