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kuri asked

Commissioning 3 phase 15kva multiplus system

Hey, I am about to commission this system and will be connecting 13 US5000B, I want to connect 3 groups of batteries (stacks of 5 - 4 - 4 batteries in 3 server cabinets), do I need to comm wire for 3 masters or can I connect all batteries to have one?

Also another issue im having on 8kva systems is inrush current on start up tripping DC Isolator. Have avoided this by plugging in to grid before switching on DC but have also read that capacitors charge directly of DC so perhaps I've just gotten lucky at times as it dosent always happen. Whats a good way to get around this and after this initial start up will capacitors hold this charge so it dosent happen again in the future?

Thanks.

Multiplus-IIPylontech
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kuri avatar image kuri commented ·
System was successfully commissioned today without issue, further reading the unclear pylontech instructions I see you can have 15 or 16 battery's on one comms string and im pretty sure the multi will charge capacitors from AC connection, not 100% on that yet but seems to work and easier than using a resistor for now.
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Rob Duthie answered ·

Hi

What is the rating of the DC breaker? can make a difference if not sized correctly or rated.

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kuri avatar image kuri commented ·
We typically use a 250A 4 pole DC breaker in an 8kva system, over this size the breakers physical size increases dramatically which can be a problem in itself, surprisingly little information I can find on what I would assume to be a big issue with how high the inrush current can be in larger systems. These are properly rated DC breakers made specifically for batterys but obviously not with inrush in mind.
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