Ammeter vs Voltmeter

[RED-Z06 2,221]

Most older machines came with ammeters, you can see at a glance if the system is discharging or charging, or neutral.  Its a very basic bit of information.  

 

My 416-H has the factory voltmeter and the needle goes past the stop on shutdown and gets stuck...so its time.  Im looking at new gauges and my C100 has an ammeter, i want to put a gauges on the 702 as well.

 

What do yall prefer and why?  I like volt meters, it tells you if its charging or discharging but also the state of the system.

[ri702bill 8,323]

I agree the voltmeter does give more information - and is not prone to a failure where it shorts out to ground. Most new voltmeters have an LED digital display and are rectangular in shape.

Not sure if you can get a digital one with a 2" round shell...

@Handy Don runs both on his 854 6 speed. He just added the wiring diagram to the Forum this week.

Bill

[953 nut 55,243]

Digital voltmeters are great,             don't even think about an amp meter.

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[peter lena 8,629]

@953 nut  thinking  of doing a   swap , amperage  / volt  , what's the hook up difference , 12 hp magnum , c 85 , Pete

[JoeM 7,874]

I have less trouble with charging systems but prefer a volt meter. 

My first choice in gauges is a fuel gauge tho. 

 

Pete the amp meter charging circuit feeds through the meter. Those two wires would have to be disconnected and coupled to each other. Then a wire could connected to a switched point (acc) and then to the volt meter positive then from the meter to ground.

 

 

Edited January 28 by JoeM

[ebinmaine 67,508]

 

 

Both voltmeters and ammeters have their place. 

They do have different functions and abilities.  

 

Voltmeters are wired in PARALLEL to another circuit.  On its own. No dependence on the functionality of another entity.  

Ammeters are wired in SERIES with some or all of the circuits of the machine. 

 

 

I like the ammeter for the tell of seeing the battery condition at start. 

 

I am NOT a fan of ammeters for the way they fail. 

The ones used in Wheelhorse tractors were - to the best of my knowledge - not prone to a short circuit as a failure mode like several vehicle manufacturer's ammeters were well known for in years past. 

Wheelhorse ammeters USUALLY have a failure mode that creates an open circuit thereby disabling the power system of the tractor.  

This creates a condition called Dead Tractor.  

 

 

So what do I use?

Mostly voltmeters. 

 

I've built full custom wiring harnesses for several tractors. 

All but the C160 Automatic I've used ONLY a voltmeter.  On the Automatic I decided to leave the ammeter in place to try it out.  

I like that I can see the discharge at start and recharge shortly after to know that the charging system is working.  

Unfortunately the particular ammeter in my tractor has been losing touch h with reality and the needle waggles about wildly while in operation.  

It won't be staying permanently.  

 

I find that the voltmeters in the other tractors I've wired will tell the same basic information to me by reading a low voltage before and during cranking and a higher voltage while running.  

 

After this tractor is swapped to a voltmeter I probably won't install another ammeter unless someone else convinces me there's a good value to having both.  

 

 

[squonk 41,118]

I prefer the ammeter. Factory voltmeters are inaccurate for the most part. I see them pegged all the time. Is it overcharging or a bad meter. When starting the ammeter goes to the charging side immediately telling me the charging system is working. A volt meter drops when starting and you have to wait until the system voltage comes up before you know if it's working or not. The ammeter bouncing at idle is due to the un-sophisticated charging system switching the charging current on and off. I have seen a couple of ammeters fail but have yet to see one burn up. If you're worried about that, put a fuse on it. Amperage does the work. Voltage is how hard the work is pushed. I want to know which direction the electricity is flowing. Actually both meters together is ideal.

 

Reminds me of an Electrical clinic we had a Napa. We had an empty battery case rigged up with 8 D cell batteries and a little lead so the weight was about right. Hooked up a key switch and a Ford solenoid and starter. Then had Techs "diagnose " why the starter didn't work. The had 12 volts but not nearly enough amps to do the work. 

[RED-Z06 2,221]

29 minutes ago, ebinmaine said:

 

 

Both voltmeters and ammeters have their place. 

They do have different functions and abilities.  

 

Voltmeters are wired in PARALLEL to another circuit.  On its own. No dependence on the functionality of another entity.  

Ammeters are wired in SERIES with some or all of the circuits of the machine. 

 

 

I like the ammeter for the tell of seeing the battery condition at start. 

 

I am NOT a fan of ammeters for the way they fail. 

The ones used in Wheelhorse tractors were - to the best of my knowledge - not prone to a short circuit as a failure mode like several vehicle manufacturer's ammeters were well known for in years past. 

Wheelhorse ammeters USUALLY have a failure mode that creates an open circuit thereby disabling the power system of the tractor.  

This creates a condition called Dead Tractor.  

 

 

So what do I use?

Mostly voltmeters. 

 

I've built full custom wiring harnesses for several tractors. 

All but the C160 Automatic I've used ONLY a voltmeter.  On the Automatic I decided to leave the ammeter in place to try it out.  

I like that I can see the discharge at start and recharge shortly after to know that the charging system is working.  

Unfortunately the particular ammeter in my tractor has been losing touch h with reality and the needle waggles about wildly while in operation.  

It won't be staying permanently.  

 

I find that the voltmeters in the other tractors I've wired will tell the same basic information to me by reading a low voltage before and during cranking and a higher voltage while running.  

 

After this tractor is swapped to a voltmeter I probably won't install another ammeter unless someone else convinces me there's a good value to having both.  

 

 

With a voltmeter, every start is a free load test on the battery.

[953 nut 55,243]

2 hours ago, peter lena said:

@953 nut  thinking  of doing a   swap , amperage  / volt  , what's the hook up difference , 12 hp magnum , c 85 , Pete

All you will need to do is connect the two wires that are connected to the amp meter thgather to eliminate the amp meter. To add a voltmeter you just connect one side (+) of the meter to the green wire feeding your light switch and connect the other (-) wire to ground. When the key is on your voltmeter will have power.

[Handy Don 12,232]

9 hours ago, ri702bill said:

I agree the voltmeter does give more information - and is not prone to a failure where it shorts out to ground. Most new voltmeters have an LED digital display and are rectangular in shape.

Not sure if you can get a digital one with a 2" round shell...

@Handy Don runs both on his 854 6 speed. He just added the wiring diagram to the Forum this week.

Bill

 

I wanted both, specifically because it’s an S/G system having a mechanical regulator which can fail to overvoltage which can cook a battery. Yes, not having the ammeter fall toward zero could tell me that, but the glaring “15.5v” was unmistakeable. I chose a marine voltmeter to get the round chrome bezel (appearance) and the weather proofing (practicality)

On a stator-style tractor with a solid state voltage regulator as on our 518-H++, I would be content with voltmeter alone for electrical info.

 

Note the gauges are mounted on my custom wood dash (it's a 702 tank on an 854 so I needed a dash and went a bit crazy) so there is no chance for a ammeter failing with a short to ground. (I think the plastic dashes of the 701 & 702 would have the same protection.)

 

5 hours ago, JoeM said:

My first choice in gauges is a fuel gauge tho. 

That’d be my third choice! 

[ri702bill 8,323]

12 minutes ago, Handy Don said:

I needed a dash and went a bit crazy

NOW who's "Guilding the Lily" ??

[Handy Don 12,232]

2 minutes ago, ri702bill said:

NOW who's "Guilding the Lily" ??

Again, guilty as charged! 🤣

[RED-Z06 2,221]

1 hour ago, Handy Don said:

 

I wanted both, specifically because it’s an S/G system having a mechanical regulator which can fail to overvoltage which can cook a battery. Yes, not having the ammeter fall toward zero could tell me that, but the glaring “15.5v” was unmistakeable. I chose a marine voltmeter to get the round chrome bezel (appearance) and the weather proofing (practicality)

On a stator-style tractor with a solid state voltage regulator as on our 518-H++, I would be content with voltmeter alone for electrical info.

 

Note the gauges are mounted on my custom wood dash (it's a 702 tank on an 854 so I needed a dash and went a bit crazy) so there is no chance for a ammeter failing with a short to ground. (I think the plastic dashes of the 701 & 702 would have the same protection.)

 

That’d be my third choice! 

My 702 has a cast iron dash 

[Handy Don 12,232]

19 hours ago, RED-Z06 said:

My 702 has a cast iron dash 

Then you probably want to add a 15amp fuse in the green wire between the regulator’s BAT terminal and the ammeter!

[953 nut 55,243]

6 hours ago, Handy Don said:

15amp fuse

Probably a 30 Amp would be better, a 15 might not be enough for recharging right after starting if the battery isn't the best.

[Handy Don 12,232]

17 hours ago, 953 nut said:

Probably a 30 Amp would be better, a 15 might not be enough for recharging right after starting if the battery isn't the best.

Interesting point. I chose that size because the ammeter I have goes only to ±15 and the rated output from the S/G is 15. If I ever have to replace that fuse, I’ll try a 20 first! 😁

[953 nut 55,243]

9 minutes ago, Handy Don said:

Interesting point. I chose that size because the ammeter I have goes only to ±15 and the rated output from the S/G is 15. If I ever have to replace that fuse, I’ll try a 20 first! 😁

When I built the 953 @Pullstart has named "Hot Wheels" I used the same logic. The Kohler Magnum charging system is a 15 amp system so I used a 15 amp fuse. The first night of the Big Show one of his daughters blew the fuse while driving with the lights on. I had never driven with the lights on so never had a fuse problem. Kevin replaced it with a 30 amp and no more problem.

Edited January 30 by 953 nut

[ebinmaine 67,508]

13 minutes ago, Handy Don said:

  rated output from the S/G is 15.  

 

Is there such a thing as a spike? Or a momentary High output?

 

I have a 20 or 25 amp fuse in Cinnamon Horse  74 C160. 

Several years ago I was using it to plow in the dark. That fuse blew when I was in the street. Luckily, being an 8 speed with manual lift, I just stuck it in neutral, lifted the blade, and pushed it forward.

I'd be a lot more irritated about that situation if it was on my C160 Automatic.  

[Handy Don 12,232]

4 minutes ago, 953 nut said:

When I built the 953 @Pullstart has named "Hot Wheels" I used the same logic. The Kohler Magnum charging system is a 15 amp system so I used a 15 amp fuse. The first night of the Big Show one of his daughters blew the fuse while driving with the lights on. I had never driven with the lights on so never had a fuse problem. Kevin replaced it with a 30 amp and no more problem.

Hmmm.

So the draw was more than 15 (or the fuse was a “weak” 15). 

I get that the fuse was somehow seeing BOTH the charging and the lighting draw currents. Maybe the Magnum is actually capable of higher than 15 amp output?

[RED-Z06 2,221]

17 minutes ago, Handy Don said:

Hmmm.

So the draw was more than 15 (or the fuse was a “weak” 15). 

I get that the fuse was somehow seeing BOTH the charging and the lighting draw currents. Maybe the Magnum is actually capable of higher than 15 amp output?

Charging system outputs are an approximation...you'll see 20amp systems spike 22-23, you'll see 25 amp systems put out 23+. When I add a fuse i figure going 5 amps high, even a 40amp fuse will pop on a dead short and thats the big risk

[Pullstart 62,889]

34 minutes ago, 953 nut said:

When I built the 953 @Pullstart has named "Hot Wheels" I used the same logic. The Kohler Magnum charging system is a 15 amp system so I used a 15 amp fuse. The first night of the Big Show one of his daughters blew the fuse while driving with the lights on. I had never driven with the lights on so never had a fuse problem. Kevin replaced it with a 30 amp and no more problem.

Some memory you have, Mr. Richard!  I didn’t even remember that!  It must have worried you more than me 

[953 nut 55,243]

3 hours ago, Pullstart said:

Some memory you have, Mr. Richard!  I didn’t even remember that!  It must have worried you more than me 

I am an experiential learner, when I make a mistake it sticks in my mind so I won't do it again.  

[ebinmaine 67,508]

2 hours ago, 953 nut said:

, when I make a mistake it sticks in my mind so I won't do it again.  

When I make a mistake it sticks in my mind AND I STILL do it again.

 

[squonk 41,118]

Fuses are mass produced from who knows where. I have seen fuses blow before the rating is reached and not blow until the the rating was exceeded by more than10 amps. That's why I like an ammeter. With just a Volt meter you don't see the spike. 

 

I used a clip in ammeter almost daily when I worked at the auto dealer. It's not a oscilloscope but a small window into the circuit.

[Handy Don 12,232]

Just thinking about minimum instrumentation.

Dad bought the ’66 VW Beetle new. It had a speedometer and lights for low oil pressure, generator warning, turn signals, and high beam. Probably all of that was by law or regulation. He did go for the gas gauge (an option for extra $)--standard was a valve under the dash to switch on the one-gallon “reserve” when the car started to run out.

Edited January 31 by Handy Don