Rough sketchup of my wiring/electrical plans so far, please comment on what I may be missing and the questions I have thus far.

[QPiepelr65]

Here.

Also to add I plan to do in series as I am loosely following Will Prowses the minimalist setup.

Even though I am following that he gives precious little information about the wiring required which is what I am having most issues figuring out. Also I plan on DC only for now and that setup is using an inverter so not sure how much applies.

So my main question is what size wire do I want for each thing given the powers stated for each item in the image.

The other questions you can see on the top right of the image I posted. Also someone mentioned in a previous post I made to buy and use all one wire gauge to save money. Is this a good idea?

Could I just work out the biggest gauge and then buy a coil of that and use that for everything as over gauge is always good right? Seems like it would be a waste of money if it cost considerably more for thicker wire.

As for the appliances I put in the image I realized that most of those apart from the heater/hob will be on usb ports. I think I recall Prowse say in one of his videos that 10 gauge will be good for most cases. Is that correct here? Here in one of the images is the data for the combihob. It looks similar to usual CDH consumption right? The other things mentioned are low draw too right.

What thickness for the other stuff charge controller to battery and fuse blade to whatever that is meant to connect to? I saw 6mm wire sold on some online stores and, making sure it is copper wire, I was thinking to just buy theirs rather than trying to make mc4 wires myself since they seem pretty commonly available and I can work out the recommended size by what renogy recommends for their panels, which is either 4mm or 6mm solar wire.

So what size wires and what other stuff? For fuses will that all be handled on the fuse blade or do I have to get them for elsewhere too? Do I have to get for the solar panels to mppt or will the circuit breaker be doing that job or is it best to have both circuit breaker and fuse? Anything else to add?

Also, beyond the panels to mppt to battery I am not sure yet how everything connects up but I guess there will be plenty of videos for that. I just want to get my itinerary of kit to buy and try and order in as few orders as I can to save on shipping fees then once I got it I can look up information for each step of the way.

 

[Dellmassive]

Each unit will have the required cable size and fuse to protect it stated in its install manual.

Start there as a rough guide.

Add that to your schematic.

Also join up as a VIP and you can get to the download section that has schematics and wire guides.

 

[Dellmassive]

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[Dellmassive]

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[DXX]

Auto & Marine Electrical Components & Accessories | 12 Volt Planet

Huge range of 12v & 24V wiring products, components and accessories for vehicle electrics, marine & leisure electrical projects. FREE delivery on orders over £100

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Have a read through the Knowledge part of this.

 

[QPiepelr65]

I have the general idea now about wire sizes and how to size the fuse for the wire for the main stuff like load items on the fuse blade thing and battery to fuse blade and battery to mppt. I just followed a few schematics from tutorials and get the general idea.

What I am still unsure of though is when and why we use circuit breakers in some places and not in others. For example I was trying to follow this video and he states to use a 30a fuse on the solar and 32a dp isolator. He vaguely states to make it higher so the fuse trips rather than the isolator but why? What is the point of using it then? It is only to have a manual cutoff rather than it acting as a fuse, as a circuit breaker would?

Also is that a good schematic to follow? Most people say he is a good resource but noticed there are some haters but dont know if there is any merit to the latter. Important to know particularly for electrics that you are following a legitimate source.

So on to inline fuses and circuit breakers. In the schematic there are both are various places as well as on other setups I have seen but not yet seen proper explanations for them. For fuses I guess it is the same method for usual fusing to the size of the wire correct? However I do not know why they place them where they do. For circuit breakers, as I think is the case in this video too, the size does not seem to follow the sizing for the wire size like fuses.

Also why and when to use them over fuses and should you use fuses as well or either/or? In this video he uses both a fuse and dp isolator and not sure why?

I have since bought 170a cable for the battery to fuse blade and battery to mppt. Was only a few pound different than lower ones so thought to overgauge for those main cables which are short.

I have bought 10m of 3mm2 wire (rated 33a) for most of my 12v load appliances as I bought to the biggest (for now) intended appliance which is the planned diesel hob which recommends 2.5mm wire. I figure that makes it easier than buying loads of different wire sizes and most stuff will be low draw like lights and usb ports.

So where should I put the circuit breakers and sizing the dp isolator since following that chaps diagram and anything else I might be missing?

 

[Deaky]

The 30a fuse on the solar panels is pointless. Those panels will never produce 30a. The isolator is purely for convenience to isolate the panels but you could just as easily remove the positive wire from the MPPT controller if you needed to. I can’t see any circuit breakers in his diagram not even the 240v side. You don’t need 12v circuit breakers, a fuse is perfectly adequate

 

[QPiepelr65]

The 30a fuse on the solar panels is pointless. Those panels will never produce 30a. The isolator is purely for convenience to isolate the panels but you could just as easily remove the positive wire from the MPPT controller if you needed to. I can’t see any circuit breakers in his diagram not even the 240v side. You don’t need 12v circuit breakers, a fuse is perfectly adequate

Thanks. My bad on the circuit breakers. I was watching many videos and one of his older ones uses circuit breakers not this one.

Doing some more reading around DP isolators it was funny to find an article on 12volt planet, which doesnt outright say it, but makes strong allusions to his video saying how both the dp isolator and even a fuse is not advised. As 12volt planet seem highly regarded I was inclined to trust their advise, as well as others here and elsewhere having recommended similar.

Why though, since you have to fuse nearly everything else in the system, do they say you dont even have to have a fuse from the panels to the charge controller? I know they say to decrease resistance as the positive benefit but why does that not risk the wire blowing as would be the case with nearly everything else? If the answer is that the panels dont generate enough amps to risk the wire does that not beg the question that if you overgauge the wire high enough you could do without fuses at all. I am not saying I want to do that it is just an academic query. Or is it for some other reason that fuses are not necessary in this case of the solar wire to controller?

So since the circuit breakers seem more of a convenience than a safety necessity I have done away with them and just gone with some mega fuses and holders for those thicker wire. That does simplify matters quite a bit.

 

[ginkster]

I’d suggest joining the ‘Campervan Electrics’ Facebook page and posting your plan on there for feedback. It’s a really useful resource and has many expert members. As always though, be prepared to get polar opposite views on certain subjects such as isolators for single solar panels!

p.s. not saying there aren’t many experts on here

 

[QPiepelr65]

How do I stay safe installing my solar if I didnt buy a battery cutoff, or isolator/breakers and general safety advice for installing/uninstalling?

I will first note that I am only working with a 12v system and have no plans to implement ac so from what I read that does limit the possible dangers.

I got, what I hope is, the remainder of my kit yesterday and realized I dont have the first clue about safety of installing this stuff. Even the Will Prowse videos that claim to be for beginners he seems to assume a previous background in electrical wiring and doesnt really explain about anything when installing stuff.

Likewise with all other so called basic videos I have seen so far. I have seen no mention of safety precautions that are required when touching wires in the system. Is that because they are not dangerous. I certainly thought it better to check that here first.

The general consensus when I was asking about breakers and isolators were that they are just a convenience rather than a safety measure and that fusing the wires is all that is required for safety. I just realized yesterday though, once your connection is live to the battery how do you then disconnect and mess about with wires without risk of electrocution.

So I thought I would keep it simple and only use megafuses for the links between battery to blade fuse box and battery to mppt. As such though how do I disconnect safely to work on the system because the act of disconnecting, without a breaker/disconnect must then entail touching a live wire to disconnect the fuse. Is this safe to do or not?

Oh btw the way on wills minimalist youtube video I am confused as to why he connects the mppt to the blade fuse block rather than the battery, the latter which seems to be most common practice in other setups. Again, he doesnt bother explaining this at all. Anyway, since this seems to be the exceptional case I am just going to connect them to the battery but I am interested to know why he did it like that.

I ask for both the link to the battery to blade fuse block and battery to mppt. Also what about the panels to the mppt? How to disconnect those since, as I made in another post, I have not used fuses or a dc isolator. In antoher reply elsewhere they mentioned to simple disconnect the positive from the panels to the mppt, but again, is this safe to touch since it will be live.

 

[DXX]

How do I stay safe installing my solar if I didnt buy a battery cutoff, or isolator/breakers and general safety advice for installing/uninstalling?

I will first note that I am only working with a 12v system and have no plans to implement ac so from what I read that does limit the possible dangers.

I got, what I hope is, the remainder of my kit yesterday and realized I dont have the first clue about safety of installing this stuff. Even the Will Prowse videos that claim to be for beginners he seems to assume a previous background in electrical wiring and doesnt really explain about anything when installing stuff.

Likewise with all other so called basic videos I have seen so far. I have seen no mention of safety precautions that are required when touching wires in the system. Is that because they are not dangerous. I certainly thought it better to check that here first.

The general consensus when I was asking about breakers and isolators were that they are just a convenience rather than a safety measure and that fusing the wires is all that is required for safety. I just realized yesterday though, once your connection is live to the battery how do you then disconnect and mess about with wires without risk of electrocution.

So I thought I would keep it simple and only use megafuses for the links between battery to blade fuse box and battery to mppt. As such though how do I disconnect safely to work on the system because the act of disconnecting, without a breaker/disconnect must then entail touching a live wire to disconnect the fuse. Is this safe to do or not?

Oh btw the way on wills minimalist youtube video I am confused as to why he connects the mppt to the blade fuse block rather than the battery, the latter which seems to be most common practice in other setups. Again, he doesnt bother explaining this at all. Anyway, since this seems to be the exceptional case I am just going to connect them to the battery but I am interested to know why he did it like that.

I ask for both the link to the battery to blade fuse block and battery to mppt. Also what about the panels to the mppt? How to disconnect those since, as I made in another post, I have not used fuses or a dc isolator. In antoher reply elsewhere they mentioned to simple disconnect the positive from the panels to the mppt, but again, is this safe to touch since it will be live.

There isn’t much risk of electrocution but there is a significant risk of fire and wasting money if you are installing without the required expertise.

 

[QPiepelr65]

Well I managed to get things going yesterday and power up the mppt and an led light via the blade fuse holder. Cut the 170a wires to size - This was really tight with little margin for error as I underestimated how little 1 meter would be for + and - for both mppt and blade fuse holder to batt. Anyway I managed it and fused them both with 150a megafuses in their holders both at the + side of the battery, as I had seen in a Prowse video.

Used the mt50 to check for power and it powered up. Later made the led connection to test that and it lit up.

Someone elsewhere has given a warning that

OK, lithium batteries can deliver much higher current than lead-acid, probably between 5000A and 20,000A.
Make sure you never short them, keep wire ends apart, don't let metal tools cause a short. Insulated handles on wrenches, of course don't wear metal jewelry.
Good to wear safety goggles, for protection from splattered molten metal.

What do others say on that?

As every other comment was saying that 12v isnt even enough to pass the skin I went ahead and put my fingers on the + and - of the battery just to get any apprehension out of the way. Only did it based on the previous comments of it being safe, not just on a whim. Nothing happened so then I felt better about working on the system.

 

[Pete C]

It’s the current that is dangerous, not the voltage.
That comment is right, short-circuit any decent sized battery and it will vaporise or quickly melt whatever is causing the short circuit, and probably damage the battery.

Pete