Stock EZGO digital vertical state of charge meter not working properly

[JohnnieB]

More than one way to skin a cat.

I like LED Bargraphs when working with audio (VU meters and octave band spectrum analyzers), but unlike the LED Bargraph voltmeters found in golf carts, the meters I use are accurate, repeatable and reliable.

I also like analog meters better than digital meters for certain tasks. In fact, I'm kicking around the idea of installing an expanded scale analog voltmeter (similar to the one linked to) in my cart for SWMBO to use as a "Fuel" gauge since she doesn't like the DVM battery meter due to the way it fluctuates all over the place while driving.

Since I have a 42V pack and nobody makes 42V analog battery meters, I'll have to modify a 36V to be on-scale at 42V, but I'd at least check the accuracy and calibration even if they were available in 42V.

For most analytical stuff where small differences are significant, I prefer Digital meters.

[simple man]

Originally Posted by radioman

I like this analog state of charge indicator. It is basically a voltmeter and you can tell at a glance how you batteries voltage is holding up under load. It can be left connected but it draws a small amount of current (.016 amps) http://aevcenter.com/cart/images/336.jpg

That's what I have on my industrial cart. It gives me a reasonable voltage indication without being obnoxious! (I personally can't stand numbers flipping up and down while driving) I just took several voltage readings with a DMM so I would know what voltages equate to where the needle indicates on the dial. It is connected directly to the battery pack and draws so little current it would take months to create a detrimental discharge on the batteries. The self discharge would exceed what the gauge draws!

[jakesnake27]

Originally Posted by sportcoupe

I copied this chart idea from another forum member as a quick reminder.

I like that 'coupe...

[chasenfish16]

I understand that the digital voltmeter is much more accurate, but it is not always convenient to stop for five minutes to see SOC. I used the digital bar meter for a rough estimate while moving.

[scottyb]

Who waits for 5 minutes? It's not gonna change that much after you let the gas off...... I never sit and wait for it but that's just me

[JohnnieB]

Originally Posted by chasenfish16

I understand that the digital voltmeter is much more accurate, but it is not always convenient to stop for five minutes to see SOC. I used the digital bar meter for a rough estimate while moving.

No matter what type voltmeter you use, you cannot measure something that isn't there.

While moving, the meter is reading Under-Load voltage rather than the At-Rest voltage that is needed to estimate the SoC.

Estimating how much energy is left in the battery pack while the cart is moving is akin to estimating how much money is in the bank account while the better half is shopping. It can't be done.

Originally Posted by scottyb

Who waits for 5 minutes? It's not gonna change that much after you let the gas off...... I never sit and wait for it but that's just me

The change can be over 10% SoC, but how long you wait does depend on how accurate you want or need to be.

Fortunately, an SoC estimate made from a voltage reading taken moments after stopping will indicate the SoC is lower than what it actually is and you are heading back to the charger sooner, so the error is on the safe side.

When I'm out and about and want to know the SoC, I stop and wait for the voltage on the DVM to stop climbing so rapidly. When it takes a second or more for the 1/10 Volt digit to increment, (my perception of a second, not timed), that is what I use to estimate SoC.

If I'm doing a test of some kind, I wait half an hour.

[yurtle]

Originally Posted by JohnnieB

More than one way to skin a cat.

"Skin a cat"? How's that PC?

[JohnnieB]

Originally Posted by yurtle

"Skin a cat"? How's that PC?

How, with the world's top athletes gathered in Sochi, would a phrase meaning to hang by the hands from a branch or bar, draw the legs up through the arms and over the branch, and pull oneself up into a sitting position, not be PC?

That would be akin to suggesting some of the Figure Skating judges might be biased.

[radioman]

What we need is a talking digital voltmeter featuring an analog output.

talking voltmeter - YouTube

talking voltmeter - YouTube

[scottyb]

JohnnieB posted :
Estimating how much energy is left in the battery pack while the cart is moving is akin to estimating how much money is in the bank account while the better half is shopping. It can't be done.