question

FRA avatar image
FRA asked

Mppt to charge 480v battery bank???

Hello I saw that there are inverters for three-phase current up to 50/100/200 kw. And they accept a battery voltage of 300/400 volts.

However, I have noticed that there are no mppt controllers capable of charging 400 volt battery banks.

I wonder, is it possible to connect many 48v mppts in series to a 480 volt bank?


I also saw that victronenergy does not produce inverters over 5kw it seems to me.

Is it possible to combine several 5 kw inverters in parallel to obtain 30/50/100 kw output?

MPPT Controllersbattery chargingmultiple inverters
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1 Answer
nickdb avatar image
nickdb answered ·

Victron inverters range up to 15kVA, you can parallel four of these per phase for a 180kVA 3-phase system.

You can parallel more of the smaller inverters, except the 8 and 10kva multi 2's which don't support it.

Its all on the product pages.

No you can't series mppt's.

You sure about a 300V DC bank?

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Thanks you. Is not for me. It's to learn and understand. And for an ipothetic 70kwh solar system of a person that need to run a industrial machine and industrial fridge cell with 35 kw power. But nothing real in a short time.

Now, I noticed that exists some chinese mppt to charge 480v battery bank with 120kw output.

And some pwm controller to charge also 480v battery bank with until 120kw output.

But these pwm controller accept only 50v Pv input.

Is possible that a pwm controller increase 50v Pv to 480v battery output? 120kw with 50v Pv are a monster current of 2400 amperes. How to manage these DC current level on wiring?

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@.francesco

Now, I noticed that exists some chinese mppt to charge 480v battery bank with 120kw output.

And some pwm controller to charge also 480v battery bank with until 120kw output.

But these pwm controller accept only 50v Pv input.

Post some links to the above products.


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FRA avatar image FRA klim8skeptic ·

These pwm controller accept until 1000v pv and 480v output and I understand that

https://es.made-in-china.com/co_bangzhao/product_Solar-System-480V-200A-MPPT-Solar-Water-Heater-Controller_egeiyohuy.html


But these model say in the datasheet that have 50v max Pv input and 480v output. And I don't understand that.

http://www.cnsandi.cn/sdp/911164/4/pd-4607850/10278586-2448621/480V-200A_Solar_Controller_for_Solar_Power_System.html


Then, why is not possible to series mppt controllers? Thank you

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These pwm controller accept until 1000v pv and 480v output and I understand that

https://es.made-in-china.com/co_bangzhao/product_Solar-System-480V-200A-MPPT-Solar-Water-Heater-Controller_egeiyohuy.html

What exactly are they selling? A solar pv to battery mppt charge controller? Or a solar pv to hot water diversion/dump/optimizer?

Sandi website is 4 years out of date regarding product documents.

Then, why is not possible to series mppt controllers?

First, each mppt would be looking for optimal power point, and they would never mesh/synchronize up. Second, each mppt has a design maximum voltage to earth failure voltage.

You series stack mppt controllers, eventually they will fail due to voltage to earth leakage.

Same goes for batteries. Eventually the voltage achieved will go beyond designed voltage to earth insulation limits.


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FRA avatar image FRA klim8skeptic ·
Ok thanks you, now is clear. I don't know enough about the earth protection because in rv low tension systems it's not necessary.
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What is the technical reason for not possible to connect mppt's in series? Thanks.
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