Alternator output amp meter? Anyone fitted one?

An amp clamp on the alternator wire plus a readout/ meter on the dash..

Anyone done such? I'm looking into it, think it might be informative.

What is the actual current draw under various operating conditions?

"Loud Music Draws AMPS!" ;-)

 

Just use an OBDIII dongle w an app if the PID’s allow.

 

For monitoring the charging function of an Alternator, a Voltmeter is what I use. Sounds like you're more interested in current draw, Amps. Frustrates me that some vehicles don't have important, in my opinion, almost essential gauges. The most glaring are Ford Heavy Duty trucks. I had a job driving supplies for Wildland Fire in a Ford 550. No Voltmeter, so I had no idea that the Alternator had failed, then I was broke down in the middle of nowhere.
Bring back the days before idiot lights!!

 

It's not automotive, but hails from solar:
500A battery monitor with shunt | rv battery monitor | Renogy

 

Yup... I remember the days when everything came with Gas/temp/oil psi/volt or amp gauge. If you wanted a tach (Which seems like everything comes with now, for some reason...) you added your own. I'd much rather have a oil psi gauge and a volt gauge over a tach, which I find completely useless.
I drive a 4 cyl with an automatic trans. What do I need a tach for??

 

For Drag Racing??
LOL!!!!!

For Drag Racing?
LOL

 

Yup! I own a lot of pinks of those guys who used to have Lamborghinis...

 

$20 Bluetooth obd reader and your cellphone. You'll have more information than you could ever use a million years. A clamp on amp meter or shunt won't tell you if your alternator is not working. It tells you how much load you're using. Other than sheer curiosity, this piece of information is not really useful for anything.

 

Somehow I get a lot of information about battery and alternator health from having an amp meter. All three of the tractors have them. No rig should be without.
What is the output of the alternators fitted to a 3rd gen with tow package? 130 amps? Wouldn't it be a good thing to know where all those amps were going?

I'll look into the OBD options, but I can't see that little screen while driving. old age will do that ;-)

Stewart- Warner might just be getting a sale...

 

Just looking ...I don't see any OBD systems/apps with an amp meter.

Suggestions?

 

Well, here is a useful thread that is great reason for knowing the alternator output.....
You even contributed your thoughts!

This Taco forum is really the best! ;-)

eta

Opps! forgot the link

https://www.tacomaworld.com/threads/amps-ratings-and-draw.827563/

 

An ammeter of the usual dashboard style doesn't really show alternator output so much as it shows the direction of system imbalance. If the electrical system was working correctly it wouldn't show the "draw" of loud music for example.

You really noticed this on older vehicles that commonly had alternators in the 37-63 amp range.

Example:
You pull up to a stoplight at night with the lights & heater fan on, older alternators didn't have much output at an idle so the lights would dim and the fan would slow due to the reduced voltage.
The ammeter would indicate a discharge - the battery was making up for the reduced alternator output.

As soon as you accelerated to road speed (and voltage returned to normal) the lights & fan would go back to normal and the ammeter would indicate a charge - replacing the energy drawn out of the battery.

After a few minutes of driving the battery would be fully charged and the alternator would carry the full load - the ammeter now indicated a tiny bit positive, perhaps just the width of the needle.

If you increased the load, by turning on the high beams for example, the ammeter would momentarily indicate an imbalance before the voltage regulator corrected alternator output for the higher load.

 

Question:
Do I want an ammeter or a voltmeter?

Example:
Alternator failure to charge, again we will use older carburetor equipped vehicles because it gives a better example.

The alternator fails during daylight driving, old vehicles had a mechanical fuel pump so the only load on the battery was the ignition system - a very small load.
Those cars would run a long way on just the battery - until they quit, and you started walking.

The ammeter would only indicate a tiny discharge, perhaps the width of the needle itself - very easy to miss.

A voltmeter on the other hand would drop noticeably when the alternator went out as the system voltage instantly would drop from normal 13.8 - 14.2 volts to the fully charged battery voltage of about 12.7 volts.

As you drove the voltage would rapidly drop as the battery was depleted and the needle would very obviously indicate this.
Please review the chart below for illustration.

Voltmeter wins the functionality challenge!

 

Just to add humor to the cause,

Back when I was a young man, I drove an NSU Prinz (look it up ;-) from Vail Colorado to Nogales AZ. without a working generator! They were hard to find, being an NSU and all that. The trip was accomplished with a single battery recharge at a filling/ service station on the way out, and a fully charged "replacement" battery sourced on the return. Thank heaven for full moon nights in west Colorado. It was wintertime!
A true "Hybrid" vehicle, gas and battery ;-)

To add: the desire is not to monitor alternator condition or performance, but rather to get a handle on what "while camping" loads are to be experienced and expected. A quick brows of typical alternator output vs rotation speed has given me an appreciation for how little current is available at engine idle. (roughly half of full rated output).



Much like trying to boost start a dead vehicle with jumper cables, "you need to rev up the rescue vehicle to get the dead battery to help out the cause".

I thought that the upgraded tow package alternator on the 2021 Taco was substantial at 130 amps. The STOCK alternator on my 2021 Volvo XC90 is 210 amps!

Progress!

eta

I find it most entertaining how each contributors comments and direction follow methods that achieve ends personal to themselves. The intent of the original post is almost irrelevant. What a great span of awareness such conversation brings.

 

Huh?

 

I think the reason why most manufacturers quit installing gauges is because most people don’t know what they’re looking at. Imagine that a lot of new car owners bring in newly purchased cars because of normal things like volt meter and oil pressure fluctuations. And it cost money and time for the dealership. And customers that felt they were lied to.

I read something recently that said that even on trucks that have gauges and meters, they are not really reading anything except the ECU.

 

Correct.

Up to the late 1960's it was common for the oil pressure light to flicker or come on at a hot idle. This was clearly explained in the owners manual.

By the 70's consumers would complain about this condition so the manufacturers lowered the "on" set point of the sending unit to 1-2 psi -- keep in mind the pressure is taken right after the oil pump, think how much (how little) oil is getting to the top of the engine by the time the light goes on.

The same dumbing down occurred with gauges, some Ford trucks of the 80's-90's used a on/off style sending unit with a oil pressure gauge having a resistor in the circuit. When the sending unit closed the gauge indicated about 1/2 scale "normal", if the sending unit opened the gauge dropped to "low".

 

Modern day alternators have enough output that you don't need to monitor the amperage. If you look at the old car/tractor ammeters, they only had markings up to 60a usually.

It's not like you're going to hop in your truck one day to find that your alternator is mysteriously maxed out by something. Well, maybe your neighbor hooked up a 1500watt light bar and didn't tell you???

 

My point exactly. I use a Voltmeter in my Chevy truck, I knew within the time to glance at the gauge that I had an Alternator problem, drove the truck 100 miles basically on the Battery only. Fortunately it has a mechanical Fuel Pump, it was only raining lightly so I didn't have to run Wipers and fudged on the California law that lights should be on if it's raining. Made it home!!

 

Here's my take, the idiot light is the best indicator for JohnQ who wouldn't know a volt from an amp. It just tells if the system is functioning and is why they eventually all went that route. If the vehicle's alternator, wiring, and battery are good and if the customer hasn't added other electrical loads a light is fine, it's a simple go/no-go indication great for soccer mom's mall trips but it falls flat for an information gathering device. If someone wants details, the amp meter values can yield a lot of useful info. In todays world it's better suited for setting something up and getting data on it's effect on the truck's electrical system but once that initial information is known (right after the mod) it's usefulness diminishes until the next mod. For data gathering a clamp on amp meter will be more useful since you can move it around and check current value from a specific load (by itself in many cases). When the system is buttoned up and working correctly you shouldn't need to analyze the amp flow on an ongoing basis IMO.

The other indication; a voltage gauge is a very crude way to do any analysis of an electrical load, IMO it's useless for that but it's the best way to see you state of charge on the battery so having one is a good idea, a simple USB port with a voltage display will suffice in many cases. I have one in the bed where I also located DC ports for various things. The battery voltage it right there to see when I plug in a device and I can glance over at it when camping, no going inside and turning on a key. With the truck off while consuming electricity a voltage gauge is indispensable and it will also give you a crude indication of the elec systems health when the motor is running.