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cst573
03-20-2007, 08:06 PM
Looking for a good place to use for a grounding point in my 2k PS190 for stereo equipment. I am using a ground distribution block and will be grounding multiple items.

Any thoughts?........ Engine Block maybe?

JimN
03-20-2007, 08:11 PM
All grounds must reference to the battery negative. If you're using a distribution block for the grounds on the stereo, the end not in the block goes to the battery negative. If you use a distribution block for power too, that needs a protection device within 12" of the battery terminal. Never try to make an existing conductor carry additional load. The type of protection device isn't important but you get more bang for your buck with a resettable circuit breaker. Stinger and other companies sell them.

Also, don't skimp on any power or ground wires or terminals. If you use ring terminals (and you should), crimp and solder them with a soldering gun, not a little iron. It'll be a much more durable connection. Use a hammer on a vise to crimp the large terminals- a dedicated crimper is a waste of money and the hammer works just as well.

To minimize the chance of alternator or switch noise, go ahead and use the + distribution block for the head unit's red lead but wire it through a relay that's switched by the normal radio red lead. You can use a Bosch or Potter and Brumfeld relay and if you need a diagram, let me know.

cst573
03-20-2007, 08:17 PM
I was planning on using stinger 4 guage wire from the battery positive to the Fused power distribution block. Then on the other side of the power dist. block I was planning on 8 guage to power 2 amps.

The ground dist. block is a straight through block.

Sound ok?

JimN
03-20-2007, 08:23 PM
I don't know if you already have the fused power block but if the amps have fuses, the additional fuses are A) a waste of money and B) just more connections that could possibly fail. The protection within 12" of the battery are to protect you and the boat, not the amps.

What kind/model of amps are you using and list the fuse sizes on the amps. 4 gauge is good for 60A on a 16' run, IIRC. If the fuses add up to more than that, I would go to 2 gauge or shorten the runs. Also, unless you need to add things later, to make the most of the 4ga, 6 ga is the equivalent. Doubling 8 ga = 6ga.

cst573
03-20-2007, 08:29 PM
I am working on a board that everything will be mounted on. 2 four channel sony amps with 2 (each) 25 amp fuses.

Very short runs (18") from the dist. block to the amps. From the battery to the dist. block will be about 24" to 36".

JimN
03-20-2007, 08:35 PM
I would have to look at my wire gauge chart but in real life use with normal speaker loads and input sensitivity, that should be fine. If you get the Stinger breaker, use the 100A. It won't be too small and constantly trip on you or way too big. The big fuses are OK but are as much to replace as a breaker is to buy unless you buy a whole bag of them. I don't know what you're using for audio cable but the shielded, twisted pair from Stinger is good stuff. Shielded, twisted pair (not Cat 7) is generally good to use in a high RF/EMI environment anyway.

To keep the amps cooler, use 1" spacers behind the mounting flanges to let some air flow behind them.

cst573
03-20-2007, 08:40 PM
Thanks!
I am looking at the stinger stp speaker wire. Just not sure yet if I can get 4 pairs of it in the hole that was factory drilled in the tower.
STP should be small enough to pull though.

JimN
03-20-2007, 08:56 PM
What gauge is that speaker wire? I wasn't aware that they had STP speaker wire, only pre-made interconnects and bulk audio cable. I just went to their site and didn't see anything about STP speaker wire.

Why not use 4 conductor home theater speaker wire? It's possibly more durable and you can get it in whatever gauge you want. If you need bigger holes, use a step drill, then remove the burrs on the inside and insert a grommet.

TX.X-30 fan
03-20-2007, 09:08 PM
I would have to look at my wire gauge chart but in real life use with normal speaker loads and input sensitivity, that should be fine. If you get the Stinger breaker, use the 100A. It won't be too small and constantly trip on you or way too big. The big fuses are OK but are as much to replace as a breaker is to buy unless you buy a whole bag of them. I don't know what you're using for audio cable but the shielded, twisted pair from Stinger is good stuff. Shielded, twisted pair (not Cat 7) is generally good to use in a high RF/EMI environment anyway.

To keep the amps cooler, use 1" spacers behind the mounting flanges to let some air flow behind them.

I have had some trouble with heat issues. All of my amp are mounted directly to the carpeted board under my glove box area. In your opinion, I should put some type of spacer behind the amps? Your stereo posts are amazing if not hard to understand for most of us. The shop that installed all my stuff seems to have followed all of your earlier recommendations very well. What did you mean about the fuse block within 12" of the battery being for the me and the boat.

JimN
03-20-2007, 10:09 PM
The board will act like a blanket, especially if it has carpet on it. 1" will usually make a difference.

The fuse or breaker close to the battery is to save you and the boat in the event that something cuts and grounds the positive cable, which will cause every bit of available current to try to pass through that cable directly to ground. The cable will never be able to do that without getting hot enough to start a fire so you want to stop the current ASAP. A battery that can deliver 650 Cold Cranking Amps will have no problem burning the insulation off the cable and anything close enough to or in contact will burn with it. The chance of grounding the positive that close to the battery is slight and the 12" is the rule of thumb for cars but there's no room inside the battery case to mount the breaker, so within 12 is very safe. Anything that grounds that cable farther away will pop the fuse or breaker anyway. The distribution block near the amps is, as I said, a waste of money and should only be used if the amps don't have their own fuses.

If you need any clarification on something, copy what you don't understand to a reply.

TX.X-30 fan
03-21-2007, 03:18 PM
Thanks JimN, that's what I was thinking after reading the suggestion about a spacer. I believe there should be enough wire to add some spacers in there and see if that fixes the heat issues. Then again could be just the 105 temp in the shade. ;)

the legend
03-21-2007, 05:18 PM
GROUND TO THE BATTERY!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!Lo oking for a good place to use for a grounding point in my 2k PS190 for stereo equipment. I am using a ground distribution block and will be grounding multiple items.

Any thoughts?........ Engine Block maybe?