Questions regarding "So, you want to setup a good electrical system in your camper?"

Good info Vic and you are a talented writer!  Looking forward to the rest.  You should be a technical writer!

 

Steve

I've done some of that Steve... 

Hi everyone.
I’m new to the forum and new campers as well but I’ve got a fair bit of experience with boat wiring. Firstly a big thanks to Vic and all the other contributors for their work as well as thoughtful and honest discussion. I’m going to upgrade the charging system of my truck and camper. I don’t see any sense in reinventing the wheel here so I’m following Vic’s recommendations pretty much to the letter. I’m aiming for adequate rather than ideal in this build so I might substitute fuses for circuit breakers etc. I’m planning on sticking with the agm battery for now and am installing a Renogy DC DC charger with MMPT and a Renogy monitor with shunt. I don’t have solar now but have got the MMPT with an eye on adding that in the future. I have a couple of questions:

First what size of Anderson connectors are you using? I’m using #2 awg wire I have had sitting around for ever. I was thinking the Sb 120 amp ones but I’m wondering if these are too big? They are rated at 120 amps but at what voltage? Would the 50 amp ones work here because the voltage is so low?

Secondly does anyone have a clean way of mounting the connector in the truck box? I see there are some flush mount kits for the smaller ones that are mentioned in the Australian sites but nothing for the larger ones that I’ve seen so far. (Full disclosure I haven’t looked as hard as I could!)

And lastly could someone please explain the reason for a circuit breaker or fuse at both the truck end and the camper end of the positive supply wire? It seems like when the camper is connected their are two breakers protecting the same wire. Are they there to protect the wires in the case of a short when the truck and camper are disconnected? That's probably it but I feel like I’m missing something here. Don’t even mention age!!!

Cheers and thanks again.

Tom

Hi everyone.
I’m new to the forum and new campers as well but I’ve got a fair bit of experience with boat wiring. Firstly a big thanks to Vic and all the other contributors for their work as well as thoughtful and honest discussion. I’m going to upgrade the charging system of my truck and camper. I don’t see any sense in reinventing the wheel here so I’m following Vic’s recommendations pretty much to the letter. I’m aiming for adequate rather than ideal in this build so I might substitute fuses for circuit breakers etc. I’m planning on sticking with the agm battery for now and am installing a Renogy DC DC charger with MMPT and a Renogy monitor with shunt. I don’t have solar now but have got the MMPT with an eye on adding that in the future. I have a couple of questions:

First what size of Anderson connectors are you using? I’m using #2 awg wire I have had sitting around for ever. I was thinking the Sb 120 amp ones but I’m wondering if these are too big? They are rated at 120 amps but at what voltage? Would the 50 amp ones work here because the voltage is so low?

Secondly does anyone have a clean way of mounting the connector in the truck box? I see there are some flush mount kits for the smaller ones that are mentioned in the Australian sites but nothing for the larger ones that I’ve seen so far. (Full disclosure I haven’t looked as hard as I could!)

And lastly could someone please explain the reason for a circuit breaker or fuse at both the truck end and the camper end of the positive supply wire? It seems like when the camper is connected their are two breakers protecting the same wire. Are they there to protect the wires in the case of a short when the truck and camper are disconnected? That's probably it but I feel like I’m missing something here. Don’t even mention age!!!

Cheers and thanks again.

Tom

 

 

The reason for a circuit breaker or fuse at each end is to protect the wire and vehicle in the case there is a short to ground anywhere in the wire because there is a battery at each end of the wire, Think of the case where the camper is off the truck  If the wire from either battery to the connector is shorted, there is sufficient energy to cause a fire in the camper or in the truck. 

 

For the case where the units are connected together, a short anywhere will be energized from both ends until the fuse/CB breaks the connection from the battery with the fuse/CB However, there is still a path from the other battery without a fuse/CB.

 

Paul

First what size of Anderson connectors are you using? I’m using #2 awg wire I have had sitting around for ever. I was thinking the Sb 120 amp ones but I’m wondering if these are too big? They are rated at 120 amps but at what voltage? Would the 50 amp ones work here because the voltage is so low?

Cheers and thanks again.

Tom

Hey Tom.   I'd just go by the wire size.  Their website allows you to filter the results by amps or wire size

Anderson Powerpole and SB Connectors | Powerwerx

Thank you Paul and Vic. That makes sense now with the breakers. Yes two batteries with ample opportunities to raise havoc. I’ll check the Anderson site this evening. I’m just making a small electrical panel out of laminated arborite that will house the water pump panel, new USB chargers, energy monitor and the thermostat for the heater. I’m hoping this will allow me to significantly enlarge the tiny drawer that’s up there. And the panel is going to be easily removable so you can get at all the wiring!

Regarding connector sizing, what matters is the current rating of the connector and whether it will accept and provide a solid mechanical and electrical connection with the wire you are using.  Any of these connectors are rated for much higher voltage than any RV DC system is using.  An SB 120 is rated for 130 amp and wire size ranging from 10 AWG to 1AWG.  An SB50 (next size down) is probably large enough for your truck charging connection from a current rating standpoint (not sure what DC-DC charger you are usng), but it accepts a maximum wire size of 6 AWG, so too small for your planned 2 AWG. 

Thanks Jon. I ordered the SB 120 connectors. They fit the #2 wire. Both the wire and the connectors are going to be ridiculously oversized for the installation as it is now but seeing as the wire was already here it seemed like an easy choice. If I do decide to upgrade to the lithium batteries in the future or even a larger Agm setup then the wiring will already be in place to handle it. I went with the 30 amp DC DC charger as I thought it to be correctly sized for the 100 ah Agm battery. It remains to be seen how much and how we use the camper as to what the rest of the electrical system will need to be. And that’s going to be the fun part!! Not crawling around on your hands and knees with a headlamp trying to turn your arm around three 90 degree corners to put in another mounting cable tie. Lol

We use SB120's at work with a right angle bracket that places the open end of one flush to the panel it is mounted on. I think that they found that bracket on the powerwerx page, but I don't know that for sure. In our truck's bed I merely bolted it flat to the bedside pointing up. I pointed it up deliberately so that water & moisture would drain thru the connection uninhibited.

 

Going back to the weight of the batteries, an example of the importance of this. Our Chucara XL has the 2x 2GC's in a box on the side of the camper, aft of the truck's RR tail light. The camper does not normally come off the truck.

 

I now need to replace the rear springs as they are slowly collapsing and losing ride height. The weight is an issue for sure, but the placement of that weight makes it an even bigger issue. I'm considering moving them to under the step that is adjacent to the forward dinette seat. Enclosing and venting them there will take some thinking, but at least then they will be inside the wheel base of the truck instead of hanging off the rear of it.

Found a pic, not that it should need it, but why not?

 

 

EDIT: Just in case there's any confusion, that is NOT house wire. It is Ancor Duplex 6 ga.

https://www.ancorpro...s.com/en/120710

 

Edited by ntsqd, 17 February 2021 - 02:04 PM.

Hey thanks for that. I’m going to do a very similar installation in my truck. I’m still waiting for the Anderson connectors to show up but most of the hard work has been done inside the camper. The DC DC charger, shunt, and fuse block are all mounted as is the new battery box and the 125 ah AGM battery. I had to do a bit of cutting of the aluminium angle so that the new battery could drop straight in but it fits in there great. Just the actual wiring now. It does look like house wire but that tinned copper boat wire is nice stuff. Use that with heat shrink connectors and Boeshield T-9 or ACF-50 on the terminal blocks and that’s as good as it gets!!