Wiring diagram - Find my mistakes!

[carmencina]

Dear Community,

I am at the initial phase of my camper van conversion in China, in which I am planning to live and work together with my wife. Camper vans in China are not popular though they produce any kind of devices and gadgets one might search for this purpose.

I am not bad at DIY and woodwork but my electric knowledge is limited. I have been researching a lot in the last weeks to plan the wiring diagram that you see below. Despite my best efforts, I am sure there are mistakes that I cannot see and I hope some more expert eyes will help me avoid potential disasters!

I would greatly appreciate any help or suggestions, especially in terms of cable and fuse sizes. What mistakes can you find? (The simple software I used didn’t have many icons, so the 12v fuse box looks like a normal breaker.)

Also, can I just use (magnetic) circuit breakers instead of fuses a bit everywhere (except the 12v box)? I also don’t understand why I should use one or another kind of breakers/fuses so I would simply go with the circuit breaker kind you see in the icons.

Thanks and safe travels!

[phantomjock]

I have a few comments I'll share. Mind you, I come from a sailing background, so prefer all grounds to be "non-chassis" for the common connections.



I think you can elminate the 60A CB between the B2B charger and the common 12vDC buss. You'd save one CB and some wire and make it work as well.

I like the main "Kill Switch" disconnect. Alternator to the starter battery of course.

You show an inverter, but for value added a Charger/Inverter with a pass through and shore power connect would be very useful. I assume you have done an assessment, and 1000W enough (even at 220v) for your consumption requirements?

Nice presentation. Best of luck - and hope these comments are useful. There are other better "sparkies" than I , and expect they'll chime in too. Welcome aboard!

Cheers - Jim

[avanti]

I am not sure whether @phantomjock is advocating a "floating" ground (i.e., one with no connection to the chassis), but if so, I strongly disagree. Boats are different from motor vehicles, and so are the tradeoffs. Pretty much every motor vehicle in the world is designed with a chassis ground, and there are very good reasons for this. First among them is safety. Just don't do it.

Now, perhaps he merely meant to use dedicated return wires, with a single point bonding to the chassis. This is perfectly OK, but usually a waste of money. A chassis ground with proper ground points is electrically superior to dedicated returns of any reasonable ampacity. Lots of people feel that they are somehow "better", but I am not one of them.

[phantomjock]

Originally Posted by avanti

I am not sure whether @phantomjock is advocating a "floating" ground (i.e., one with no connection to the chassis), but if so, I strongly disagree. Boats are different from motor vehicles, and so are the tradeoffs. Pretty much every motor vehicle in the world is designed with a chassis ground, and there are very good reasons for this. First among them is safety. Just don't do it. .

I AGREE 100% My suggestion was:

"non-chassis" for the common connections.

Which is what the diagram shows. In fact, I was suggesting as you pointed out here:

Now, perhaps he merely meant to use dedicated return wires, with a single point bonding to the chassis. This is perfectly OK, but usually a waste of money. A chassis ground with proper ground points is electrically superior to dedicated returns of any reasonable ampacity. Lots of people feel that they are somehow "better", but I am not one of them.

I believe a Solid Ground is the best you can have. Unfortunately unless the vehicle is new, the difficulty of achieving that can be difficult. It is often the problem that bewilders many people when things don't start, run, or operate as expected. These are reasons I don't think it a waste of money. Corrosion and poor contact can be a problem with older vehicles. However, the vehicle shown in the initial posting looks new.



So I have suggested retaining the existing chassis grounds, and tie the others together via the buss bars as shown and then to the chassis. Which is what his (and my modified) diagram show.

OTOH - complying with the Chinese Regulations may have a different set of rules/requirements. Thank you for clarifying.

My suggestion to remove the extra wire and CB (crossed out in my edited diagram). I believe these add no added value to the wiring, but this was lost in my poorly worded response about grounding.

Maybe someone can answer: Why would you want to isolate the DC2DC charger?

Cheers - Jim

[avanti]

Originally Posted by phantomjock

I AGREE 100% My suggestion was:

Which is what the diagram shows. In fact, I was suggesting as you pointed out here:


I believe a Solid Ground is the best you can have. Unfortunately unless the vehicle is new, the difficulty of achieving that can be difficult. It is often the problem that bewilders many people when things don't start, run, or operate as expected. These are reasons I don't think it a waste of money. Corrosion and poor contact can be a problem with older vehicles. However, the vehicle shown in the initial posting looks new.



So I have suggested retaining the existing chassis grounds, and tie the others together via the buss bars as shown and then to the chassis. Which is what his (and my modified) diagram show.

OTOH - complying with the Chinese Regulations may have a different set of rules/requirements. Thank you for clarifying.

My suggestion to remove the extra wire and CB (crossed out in my edited diagram). I believe these add no added value to the wiring, but this was lost in my poorly worded response about grounding.

Maybe someone can answer: Why would you want to isolate the DC2DC charger?

Cheers - Jim

I agree with all of that. I especially support the idea of using factory engineered ground points as the root of a tree of ground busses. I do believe that it is OK to have more than one such root. Such an architecture avoids ground loops, which, of course, is virtuous.

[avanti]

Originally Posted by phantomjock

[COLOR="RoyalBlue"][B]
Maybe someone can answer: Why would you want to isolate the DC2DC charger?

You wouldn't in a van. Isolated B2Bs exist for use in boats, for reasons which you probably understand better than I do.

Lots of folks have trouble accepting the fact that two circuits that share a common return are NOT "interconnected".

[phantomjock]

Originally Posted by avanti

You wouldn't in a van. Isolated B2Bs exist for use in boats, for reasons which you probably understand better than I do..

Right - that was my question regarding the "extra" leg here [shown in orange] and replace with the wires shown in blue:


Just sayin'... (keep the ground leg that I 'over circled' - of course!.)

Cheers - Jim

[carmencina]

Thanks @phantomjock and @avanti, your contribution is very much appreciated.

a Charger/Inverter with a pass through and shore power connect would be very useful

Unfortunately, in China there are not many campsites or RV parkings as in Europe or the US, so chances of plugging into mains are low. On the other hand, solar panels are quite inexpensive, so I oversized the array (600W for a 250A battery) to charge fast. Plus, both the battery itself and the 12v fridge can be connected to 220 directly if I can find a plug!

1000W enough

Yes, my biggest appliance is 800W. I chose to keep the inverter small to avoid wasting amps when it's idle.

Why would you want to isolate the DC2DC charger?

I'm a beginner, I just thought it would be wise to isolate each section after a device/appliance to protect what comes next in case of overcurrent Is the CB after the B2B charger not similar to the CB after the MPPT in terms of protecting appliances downstream?

Related to this: I am wondering if I can use Circuit Breakers everywhere, instead of fuses, so I can reset them. Should I, instead, use fuses in some points for any specific reason?

using factory engineered ground points

I am not sure I fully understand all the implications of the "grounding" issue you guys are debating. I thought of connecting the negative bus bar to a dedicated ground point (I am not sure I can find one, the vehicle is from 2017 but second hand, no instruction manual, poor Chinese online documentation) or, alternatively, a bolt in the chassis. And the 220v ground to another ground point. Is this useless/wrong?

Thanks again for your help and please forgive my ignorance!