New CA displaying wrong voltage

[Philistine]

I recently got two new large screen cycle analysts. When I attach one to a new build it correctly displays the voltage of the pack at 50V, but when I attach the other one it shows the voltage at 45V. I have adjusted the Volt sense in advanced settings, and can now get the other one to correctly (or close to correct within .3V) show the voltage at 50v. Is this normal having to do this? This is about my 7th cycle analyst (from doing builds for friends), and this is the first time the CA hasn't read voltage correctly straight out of the box. Is this normal or has anyone else had to do this? If it correctly reads the voltage now does that mean it should be accurately calibrated?

EDIT: it is a large screen DP CA with speedo

 

[itchynackers]

I had the same issue with my new CA-DPS. The problem wasn't the meter, it was me. I incorrectly transferred all the old CA stats (including the volt sense) to the new one. I didn't know I shouldn't have done this. Luckily I wrote down the factory setting. I reset it, and all is well. But, I really don't have an accurate volt meter, so I'm not really sure how accurate the CA's are.

 

[Philistine]

I hadn't touched the settings and I had two brand new ones, and straight out of the box one read 45V and one read 50V on the same setup, that was what I found weird.

 

[MadRhino]

I've got one that I had to select the Zero Amp option in the menu, because it was showing 27000w usage from my controller at rest. Yet it was a matter of a minute and it's been working fine since. I believe it is possible that when the new chip is flashed to install the initial program and settings, it could happen that some bytes may be corrupted. A new CA has to be set for one's specific needs anyway, so why not make sure it is properly calibrated while we are at it.

 

[nicobie]

Every CA I've owned has been slightly off. But not by 5V, 1 or 2 at the most.

 

[itchynackers]

Tell me if I'm hijacking here... would an acceptable way to calibrate the CA voltage be to:

1) charge battery pack to a known voltage with my hyperion 1420i charger.
2) adjust CA volt sense so that it reads the same voltage.

In other words, can I assume my hyperion is accurate?

 

[MadRhino]

Tell me if I'm hijacking here... would an acceptable way to calibrate the CA voltage be to:

1) charge battery pack to a known voltage with my hyperion 1420i charger.
2) adjust CA volt sense so that it reads the same voltage.

In other words, can I assume my hyperion is accurate?

You can trust your RC charger to be pretty accurate, especially if it reads the same as your multimeter :wink:

 

[SamTexas]

In other words, can I assume my hyperion is accurate?

Good question. I have a similar one: How do you know how accurate your voltmeter is? I have 3 of them and they never agree with each other. 4.19, 4.18 and 4.17 on one same fully charged cell.

So what can you use as a RELIABLE base to determine the accuracy of your voltmeter? Obviously I'm not interested in outrageously expensive tools. Something that's common but always has a reliably fixed voltage.

 

[itchynackers]

[quothino"]

Tell me if I'm hijacking here... would an acceptable way to calibrate the CA voltage be to:

1) charge battery pack to a known voltage with my hyperion 1420i charger.
2) adjust CA volt sense so that it reads the same voltage.

In other words, can I assume my hyperion is accurate?[/e="MadRquote]

You can trust your RC charger to be pretty accurate, especially if it reads the same as your multimeter :wink:

I wouldn't trust my multimeter to within +/- 0.5V. It's one of those $3 Harbor Freight DMMs. Not very good. I will adjust my CA volt sense tonight. I know my pack is charged to 3.823V/cell with the hyperion, and is holding at that voltage. However, now I may need to readjust my Rshunt value :x