Powering up multiple amps

[Arnold]

Hello.

My new install will consist of three amps.. one for the front, rear and sub... but i was just wondering the best way to power them.

I know its possible to run three power cables from the battery back, but there must be a better / tidier way of doing this. Is it possible to get just one ultra thick power cable and somehow split it three ways?

Thanks guys

 

[quickdraw]

run one nice thick 2-0 awg wire from your battery to the boot then into a fused distribution block, then you can run 3 seperate 4 awg cabling to each amp. ANd most prob get it hidden sumwere!!

or the other option is a second battery to the boot one 0 awg cable to the back and thena nice thick grounding wire to the chassis and you have a second battery in the boot

 

[NeX]

yea, i have three amps in a similar setup and i got two fused blocks from hellfrauds and used one for positive and one for negative. i even put LEDs in the bottom so they glow

i'll see if i can get some pics

 

[NeX]

here are a couple of pics of the fueses and the cable tunnel that hides the cables.. aldo you might be able to see the negative wire comming from the hatch loop...

 

[Retepetsir]

Just to say - you dont want fused distribution blocks on the negative side of the amps!

Arnold, size of cabling depends of what kind of power you will be running. Anything upto 1000wrms should be fine with 4awg down the length of the car, split into 4awg/8awg in the boot.

However for future proofing, the 0awg kit from CAD is extremely good value at £50. You can use the remainder of the other kit for the fuse block to amp connections!

Pete

 

[NeX]

why don't you fuse the earth? can't hurt surly?

 

[quickdraw]

u WANT as much current to go down it and not blow. if the fuse blows you have no connection to the earth thus actually nulling why u have an earth!!

 

[NeX]

well the fuses don't blow so it must be ok

 

[Retepetsir]

Hmmmm - you really only need a fuse on the positive distribution block...

What power/amps are you running and what cabling?

 

[Arnold]

Well thanks guys, some great advice there!

Will definitly go for the fused blocks thing, however my local frauds is useless and stocks hardly anything. Has anyone got a link to something on the net that would meet my requirements? I wouldnt wanna buy the wrong thing

Cheers people

 

[quickdraw]

cad

 

[Retepetsir]

Maplin are very good, good quality distribution blocks (4awg and 8awg) at really good prices.

Otherwise for 0awg/2awg go with CAD imo

I'll be ordering a 0awg wiring kit from them soon as my install will be completed (finish uni next week)!

 

[Andrew]

You should fuse the heavy gauge wire as close to the battery as possible. This protects the cable in the even that it shorts to the car bodywork.

There is little point in having a fused distribution block in the rear of the car. The fuses in the amps will protect the amps, and the cables running from the distribution block should be short enough to be protected by the fuse close to the battery.

Fusing twice doesn't cause any disadvantage compared to fusing once. It's just totally pointless. What quickdraw says isn't true really - one fuse or the other will blow first, and it doesn't matter which one it is.

 

[quickdraw]

What quickdraw says isn't true really - one fuse or the other will blow first, and it doesn't matter which one it is.

????
what?

i never mentioned double fusing. i mentioned using a distribution block. and since it is a live cable. "pointless" or not. i would rather be safe than sorry and use a fused one when it is to my option.

i agree fuse it as close to the battery as possible.
but fusing the line at the rear of the car will stop ne thing travelling back down the car aswell for sure? say for instance the power lead shorted half way down the line or summit?

please elaborate what you mean.
thank you

 

[Arnold]

Right i've ordered aload of bits so i can carry out the multiple amp installation successfully Thanks to pete (again!) for identifying specific products. Think i must owe ya a couple of pints by now

Thanks for all the replies tho, some useful information there for future reference

 

[Retepetsir]

i agree fuse it as close to the battery as possible.
but fusing the line at the rear of the car will stop ne thing travelling back down the car aswell for sure? say for instance the power lead shorted half way down the line or summit?[/quote]

Correct, its always best (for an extra £20 or so) to fuse at both ends of the cable.

I need to sort my install out next - I still cant decide what to do! One option will be under £50........the other will be nearer £400!!!
I'd rather have 50cm of wire fail than 4m of it.......

 

[Andrew]

I'll clarify what I meant.

u WANT as much current to go down it and not blow. if the fuse blows you have no connection to the earth thus actually nulling why u have an earth!!

Current in the wire from the battery should be equal to the wire going to the chassis, assuming none of it goes through the casing of the amp. If either a fuse in the positive or negative wire blows, you have the same effect - the circuit is broken.

Saying that the point of the earth is nulled when it blows, well, it's a bit of an odd way of saying it. It's used all the time when the device is in operation, and you want it to not be carrying current when the fuse blows. It's not safety ground, it's the current return.

If the power to the back shorted halfway along the car, the fuse at the battery would be the one to blow. There is no concept of anything going back along the line, unless of course you have a battery in the back as well.

If there are two fuses in series (one at the front, one at the back), then the one at the back needs to be rated lower than the one at the front to be of any use. If they are rated the same, then a short in the back could blow either fuse - it's anyones guess, as they have very poor tolerances.

If you have an unfused distribution block with thinner but shorter cables, they should still be totally capable of blowing the fuse by the battery. When you start talking about high currents at low voltages, voltage drop over fuses can actually become noticeable as well.

This kind of stuff is just generally accepted in power engineering. That's why your ring main has a 32A breaker, then you have 13A fuses in the plugs, and then smaller fuses in the device itself.

 

[TONEY]

RE: RE: Powering up multiple amps

This kind of stuff is just generally accepted in power engineering. That's why your ring main has a 32A breaker, then you have 13A fuses in the plugs, and then smaller fuses in the device itself.

there not always 13A it matters what it is used for

and ur right about the ring main

 

[Andrew]

there not always 13A it matters what it is used for

and ur right about the ring main

It's a choice of 3A or 13A, and it's only there to protect the flex of the appliance, so it's only based on the cross sectional area of the conductor in the flex.

 

[TONEY]

RE: RE: Powering up multiple amps

there not always 13A it matters what it is used for

and ur right about the ring main

It's a choice of 3A or 13A, and it's only there to protect the flex of the appliance, so it's only based on the cross sectional area of the conductor in the flex.

they cum in 3A 5A 10A AND 13A


they are to protect the appliance as well as the flex

 

[quickdraw]

thanks pete. thought how i understood it was wrong there. hall carry on the way i normally do

 

[Andrew]

they cum in 3A 5A 10A AND 13A


they are to protect the appliance as well as the flex

They might be available in those ratings, but you can't buy an appliance with anything other than 3A or 13A, and a qualified electrician shouldn't replace them with anything else. It's what BS and IEE say.

The fuse is only for overcurrent protection on the flex. The appliance itself must have it's own protection inside - think about the rest of Europe and the US, who don't have any plugtop fuses at all - do you think the entire appliance has no fuse? Even at GCSE they teach this right now.

 

[Retepetsir]

thanks pete. thought how i understood it was wrong there. hall carry on the way i normally do

Whats happening with your install then???

 

[quickdraw]

full FG reet through the car complete with 4 lcd screens, xbox, 3 amps,
fg dash the works

 

[Retepetsir]

What brand of equipment will you be running and what power?

I'm redoing my boot, and if I do go with the split charge system I'll be running an RE XXX with 1.1kwrms, then front components with 200wrms a side.

Should be enough headroom....!

Then if I get round to it, a touchscreen in the centre console for gps, etc, etc.

 

[Andrew]

i agree fuse it as close to the battery as possible.
but fusing the line at the rear of the car will stop ne thing travelling back down the car aswell for sure? say for instance the power lead shorted half way down the line or summit?

Correct, its always best (for an extra £20 or so) to fuse at both ends of the cable.

So you agree that something can "travel back down the car"? A fuse at the end does nothing for the cable running down the length of the car, yet you say "Correct", like it is...

 

[Retepetsir]

No I dont agree on that part, I agree for fusing as close to the battery as possible.

SORRY if my quoting was slightly incorrect.

ffs, theres no harm in double fusing, I'd rather have more protection than less.

 

[Guy]

Fuse it near the battery. Even with 'just' 4 guage, you're talking about alot of copper potentially turning white hot in your car :suspect:.

 

[r-reg-sr]

intresting thread very usefull

 

[Arnold]

I started this thread 5 years ago

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