multiple batteries vs. high output alternators

[Thnking 10+ year member]

talk common sense you do realize that if you are really getting the high output alt to drop to 12.5-12.8 v that somewhere along the line until the charging system catches up its going to be below 12.8. people will say this doesnt happen because they "test " with their dmm. thing is a digital dmm without the right setting avalible on it reacts VERY slow (this is where analog would show that the voltage is actually moving all over) the load is constantly changing so the output does too. i am talking miliseconds covering peaks. if you were to graph the alt out put it would look alot more like a moutain range than any type of a clock signal in real time.

DMM's react very fast, beyond our capability to sense a change.

Someone should only be trying to reduce large voltage drops, not unnoticeable ones. This is one reason things like capacitors are used in amplifiers, to make up for an unstable energy source.

Changes in voltage over a couple miliseconds aren't affecting anything significantly.

 

[Thnking 10+ year member]

Battery up front is grounded to factory point on the block with 1/0. Rear battery is grounded to bolt that holds body to the frame. That's where the sub amp was originally grounded, now it's going to the rear battery.
System is 2200+ RMS. 200a was the biggest stock case offered for my car. Don't believe it was a ground issue, just too much demand on what I had, but the 2nd battery has taken care of that....

Guessing at a good grounding location still doesn't mean it's good. My stock engine ground had a resistance of .5ohm.

Also, your amps and Hu need the same low resistance grounds.

Too many people take a look at a ground and say "its good". The only way to find a good ground is to measure the resistance.

 

[CJL 10+ year member]

Too many people take a look at a ground and say "its good". The only way to find a good ground is to measure the resistance.

At what ohm would be considered a good ground?

 

[audiolife 5,000+ posts]

At what ohm would be considered a good ground?

SAME AS THE GROUND UP FRONT.

 

[audiolife 5,000+ posts]

DMM's react very fast, beyond our capability to sense a change.
Someone should only be trying to reduce large voltage drops, not unnoticeable ones. This is one reason things like capacitors are used in amplifiers, to make up for an unstable energy source.

Changes in voltage over a couple miliseconds aren't affecting anything significantly.

basic analog is much faster than a regular dmm... //content.invisioncic.com/y282845/emoticons/rolleyes.gif.c1fef805e9d1464d377451cd5bc18bfb.gif alts in use also fall below 12.8 v at times even if it is a highoutput alt ..still has to react to the changing load.//content.invisioncic.com/y282845/emoticons/rolleyes.gif.c1fef805e9d1464d377451cd5bc18bfb.gif

 

[Thnking 10+ year member]

At what ohm would be considered a good ground?

0 of course //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

It's not going to happen, so the lowest grounding resistance should be found. Anything over .2ohm, IMO, is too high.

 

[Thnking 10+ year member]

basic analog is much faster than a regular dmm... //content.invisioncic.com/y282845/emoticons/rolleyes.gif.c1fef805e9d1464d377451cd5bc18bfb.gif alts in use also fall below 12.8 v at times even if it is a highoutput alt ..still has to react to the changing load.//content.invisioncic.com/y282845/emoticons/rolleyes.gif.c1fef805e9d1464d377451cd5bc18bfb.gif

Did I compare non digital multimeters to DMM...?

Not that it matters, but DMM's can be and many are faster than non-digital ones. We can't see changes in measurement samples that fast, which is why they are hooked up to computers and graphed.

You're point was the circuit's voltage dropping for milliseconds, and I said a drop for a few milliseconds isn't going to affect anything, so there is no reason to worry about it. The stator's field doesn't even change that fast, anything that's significant is based on an average over a time we can substantiate into affecting electronics negatively and visibly. That's all people should be concerned with.

 

[audiolife 5,000+ posts]

yet depending on the vehicle results are visable..../story

an average run of the mill 20 dollar dmm is slow.../story

 

[Thnking 10+ year member]

yet depending on the vehicle results are visable..../storyan average run of the mill 20 dollar dmm is slow.../story

No it's not.

Something that's visible has to occur for a time period we can detect... We can't see a millisecond of voltage dropping in light dimming. Take a look at your computer screen, more than likely the screen is set at 60hz. That's 16milliseconds. I bet you can't see the screen refresh itself...lol

A 20$ DMM probably samples at around 10ms. I bet you can't see that either...lol.

 

[audiolife 5,000+ posts]

lights dimming would be 1 effect. flashing protection lights are another...

bet you its slower than that. when we were testing reactions to working circiuts we had to use anolog to see what circuits were doing.....

 

[Thnking 10+ year member]

lights dimming would be 1 effect. flashing protection lights are another...bet you its slower than that. when we were testing reactions to working circiuts we had to use anolog to see what circuits were doing.....

Bet me what is slower than what?

 

[audiolife 5,000+ posts]

http://audioforum.termpro.com/topic/22/3982.html........

 

[audiolife 5,000+ posts]

Bet me what is slower than what?

hi speed dmm is only good for saving info you cant watch even what the numbers even say particularly if it has a variance of more than 1v.....analog you just watch the needle

 

[Thnking 10+ year member]

And what's your point and how does it relate to this discussion?

 

[audiolife 5,000+ posts]

88888 on an lcd screen is pretty understandable lol (meaning numbers are moveing lol)