Adding additional electrical components

[mcerbm]

I have a k-series caterham superlight R, it has a battery master switch and a flip style aero ignition switch (there is no ignition barrel). I have a retro fitted water-resistant 12V socket which I purchased off amazon. That allows me to charge a phone (through a usb 12V plug) or power a tom tom etc.

 

I am wanting to expand with a few extra electrical items but keep it looking factory fit or hidden.

 

I also compete in Hill climbs and sprints so I need everything that would be connected to be killed with the battery master switch. I essentially use the battery master switch as the key.

 

I have a pdf of the current and proposed wiring diagrams for my car. Which are kept here:

">current

">Planned

 

The 12V socket at the engine bulkhead isn’t connected to the battery master switch, Its kept live to allow a battery conditioner to be plugged in if required. It also is a broken circuit when I compete, as I don’t have a device attached.

 

As you can see I was planning to run a live cable from the last free fuse on the caterham fuse box to an additional fuse box in the boot. This may not be required but I would rather have the comfort of knowing there is a fuse upstream of the live cable that could get quite hot next to the passengers arm. Its also a convenient point to take a live feed from.

 

I don’t have an electrical background so the diagram may not bet the best. Is this the best approach to get the items listed connected? The fuse ratings in the diagram are not final, I will find out what each device needs first, the cables will be rated appropriately too.

 

I was going to use:

 

USB Socket

 

12V Socket

 

4 way Fusebox

 

Heated Seat

 

I have the heated seat already (request from girlfriend!) and it actually fits quite well into a tiller seat.

 

The fuse box will be hidden in the boot, the sockets being black should blend into the black carpet of the bulkhead reasonably well.

 

The microphones were after reading a few trial runs from other caterham owners on mic placement. It allows an exhaust & induction sound to be picked up and linked in stereo.

 

Thoughts / improvements?

[Jonathan Kay]

The links to the PDFs don't quite work, although I could find them.

 

How many of those devices do you want to be switched with the ignition?

 

As you say you need to discover the nominal peak current for each of the devices you're planning to power from that additional accessory feed. You may need some relays.

 

What sort of connector are you thinking of for the wiring to the heated seats?

 

(I don't know the rules on modifications or electrical safety for the competitions in which you want to participate, but you need to find out before you start wiring.)

 

Jonathan

 

Edited by - Jonathan Kay on 21 Apr 2014 00:52:23

[Ian B]

These links should work Proposed and Current

 

All looks fine subject to wire sizing and fuse rating.

 

Re linking phone to comms, and charging phone from car/usb: I would use a bluetooth receiver on the comms system for the audio link, and a simple charging lead from the usb socket. Separating the phones power and audio like that will eliminate any ground loops through the phones power connection that could cause interference on the audio.

 

I'd go for a 6-way fusebox for "future use", and you might find something like this fusebox from CBS means the connections have a bit more physical protection from other stuff in the boot, as they're 'behind' the body of the fusebox

 

I'd also have everything ignition switched as you've shown it

 

 

 

Edited by - Ian B on 21 Apr 2014 02:32:55

[mcerbm]

The heated seats are terminated in a 12V plug. I would just use them when touring with the 12V sockets in the boot bulkhead. For competitions I would unplug and remove them. This leaves the two empty 12V sockets as a broken circuit. The whole lot would still be killed with the battery master switch anyway so should be ok for scrutineering.

[GF04RCE]

Something else to be aware of..... Following my k-click problems and investigations etc. my conclusion (unsubstantiated) was that the additional items wired into my loom were causing power leakage, which brought on the K-click effects....

 

x2 12v sockets (x1 of those connected to a multi-socket)

Autocom system

 

All sorted now thanks to revilla's guidance, new relays and direct feed....

 

Just something to file away in the back of the mind just in case...

 

David M

[Jonathan Kay]

Have you got those current estimates? I strongly suspect you're going to need one or more relays to avoid putting too much current through the ignition switch.

 

I've come across a lot of poor connections with "cigar lighter" plugs and sockets. They might be OK but I'd look at better connectors.

 

Jonathan

[mcerbm]

Jonathan, this is where my electrical knowledge starts to fail me. I'm not sure at what point a relay would be required... I understand the concept with the starter motor.

 

Would I need a switch effectively to activate the relay and make the additional fuse box live?

 

So far I have found that the heated seats are 45W so would be 3.75A each, the usb connector can provide 2.1A presumably to each usb socket. The starcom / autocom system is 0.7A (from stardom manual) so with everything running that would be 12.4A running through the ignition additional.

 

The diagram I made up was just a guess I need to actually get a caterham wiring diagram. I wouldn't of thought the full battery current goes through the ignition? wouldn't there be a spark when you flicked the aero switch? I'm guessing there must be a resistor somewhere between battery and ignition?

 

The heated seats are temporary items they will get whipped in and out quite often, they are only covers after all. I need a connector that is good for that purpose which the 12V is. If there was a tiller type heated seat then I would want a proper connection with a suitably "factory fit" look switch. That probably goes against the ethos of caterham ownership though!

 

Is an additional ~13A too much to add through the fuse box (which is presumably through the ignition)?

[Ian B]

I'm not sure what the leeway is on the ignition switch rating, but if you want to be sure, add a relay to switch the supply to the auxiliary fusebox.

 

You can use a regular 40A relay such as this one, connected as follows:

Terminal 85 to a good earth

Terminal 86 to a switched ignition feed

Terminal 30 feed from battery via an inline 40A fuse near the battery

Terminal 87 to the input side of the new auxiliary fusebox

 

HTH

[Jonathan Kay]

Quoting mcerbm: 

The diagram I made up was just a guess I need to actually get a caterham wiring diagram. I wouldn't of thought the full battery current goes through the ignition? wouldn't there be a spark when you flicked the aero switch? I'm guessing there must be a resistor somewhere between battery and ignition?

It's not really through the ignition: the possible problem is the additional current through the ignition switch and existing wiring.

 

I suggest you have a look at Ian B's post and read around to understand why a relay might be a good idea. The way that you have described you'd only need one and it could be at the start of the long feed run: it doesn't have to be near the new fusebox at the rear.

 

Jonathan