Help with leisure electrics - Cable sizing, distribution, etc.

[skahigh]

Hi all,

I'm currently planning my camper build (T6 SWB) to incorporate the below.

Under driver's seat:

- Leoch Xtreme 110 Leisure battery (12V 110AH Xtreme AGM Leisure Battery (XR1750) NCC Class A - Alpha Batteries)
- CTEK D250SE DC-DC charger
- Starter battery -> DC-DC charger isolation switch
- Leisure battery -> 12v distribution isolation switch

Rearmost side panel, driver's side:

- CBE PC380 kit including DS300 12v distribution (CBE PC 380 Digital Control Panel Kit)

Behind rear bumper:

- 240v hookup

Components:

- Vitrifrigo C42L 12v fridge (C42L (external cooling unit) - Camper/Caravan - Vitrifrigo)
- Autoterm Planar diesel heater (either air 2d or 4d) (Autoterm.com - Air heaters Overview)
- CBE double USB sockets (CBE 2.1A Double USB Charger - Grey)
- Map light x 2 in pop top
- Spotlight x 3
- Evo design shelf with lightbar
- Water pump for sink


*********************************
Questions so far...

Is there anything obviously wrong with my proposed layout? We have a double passenger seat on a swivel so no option to place electrics there.

Where I'm starting to get most confused is on cable sizing and fuse requirements. I had looked at the total current for the components and planned to fuse the leisure battery to 12v distribution at 30A using 6mm2 cable however, reading the various manuals I can see that the fridge should be fused at 15A and the heater at 25A which immediately takes me way above the 30A main fuse rating, do I need to uprate both the main cable and fuse? If so, to what?

Secondly, I would prefer to run the fridge from the DS300 12v distribution rather than via a direct connection to the battery, I know I need to account for voltage drop but, does the DS300 12v distribution provide regulated 12v outputs (by which I mean 12v outputs regardless of the input voltage)? I think this would mean I only need to accommodate voltage drop from distribution to fridge when sizing cable rather than the full run from battery to distribution to fridge.

I'm sure I'll have loads more questions and appreciate any help!

 

[Dave Lawson]

Diagrams, Schematics & Wires -- How I Done It --

Diagrams, Schematics & Wires -- How I Done It -- ************************************************** Dellmassive`s -- "how I Done It" -- Thread ************************************************** Kit List And Stuff -- How I Done It & What I Use --...

www.t6forum.com

If you type “how I done it” into the search bar you’ll have pretty much everything you need.

 

[Pete C]

I can’t help with the CBE kit, but I ran 2 cables from the leisure battery (both fused). One for the fridge and one for everything else. The startup current for the fridge can be a problem, and this removes the voltage drop issue.

Pete

 

[Sackmycook]

No reason why you can't put electrics under the passenger swivel ?

 

[skahigh]

No reason why you can't put electrics under the passenger swivel ?

It's a double seat so the whole base swivels and slides.

 

[skahigh]

Diagrams, Schematics & Wires -- How I Done It --

Diagrams, Schematics & Wires -- How I Done It -- ************************************************** Dellmassive`s -- "how I Done It" -- Thread ************************************************** Kit List And Stuff -- How I Done It & What I Use --...

www.t6forum.com

If you type “how I done it” into the search bar you’ll have pretty much everything you need.

Thanks, I have read a number of these threads and have not been able to find answers to my specific questions.

 

[skahigh]

I can’t help with the CBE kit, but I ran 2 cables from the leisure battery (both fused). One for the fridge and one for everything else. The startup current for the fridge can be a problem, and this removes the voltage drop issue.

Pete

I suspect I might have to do this but, was hoping to avoid it to minimise direct connections to the battery.

Do you know if any of the other components exhibit similar spikes in power draw? The diesel heater or water pump perhaps?

 

[Deaky]

Diesel heater will pull around 11a when first turned on.

 

[oldiebut goodie]

15 to 20A if a 3.9/ 4 Kw heater. ( possibility as it has a 25A fuse listed )

 

[skahigh]

So what's the knock on effect? I need to accommodate both inrush draws simultaneously in the main battery fuse/cabling? So more like 50A?

I guess not an issue if I take the fridge directly from the battery as I may have to do to accommodate the voltage drop.

 

[oldiebut goodie]

I always advise connecting heaters directly to the battery avoiding all distribution points etc, this lessens opportunities for voltage drop to creep in.