I'm installing new gagues in the 40 and am wondering which is better an amp gauge or volt. The 40 has a v-8 with dual battery if that makes a diff. thanks
amp or volt meter?
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desertdude said:
I prefer the volt meter for a couple of reasons
1 Shows battery voltage with the key on/engine off, very handy in diagnosis.
2 You don't have 2 large high amperage wires running all the way from the alternator inside and back....in my work I have seen a number of these short to ground and cause major fire.
Both have advatages but these are the 2 which make me choose a voltmeter
Butch
i agree with butch. i don' t like the power wire either...both serv as a good diagnostic tool. diff is, if your voltmeter starts dropping, you have two areas to look (batt and alt) whereas, altmeter leaves you checking out the alternator...but, if your battery goes bad, alternator may not show that. i don't think either item is a common enough problem and aren't engine threatening (like lack of oil pressure or temp), so it all depends on your feelings.
In order for an amp meter to measure the power going into and coming out of the battery it has to be in line with all the power going into and coming out of the battery, less the starter draw. that means all your electrical has to be run through the amp meter. Big ol wires running up to your dash. That is unless you can find one with a magnetic pick up. I would expect that to be spendy.
Volt meter runs in parallel. No big wires in your dash. Much safer. That's the big thing. Also, you get more options for running wires. You can diag during start up because it looks at your voltage during cranking. You can even watch your voltage during winching.
A volt meter does not give you the exact power your alternator is putting out, but it does tell you if it's working or not. If your voltage is above static battery voltage, it must be working. With all the other advantages, that disadvantage is a minor one.
Volt meter runs in parallel. No big wires in your dash. Much safer. That's the big thing. Also, you get more options for running wires. You can diag during start up because it looks at your voltage during cranking. You can even watch your voltage during winching.
A volt meter does not give you the exact power your alternator is putting out, but it does tell you if it's working or not. If your voltage is above static battery voltage, it must be working. With all the other advantages, that disadvantage is a minor one.
If you are running a stock wiring harness, you can't avoid the large wires carring current up to the dashboard, but you can wire around your amp meter (recommended by many). Take the screws out of your gauge cluster and pull it back. Take the two large white wires off of their posts (they run through the amp meter) and cut the ring connectors off. Next, solder the two wires together and put the gauge cluster back in place. Recommend installing the volt meter now so that you have some monitoring device of your electrical system.
James H
James H
Minus all the extra verbage... sounds like you need both
An amp meter tells you more useful information: Whether your alternator is putting out enough current, if your battery is fully charged, charging or discharging and whether the battery is good.
A volt meter will tell you if the alternator is putting out and if your battery is discharged. So will an idiot light.
Toyota got rid of the somewhat dangerous high current wring in the cab in '78 with the introduction of the external shunt amp meter. You can get one of these and wire it in line with the white wire that goes to the battery + post. All marine amp meters have an external shunt.
There is no getting around feeding some high current into the cab. It has to run everything in the chassis. The difference with the external shunt is the current doesn' have to go back out to the battery, so there is one less long wire to go bad.
A volt meter will tell you if the alternator is putting out and if your battery is discharged. So will an idiot light.
Toyota got rid of the somewhat dangerous high current wring in the cab in '78 with the introduction of the external shunt amp meter. You can get one of these and wire it in line with the white wire that goes to the battery + post. All marine amp meters have an external shunt.
There is no getting around feeding some high current into the cab. It has to run everything in the chassis. The difference with the external shunt is the current doesn' have to go back out to the battery, so there is one less long wire to go bad.
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I vote volt meter. Installed one in mine when I put new gauges in after the rewire. Why did I have to rewire my cruisr? Because I had shorted out the big ass power wire coming into the cab, intertwined with the rest of the harness, from the alternator, causing multiple electrical fires.
Also, you need to make sure that youre running the proper amp meter for your alternator. If you upgrade your stock alternator to some uber high output one and leave your stock amp meter in there, youre going to burn it out over time. If youre amp meter burns out, it acts like a fuse, and your alternator wont be able to charge your battery.
<hijack> Is it possible for an alternator to go out partially, and still charge some, just not as much as its supposed to?If not, then a volt meter is more than adequate IMOP</hijack>
-Dustin
Also, you need to make sure that youre running the proper amp meter for your alternator. If you upgrade your stock alternator to some uber high output one and leave your stock amp meter in there, youre going to burn it out over time. If youre amp meter burns out, it acts like a fuse, and your alternator wont be able to charge your battery.
<hijack> Is it possible for an alternator to go out partially, and still charge some, just not as much as its supposed to?If not, then a volt meter is more than adequate IMOP</hijack>
-Dustin
Yes. If a diode goes bad, then the alternator can put out the correct voltage at diminished amperage. When you turn on all of your accesories it would be noticeable as your battery would drop below normal running voltage.
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I thought that the amp meter was only suposed to show the amp flow to the battery and thus the drain or charge on the battery, and not the amps that the alternator was putting out. I like the amp meter as it shows the charge on my battery but don't like that it does not show how many amps the alternator is putting out. The amp meter is not as efective if you have things directly wired to the battery as it will show like the batter is being charged more than it is and you have more amps running through the cab.