i'm redoing my wiring and something just don't seem right.....
i want to use a main battery Shut-Off switch (excluding the winch) and am unsure of the location of the AMP guage.......(not voltage)
anyone see any other problems, please point them out :eek:

sorry about the bad pic.....

edit, i just noticed that i forgot the 10 ohm resistor in the wire going from the igntion to the alternator:)
sh!t, there should be a main battery cable going from the battery to the starter also.........Hmmm, getting sleepy on the east coast already


deleted picture..........i re-posted it in a reply

A couple of things:

You wouldn't want to run the starter current through the amp gauge and fuse like you have it drawn, as it would have to pass 300-400A peak current. Use a 1 or 2 gauge wire from the battery + directly to the starter. The best type of ammeter would be a milliamp meter across the fusible link as a shunt. That way you aren't running high current all the way into the cab.

The amp gauge works best in series with the fusible link; that way it reads both the charging and discharging of the battery.

300 A is a little too stout for a fusible link to be useful. It needs to match your total current in from the alternator and out to the system.

Why bother with an additional push button starter, when you could just get a conventional ignition switch?

I don't see any reason to have the ignition relay. It just looks like an extra expense and another part that can fail.

Another way to wire the exciter wire on the alternator would be to wire it directly to the acc side of the ignition switch.
You probably knew this, but a small dash lite makes a fine resistor.

here's an picture of the dash........

here's an updated diagram

Sweeet...:D nice dash
though I don't envy you... wiring at this time of night...:beer: :beer: :beer: +:zzz: =:nuke: ha

Here ya go.
Keep it simple!
Don't run high current anywhere it doesn't absolutely have to go.

http://members.cox.net/cglabe1/Photos/scheme.jpg

thanks,
do you think the alternator will supply voltage/current to the fuse box if the "kill Switch" was opened to keep the engine running?
i know some cars will stay running with the battery cable off......i just had the idea of putting the kill switch in the ground cable, (but then winch current would go through it also................Hmmm

If you wanted to kill the engine with the main kill switch without turning off the ignition switch you would have to wire the alternator's output to the battery side of the kill switch, right? But then would you lose the benefit of the kill switch on the alternator output wire? I'm not sure if a kill switch on the neg. side would work for shutting off the engine either

On another note,I think I would wire in a 60 amp circuit breaker to the beginning of the main feed wire for the fuse box so it has some protection too.

Dump the ammeter for a volt meter. No reason to have a potential fire under your dash. The volt meter is a better indicator of what's happening with the charging system and battery.

Joe

I second the idea of deleting the amp gauge for the volt gauge.

Think about this - that amp gauge reads up to, what, 30-40 amps - max, but you have it inline behind a 300 amp fuse and 125 amp switch....so you push 100 amps and melt the gauge.

The only amp gauges really heavy enough are Marine units, which are big and expensive.

Also - I think the 300 amp fuse and 125 amp switch ratings are backwards...otherwise you could push 200 amps through the fuse and melt the switch.

Better a 100 amp fuse and 300 amp switch.

Originally posted by 3/4tonYJ
thanks,
do you think the alternator will supply voltage/current to the fuse box if the "kill Switch" was opened to keep the engine running?
i know some cars will stay running with the battery cable off......i just had the idea of putting the kill switch in the ground cable, (but then winch current would go through it also................Hmmm

It would depend on what the switch is supposed to kill. It won't stop the engine once it is running, but you have the ignition switch for that. It will disconnect the battery from everything in case of an electrical problem.

The ammeter is not a problem as I have drawn it. All modern high current ammeters are wired in parallel across a "shunt" so that the meter only actually conducts 0.1% of the total current in the circuit. The point is to move the shunt as close to the battery as possible so that you won't have to run high current into the cab just to measure the charging. The ammeter will tell you a lot about the condition of the battery that a volt meter won't, like is it actually charging and is it fully charged. If you just want to know that the alternator is working, an idiot light will work too.

The ammeter will tell you a lot about the condition of the battery that a volt meter won't, like is it actually charging and is it fully charged.

caution: this is not meant to sound as argumentative as it is going to !

Since when does a voltmeter not tell you if the battery is charging or discharging? And an ammeter will not tell you if the battery is fully charged - the only way to "really" tell that is with a device that will put a controlled and measured load on the battery.

I see the old perpetual motion thing going on there...The alt is spinning, so it puts juice to the HEI, which fires the plugs, which spins the alt... ...
Amp meters just tell me if I'm charging, not charging or dis-charging...

Originally posted by dirtrod
Amp meters just tell me if I'm charging, not charging or dis-charging...

mine tells me that my plow pump is drawing 75-90 amps because the needle pegs to the - side then the alternator catches up and when I release the switch she goes to +40 to +60 til the battery tops off . unless wired incorrectly a amp gauge is better then a volt gauge. if the alternator is spinning the volt gauge is going to show 12+ volts regardless, whereas if the battery cable comes off a amp gauge will show a draw of 30+ amps because the alternator is producing all the power and the battery isn't providing any. the volt gauge will show nothing cause the volt gauge will read the volts from the alternator.

~Nate~

Originally posted by BillaVista


caution: this is not meant to sound as argumentative as it is going to !

Since when does a voltmeter not tell you if the battery is charging or discharging? And an ammeter will not tell you if the battery is fully charged - the only way to "really" tell that is with a device that will put a controlled and measured load on the battery.


It's OK to be argumentative. :D

I didn't say that a voltmeter won't tell you that a battery is discharging; when it is discharging very rapidly the voltage will drop. An ammeter will tell you how fast it is discharging too. This is very useful information if your alternator quits. If you use a typical automotive ammeter with the center zero and + and - amps, you can tell which direction the current is flowing too, so you can distinguish charging from discharging and again tell how fast. You can also tell when the battery is fully charge because the net flow to the battery will drop to near zero when it is charged. Again, this is useful information if you are trying to decide which winch to use. An ammeter will also tell you about the condition of your alternator. If it should be capable of putting out 100A, but only puts out 33A, you can suspect that the diodes have burned out on 2 of your 3 phases.

Heck, get both.

i like an amp guage (ammeter), i've used them before and like to know when and how much the battery is charging. (or how long it takes to get back to a "full"........

i also never liked the high current wires under the dash...........

i've never heard of a "shunt", as wired in Pin Head's diagram but it really looks much safer...............i like....

how bout where to purchase one of these "Shunt's" and should it work with my "standard" -60 to +60 ammeter............

Dump the ammeter for a volt meter. No reason to have a potential fire under your dash. The volt meter is a better indicator of what's happening with the charging system and battery. NO! The meter tells you what the system voltage is - nothing more. You have no idea if you are in the bulk charge or float charge part of the battery charge cycle. You need to look at current flow to figure out what is happening with your battery. As an extreme example, what happens if your battery has an open circuit between to cells due to damage? Your volt meter will keep indicating normal system voltage, but there is no current flow (ie no charging) to the battery due to the open circuit!

The major distinguising rating between automotive batteries is amp - hour rating (often specified as cold cranking amps, hot cranking amps, reserve capacity etc - all of these figures are amps delivered over time at a specified temp). It only makes sense to use an amp meter or even better an amp hour meter to monitor your battery.

I second the idea of deleting the amp gauge for the volt gauge. ... The only amp gauges really heavy enough are Marine units, which are big and expensive. See my post above for the comment on why the amp meter is far more useful than a voltmeter. And read other peoples posts about the use of shunts to limit amp meter current - even "marine units" should not be wired in series with the power circuit. Most meters take advantage of Ohm's law to calculate current using a shunt or use "loop type" influnce sensors to measure current (loop type is less accurate).

In fact, I have never seen a reputable amp meter that was designed to be wired in series with a circuit because if the current was too high you risk fire and with low current circuits the amp meter influences the reading! So what amp meter manufacturer do you know of that specifies their meters be placed in series with the circuit?

All high current aqmp meters have a shunt. The difference is whether it is built in or internal or whether it is an external, remote shunt. External shunts were used after about 1975 in most trucks that had an amp meter. After market gauge makers haven't figured it out yet. You can get a remote shunt gauge at your local boat dealer or make it yourself. You get a 50 - 0 - 50 milliamp meter and measure the resistance across its coil. Divide this resistance by 1000 to get the shunt resistance (and so the meter will read directly in amps). Look up the length of 6 ga wire that you would need to get this resistance value and that will be your shunt. You also need to put a 1 amp fuse in series with your gauge in case your shunt burns out.

With some meters, you can convert the internal shunt to external. You just take off the brass or copper strap that goes between the two lugs and use it as your remote shunt near the battery and then run 18 ga wires from the shunt to the gauge.

Originally posted by Pin Head
With some meters, you can convert the internal shunt to external. You just take off the brass or copper strap that goes between the two lugs and use it as your remote shunt near the battery and then run 18 ga wires from the shunt to the gauge.

thanks again pinhead.......

well was at a family Xmas party tonight thinking about my dash :rolleyes:

and decided to take apart acouple amp meters i have when we got home......
the one on the right looks to have a "shunt" that i could remove......it's a 40 amp guage i got out a 78 postal jeep, the 60 amp (J.C.Whitney special, that i wanted to use), left side of pic don't appear to have a shunt that i can remove. i think i'm going to remove and remote mount this in the eng.compartment between the alternator and battery......(with fuseable link) as pinhead has shown......

fyi, i found this link http://www.bluesea.com/Products/ME/ME.html on billavista's site it has some great marine electrial stuff......including ammeters and shunts.....

also i'm planning on replacing the 300 amp fuse (i just had this laying around) with a 100 amp......and wiring a light in-line with the alternator feed instead of getting a 10 ohm resister.....

The brass doodad under the black meter panel on the left looks like the shunt; the one on the right is the brass strap directly under the red indicator on the meter, but doesn't look easy to remove unless the brass screws holding it down come out. The shunt always conducts current directly across the two big electrical connections. Just remove the shunt, screw its ends down across an insulator terminal strip and wire the meter lugs to the shunt terminals using 1 amp fuses in line and you are set.

WTF is up with the fairy; that's :rainbow:

Originally posted by Pin Head
The brass doodad under the black meter panel on the left is the shunt; the one on the right is directly under the red indicator on the meter, but doesn't look easy to remove. Just remove the shunt, screw its ends down across an insulator terminal strip and wire the meter lugs to the shunt terminals using 1 amp fuses in line and you are set.

there's no brass anything on the underside of the left one (i thought maybe it could be inside the molded plastic or the brass "U" shaped piece is the shunt and needle mount.
are you i saying i need to use "2" 1 amp fuses, one on each side of the "shuntless ampmeter"?

and the fairy is my 5 year old daughters, they were both helping my out......:)

I'm talking about the brass strip with two large holes that is partially under the face panel with the numbers on it. That looks like the shunt. Use at least 1 fuse, but most of them use 1 on each wire for a total of two.

unless is fell off when i took it apart and i didn't notice, (i looked around for it also) it don't have one there,
here's another picture of the back side of the face and the needle mount.....(the other guage with the shunt clearly pictured has a complete alluminum needle mount, no brass like this one)

Here ya go; these are the shunts.

http://members.cox.net/cglabe1/Photos/shunt.jpg

sorry about all the posts, but thanks again for your help,

that piece you have pointed to in the picture is a cardboard insulator that was on the outside/back housing of the guage, keeping the terminal posts from contacting the housing itself........

or did you just want to post the fairy pic again? :rolleyes: