question

edvanz avatar image

Venus GX nmea2000 , VictronConnect

Hi,

We are building a new boat which will have Winston cells 1600 amps at 24 v. The cells will be monitored via 2x Rec-Q in slave mode and 1x Master Unit 9 M. The charging and inverting will be done via 2x Quattro's 8000, 1x Skylla 100, 2x MPPT 150/70. The Venus GX is chosen to hook it all up.

The goal is to be able to charge with 100, 200, 300, 400 or 500 amps depending on which generator is running or based on how much shore power is available. How do I connect this to the Venus GX. I want the Quattro's working together in inverter mode but want to be able to disconnect them in charging mode so I can make use of the maximum number of steps to charge ie 100, 200, 300, 400 or 500 amps. We would also like to have all the data available on the nmea 2000 bus so that we can view it on our Maretron N2Kview software as well via VictronConnect on a Windows 10 pc via VictronConnect. For the VictronConnect I think I need a MK3-usb cable? Is this the right assumption? For nmea 2000 out from the Venus GX I understood that the functionality would be available from firmware 2.30 but I haven't been able to find confirmation of this(probably user error)

Is this a doable setup? If not could you tell me where I go wrong!!

Thanks,

Ed

Venus GX - VGXNMEA 2000 - N2K
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2 Answers
ben avatar image
ben answered ·

You've asked a lot of questions about a complex installation, so I'm not going to try to answer every one of them here in one go. (You can break your questions out into separate Questions, over time, and that will work better.)

Regarding the Quattros working together: you can set charging current on each of these units to any arbitrary value, so there is no need to break them apart when you want specific intervals. (And, breaking them apart would be a configuration change that you do not want to be doing all the time, anyway.)

What is the rationale for having a Skylla charger as well? Can you post a picture of your circuit design?


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edvanz avatar image
edvanz answered ·

Hi Ben,

I'm on the water at the moment so it is a bit difficult to get the circuit design uploaded. But the rationale is that sometimes I want to charge with 100 amps on the small genset when using the airco at night. Sometimes I want to charge with everything I have left over. The goal is to be fully flexible with charging based on the power available. I know that the Quattro's will scale back based on power available but that would mean that the smaller genset will run at 100% for 8 hours. That I thought wasn't a good solution and with the Skylla I can switch off the Quatro's and keep my genset on 80%

Please feel free to correct me


Ed

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I'm fairly convinced you don't need the Skylla, but maybe your scenario can prove me wrong.

Let's start by putting everything in watts, since you have at least three different voltages in play.

How many watts (or KVA) are each of your generators?

How many watts is your aircon load?

Hi Ben,

Airco Webasto VM 50 x2 will use only 1 at night. Max 3930 W each but I can run 1 unit in eco mode 1 at 1840W or eco mode 2 1150W + circulation pump 345W seawater cooling pump 370W 1 airhandler 300W. So in eco 2 mode total 1865W or in eco 1 mode 2555W.

Fridge/ freezer galley 200W

2x pc 345W each

Maretron network 90W

Lazerette freezer 250W

Skylla 4508 W


So in eco 1 mode with all other users we are at 8293 W

The generators are 10 and 26 Kva

I’m sure I have forgotten somethings so maybe we have to run in eco 2 mode.

Tx

Ed

Okay, so if I'm reading right, you're thinking that sometimes at night you have 2kW of air conditioning plus some other loads, between another 1kW and 5kW? And you want to use your 10 kVA generator and do a little charging on the side with what it has left over, sometimes?

You can totally do that with Quattro. You just use your Venus device and tell it to limit its "shore current" to the maximum you want to take from the generator.

It will pass through that power to the loads you have on at night, and whatever is leftover will go to battery charging.



Hi Ben,

But the next morning when I start the big generator I have to reconfigure the Venus, correct?


Ed

Well, either way you’re going to be reconfiguring something, right? You’ve got a different generator to start, a transfer switch of some sort to flip, and a Skylla to reconfigure each time if you go with your proposed path.


I mean, I can think of ways to automate away that stuff, but I’m still just focused on why you have this extra kit in your design for now.

Well my logic was Skylla for night and Quattro's for day time , switch skylla off and switch Quatro's on but only when running airco at night. I'm sure there are smarter ways of doing this so please enlighten me.

Do you know about nmea out of the Venus? There has been talks about it being available from v2.30

It will take you more clicks to toggle three devices than just to set the current limit appropriately.

And, in so doing, you save buying something and dramatically simplify your design.

I think! (Need a picture to be sure... not enough detail in the words.)