Knodty

I think there is a diode fitted to the boat and I think you are correct with your guess at how it is wired. Tbh I need to do a little more investigating as to how it is wired as most of the wiring disappears behind the triple battery boxes I have and it is a bit like a plate of spaghetti 🙄 The battery fitted that has been fitted to the Bow thruster is a leisure battery, so I understand that will have to be replaced. Thanks for all your comments Guys they have been very helpful, and a little confusing as well, as my knowledge of domestic systems on a boat is very limited. Thanks Peter

No this is why i think it is wrong relay to have fitted as it is not being used as it was designed a starter assist and not a relay, to start the charging circuit.

It doesn’t have a leisure battery fitted to the thruster. The alternator is putting out 13.8 volts and I have that going to the Black box terminal 1 but nothing out of terminal 2 going to the thruster battery

This is the diagram from Victron and as far as I can see from tracing the wires it is not wired as the diagram. It is wired through the cable on the charging circuit from the alternator not the battery. This is why I asked if it was installed incorrectly?

Great thanks Grendel, I understand it a little more now. I had the engines running for at least 30 mins the other day and there was no sign of it switching over to my knowledge. I will have to check it again when I’m next on the boat. I think I will get a replacement just in case. I seem to remember a few months back noticing that the thruster was not sounding as powerful as it was, which might have been the start of the fault in question, and the battery not charging properly. Would this switch over happen once the voltage in the starter battery had recovered enough, and then it switches over to start both batteries together? What does the black wire under the module do, is it used to energise the Cyrix to switch over? Peter

I really appreciate all your input guys, however nobody has answered my main question. Can I omit the Cyrix module, Yes or no? If no, why not?

Colin you mentioned that it can be used for start assist, however it is not wired in the configuration, so can it be omitted? Peter

Thanks guys, Vaughn to answer some of your points raised. The fast fuse mentioned has continuity. The Thruster does have its own battery I have 5 on the boat, 1 for each engine two for domestics and 1 for the thruster. Thruster is 110 CA if I remember correctly and I’ve taken it home to charge overnight. I checked it once disconnected from the charger this morning and it was showing 12.7 volts and will check it tonight to see how much it has dropped by or if it is holding a charge. That battery is not charging as I mentioned in the original post, as I have no voltage after the Cyrix-CT module. My main question was can I remove the Cyrix-CT or is it needed on this type of circuit? Regards Peter

Is there any need for it in the charging feed to the Bow thruster Battery. As far as I can see it is only wired through it to the battery?

Hi Guys, My first post on here and fairly new to owning our own boat. Our bow thruster has been working for the last year of ownership, and has just suddenly packed up. I carried out electrical tests and realised the Battery was completely flat, only 1.0 volts. Not knowing how long this has been not charging and just working off the battery voltage. We haven’t used the boat for a 3-4 months now and the thruster worked ok beforehand. Tracing the Charging cables back to the engine bay it has a Victron Cyrix-CT fitted inline on the charging circuit. It has voltage going to it but not through it. Is this needed on the charging circuit or can it be omitted? Being new, to the somewhat complex nature of boat electrics, and trying to get my head around, how all the different systems work, it doesn’t seem straightforward to fit this to a charging circuit, and over complicating the system. I’ve had classic cars for over 30 years and have always worked on their electrics, and I’m not a beginner. I’m just wondering if I am missing something, as to why this is needed or been fitted in error? Thanks Guys Peter