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Voltmeter at tech station.

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Voltmeter at tech station.

Old 10-15-2023, 06:15 PM
  #31  
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all digital meters except vert high end are +or - one digit as a normal spec read the specs of a meter. So it could read 4.29 4.3 or 4.31 and still be in spec
fluke 77 VI Voltage DC Range 6.000 V Ė 1000 V Best accuracy Ī(0.3% + 1) Best resolution 0.1 mV

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Old 10-15-2023, 08:17 PM
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Originally Posted by Zerodefect
There has to be a tolerance or grace range. And while we've generally been getting by with whatever nonsense voltage the RD chooses.......

4.3 would be the best cutoff voltage for DQ at all the tracks I've seen. Hundredths, should be ignored as insignificant.

4.2 and 4.27 are the same based on the tolerances of the meter. Do we see repeatable results down to hundredths? Sure. But it's sloppy.

I just dial in my charger to a few hairs over the RD's cutoff, then use his meter and infrared to check my battery before practice. (Keep in mind that your battery will cool, away from the charger)
A few general rules guidelines not just for this but pretty much all motorsports.

1. There is no tolerance on minimums and maximums. The room for error is above or below the line and how close you get to it is your choice and the risk you take.
2. Set values have tolerances. If something has to be 20mm, it should list a tolerance like +/- .1mm. So 20.1mm is good, 19.9mm is good. 20.11 or 19.89 is illegal.
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Old 10-15-2023, 10:28 PM
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Originally Posted by Zerodefect
Nothing wrong with my meter.

It's saved my life, literally, about 11 times.
Saved your life by detecting extremely high voltages? Doesn't need to be 0.02V accurate to do that.
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Old 10-15-2023, 11:29 PM
  #34  
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Originally Posted by wingracer
A few general rules guidelines not just for this but pretty much all motorsports.

1. There is no tolerance on minimums and maximums. The room for error is above or below the line and how close you get to it is your choice and the risk you take.
2. Set values have tolerances. If something has to be 20mm, it should list a tolerance like +/- .1mm. So 20.1mm is good, 19.9mm is good. 20.11 or 19.89 is illegal.

In this case there is no lower limit needed.As an organizer running your own set of rules you can hold on to the roa/EFRA/FEMCA etc guide lines os set some own limits.
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Old 10-17-2023, 07:35 AM
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Originally Posted by gigaplex
Saved your life by detecting extremely high voltages? Doesn't need to be 0.02V accurate to do that.
My point exactly.

Ya'll using an even lesser meter in tech. But it says "Fluke" on it. So its accepted by racers.

We make do. But it's amusing to me.
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Old 10-21-2023, 08:06 AM
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Originally Posted by Roelof
In this case there is no lower limit needed.As an organizer running your own set of rules you can hold on to the roa/EFRA/FEMCA etc guide lines os set some own limits.
That's what I said, minimums and maximums do not have a tolerance, only set values have tolerance and this is not one of them.
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Old 10-23-2023, 02:12 PM
  #37  
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Originally Posted by mrreet2001
Ichargers read out that far.
I have an iCharger. Setting the endpoint cutoff voltage is only to the hundredth.
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Old 10-24-2023, 12:53 PM
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Originally Posted by gotheframe
I have an iCharger. Setting the endpoint cutoff voltage is only to the hundredth.
I answered your original question.

Originally Posted by gotheframe
What charger are you using that is accurate to the thousandths?
... and still not relevant to my question ... ie the whole point of this thread.
What voltmeters are everyone using at the tech station? Anyone using one that reads 3 past the decimal at 4 and 8 volts? So like 4.22x or 8.44x?
Which is a simple question that didn't need discussion or whatever this fustercluck of a thread has been derailed into.
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Old 10-25-2023, 10:51 AM
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Originally Posted by mrreet2001
I answered your original question.
... and still not relevant to my question ... ie the whole point of this thread.
Which is a simple question that didn't need discussion or whatever this fustercluck of a thread has been derailed into.
Relevancy, whats the point of reading thousandths if you cant charge thousandths?
Or seeking advice on a forum when clearly you would have been better off with Google and simple logic?
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Old 10-25-2023, 01:29 PM
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I also know a guy who adjust his charger end voltage to match the 8.40v on the tech meter. As if the few mV gain can be noticed....
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Old 10-25-2023, 01:54 PM
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Originally Posted by gotheframe
Relevancy, whats the point of reading thousandths if you cant charge thousandths?
Or seeking advice on a forum when clearly you would have been better off with Google and simple logic?
You can press the stop button before it reaches the end point.
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Old 10-26-2023, 05:29 AM
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Originally Posted by gotheframe
Relevancy, whats the point of reading thousandths if you cant charge thousandths?
Or seeking advice on a forum when clearly you would have been better off with Google and simple logic?
Google isnít going to tell me what model of volt meters tracks are using or what digits they are looking at Ö what is wrong with you?
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Old 10-26-2023, 07:31 AM
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The guy that used to tech the big races at my local track used a Fluke 8808, which is a 5.5 digit meter. Which to simplify that, it reads a total of 5 digits when measuring a 2s lipo. A pass will be <= 8.4049. Why is that a pass, because Roar rules says 8.40 and on a 3.5 digit meter, 8.4049 will read 8.40, with some variance for accuracy.

If I were to tech a race, I would use a meter with at least 4.5 digit display, because most meters have an accuracy that is off a number of digits on the least significant number. Its one thing to be off a couple of thousandths, but arguments can arise if your meter is off a couple of hundredths.

If you are looking for a meter to suggest to your track, or pick up for yourself, I suggest the HP3478a, it has a 5.5 digit display (it is one of the meters on my bench). You can get them on ebay for <$150, they are old, but they are tanks and extremely accurate so long as the cal data hasn't been lost. But there are 2 things that need to be checked every so often. One is check the rifa caps for cracks, and if they have cracks replace them. The second is the onboard battery needs to be 3.00v or higher, that one requires some precautions to change as it holds the cal data.
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Old 10-26-2023, 01:27 PM
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Originally Posted by gigaplex
You can press the stop button before it reaches the end point.
I could, I'm just not going to. A thousandth of a charge isn't going to make a difference with errors on the track that costs tenths (or tens of tenths lol). Heck, pre-race I'd just burn it off with a lap or two warm up and then sitting, waiting my turn to start (with the cooling fan just whirring away like its not filled up with carpet fibers).
Originally Posted by mrreet2001
Google isn’t going to tell me what model of volt meters tracks are using or what digits they are looking at … what is wrong with you?
You missed the simple logic on that one. Bc google (or just head straight to amazon) is going to show you similar results for everyone else that typed "accurate voltmeter". Read some reviews, compare accuracy, look at prices. Oop... not going to buy one that costs $xxx. Narrow search by price, cause what track is actually going to spend three digits for a voltmeter. Which one has free shipping? Done, just like the person at the track that bought the voltmeter. You're way over thinking this, and its not going to matter (or be relevant).
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Old 10-26-2023, 02:15 PM
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Originally Posted by gotheframe
I could, I'm just not going to. A thousandth of a charge isn't going to make a difference with errors on the track that costs tenths (or tens of tenths lol). Heck, pre-race I'd just burn it off with a lap or two warm up and then sitting, waiting my turn to start (with the cooling fan just whirring away like its not filled up with carpet fibers).

You missed the simple logic on that one. Bc google (or just head straight to amazon) is going to show you similar results for everyone else that typed "accurate voltmeter". Read some reviews, compare accuracy, look at prices. Oop... not going to buy one that costs $xxx. Narrow search by price, cause what track is actually going to spend three digits for a voltmeter. Which one has free shipping? Done, just like the person at the track that bought the voltmeter. You're way over thinking this, and its not going to matter (or be relevant).
Thanks for the input. But I was simply asking what tracks are using. Not some philosophical reasoning to a question I didnít ask. Itís not hard to say we have model xxx by zzz brand. You seemed to be making it overly complicated. I donít care what a bunch of paid Amazon reviews say.
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