parallel battery systems (attention for BYD users !!!)

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belmont asked May 4, '24

parallel battery systems (attention for BYD users !!!)

Can you parallel connect BYD Battery-Box Pro 10 and BYD Battery-Box Premium LVL 15 ?

Both are 48VDC, one is 10kW and other is 15kW but they are different product line?

If not recommended, how would you utilize both battery system on the same site?

Should these have their own inverter/charger like quattro and parallel them on the AC out side?

If I parallel two Victron Quattro, is it fine if I use different power rated ones? One for each battery system, lets say for the 10kW BYD battery would have a 10kVA Quattro and the 15kW BYD battery would have a 15kVA Quattro?

Do I need two Cerbo GX in case I would use two Quattro?

MultiPlus Quattro Inverter Charger BYD

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Answer 1 · 2024-05-04T18:10:02Z

Kevin Windrem answered · May 04 at 06:10 PM

Parallel Victron inverter/chargers requires all AC in/out and DC cables to be connected to a common point and the same length from that point to the units. You can't have separate battery banks. You also must use identical units (same power rating and even down to the specific model version).

Batteries of different size can often be paralleled but it's not the best choice. I can't speak about BYD batteries specifically. Check their documentation.

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Answer 2 · 2024-05-04T19:48:10Z

belmont answered · May 04 at 07:48 PM

can i connect both battery system in the cerbo gx, will it recognize both ? This case the DC 48V would be on the common busbar. Are there others who use multiple different smart battery systems with one common cerbo gx?

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Kevin Windrem commented · May 04 at 08:14 PM

The GX device will choose ONE battery system to incorporate into the overall system. Others are shown in the device list only.

The Victron ecosystem assumes one battery bank for the entire system.

There is a third party add-on called Battery Aggregator that will combine multiple batteries and present that to the GX device but I don't know the details.

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belmont Kevin Windrem commented · May 04 at 08:48 PM

thanks, clear now, to be honest it is huge downside of cerbo gx that it can not handle two or more different self managed smart BMS systems. I hope there is some raspberry pi venus os solutions or i will search that Battery Aggregator plugin, Many thanks !!!!

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nickdb ♦♦ belmont commented · May 05 at 06:02 AM

The battery manages the system, when you have two management systems asking for different things what is the GX supposed to do? This is why BMS's have to integrate with each other so they can send one set of parameters for the whole pack,

You need to speak to BYD, some manufacturers allow systems to be mixed and have clear rules how to do it, others prohibit it and will void your warranty. It is not up to Victron, they purely report what a certified config is.

You could do away with a BMS connection all together and use a shunt instead.

There are various existing posts on this topic (for various batteries).

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