Ive just watched a video on YT about Rea solar panels.
They start producing energy as low as 22v but theyre AC coupled so not compatible with my system. How many volts are required to get the GE system started? What do I look for on my panels data sheet that will give me this figure?
The GivEnergy inverters are supposed to startup when the PV string reaches 120v, but it also depends on the amount of current being generated. Sometimes you get power at a lower string voltage, sometimes at a higher voltage.
Is it the panel or the micro inverter on the back? micro inverter vs string. Higher costs with this but better performance. If I had a smaller roof and less panels I would of gone for the micro's to gain more. But I now have 45 panels so 45 micro inverters at £150 each....... expensive inverter! But yeah they are good.
Wow thats expensive
I think the gain for similar sized, direction, tilt systems is around 25% which is really good but hard to justify the costs.
8kw 16x500w panels, a solis inverter £900 ish micro inverters with controller £2500 ish. Might save/earn extra £250 per year maybe, 7 years?
I would if I could though....
In winter, with cloud cover, we generated 0.2kwh for an entire day. It did make me think are there better designs out there. Like modern engines, if you want big numbers you fit a big turbo but a big turbo will be less efficient at low revs. It seems my autarco panels are basic panels. 20.9% efficient.
We also had a day in December where we only generated 0.2kWh but it was a very dull day. I don't think there is anything wrong with the panels and inverter at low light levels as we can get 1W from a full moon when the sky is clear and it is directly overhead.
The REA panels would generate considerably more electricity under the same conditions.
SJB The GivEnergy inverters are supposed to startup when the PV string reaches 120v
The default is 150V, not 120V. Support will change it if you ask.
Vestas interesting
Is 120v the lowest it can be set to, and why wouldn’t we all do this? Could be useful for winter, but any disadvantages?
According to an app someone in here made my inverter says starting voltage is set at 100v. I think.
geoffreycoan It's not really relevant which values your inverter is set to it is unless you only have 3-5 panels per string. Any more panels and you'll easily get over 120V or 150V before there is enough current to generate more than a watt.
SJB My shortest strings are 6 panels each
I found the value for my startup voltages in Home Assistant, its not presented as a GivTCP entity (probably no need for it), but with MQTT Explorer I found it under topic GivEnergy / <inverter serial> / raw / inverter
value v_pv_input_start = 150.0
geoffreycoan Six is plenty for 150V. You'll probably be seeing 190V+ before any current can be drawn.
I have four panels on one string and reducing the voltage helped it track better - now produces the same current as the string above it. Used to sometimes get "stuck" until a cloud passed over later in the morning and then it'd be fine.