The Toyota Landcruiser Owners Club

uk_vette · Posted: Sat Jun 06, 2009 19:31 Post subject: Twin rear power points fitted

Well, getting bored with this time on my hands.

15 amp power point to right rear pillar

.
15 amp power point to left rear pillar

.
Power cables run along near side of vehicle in standard cable channel by sill kick plate.

Both fused with 15 amp
Both run separate with 2.5mm for supply and earth right back to battery.

.
I may change one, and run one of them through a 40A relay, which is only energised with engine running.

Cooler box, etc.

'vette

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uk_vette · Posted: Sat Jun 06, 2009 19:32 Post subject:

Duh,

'vette

leon · Posted: Sat Jun 06, 2009 21:04 Post subject:

2.5 the right size ? how did you work it out ?
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uk_vette · Posted: Sat Jun 06, 2009 21:33 Post subject:

Hi Leon,
2.5mm is generally good for 26 amps, or there a bouts,
not taking into consideration length of cable for volt drop, as it is only about 4 meters at most.

'vette

leon · Posted: Sat Jun 06, 2009 21:57 Post subject:

26 amp's at 12v ?
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uk_vette · Posted: Sat Jun 06, 2009 22:31 Post subject:

leon · Posted: Sun Jun 07, 2009 0:51 Post subject:

250w / 12 v = 20.8 amp's ...for a volt drop of 0.4v over 5m your looking at between 10.00 and 16.00mm cable (ish ) depending how you ran it through the car

http://www.electacourse.com/cableselector.html

http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html

thats worked out on twin and eath cable ..but am thinking your still well under to pull 12volts over the lenth of the car (5m ? ) with any kind of load ?

hate your wiring to melt in Africa or set fire Shocked

dont know who to check with (its 10 to 1 now brains dead )
_________________
Should I have these bit's left over ?
1998 V8 LC Amazon VX work in progress
2008 pug boy
2009 pug boy
2010 pug girl
^ dogs Smile

leon · Posted: Sun Jun 07, 2009 0:59 Post subject:

a proper DC 12v one http://www.solar-power-answers.co.uk/cable_calculator.html

250 watt's divided by 12 volts gives you the amp's

250/12=20.8 amps

In a house it would be 250w /divided by 230 volts = 1.08 amp's

the voltage is way more importent then the insulation resistance break down piont of 2000 volts you only have 12v Wink

to smal la cable will work just liek a cig lighter ...it will glow red ! Shocked

_________________
Should I have these bit's left over ?
1998 V8 LC Amazon VX work in progress
2008 pug boy
2009 pug boy
2010 pug girl
^ dogs Smile

uk_vette · Posted: Sun Jun 07, 2009 9:17 Post subject:

leon · Posted: Sun Jun 07, 2009 10:25 Post subject:

if your happy with 2.5 vette am happy with 2.5 Razz

_________________
Should I have these bit's left over ?
1998 V8 LC Amazon VX work in progress
2008 pug boy
2009 pug boy
2010 pug girl
^ dogs Smile

leon · Posted: Sun Jun 07, 2009 10:48 Post subject:

uk_vette · Posted: Sun Jun 07, 2009 11:07 Post subject:

Hi Leon,

No problems.

Look here

http://www.eland.co.uk/documents/Tri-rated%20Cables.pdf

Look 3rd table down.

'vette

leon · Posted: Sun Jun 07, 2009 13:25 Post subject:

thats hight voltage ratings not 12v Confused

am not a pro at auto Electric's but house, factory ,pubs and clubs is what i do for a living witch is 110-600 AC volts and going off what i know you need to know what power your going to pull over what lengh at what voltage ...am just asuming its the same in auto wiring

http://www.the12volt.com/ohm/ohmslaw.asp

so we know you have 12v and you set a limit of 20 amps (250w ) lenth of 4-5m table's say 10mm + from what i can find ..ill look some more see if i can prove what i think

http://www.the12volt.com/wiring/awg.asp

Have a read of this it explains beter then i do study

http://www.smartgauge.co.uk/cable_type.html
_________________
Should I have these bit's left over ?
1998 V8 LC Amazon VX work in progress
2008 pug boy
2009 pug boy
2010 pug girl
^ dogs Smile

uk_vette · Posted: Sun Jun 07, 2009 15:09 Post subject:

Leon,
The voltage is the 'pressure'
the amps is the volume of current

volts x amps is the total power.
20 amps at 12 volts is the same 20 amps at 200000000000000000000volts.

Amps is amps, regardless of the voltage.

I think where you may be getting confused is the power.
Power is VxA

But we are not talking power, we are talking amps.

20 amps is 20 amps.

The cross sectional area of the Cu. determines the amps.
The cross sectional area has no bearing on the volts applied.

if I had 2,5mm sq cross sectional area, that is the conductive capacity of the copper.

Ampacity.

'vette

leon · Posted: Sun Jun 07, 2009 18:03 Post subject:

volts x amps
20 amps x 12v = 240watts
20 amps x 20000000000000000 volts = 400000000000 watts

an amp is a musurment of power ,using the examply above 2.5 can not carry 20 amps at 20000000000000000 volts
The volts part is more importent then we seem to agree on so we agree to diagree

2.5 is to small at that lengh for 250 watts @ 12v coverd by a 20 amp fuse in my opion Razz

and ill leave it at that Cool

_________________
Should I have these bit's left over ?
1998 V8 LC Amazon VX work in progress
2008 pug boy
2009 pug boy
2010 pug girl
^ dogs Smile