question

powerhungry avatar image
powerhungry asked

Using PowerAssist and PowerControl only when the input is from a generator

I would like to know if the following is possible on a MultiPlus 2 inverter/charger.

I have power coming into my house from the grid as well as from a generator. Both of them are connected to an Automatic Transfer Switch which switches between the one that is active with grid being prioritized. I want the inverter/charger to draw only 5 Amps (and compensate the rest with PowerAssist) when the source is a generator and draw without any limits when the source is the grid.

So if I connect the current transformer around the generator's live wire as shown in the picture below will it work as intended?

victron-grid-and-generator-ats-current-sensing.png

I guess Quattros can do this as they have two AC inputs. But they're too expensive for me.

Multiplus-IIGeneratorcurrent limitpowerassist
victron-grid-and-generator-ats-current-sensing.png (8.1 KiB)
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2 Answers
carlrx7 avatar image
carlrx7 answered ·

Easy if your ATS has a relay output. Use the current control assistant. Note: depending on your inverter, it may not be able to go down to 5A.


More info: https://community.victronenergy.com/questions/97670/charge-current-control-explanation-of-use.html

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powerhungry avatar image powerhungry commented ·

Thanks for the answer @carlrx7.

> Note: depending on your inverter, it may not be able to go down to 5A.


I'll be buying the 48/3000 version of Multiplus 2 so the minimum current limit can go down till 4A.


> Easy if your ATS has a relay output. Use the current control assistant.


I'm using [this ATS](https://www.havells.com/en/consumer/switchgear/energy-saver/automatic-source-changeover-with-current-limiter/3-module-spn-accl-(8).html) and it doesn't have a relay.

But the same brand has [another ATS](https://www.havells.com/en/consumer/switchgear/energy-saver/automatic-source-changeover-with-current-limiter/premium-spn-accl-with-gen-start-stop-(5).html) with a generator start/stop function.


![ATS with generator start/stop](https://www.havells.com/content/dam/havells/consumer/switchgear/energy-saver/automatic-source-changeover-with-current-limiter/premium-spn-accl-with-gen-startstop/DHABWSN3006/cover.png)


Do you think the ignition X1 and X2 can be used as a relay for the AUX input?

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JohnC avatar image
JohnC answered ·

@powerhungry

I think the only way to do this automagically is with an Assistant. @carlrx7 is close, but you want the Input one rather than the Charge one. Here an example..

1701756299952.png

You'd need to devise a relay from the genset or ats to provide a simple open/close function of a wire pair across Aux1 (in this example). No V need be applied, when closed it will be 0V, and when open it will 'pull up' internally above 2V.

You'll need to disable 'Dynamic Current Limiter' in the Multi (or the Asst will do it for you), so if your genset needs that it might be a problem.

I haven't used this myself. Manual adjustments are available via Remote Console, VRM, VEConfigure, and MFD App (my preference), so I haven't bothered.


1701756299952.png (69.7 KiB)
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powerhungry avatar image powerhungry commented ·

Thanks for the answer @JohnC.


Can I connect a 3V DC wall adapter from the mains to the AUX input? This way when the main power is available, aux1 will receive 3V and when the power goes out it'll be open and pull up to 2V irrespective of whether the generator is ON or not. So by the time the generator is switched on the current limit will already be in place.


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JohnC avatar image JohnC ♦ powerhungry commented ·
@powerhungry

You can be as inventive as you like. But again, all you need is a potential-free open/close of the two Aux contacts.

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