Analog AMP meter, anyone try something like this?

[labatt50]

Anybody try something like this?

http://www.ebay.com/itm/New-Round-An...item3a5d37c905

I'm looking for some ideas for an in dash AMP meter.

[Revolution]

I haven't seen anyone using an analog gauge yet, I would think it would have quite a bit of needle bounce on a cart but it may work fine.

I don't know what to believe on my carts, the Alltrax controller tells me one amperage my cycle analyst tells me another and my clamp on meeter says something else. 100 amps difference in some cases.

[labatt50]

Originally Posted by Revolution

I haven't seen anyone using an analog gauge yet, I would think it would have quite a bit of needle bounce on a cart but it may work fine.

I don't know what to believe on my carts, the Alltrax controller tells me one amperage my cycle analyst tells me another and my clamp on meeter says something else. 100 amps difference in some cases.

Thats a crazy range, wow. I figured there would be quite a bit of bounce with an analog, just hoping on hill climbs I could see a range. Part of me wants to run the usb wire from the controller to an in-dash tablet of some sort. Monitor it that way, just read it off the Alltrax software. I guess I'm just looking for ideas...

[JohnnieB]

Measuring the amp flow gets a little tricky because as strange as it sounds, the amp flow is different in different parts of the the high current circuit in a series drive when the PWM from the controller to the motor is less than 100% duty cycle.

Alltrax measures and logs battery amps and motor amps as well as throttle position. If you look at the data log, whenever the throttle is pushed, motor amps will be higher than battery amps unless the throttle is at 100%, then they are equal, or close to it. This is due to the motor being fed pulsed DC and the amps being drawn from the battery is only the energy in the positive going pulses while the motor amps is the energy in the positive going pulses plus the energy that is generated by the field (stator) windings and armature windings when the magnetic field created by the positive going pulse collapses.

The attached page is from a Curtis 1204 manual, but all cart controllers work about the same, so it applies just about all controllers used in series drive golf carts. SepEx drive systems are more complex than Series drive systems, but are essentially two series controllers, plus a regen braking controller in one box.

Anyway, in a series drive system, the dashed line is battery amps and the dashed lines plus the dotted line is motor amps. The wave-shapes are pretty wild and not being synchronized with the frequency of the wave-shape, digital ammeters randomly sample at peaks and valleys, so they may appear to be reading erratically while analog meters tend to give an average reading.

A capacitor with a bleed resistor will make a digital ammeter do average readings and connecting a digital ammeter within the battery pack (which is seen as a huge capacitor by the wave-shape) reads average.