clinton-george-andrea avatar image
clinton-george-andrea asked

Un-centralized victron inverter

I have a system that is un-centralized with same battery bank and it supplies power to different areas as the system comprise of two multiplus 5000VA, two Quattro 10000VA and one Quattro 5000VA. Battery bank is 75KWH MG batteries @7.5Kwh 10 pieces. I experience a problem of power outage due to battery temperature on the Master LV BMS. Can I get a suitable solution on this system

MultiPlus Quattro Inverter Chargermultiplus in parallelquattro 10kva
2 |3000

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1 Answer
nickdb avatar image
nickdb answered ·

It is not supported to run multiple independent inverters off a common bank, so you're going to struggle to find support.

With that number of systems (35kVA) all trying to charge/discharge in an uncoordinated way, it isn't a surprise the battery is overheating - that is a great way to damage it.

Are these 24V batteries in a 2 x 5 configuration?

What is the DCL/CCL for the pack?

Have you any charts that show what the loads are on the battery and how it compares to specs?

Are all inverters allowed to charge or have you set any to inverter only?

If I have the right battery specs the recommended discharge is 60A per pack, so 300A for 10 (assuming 2 series, 5 parallel) at 48V. That is way under the total rating of your inverters.

Some more detail would be helpful but there may not be easy answers with such an eclectic setup.

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clinton-george-andrea avatar image clinton-george-andrea commented ·

it is a 48 system and single battery of MG has 25.2V they are connected 2S 3P on one BMS and the second BMS is connected 2S2P

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clinton-george-andrea avatar image clinton-george-andrea clinton-george-andrea commented ·

All inverter are allowed to charge as each inverter charging current is limited to 50A therefore they make a sum of 250A and DVCC is on and charge limit is set 300A

DCL 1200A for two BMS @ 600A

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janieronen avatar image janieronen clinton-george-andrea commented ·

Have you measured with clamp meter are the current shared equally in parallel sets and does you series have equal voltages?Specially during his charge/discharge situation. If internal BMS is located on top of batteries have you measured temperatures and does all have same environment like not stacked too tight?

Why I have these questions is that I have 2S4P LFP battery bank built also from 25,6V batteries. In my battery manufacturer documentation is strictly prohibited to link middles to each other so all series mid-points must be separated. First I stacked batteries and top ones were always higher temp than bottom ones so they did not charge and discharge equally. After some months bank worked only 70-80% capacity due different charge capacity. I top balanced all series with laboratory PS and modified rack. Now I get full capacity and bottom and top balancing happens automatically during daily use.

You can get control of your energy storage by assigning one Victron unit as main system with GX device and master shunt. Then install additional shunts to other machines and connect these to main control system as DC-loads/source. As earlier stated this is not Victron officially supported setup but you can definitely control other inverters example with node-RED installed to main Victron control system and send messages to other inverters like limit current when any of your batteries give alarm.

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