MurphyGuy
It just needs a bigger hammer
- Joined
- May 20, 2020
- Messages
- 4,129
I figure I'm less likely to get lightning damage, due to location and because utility feed is underground from an underground transformer. Half a block away the (12kV?) input goes up a pole and is above ground beyond that. I'm in the process of installing a hefty TVS system since discovering that my Delta lightning arrestors happily let 5000 Vrms go by; they obviously aren't the "Varistor" claimed on vendors site. Rumor has it they just contain sand; that is the "silicon oxide" part of "silicon oxide varistor"
I will also add varistors on the DC side. There are small ones on input of some of my Sunny Boys but SMA recommends more. I also have the Delta sand-filled bottles there.
I have manual transfer switches in a few places, so I can put the house direct on grid if Sunny Island is down. Was going to do that with the Sunny Boys as well, interrupting RS-485 so it would know Sunny Island was no longer performing UL 1741 and Sunny Boy should resume doing that. But because 10000TLUS doesn't respond correctly to RS-485 I didn't, it is only on Sunny Island's output.
It isn't quite there yet, but I want to set up UPS operation for the house (keep internet going for work at home), also my lab. Sunny Island will detect brownout and protect things from damage (which I've seen before.) I need to set up load shed of heating/cooling loads at about 10% DoD so they don't drain the small battery.
I have a load shedding contactor on my unit that shuts down the house at around 3.3 volts per cell. Better to have a controlled crash rather than the SI's or the BMS forcing shutdown.
I don't trust any of those lightening protection devices when it comes to thousands of dollars of inverters..