Camper Van mis-wired?

[Foxen]

Hello,

My sister bought a small camper van from a California based manufacturer of van camper interiors. This was their demo vehicle they used for marketing. It was completely built out.

I am helping her with adding solar to the van and got to looking at the 12V wiring the company had done. I "assumed" the fuse block with. the yellow label was all the 12V accessory "positive" wires and on the far right they stacked all the "negative" accessory wiring.

However, looking closer, it appears they stacked all the positive wires (shown on the right) because it looks like a larger gauge RED wire (maybe 6 gauge) is stacked along with these accessory wires. The fuse block doesn't appear to have any positive 12V DC power going to it.

Am I missing something? I plan on digging into it but the van is a few hundred miles from me and time is limited. I know that it can have the neg. wires at the fuse block and work but it is not how I wire our vans. Just wondered what others thoughts are. Appreciate any comments.

Thank you,
Jon

 

[Herbie]

My bigger concern is not that it's (apparently) fused on the ground, it's that the fuses are not directly near one of the battery terminals - it looks like there's a larger-gauge wire in that left bundle which perhaps eventually feeds back to battery negative. Every inch of wire between the battery and the fuse is a lightbulb filament just waiting for enough current to set it free.

Personally, I'd have to trace it all out, and then I'd consider re-working things such that there was a clear (and short!) link between the fuse-common terminal and the battery. (And maybe fuse the positives...) Depending on the solar setup (like if you're including a shunt, etc.), then you may end up having to interrupt or re-wire some part of it anyhow, so hopefully the bundles aren't done in a way that makes that harder...

 

[llamalander]

The van is missing a few things, and Herbie is right that fuses are the big one. Any power source should have a fuse in the first 12" of wire, same with any step-down in wire size. Fusing the negatives in a metal vehicle is really poor design--if anything shorts on the body or frame it will bypass all the fuses and keep going till something gets destroyed, up to and including the vehicle.

A good start might be putting AMRB fuses on the positive terminals of the house battery and the starter battery before it feeds the VSR on the right.

Probably more important is deciding what you want the system to do, and seeing if any of the components or cables will help that plan, and abandoning or removing the rest, however pretty it might be. If time is limited, don't waste it trying to make someone else's half-formed plan work.

Buy new cables and crimps rather than "seeing if you can make it work," and you'll have a better system in less time. If you do reuse cables, make sure the sizing and fusing is what you need & give every crimp a real tug to confirm it's solid.

If you don't have one handy, this is an excellent chart for choosing cables:

http://assets.bluesea.com/files/resources/newsletter/images/DC_wire_selection_chartlg.jpg

It's worth remembering the circuit length is for the entire run, positive to the device + negative back to the source.

More of a sales pitch, but still very useful is their fusing chart:

http://assets.bluesea.com/files/resources/newsletter/images/Choose_the_Fuse_Amperage.jpg

The different shades of each column and the different values for single or bundled wires is how they show de-rating the circuits for the heat they might experience. The chart is pretty generous to minimize tripping, so respect the heat limitations and use quality wire rated for 105ºc or move to the next column to the right if using 90ºc wire (or use the wizard linked on their website).

I'm guessing this is a pretty modest system with an AGM (or 2) for a house system charged from the van alternator. Something like the Blue Sea safetyHub 150 might make a compact common buss to replace the yellow block on the left and make fused connections to the VSR, solar and an inverter simple. If you can add a battery monitor, it is invaluable for seeing what is normal and being aware when things go wrong.

I have no stake in Blue Sea, but I appreciate their quality products and support, so I recommend them. I'd actually recommend any marine-grade equipment over Renogy or other RV-grade brands, if your sister can afford it. The reliability and reduced remote troubleshooting seems worth the price difference.

Hope that's useful, good luck.

 

[Foxen]

Appreciate all the great info. Thank you Herbie and Llamalander!

I am replacing the Switch with two Blue Sea disconnect switches. One for a battery disconnect that separates the load side and another facing the starter battery. Also a Blue Sea fuse block where I will land the positive and negative load side cables. New 4awg cables coming off the House battery where each cable will be fused with a quality ANL type fuse.

Regarding Verkstad's comment. You are right, it is really impossible to know how everything is connected based on a picture. I plan on getting into this next week and seeing "if" the negative wires are actually what are fused. (It just appears that the stacked load side cables (whether neg or pos ends) have a RED power cable that looks to be stacked along with the cables) I will get in there with a VOM and see what I find. I would love for this not to be the case but regardless, I will be adding the Blue Sea fuse block and re-landing the load side cables. I don't even like the fact the cables used for her 12V DC loads appear to be 16 or possibly even 18awg cables. Again, I will need to maybe even clamp the load and see if they are to sized to small. Not a very good first swing for a commercial van builder.

Thank you everyone.

 

[DaveInDenver]

Nothing wrong with 16 and 18 AWG wire if those labels are right about 3A load. Probably would be for 7.5A, too, although voltage drop could start to factor in on a very long run. An 18AWG wire with PVC insulation that's 72 inches long with 7.5A will have 0.30V of drop and around 7°C temp rise, completely sufficient.

Negative grounds can work but like mentioned it's poor practice in a chassis ground vehicle like this if that's the only fuse in the circuit. I wouldn't necessarily take them out if that is actually true, although I would add positive side protection.

There is a benefit to a fuse in the return because it can prevent a negative wire from inadvertently getting an overcurrent on it from another circuit. If you have a metal case on a device that is wired to the negative, like a fridge or radios sometimes are for noise interference shielding, this negative side fuse can prevent that circuit from carrying a damaging fault if you drop a hot on it. Like if you touch the case with a jumper cable. You'll see fuses in both legs with some factory harnesses included with mobile radios for this reason.