Voltage at Raymarive display super low but everything works

[wawando]

Hi,

Can anyone help me to understand how can Raymarine display voltages of 18.8v for the engine batteries 24v for house batteries and 5v for genset batterie but the genset starts and engines too?
Has anyone seen this? What can be wrong?
Does a genset start with 5v?
Any help is much appreciated!

 

[PaulRainbow]

Is the Raymarine actually connected to the engine and genset batteries ?

I'd suspect that it is not and is just displaying random figures. The genset would not start from a 5V battery and the engines would not start from 18.8V.

Do you not have dedicated volt meters or battery monitors ?

 

[wawando]

Is the Raymarine actually connected to the engine and genset batteries ?

I'd suspect that it is not and is just displaying random figures. The genset would not start from a 5V battery and the engines would not start from 18.8V.

Do you not have dedicated volt meters or battery monitors ?

The boat is new, I dont know (nor does the owner nor the seller!!!)
When the engines or genset start, the raymarine displays normal voltages…

 

[johnalison]

My different Raymarine set-up over-reads at most of its outlets but under-reads markedly when the illumination is switched on. It is quite consistent within these errors though.

 

[PaulRainbow]

Impossible to answer without some information.

 

[wawando]

Impossible to answer without some information.

I will try to measure battery voltage next time I go to the boat. I was just asking if someone had seen this before for any clues. Thank you!

 

[PaulRainbow]

I will try to measure battery voltage next time I go to the boat. I was just asking if someone had seen this before for any clues. Thank you!

It would be useful to know how the Raymarine equipment (whatever that is) has a connection to the batteries. The domestic battery voltage is usually available because displays are connected to it, there is no direct connection for genset and engine batteries, so you need to find out how it's all put together.

I asked in post #2 "Do you not have dedicated volt meters or battery monitors ? "

What is the boat ?

 

[pvb]

What is the boat ?

The OP's avatar looks suspiciously like a Nautitech 47 catamaran.

 

[wawando]

It would be useful to know how the Raymarine equipment (whatever that is) has a connection to the batteries. The domestic battery voltage is usually available because displays are connected to it, there is no direct connection for genset and engine batteries, so you need to find out how it's all put together.

I asked in post #2 "Do you not have dedicated volt meters or battery monitors ? "

What is the boat ?

It is a Sirena 58 with axiom displays, cummings genset and cat engines.
What puzzles me is why voltage displays correctly on Axioms ONLY when genset is running… if genset is off or even when engines are running the Axiom display those low voltage values (most probably dummy values as you suggested)… When engines are running the cat engine display shows 24.8 while Axioms still show 18.8v to 19v values (the value varies a bit)…

 

[wawando]

The OP's avatar looks suspiciously like a Nautitech 47 catamaran.

That is correct, but it is not my boat with this issue, it is a Sirena 58

 

[pvb]

That is correct, but it is not my boat with this issue, it is a Sirena 58

As you've said that the boat is new, can't Sirena fix it under warranty?

 

[wawando]

As you've said that the boat is new, can't Sirena fix it under warranty?

Trying, but not easy, representative knows nothing and cant solve. At the end some boat electrician will solve it, I am just trying to understand and see if someone has seen this before.

 

[pvb]

Trying, but not easy, representative knows nothing and cant solve. At the end some boat electrician will solve it, I am just trying to understand and see if someone has seen this before.

If I'd spent over a million quid on a motor boat, I can assure you I'd get any problems fixed at the maker's expense.

 

[PaulRainbow]

It is a Sirena 58 with axiom displays, cummings genset and cat engines.
What puzzles me is why voltage displays correctly on Axioms ONLY when genset is running… if genset is off or even when engines are running the Axiom display those low voltage values (most probably dummy values as you suggested)… When engines are running the cat engine display shows 24.8 while Axioms still show 18.8v to 19v values (the value varies a bit)…

Genset and engine battery data has to be fed into the STNG network by something, perhaps that something is connected to the genset by mistake. An example would be a Victron GX system, supplying battery data to the network, but the GX system only being powered by the genset. Would be a very odd and incorrectly installed system. You need to forget about Raymarine, especially the Axioms and concentrate on what should be supplying the data to the network, IMO.

 

[wawando]

Genset and engine battery data has to be fed into the STNG network by something, perhaps that something is connected to the genset by mistake. An example would be a Victron GX system, supplying battery data to the network, but the GX system only being powered by the genset. Would be a very odd and incorrectly installed system. You need to forget about Raymarine, especially the Axioms and concentrate on what should be supplying the data to the network, IMO.

Makes ALL the sense.