Wiring diagram

[Scubaseas]

Originally Posted by Wotname

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.

Oops, my bad, Ready, fire Aim... 3 pack indeed.

[Scubaseas]

Knew I saw it thumbing through the latest Waytek catalog. 7 pack.


https://www.waytekwire.com/item/4554...-Fuse-Holder-/

[Wotname]

^^ Nice!

[Tin Tin]

If you have'nt seen it already, this maybe useful (note Victron booklet shows fuse at least between PV and MPPT)

https://www.victronenergy.com/upload...Systems-EN.pdf

[Wotname]

Originally Posted by Tin Tin

If you have'nt seen it already, this maybe useful (note Victron booklet shows fuse at least between PV and MPPT)

https://www.victronenergy.com/upload...Systems-EN.pdf

Those diagrams have to cover all possible combinations of solar panels and there are times when fusing is appropriate between panels and controllers however the devil is in the detail so there are many times when no fusing is required.

No need to add additional components unless they are necessary; if necessary though, then it is imperative to use them. One size does not fit all, horses for courses etc.

[mait]

Thanks for making it clear for me!

Originally Posted by Wotname

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.

[mait]

To be honest my current 29' boat is equipped with 2 solar arrays which feed their own MPPT-s and there are no switches between the panels and controllers nor controllers and house battery.

One array consists of 2x40W panels in series which are fixed on the deck.

The other array is 3x30W in series (so putting out more than 60Volts) and this is a removable panel - only used at anchorage or fine weather sailing. Connected or disconnected via MC4 connectors.
Has worked fine for 3 seasons.

So if the double pole breakers are really not needed between the solar panels and MPPT controllers, I would not waste space and time on them. Money could be found easier than all that space and time

Originally Posted by 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.

[mait]

Thank you both for the "MRBF Surface Mount Fuse Block - Common Source" idea, that's a real space saver

Originally Posted by Scubaseas

Knew I saw it thumbing through the latest Waytek catalog. 7 pack.


https://www.waytekwire.com/item/4554...-Fuse-Holder-/

[s/v Jedi]

You’re welcome to use my diagrams any way you like

For fusing I agree with most that has been posted in the thread.

I do recommend to add a fuse in the “emergency switch” circuit at each side. Imagine when the switch is in it’s normal open position: in that case the single fuse does not protect the cable at the other side of the switch, but it can still short out.

[mait]

Thanks Jedi,
I’ll continue editing the diagram according to the advice received. I’ll also add the missing negative side.
Once done, I will repost it

Originally Posted by s/v Jedi

You’re welcome to use my diagrams any way you like

For fusing I agree with most that has been posted in the thread.

I do recommend to add a fuse in the “emergency switch” circuit at each side. Imagine when the switch is in it’s normal open position: in that case the single fuse does not protect the cable at the other side of the switch, but it can still short out.

[mitiempo]

Quote
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)

The charger outputs are not in any way different. The profile set is the same at each output.

[mait]

Thank you for drawing my attention to this!

Originally Posted by mitiempo

Quote
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)

The charger outputs are not in any way different. The profile set is the same at each output.

[mait]

When I started this thread a week ago I was pretty confident that I knew what and how I wanted. I am not sure any more

This has been discussed many times before and there is probably no right or wrong. I am talking about options to charge the battery banks from the alternator:

A. Alternator (stock) - Start Batt - DC/DC - LifePo4 House Batt

B. Alternator (externally regulated) - LifePo4 House Batt - DC/DC - Start Batt

I have always felt that B is the more efficient way, but to keep things simple
and somewhat cheaper I had decided for option A earlier.

Now after some research I am pretty sure I can manage with option B if I wish. I am able to convert the stock (Mahle 446 / Letrika IA1393) 75A alternator for the external regulator myself, and the cost of adding a Balmar MC-618 while not cheap is not mission impossible either.

No matter which way I choose there is one thing bothering me - connecting the windlass to the house battery.
Would it work with a DIY 280AH Eve cells LFP battery with Daly 200BMS?
https://lifepo.de/en/products/daly-s...00a-lifepo4-4s
The BMS data looks promising
Discharge: 200A (2560W)
Charge: 200A (2560W)
Short-term discharge current: 600A

The windlass (12V Lofrans X2 1000W) will be about 9 meters from the LFP house battery. I am OK to run (very) thick cables for it.

I drew a new wiring diagram for option B. If you see something wrong there, please let me know

[mitiempo]

You can run the windlass from the house bank. The engine will be running and the alternator will provide part or all of the current needed so not all is drawn from the bank.

Your alternator should be de-rated by the regulator to about 70% and you need the temp sensor for the alternator.

[mait]

Originally Posted by mitiempo

You can run the windlass from the house bank. The engine will be running and the alternator will provide part or all of the current needed so not all is drawn from the bank.

Your alternator should be de-rated by the regulator to about 70% and you need the temp sensor for the alternator.

For the alternator I am planning Balmar MC-618 so it should be safe with correct settings.

What about using windlass without running the engine at the same time?
Would the BMS carry the current? Probably have to test it to find out.