Wiring diagram

[mait]

Here I am asking for a little help again.
I have finally reached to a point with my refit of OE36 that the new engine (Sole Mini 29) is installed.

Now I have to decide the location and type of all electrical components. I have a good idea what I need in the boat and I want to keep things simple as you can see.

I've made my decision to charge the LFP house battery via DC/DC converter. So this topic is not to be discussed here.

I would be more interested in your opinions on fusing, as well as their type and placement in my diagram. Also what type of busbars would you recommend?
Main switches?
And if you see obvious flaws in other areas please let me know.

Ahh, almost forgot. I am terribly sorry that I took someone else's diagram and modified it instead of creating my own from scratch.

[Wotname]

At first glance, the fusing arrangements looks good to me although I wouldn't bother with the breaker switches of the solar controllers. They are internally short circuit protected.

[Tin Tin]

I would put double pole breakers on the solar panels before the MPPTs - you can google the reasons why.


Your house battery seems to be only charged by the solar panels. The DC DC charger just charges the start battery. No desire to use the engine alternator at all?


I would use tinned cables and there are recommended cable sizes for the distance to be covered and their ampacity so correct fuses or breakers to protect the cables are applied. Personally I use breakers instead of most fuses - expensive but convenient. I use Blue Seas bus bars, there are cheaper alternatives.



I would also run the inverter from the primary bus bar with its own breaker.



Again, only personal opinion, I would install an inverter-charger - say a 1200W victron. The 700w won't be good for much.


You might want to consider a cable + emergency switch from house to start battery in case start battery dies.




Just my 2 cents.

[flee27]

I agree with most of the above comments.

Fuse location-They need to be as close as possible to the source. And remember you are fusing to protect the wire and not the device(s).

The inverter needs a class T fuse and definitely a cut off switch of some type.

As Tin Tin eluded to. Depending on you usage and alternators ability you might want to consider allowing it to also charge your house bank.

Good luck with you wiring upgrade. It is very comforting to know your system and have confidence it's architecture is solid.

Foster

[mait]

Thanks for the suggestions! Below are my answers

Originally Posted by Tin Tin

I would put double pole breakers on the solar panels before the MPPTs - you can google the reasons why.
Thanks, I'll check this out!


Your house battery seems to be only charged by the solar panels. The DC DC charger just charges the start battery. No desire to use the engine alternator at all?
The alternator charges start battery and from there via DC-DC charger the house battery. You probably missed it.
House battery is also charged by BlueSmart 30A shore charger. That has 3 different outputs so it can be connected also to start battery using a different profile (forgot to draw this wire)

I would use tinned cables and there are recommended cable sizes for the distance to be covered and their ampacity so correct fuses or breakers to protect the cables are applied. Personally I use breakers instead of most fuses - expensive but convenient. I use Blue Seas bus bars, there are cheaper alternatives.
Breakers instead of fuses is not bad option, I just have to check where and how to fit everything.

I would also run the inverter from the primary bus bar with its own breaker.

Again, only personal opinion, I would install an inverter-charger - say a 1200W victron. The 700w won't be good for much.
That's a personal preference, but I prefer them in separated units. I only need an inverter to charge a laptop, occasionally a cordless drill battery. Small loads only. No kettles, hairdryers, microwaves etc...

You might want to consider a cable + emergency switch from house to start battery in case start battery dies.
Should I just draw a wire from "Always On positive bus" to start battery positive terminal with a main switch in between to achieve this?


Just my 2 cents.

[mait]

Thanks for the comment about the inverter fusing.

I am afraid the diagram is confusing, the alternator (engine on the diagram) should charge both batteries - start battery and then via DC/DC the house battery

Originally Posted by flee27

I agree with most of the above comments.

Fuse location-They need to be as close as possible to the source. And remember you are fusing to protect the wire and not the device(s).

The inverter needs a class T fuse and definitely a cut off switch of some type.

As Tin Tin eluded to. Depending on you usage and alternators ability you might want to consider allowing it to also charge your house bank.

Good luck with you wiring upgrade. It is very comforting to know your system and have confidence it's architecture is solid.

Foster

[mait]

Originally Posted by flee27

...
Fuse location-They need to be as close as possible to the source. ...
Foster

What about the "Always on charge bus" fuses? Wouldn't the sources be MPPT chargers, BlueSmart shore charger and Orion DC-DC charger? The fuses are in the wrong end of the string in that case, aren't they? Each of these devices have internal fuses (I suppose). Do I need a fused busbar there at all?
I'm getting confused

[Scubaseas]

What everyone else said.

Fuse on the + shunt wire?

[Off Trail]

The dcdc charging direction (goes-in vs goes-out) is ambiguous in the pic which I think is confusing some folks.

[mait]

Originally Posted by Off Trail

The dcdc charging direction (goes-in vs goes-out) is ambiguous in the pic which I think is confusing some folks.

Probably so. I didn't even think about the other possibility, because it was clear and set in my head

[Wotname]

Originally Posted by mait

What about the "Always on charge bus" fuses? Wouldn't the sources be MPPT chargers, BlueSmart shore charger and Orion DC-DC charger? The fuses are in the wrong end of the string in that case, aren't they? Each of these devices have internal fuses (I suppose). Do I need a fused busbar there at all?
I'm getting confused

Having two sources connected to each other needs (sort of) special consideration. It depends on the design and maximum current capability of each source. If the max current the source can deliver is lower than the rating of the wire, no fusing is needed. Typically this is the case of an alternator. If the alternator can only deliver say 100A and the wiring is rated higher than that (as it should be), then fusing at the alternator end is not needed. Fusing at the battery end is needed because the battery can deliver a huge current.

So if you MPPT controller is connected to the battery charge bus, a fuse is definitely needed at the battery end. The MPPT end is dependant on the design of the MPPT internal circuitry. The Victron units you have selected do not need fusing at MPPT output. Victron has provided internal short circuit protection (inside the controller). If the output wiring is shorted i.e. the current delivered by the MPPT controller exceeds it's max design capability, the MPPT controller shuts down. This protects the wiring (and the controller) without needing external fusing near the source.

[Wotname]

I just have to check where and how to fit everything

Space is often tight when you need multiple fusing.
I have used the Blue Seas MRBF Surface Mount Fuse Block - Common Source for a charging bus. While they are only available with 3 fuses, I paralleled 3 of them to get 9 fuses into a small space.

https://www.bluesea.com/products/519..._Common_Source

[Wotname]

While double pole breakers on the solar panels are very necessary on roof top house solar panel installations, they are not really necessary on most boat installations. In fact IMO, they are another failure point without providing any substantial benefit and are a waste of money.

Just make sure you wiring is rated higher than the short circuit current rating of the panel and keep the total voltage of any series connected panels below say about 50V.

[Scubaseas]

6 pack MRBF
https://www.waytekwire.com/item/7826...Surface-Mount/

[Wotname]

Originally Posted by Scubaseas

6 pack MRBF
https://www.waytekwire.com/item/7826...Surface-Mount/

Are you sure you have the correct link?
The link shows me a 3 pack MRF with independent sources; really need common source unless you want strap the independent sources yourself.