Technical Trunk/Boot grounding point.

[Jaka Cvajnar]

I need some help finding the best grounding point in the trunk for my amp.
I used some waird grounding point till now, and yestrday when i went to check it i tried to tie up the bolts so i still have a good conection and now the amp stoped working.. so i think it was a rlly bad ground and i was just lucky so far until i moved it abit and it went to bad.. i saw one post where people sugested something about the seats but i dont get what they mean. So im asking again if anyone knows a good grounding point, preferably out of sight, dont want my cable runing across the whole trunk.

would be rlly happy with some pictures.


Edit: this is where i putted it now,i couldnt think of another idea, the woofer works now, but is this even a viable safe option? it is not 100% on the car body but there is a metal in between it.
i hope you can see where this is, its conected to the hook that holds the backseats.

 

[brinker]

That should work OK. In mine I had removed the rear seats, and installed a flat floor using the two front bolting points for the rear seats. I simply attached my ground point on this bolt (that pulled the ground from the body through the thread hole).
If you're in doubt whether it's good enough, do an impedance measurement between battery negative and your grounding point. It should read no more than 0.03ohm.

 

[Jaka Cvajnar]

That should work OK. In mine I had removed the rear seats, and installed a flat floor using the two front bolting points for the rear seats. I simply attached my ground point on this bolt (that pulled the ground from the body through the thread hole).
If you're in doubt whether it's good enough, do an impedance measurement between battery negative and your grounding point. It should read no more than 0.03ohm.

yeah that seems way to complicated for me, dont rlly understand what you mean, and yeah i read about mesuring your ground today, i dont have a multimeter at home yet.will try to borrow from a someone and test it to be sure. i heard under 0.5 ohm is okay to. 0.03 is rlly low?

 

[PuntoHowTo]

Is the amp not working at all? You’ll need to rule out all other possible problems before blaming the ground as there is very little complexity, it’s either connected or it isn’t.

Have you checked the fuse in the amp? The fuse on the live (which you should have) at the battery. Check that the live isn’t damaged and shorting to ground, check that the ignition live or power on from the radio is working as it should.

Lots of other things can be more of a problem than a single unfused wire that’s bolted directly to the car body.

 

[jonik]

Best ground point is seat belt buckle bolt under rear seat, I've tested. I now have about 50000 watts and there will be more in summer

 

[judderbar]

I now have about 50000 watts and there will be more in summer

First the windows and next it will be the roof. Hopefully you have plenty of cameras ready for that one!

 

[Jaka Cvajnar]

Best ground point is seat belt buckle bolt under rear seat, I've tested. I now have about 50000 watts and there will be more in summer

Firstly for Andy: yeah it was the ground, the amp works now after changing ground, and the "quality" of the ground point matters.



jonik yeah i was hoping you would respond as i seen ur car and videos, but yeah alot mention the belt buckle bolt, but as said i have no idea what they mean by that and where it is, so is it posible to get a picture please?

 

[jonik]

Here

 

[Jaka Cvajnar]

Here

tnx ,but i still dont get it.... do you need to remove seats to get to there?

 

[Jaka Cvajnar]

update:
i tested the ground today with a multimeter set to ohms, it reads 2.4ohms ... i tested several other mounting points but they all read over 2ohms. shauld i be consirned? i read some say under 5 ohms is okay, some say it has to be under 0.5ohms. my amp and speaker works fine so i dont see the problem for now, but dont want any problems in the future. shauld i search for better ground or leave this one as it works for now?

 

[jackwhoo]

How good is your test meter? What ohms does it read with test leads connected together?
Plus Just clean the ground point anyway.

 

[Ziggy122]

Ensuere battery clamps and battery ppsts are clean and shiny

Clean the battery to body strap
And its best to also do body to gearbox too....

Dont forget the terminals are gonna need cleaning too

Puntos are gettin to that age where the copper is statted to go brittle and fill with the green crustys

May need to add additional / replace / repair to help maintain a good earth return


Ziggy

 

[Jaka Cvajnar]

its a cheap multimeter i admit that, it reads around 0.2/0.3 ohms just by touching leads, ill clean the ground point again to make sure.

ziggy, the topic is still about amp ground point in the trunk, no idea what battery and front grounds have to do with this? i did clean the battery posts and battery clamps not long ago to. but did not get to do the grounding points as im unsure where they are(i followed the cables a few time but i always get lost.

 

[Ziggy122]

its a cheap multimeter i admit that, it reads around 0.2/0.3 ohms just by touching leads, ill clean the ground point again to make sure.

ziggy, the topic is still about amp ground point in the trunk, no idea what battery and front grounds have to do with this? i did clean the battery posts and battery clamps not long ago to. but did not get to do the grounding points as im unsure where they are(i followed the cables a few time but i always get lost.

The car chassis is the negative return to battery aka ground
If the front grounding point (near battery) goes catty wompus then all the other earths will as a result have increased resistance

Note on the battery clamp there are only 2 wires
Big fat juicy and 1 that spurs off somewhere no idea where like

Ziggy

 

[Jaka Cvajnar]

The car chassis is the negative return to battery aka ground
If the front grounding point (near battery) goes catty wompus then all the other earths will as a result have increased resistance

Note on the battery clamp there are only 2 wires
Big fat juicy and 1 that spurs off somewhere no idea where like

Ziggy

oh.. that makes sense... will take a look at the battery chasis negatives. tnx!