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iand avatar image
iand asked

Multiplus II / Quattro II external fan control

Simple question -- are external fans (using an assistant and the relay) turned on as soon as the internal ones start (at minimum speed), or only when they reach maximum speed, or somewhere in between?

I never got any answer to this question about when the external fans turn on so I'm asking again.

I can't see any need to keep this secret, it would be useful information for anyone needing an external cold air feed to keep the Multiplus II / Quattro II cool and reduce temperature derating.

Maybe @Guy Stewart (Victron Community Manager) can help?

Multiplus-II
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iand avatar image
iand answered ·

Still no answer... :-(

I know @Guy Stewart (Victron Community Manager) is around looking at answers on other threads -- any chance of a reply on this one? There doesn't seem any reason to keep this info "secret", and deciding how to control an engine room cooling system is difficult without it... :-(

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Johannes Boonstra (Victron Energy Staff) avatar image
Johannes Boonstra (Victron Energy Staff) answered ·

Hello

Most models have thier fans run at low load (at a fairly low rpm ) , then an external fan control doesn’t make sense so only on full rpm the external control is triggered

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iand avatar image
iand answered ·

Thanks @Johannes Boonstra (Victron Energy Staff) -- I'm specifically asking about the MP II 48/10000 which will be installed in a boat engine room, I have to decide how to control the external fans because I don't want them running at times of low load (e.g. nighttime) if the internal ones are only running slowly.

If they only come on at full rpm (big load on the MP during daytime) then that's fine. Can you confirm this?

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iand avatar image
iand answered ·

@Johannes Boonstra (Victron Energy Staff) now I have a contradictory answer from @Margreet Leeftink (Victron Energy Staff) saying the external fans come on as soon as the internal ones do:

https://community.victronenergy.com/questions/158006/multiplus-ii-4810000-external-fan-control.html

Which is correct for the MP II 48/10000?

-- yes this is a duplicate thread, but it seems impossible to get a definitive answer to what should be a simple question, it's very frustrating... :-(

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Alexandra avatar image
Alexandra answered ·

@IanD

The best way to avoid derating is climate/environment control such as AC.

However in ve config if you play around there, there are programmable relay (of which there are many choices on the quattro 2) controls that can be triggered when the fan built in does.

The best way to find out is to do and see.

The other way is to use a temparature sensor on the cerbo and trigger the relay thay way with ambient temps, not based on the quattro.

It really depends on your application and how it is set up, so there is no difinitive answer.

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iand avatar image iand commented ·

@Alexandra I know there's a programmable relay and a fan assistant which can turn on external fans "when the built in fans run" -- what I can't find out is what speed of the internal fans triggers this relay to close and turn the external fans on :-(

It could be either as soon as they turn on (at low power/fan speed), or only when they reach maximum speed (high power), or somewhere in between -- the problem is that even Victron don't seem to be sure which is the case (for the 48/10000)...

The MP II will be inside the stern of a boat, the external fans will blow cold air from outside the boat over the Multiplus, but I only want these to run when needed not all the time.


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Alexandra avatar image Alexandra ♦ iand commented ·

And sometimes if you just set it up and see for yourself, you could have a definite answer that way.

The Victron core team is quite small and can't try every scenario that can exist in the field.

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iand avatar image iand Alexandra ♦ commented ·

I'm not asking the Victron team to try *any* scenarios in the field -- surely they should already *know* when the external fans switch in, after all they designed the MP II and wrote the code for the fan assistant? The effort needed to answer this question should be negligible... ;-)


Trying something out when it hasn't been built yet is difficult -- and it hasn't been built yet because I'm still hoping that the Quattro II 48/10000 will be launched by the time I need it early next year, and I'm not going to buy a MP II 48/10000 and ATS before then just to try it out...


If I have to wait until after the build and try this out then that's what I'll do, but I don't understand why it seems so hard to answer a very simple question... :-(


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