Sunny Boy SB3.0-1AV-40 continually rebooting

[Ultima357]

Hi everyone. I have a Sunny Boy SB3.0-1AV-40 inverter, about 7 years old now, having churned out just over 35Mw in its life. It has 2 strings of 10 x 150w panels each, all due south and no shading. (Location in sunny Cyprus, hence the power generation). I'm now trying to fault find an issue where it is constantly restarting, relay clicking in and out, sometimes a few times a minute. It's not consistent which is also a head scratcher but always occurs from around 9am to 11:30 ish but can also happen at other times too. 

 

So far I've found the strings are iffy, panels now some 12yr+ old as previously powered a battery support system. One string is 265v and the other 365v. Plan to sort that out this weekend having sourced some equivalent replacements from a similar system that has been dismantled. £0 so a good find. 

 

But, not withstanding the above, further experimentation of running on just one string, it still exhibits the same problem. I've only got basic voltmeter and current clamp and the inside of the inverter is one of layered circuit boards, so very unfriendly. Nothing obvious fried or smelly though. Curiously, the 8 large capacitors at the top of the unit are 4 at 178v and 4 at 0v. That seems odd. Measured simply from capacitor top to ground. 

 

Unable to find a circuit diagram, so at a loss as to what else to measure, but beginning to think the inverter is the issue. Oh, no great problems reported on the monitor either. Used to get grid over voltage shutdown but not now, it being typically 240 to 245v. Any ideas? 

[SteamyTea]

SMA are a bit iffy about people tinkering with their inverts.

Is it still covered by warranty. Seem to remember they offered replacement once the old one is sent back. Call the local agent and see.

 

1 hour ago, Ultima357 said:

35Mw

That would fry it for sure, especially when written correctly, kW.

But you mean kWh.

[Mr Punter]

35 minutes ago, SteamyTea said:

But you mean kWh.

 

I think they meant MWh.

[Ultima357]

Yep, meant MWh. 

[Ultima357]

46 minutes ago, SteamyTea said:

SMA are a bit iffy about people tinkering with their inverts.

Is it still covered by warranty. Seem to remember they offered replacement once the old one is sent back. Call the local agent and see.

 

That would fry it for sure, especially when written correctly, kW.

But you mean kWh.

Not sure what the warranty is, but support is limited out here. Yes I meant MWh produced since installed. 

 

Just checked, warranty 5 Yr. 10 Yr if installed after October 2021. Dang! 

Edited 13 hours ago by Ultima357
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