Wiring help, beer tokens on offer

[mcc1979ian]

ok so I’m about to wire in a few bits into my 90 but need a little advice

iv figured out the schematics as I believe to be correct but open to criticism as I’m no expert. I’m not 100% on amperage’s etc and figuring out which fuses, wiring gauges I require. I’m lead to believe if I go overboard I could be looking at voltage drop and if to low I’m looking at a fire 😱

Ill post my schematics below and hopefully one of you chaps will be clued up and let me know exactly what I may need and point out my mistakes. 
 

If someone can advise me on everything I’ll send an alcoholic gift to them


 

[FridgeFreezer]

Rotated to save people's necks...

 

[Escape]

After a quick look, my 2 cents:

- second alternator: no real reason to use a relay for the charge light. In general it is a good idea to have an ignition relay to provide an ignition switched feed to all the items that need it, so all the current doesn't pass through the ignition switch.

- air horn: you’ve mixed terminals 85 and 87, 87 needs to go to the air horn, 85 to ground (as you drew for the heated seats for example)

- CB: OK, but best make sure there are no other big loads on that fuse box to avoid interference.

- heated seats: OK, with one switch and relay per seat. You don’t need to connect everything to the same earth bar, the seats will probably have a good ground through the mounting bolts, that will keep wiring runs as short as possible.

- 12V socket: OK, earth only needed if the switch has a tell tale light.

- rear work light: OK, you don’t need a 30A switch as it’s only powering the relay, so more like 50mA. A 5A fuse allows for 2x 30W lights, upgrade as necessary (make sure the wiring can handle it!).

- strobe lights and side working lights: OK, again a lower rated switch will suffice. 30A switches are hard to find, a Carling will safely handle 10-20A which is enough for most, otherwise use a relay as for the heated seats.

- heater fan: OK, apart from the type (writo?), 87 goes to the blower

- LED light bar: for a 300W LED light you need at least a 25A fuse, better 30A. As for the switch, I think you want the LED to come on with main beam or separately? For that you need to connect the common input for the switch to the relay, output 1 to main beam (fuse not really needed) and output 2 to either ignition switched or permanent 12V (depending on if you want to be able to use the LED with or without ignition on, I’d use permanent 12V). As above, a switch for a relay hardly takes any current.

- spot/marker lights: not sure what you’re trying to do, but the fuse needs to be at least 3A for 2x 15W lights

- Volt gauge: no switch needed, but if left connected permanently the gauge will drain the auxiliary battery. Piggy back from an ignition switched feed from the aux battery or provide an ignition switched earth (very useful for dashboard accessoiries).

- interior lights: OK

- cooling fan: as the air horn, terminals 85 and 87 are the wrong way round. What are you trying to do with the switch? In this circuit, it will only prevent the fan from coming on. You probably want a switch in parallel with the X-eng temp switch, powered from ignition 12V. And as above, a small switch will do for the relay.

- diesel heater: OK, if the heater isn’t more than 100W (depends on the fan fitted). Otherwise better to use a relay.

It’s good that you’re being methodical, this will prevent mistakes and will make life easier. But I suggest you try and talk things over with someone who’s good with elektrickery, to iron out the details.  

Filip

[mcc1979ian]

Cheers, I’ll alter my mistakes in the morning.

For the fan Iv a 3 terminal switch in the top hose and an electric fan with an earth and a brown and a grey wire which I presume are low speed and high speed. The idea with the switch was to hopefully leave the witch deactivated when needed. 
 

2nd alternator was taken from the instructions that were on the listing when I bought it so thought that was just the correct way. I presume I wouldn’t really need the warning lamp connections for that

[Escape]

It is best to include the warning light circuit for the second alternator, as that also provides the exciter current. Without it, you might have to rev the engine before the alternator starts charging by itself. It's just the relay that isn't needed.

You didn't include the 3 wires on the cooling fan, so no way of knowing it's a 2-speed motor. 😉 And I'm still not clear on what you want the manual switch to do? Turn the fan off (ex when crossing deep water) or on manually as a precaution. 

[mcc1979ian]

Im hoping the manual switch will stop it activating when I don’t want it too 
 

The fans a kenlowe job with black, grey and brown cable so I presume blacks earth, and either off the others are a fast speed and slow speed

[FridgeFreezer]

11 hours ago, mcc1979ian said:

The fans a kenlowe job with black, grey and brown cable so I presume blacks earth, and either off the others are a fast speed and slow speed

Do they not come with a manual?

Brown is ground on some vehicles

[Bowie69]

2 minutes ago, FridgeFreezer said:

Brown is ground on some vehicles

Yes, 80's Vauxhalls I seem to remember.... used to fit stereos when I was at uni for a local car accessory shop, took me a long while to work out what on earth was going on.....

[FridgeFreezer]

1 hour ago, Bowie69 said:

what on earth

I see what you did there

[Bowie69]

Just now, FridgeFreezer said:

I see what you did there

Glad someone did....

[mcc1979ian]

7 hours ago, FridgeFreezer said:

Do they not come with a manual?

Brown is ground on some vehicles

It came with a relay type board and a probe that sat between the radiator fins but as far as I remember there wasn’t instructions with it. Was along time ago I actually bought it for another project that’s now 15yrs in 🫣

[Escape]

On 10/24/2022 at 12:09 AM, mcc1979ian said:

Im hoping the manual switch will stop it activating when I don’t want it too 
 

The fans a kenlowe job with black, grey and brown cable so I presume blacks earth, and either off the others are a fast speed and slow speed

In that case you really want a 3-position switch: off, automatic (activated by the sensor) or manual. The "off" setting should probably come with a warning light, as it's easy to miss and you don't want to see your temp gauge rise too much before you notice it!

I did a quick google for the 3 wires, seems grey is for normal speed and grey+brown for high speed, black for earth. That would make it a bit harder to wire, especially if you don't know what the board does exactly. Easiest would be to only use high speed and be done with it.

As an aside, when Triumph gave the Stag a facelift, they changed the interior lights from earth switched to live switched. But they didn't bother to change the wiring, so you'd have a few black wires running through the interior that were permanent 12V!

[Bowie69]

A few questions:

• Have you decided on a type of switch you want to use? You have most rated on the diagrams at 30A which is completely unnecessary and expensive if you are using a relay to do the actual switching, relays consume ~150mA, so this is all the switch needs to be rated at, though in practice you won't find much rated under 5A for automotive use.
• Some of the items you want will be run on ignition switched live, ideally you want a new busbar or similar which is switched via a big relay with the ignition switch -is that something you have plans for?
• Sort of related, while individual diagrams are useful, you are building an electrical system, not a series of separate circuits -it would be good to start to think how you are going to get power from where (i.e. the bit before the fusebox) and also to optimise the wiring the other side of it. 
• You have some switches earthed, is this for a warning lamp or....?
• If your switch rating is high enough, you don't need a relay.

All that affects the wiring gauge, so once we know that then we can help more, that is assuming that is a help  

[FridgeFreezer]

Just to add - even if a switch is rated at 20-30A I would not be running much more than 10A continuous through it for reliability.

[mcc1979ian]

Iv around 20 30amp switches with warning lights I bought a few year back and never used. That’s my only reason for the 30amp switches. I’m running a second alternator feeding a 110ah leisure battery which will lead to the fuse board through a 150amp breaker then distribute from there. Iv a pair of bud bars which I’m looking to run from the battery to then supply my earths. Iv got plenty 40mm battery cable which if I remember correctly handles over 200watt. I’ll most likely have one bus bar behind the raptor dash to handle earths for warning lights, cb etc 

[Escape]

That seems like a good plan, and a good reason to use the 30A switches. 40mm² cable will easily handle 200A continuously, that's about 2500W! It's thicker than any cable in the standard wiring loom and more than what most people use for an electric winch. Just not so easy to use as it will be very stiff.

As above, individual diagrams are very useful, it's how most if not all car wiring diagrams are supplied (as opposed to the old all-on-one-sheet diagrams that got terribly complex even before all the 'modern' elektrickery was introduced). But you do want to add a diagram showing power distribution and fuses etc.

[FridgeFreezer]

I'd suggest 40mm² cable is not only overkill but is going to make your life hard - for charging a leisure battery you can probably safely stick with 16mm² as it's never going to draw the full 110A out of your alternator, and it will be way easier to run & terminate.

I made a cable-size calculator tool a while back that will work out amps form watts & vice-versa plus appropriate cable sizes, fuse ratings, voltage drop per metre, etc.:

https://fuddymuckers.co.uk/tools/cablecalc.html

[henk]

Relay for lamp second alternator is a good idea as this lamp is not switched if you put contact on so it will be on even if the engine is not running (guess how I know)

 

Carling switches are rated 20 amp but I would always use a relay to switch something heavier

Blue Sea makes nice 12 way fuse blocks with earth connections, they also have a version with 2 banks of 6 fuses if you run 2 batteries 

Tinycad is a nice free tool to make drawings of your scheme's

Edited October 26, 2022 by henk

[mcc1979ian]

On 10/26/2022 at 9:06 AM, FridgeFreezer said:

I'd suggest 40mm² cable is not only overkill but is going to make your life hard - for charging a leisure battery you can probably safely stick with 16mm² as it's never going to draw the full 110A out of your alternator, and it will be way easier to run & terminate.

I made a cable-size calculator tool a while back that will work out amps form watts & vice-versa plus appropriate cable sizes, fuse ratings, voltage drop per metre, etc.:

https://fuddymuckers.co.uk/tools/cablecalc.html

Now that could be very handy 👌