question

Hi @blskevin, I can not answer the question regarding dual MultiPlus as I only have one.

You an use the temperature input on the Multi and an Assistant doc change the charge current. You want to use the Charge Current Control Assistant. This will let you change the charge current based on the voltage on a dry contact. It can use either the Aux Ports or Temp sensor input. I have not tried this yet, but plan to for the exact same reason. If on Shore power and I start the engine I do not want both charging.

If you do not have the VE.,Bus BMS in the system then you should be able to change the Shore Current Limit from within the Cerbo. See screen shot below. How this works with multiple Multi's installed I do not know, but a trawl of the manuals (VenusOS and MultiPlus) should advise as I have seen something as I went through my setup.

If you have a digital multi control you can use the contact on the back of it to set the generator input current (I assume you have an AC generator and this is why you want to limit the charge current when the engines are running)

To be honest I would leave the multi to its own devices. When the Genny is running it will charge the batteries though absorption and equalisation which the alternator might not do depending on how smart it is. But if the ac load increases the multi automatically cuts the battery charge current anyway and then uses power assist if the load goes up that far.

If you haven't got a generator and its just the big alt on the main engines then, the short period your plugged in and running, wont be a problem and you can simply specify the current limit on the cerbo depending on the outlet your using.

Only the master needs the inputs, the slave will follow, but the charge current and input current are per multi, I.e if you set it to 12.5 amps you get 25 if you have 2 multis.

Thanks both of you!

I have not been able to find the ability to configure a input on the CERBO to limit charge current or change shore power size.

The information regarding the input on the multi in parallel is fantastic!

Here’s what I’ll do...

Wire input #1 to a relay tied to the main engine injection pump circuit at the key switch. This will trigger a assistant that reduces the charge current to 100 amps.

This allow the ability to run my generator while under way and not over current my batteries.

While in port I will manually change the shore power breaker size on the cerbo to match the shore power feed available at that location. I am not going to automate this through another assistant on the multi as I want to be able to set this using the CERBO display to match the local harbor.

If I use an assistant in the multi to do this I loose the ability to perform the same function manually using the CERBO display.

What I will also do is to wire input #2 to a shore power available relay. This will trigger a second charge current control assistant limiting charge current to 50 amps. This will provide protection against my forgetting to change the shore power breaker size to match the shore power, and tripping the shore power breaker after shore power outage while I am away from the boat.

Thanks again for all your help!