Working AmpMeter people chime in

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Working AmpMeter people chime in

Reply #15 – February 03, 2015, 11:17:58 PM

I really want to wire in a different connector to my watt meter that i use for my model airplanes. I tested the wattage/amprage of the taurus fan i installed just for fun.

Instead of soldering or crimping terminals to the fan, i used "heavy duty" alligator clips, just to test the fan.

At 16.4v's, low speed takes 16 amps and around 270 watts. The high was 448 watts, but it had enough load it brought the lipo battery i tested it with down to 14 or 15v's. Don't remember exactly. It was bout 32 amps. If i spun it on low then connected high, it settled down to about 20 amps, never exceeding 25 amps. It did however burn up one of the wires on my clips before i really rung of out well.

My personal opinion, i don't see a point in a non fully digital amp gauge. Most changes that you would see would be minuscule and hard to read on such a small buttstuffog gauge.

Assuming same wattage under load, when the voltage goes down, amprage will increase, again assuming the same wattage(overall work performed).

One thing i found funny. I have a 19oz airplane that pulls more then my electric fan. It actually pulls 365 watts and produces over 40 oz of thrust. I hooked my fish scale up to the electric fan, it didn't appear to pull much of any thrust. Im also surprised how quiet and relatively weak an electric fan actually is, and how well it actually cools.

Working AmpMeter people chime in

Reply #16 – February 04, 2015, 09:19:18 AM

BTW, where is the shunt for an A-meter located?

I have working A-meter on my red car, but the needle movement difference between no load, max load and max charging is so small, you can't even notice the difference for the first signt. I experienced an issue, that my battery was completely flat after driving in traffic jam with A/C and headlights on. And I didn't notice this, unless I wasn't able to start at a petrol station. What a shame.
The meter should be much more sensitive, or you can't see anything.

And as Tom mentioned, current isn't as important information, as voltage, because if there is a short, it will blow a fuse and that's all.

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Reply #17 – February 04, 2015, 04:23:44 PM

Quote from: jcassity;443879

I will now speculate that you have vast experience working with switch mode power supplies and ,, to include valve regulated lead acid as well as flooded cell batteries. most people to get to see this in real life because of the equipment they are working on don't include the variable of COUP DE FOUET .

LOL........... clearly not as much as you. I had to look up Coup De Fouet to figure out it was the whiplash effect. My experience comes from motive power generation.

Just incase anyone is wondering
coup de fouet" (whiplash) effects. This effect is a temporary, severe voltage drop which occurs when a heavy load is suddenly placed on the battery and is caused by the inability of the rate of the chemical action in the battery to accommodate the instantaneous demand for current.

John

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Reply #18 – February 04, 2015, 05:59:43 PM

Quote from: Trinom;443894

BTW, where is the shunt for an A-meter located?

I have working A-meter on my red car, but the needle movement difference between no load, max load and max charging is so small, you can't even notice the difference for the first signt. I experienced an issue, that my battery was completely flat after driving in traffic jam with A/C and headlights on. And I didn't notice this, unless I wasn't able to start at a petrol station. What a shame.
The meter should be much more sensitive, or you can't see anything.

And as Tom mentioned, current isn't as important information, as voltage, because if there is a short, it will blow a fuse and that's all.

87 evtm for the 2.3L say the splices were the Ammeter & single wire shunt wire are spliced are located at the starter relay.

one side of the bonded Ammeter and shunt is sourcing battery
one side of the bonded ammeter and shunt is sourcing alternator output.

in my opinion only, I prefer volt meter,, again for this drill my son wants to attempt to find out where the fault is.
good observations and points you did make above.

attached are the kind of shunts I deal with all the time.. 50mv rated XXXX amps

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Reply #19 – February 04, 2015, 06:03:04 PM

Quote from: Skunk;443902

LOL........... clearly not as much as you. I had to look up Coup De Fouet to figure out it was the whiplash effect. My experience comes from motive power generation.

Just incase anyone is wondering
coup de fouet" (whiplash) effects. This effect is a temporary, severe voltage drop which occurs when a heavy load is suddenly placed on the battery and is caused by the inability of the rate of the chemical action in the battery to accommodate the instantaneous demand for current.

John

and further shows that when high tech equipment loads with non Fero loads are being powered (switch mode power supplies), it clearly illustrates when voltage goes down, the battery "current demand" increases..

yet this seems to break ohms law in some cases ,,,, oh well, nuff of that stuff

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Reply #20 – February 04, 2015, 06:10:29 PM

Bottom line here is an AMMETER is useless. You are better off with a voltmeter and an idiot light.
By the way those so called idiot lights really work great. They will tell you if you have an open diode trio and that is a fact

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Reply #21 – February 04, 2015, 06:11:37 PM

Yes J that is a mother SHUNT FOR SURE!! Big amp numbers those bad boys can handle

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Reply #22 – February 04, 2015, 06:13:36 PM

By the way as J points out the shunt is between the ALT and starter solenoid. I will take his word for that as i never looked at the print. But if so that is a dead giveaway that the AMMETER is useless. reason being it does not monitor the full load of charge and discharge if i am thinking correctly

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Reply #23 – February 04, 2015, 07:04:32 PM

here is the 87 print

its a difference of potential thing,, each side of the parallel ammeter/shut is positive

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Reply #24 – February 04, 2015, 07:14:10 PM

keep in mind though,, there is not a single illustrative representation for an ammeter tied to a 5.0car!!!!!!!!!!!!!!! that's my original point to post 1 and wondering who in a 5.0 has a working unit.

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Reply #25 – February 04, 2015, 07:23:33 PM

try to ignore ckt 36,, ,, just ignore it being the regulator input for the moment and you see that one side of the ammeter is battery, the other side "see" or feels alternator,, the imbalance would be the difference and cause needle deflection.

in my opinion, the windings inside the ammeter should have been of a smaller conductor with many more windings to ultimately result in a resistance , lets say 20ohms.... then put the ammeter in parallel with a 20ohm shut wire, that would make it better.

the meter on the left is a volt meter
the meter on the right is an ammeter. note the windings and size conductor + qty of turns.

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Reply #26 – February 04, 2015, 09:18:50 PM

J, mine is a 87 2.3 converted to a 5.0 if that's of any help. As Tom states, the circuit doesn't work very well as it is since both sides of the meter connect to a common point at the start solenoid. In my experimentation I found the divider circuit needs to force more voltage to pass through the ammeter to amplify the miniscule voltage differential just to get a large enough deflection to actually see. I also found it will always show in the middle never indicating level of charge or discharge because the field excitation from the battery and output of the alternator are always at the same potential due to common connection. IMO the only way to get it to actually work as intended is to run full load though the meter BUT that's not a safe option, hence the movement to using Voltmeters over the Ammeter.

John

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Reply #27 – February 04, 2015, 09:32:17 PM

are you guys blind?

I have typed words, shown pictures and drawing.. not sure what more I can say.

*one side of the parallel shunt / meter references battery ~ see fuse link L
*one side of the parallel shunt / meter references alt ~ see fuse links G, H & I

~edit out in your minds eye circuit 36 by pretending it isn't there for a moment.

Both sides of the meter are not on the starter relay,, I have no idea where that comes from other than assumption based posts prior to this.

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Reply #28 – February 04, 2015, 10:32:16 PM

J.... not blind nor assumption, Ok maybe a little blind...I am getting old.......... The fact is the ammeter is not seeing/registering the imbalance due to the design of the field windings/core and I never attempted to alter that part of the circuit. The large yellow wire is the path of least resistance and the meter is not getting enough flow to deflect the needle. If you put your voltmeter across S261 and S262 you will read at or near Zero which may as well be connected directly to the starter relay. I apologize for oversimplifying. Circuit 36 has to taken into account due to its draw to drag down the battery side of the connection anytime the key is on thus bypassing the shunt before load distribution when not running and after the shunt when running. I believe it will reduce the amount of imbalance thus reducing deflection of the needle. Removed from the circuit yes it should without question work since power has only the parallel path of the shunt and the meter.

Feel free to beat me over the head with a dummy stick......... I never claim to be right........ just self educating discussion.

John

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Reply #29 – February 05, 2015, 05:48:28 AM

Ok here is my take on this. The ford engineers wanted an ammeter on the 2.3 so they went cheap and dirty. The meter is in parallel with the A terminal which does not see enough accessory or vehicle load. hence it does not work or works like shiznit. Installing the meter terminals like across the alt and the feed to the ignition switch would work. This way the meter shunt will see in and out loads and charging rates. A simple set of wires from the ammeter to these locations will be my bet to get it to work much better. But you will have to experiment to how much wire you need or should i say the point of connection to engineer the shunt length. I am willing to bet alt and ignition switch has the most drop and will allow the meter to work properly. Where it is right now is useless because it does not see all the loads of the vehicle only alt reference.

Note you will have to extend only the meter coil portion of the gauge to these locations. And leave the A terminal wiring. I would bridge it at the battery side of the solenoid and or the alt big lug to see if that works and ignition switch and it will work better but you will have to try different points in the circuit to get the deflection you desire on the gauge. But the alt charges through the connection at the solenoid so that is an issue. That lead would have to be moved past the solenoid and closer to the ignition switch. Bottom line again is to forget the ammeter and install a voltmeter case closed. You need to get the meter in parallel with in and out loads and the solenoid and ignition switch feed. No need for cutting either as the meter coil is all you need and some 18gauge wire to the gauge coil just might be the best place. You will have to experiment. Maybe from the battery + side to the ignition switch. Some experimenting is needed. You can use an old dash if available with 2 leads soldered to the back of the ammeter as a test.

Bottom line an ammeter has to see in and out loads. So pick a spot and experiment. I will stick with a voltmeter and keep my headache at a minimum. I have other fish to FRY