2003 Yaris - 12v Cable through bulkhead

[Sterling01]

Hi,

I need to get a 12V (20amp) cable connected to the Battery and run to the boot of my Yaris. Anyone know how I get the cable through the bulkhead? Or can you offer an alternative suggestion?

Cheers, Kenny

[Anthony Poli]

Hi,
I need to get a 12V (20amp) cable connected to the battery and run to the boot of my Yaris. Anyone know how I get the cable through the bulkhead? Or can you offer an alternative suggestion?
Cheers, Kenny

If you have a light in the boot then you should be able the wire going to the switch.


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[Mooly]

I wouldn't think any wiring and connections to any of the lights would even come close to 20A handling capacity. It could be asking for trouble to try and pull significant current through them (overheating and fire risk). There is also the volt drop seen at the load end of the wire.

20A capability needs wire of at least around 35A capability and that is pretty thick cable, around 2.5mm diameter of copper which would lose you around 0.3 volts at 20A for a single core 3 metre run.   

 

[Madasafish]

Just what are you connecting that pulls anything like 20Amps?  Becuase unless the engine is running to recharge the Battery, the Battery will go flat fairly quickly if it is elderly..

[mrpj]

1 hour ago, Madasafish said:

Just what are you connecting that pulls anything like 20Amps?  Becuase unless the engine is running to recharge the battery, the battery will go flat fairly quickly if it is elderly..

A bass speaker and amplifier for the hard of hearing?!

[Sterling01]

A small bass speaker - https://www.halfords.com/technology/car-audio/car-amps-subs/vibe-optisound-auto-8-active-underseat-subwoofer-enclosure

 

[Madasafish]

I see peak power is 900watts. AT 12volts, that's 80amps...

RMS power is 300watts:  25Amps.

 

Your 20amp cable is not big enough - it will melt at RMS power.

[bathtub tom]

1 hour ago, Madasafish said:

Your 20amp cable is not big enough - it will melt at RMS power.

Does it matter? The bass will rattle all the rust out of a 2003 car that's holding it together.

[flash22]

I doubt that will even see 300 rms unless its at its 14.4 volts under max load with a perfect sine wave input, No amp is 100% efficient a Class D is around 70-75% at its peak optimum output resistance, peak wattage its theoretical and means absolutely nothing

That sub is for under seat usage, it will have very little effect in the boot, You will be better off with some decent Speakers up front and sound deadening the doors

That sub is rated to 20amp so a 10 gauge kit  (6mm2) will be plenty don't forget to fuse it within 12" of the Battery too

 

MR PJ

Each to their own, you can have bass without rattling the windows its called SQ - sound quality

[Sterling01]

I have bought this sub brand new. It comes with cables including the 12V power cable that needs attached to the Battery. The 20A fuse is approx. 12 inches from the terminal connector.

I am not some crazy teenager looking for "pumpin tunes". I have installed a double din Alpine head unit and replaced the 4 Speakers with Alpine units. I bought the sub, just to add a little extra depth to the sound. 

This car is my daily driver for my 55 mile commute. Saves me putting over 1000 miles a month on my 67 plate Range Rover. And it saves the RR getting bashed in the NCP car park.

I am disappointed that everyone wants an opinion on what I am doing or why I would do it in the first place. 

Really I just wanted a little help with my original question. How do I get the cable through the bulkhead so I can connect it to the Battery.

[Sterling01]

5 hours ago, Madasafish said:

I see peak power is 900watts. AT 12volts, that's 80amps...

RMS power is 300watts:  25Amps.

 

Your 20amp cable is not big enough - it will melt at RMS power.

This is the cable the manufacturer supplied with the unit. I have to trust they know the correct cable to supply.

[Sterling01]

3 hours ago, bathtub tom said:

Does it matter? The bass will rattle all the rust out of a 2003 car that's holding it together.

Really !!! The car may be 2003, but it only has 88k, 12 months MOT with no advisories. No rust on arches or sills. Maybe you can keep you opinion to yourself unless you are in possession of facts.

[flash22]

The only real place is behind the glove box and follow the loom, imho it will be easier to drill a hole and use a blind grommet and silicone to seal it

I wasn't aware that the wiring was supplied with it, is there enough length on the cable ?

[Sterling01]

Thanks, Supplied cable loom is about 5 meters long

[Madasafish]

There is a fuse box in front of the driver inside the cabin.. panel to right of steering column. Knee  height

 

Wire from there - along sills and through boot. No need to go through bulkhead.

[flash22]

2 hours ago, Madasafish said:

There is a fuse box in front of the driver inside the cabin.. panel to right of steering column. Knee  height

 

Wire from there - along sills and through boot. No need to go through bulkhead.

Not at 20 amps, the internal fuse box is fused at 40 amps may be 60 (possibly even split across 3+ lower rated fuses)

Direct connection from the Battery is the safest option, and fused as close to the Battery as possible - in the unlikely event something does happen it just blows the fuse(s) and it doesn't effect the car it any other way eg. spiking the bcm

[Madasafish]

1 hour ago, flash22 said:

Not at 20 amps, the internal fuse box is fused at 40 amps may be 60 (possibly even split across 3+ lower rated fuses)

Direct connection from the battery is the safest option, and fused as close to the battery as possible - in the unlikely event something does happen it just blows the fuse(s) and it doesn't effect the car it any other way eg. spiking the bcm

Nothing to prevent you using an inline fuse at 20Amps.. and then connecting to the fusebox.