Re: Shore - Generator Switch-over box on A54 #solution

WASABI - Rudolf Waldispuehl

Hello Mohammad


This is a lot of Inverting power. You probably not need that much unless you want to run everything simultaneously in the boat 😉

Nevertheless, I ordered the MV MassCombiPro 24/3500W since I have already 2 Solar controllers separately and do not need in the same box.


Did you installed the MV Mass Combi Ultra 24/3500 at the same place/pedestal where the 2500W inverter was? Or you found another place?

                - I’m asking because the installation manual says it should be installed vertical and the existing A54 inverter pedestal is somehow more horizontal then vertical.

I guess you use it as 2500W inverter replacement and not for charging? So probably no issue with the ventilation so far?


Thanks for advice and best regards

Ruedi Waldispuehl

WASABI A54. #55

Currently in Gibraltar


Von: "" <> im Auftrag von Mohammad Shirloo <mshirloo@...>
Antworten an: "" <>
Datum: Sonntag, 19. September 2021 um 10:45
An: "" <>
Cc: Ian Fraser <keyproperties@...>
Betreff: Re: [AmelYachtOwners] Shore - Generator Switch-over box on A54 #solution


Hello Ian;


My knowledge of the LN175 and Dolphin charger is limited, so I will not be of much help there. I can share with you our current approach for our charging and inversion plans, as we make the necessary upgrades, as equipment fails.


Our 2500W Mastervolt inverter failed at the end of the 2019 season. We would like to use the existing charger wiring in the engine room. We have replaced our inverter with a MV Mass Combi Ultra 24/3500. These inverter /chargers can charge at 100A, provide 3500W 220V and have solar controllers built in. They can also be connected in series for additional charging and inversion output. We intend to have 2 in series, giving us 200A charging/7000 W inversion. We will still have our existing 40A MV charger, for a total of 240A charging. I have not checked the existing 40A charging wiring size. It is possible to add a third combi Ultra for  max of 300A charging and 10,500W of inversion. The Combi Ultra can also be programmed to limit the charge/inversion output to match the wiring size. The plan is to be able to supply the entire 220V panel from the inverters.


We have not gone far down the design phase, as this is some time away for us. However, I like the small size (same appx footprint as the inverter we replaced) and light weight of  combi/ultra. We should be able to fit 2 and possibly three in the same footprint and location of the existing chargers. Minimal wiring and full integration, monitoring and control of the Lithium batteries, chargers, inverters and solar.


All of this is very preliminary. In the next 2-3 years that it will take for us to be ready to make the upgrade, I’m sure may thing have changed  that will require changes to our basic design concept.





Mohammad and Aty

B&B Kokomo

Amel 54 #099


From: <> On Behalf Of Ian Fraser via
Sent: Friday, September 17, 2021 2:16 PM
Cc: Ian Fraser <keyproperties@...>
Subject: Re: [AmelYachtOwners] Shore - Generator Switch-over box on A54 #solution




Thank you for your insights on Lithium. We are in a similar situation and agree that Lithium is too early for us.


Will really appreciate your guidance on best solutions for changes to LN175 alternator (and Dolphin 100A Charger) when upgrading to 8AGM 105Ahr on AMEL54 #009.


Ian Fraser

On 17 Sep 2021, at 03:27, Mohammad Shirloo <mshirloo@...> wrote:


Hi Ruedi;


We are currently in the Med and, in my opinion,  Lithium is not a huge advantage in our cruising style here. Also our AGMs that we installed in 2018, have been working better than expected and almost as good as when installed new.


I believe that Lithium technology for yachts is in its infancy and the improvement curve fairly steep. Our plan is to convert to Lithium in about 2-3 years, before leaving the Med, so we can benefit from all the advancement in technology and safety. 





Mohammad and Aty

B&B Kokomo

Amel 54 #099


From: <> On Behalf Of Rudolf Waldispuehl via
Sent: Thursday, September 16, 2021 11:28 PM
Subject: Re: [AmelYachtOwners] Shore - Generator Switch-over box on A54 #solution


Hi Mohammad and Aty


Thank you for the drawing which helped me a lot. Exactly this page was not in my documentation. Don’t know why?

I found in the 220V Panel drawing K1- and K2-source referenced, but without any detail about K1 and K2. Now everything is very clear and you are absolutely right with the priorities.


  • When there is Power from the Generator, K1 is interrupting the Shore supply and switching to Generator with the K1 Relay.
  • When there is any Power from any K1 source (GE or Shore), K2 is active and the Inverter is not switched because K2 is keeping the Inverter 220V output unswitched (offline).
    • Even if the inverter is ON, it can’t deliver 220V to the panel, because K2 is ON as long as K1 delivers power.


This sound a bit complicated but it’s finally the priority GEN, Sore, Inverter as you said.


BTW: What is your Lithium Project doing? You have changed KOKOMO to Lithium meanwhile?


Thanks and fair winds

Ruedi & Sabina Waldispuehl


Amel 54. #55

Currently in Estepona heading to Gibraltar



Von: "" <> im Auftrag von Mohammad Shirloo <mshirloo@...>
Antworten an: "" <>
Datum: Donnerstag, 16. 
September 2021 um 07:40
An: "" <>
Betreff: Re: [AmelYachtOwners] Shore - Generator Switch-over box on A54 #solution


Hi Ruedi;


There are electrical schematics in the original AMEL operator’s manual in the Appendix section, that came with the yacht, that show how they are wired. Attached is the schematic for the K1-K2 switchover relays.


I believe K1 and K2 switch/relays make the selection of power source.  Power first  goes through K1 which selects the source between shore power and generator. I believe that generator has priority over shore power. Once this source is selected, it goes through K2, which selects between the output of K1 and the inverter, with the output of K1 having higher priority.


I am fairly certain that the priority is: 


  1. Generator
  2. Shore power
  3. Inverter





Mohammad and Aty

B&B Kokomo

Amel 54 #099


From: <> On Behalf Of Rudolf Waldispuehl via
Sent: Wednesday, September 15, 2021 8:31 PM
Subject: [AmelYachtOwners] Shore - Generator Switch-over box on A54 #solution


Hello Amelian's


I tried to find out how the Shore/Generator Switchover Box in the Engine room of my Amel-54 is exactly working. I do have in addition a 2500W MV inverter installed originally from AMEL. Last few weeks the Switch-over is doing strange things and fuses are blowing. 


I have not found any accurate information (drawings) electric scheme of that AMEL specific switch-over mechanism. I don’t know how it detects either one or all 3 of the 240V sources, and which is the master over-ruling the Generator or Shore and/or Inverter. How it protects the Inverter when Shore or Generator is running, etc… 
Does anyone out there have any detailed information how these system works and may have an Electric scheme with in dept knowledge how it works?


Thanks a lot for investigation and best regards
Ruedi Waldispuehl

WASABI A54. #55

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