Fluke meter accuracy and recommendation

[NeilP]

I have seen a few threads here about Multimeter recommendations and accuracy, but have not seen anyone recommend a Fluke...probably because of the cost and the fact for our general needs the cheapo flea bay style meters do well enough.

But if I want a good accurate meter to help calibrate the iCharger/Celllog etc for checking cell balance, what Fluke (or other quality meter) to go for?
I have been looking at these
http://www.fluke.com/fluke/uken/Digital ... ?PID=56061

But was wondering about the accuracy..not sure I am reading the spec correctly

Regarding the DC voltage accuracy
Voltage DC Accuracy 0.025 %
Range and Resolution 50.000 mV,500.00 mV, 5.0000 V, 50.000 V, 500.00 V, 1000.0V

those are the figures from the Fluke website...so 5 volts at 0.025% accuracy so that is to within 1.25mV accuracy in he 5 volt range? correct?

Gotta be good enough for cell balancing surely..but is it worth paying the extra for one of these over a cheap $30 meter from Harbour Freight/ Canadian Tyre/Halfords/Sealey etc etc

Anyone else got any other recommendations for quality meter?

[NeilP]

just seen the price...I knew they were going to be expensive..the Flukes, but not that much...Yikes..the 289 is $675 US dollar..I was expecting maybe 250 to 300 dollar

[nicobie]

You might look at the Fluke 87. I picked up one used a while back and like it a lot. I also have a Ideal 'true rms' that I use most of the time. The meters results match each other.

[Ykick]

I realized a long time ago any meter can drift and become inaccurate so I hedge bets with volume and use many different cheap meters. The average of 3 or 4 different meters will almost always be an accurate value.

[NeilP]

Screen shot 2012-03-05 at 19.39.58.png (41.35 KiB) Viewed 611 times

and accuracy looks good too. was not sure about the accuracy of the smaller models but it looks good on the manual

[NeilP]

I realized a long time ago any meter can drift and become inaccurate so I hedge bets with volume and use many different cheap meters. The average of 3 or 4 different meters will almost always be an accurate value.

What I was looking for was a meter that goes down to 3 or 4 decimal places, so i can (hopefully) calibrate the iCharger and Cell log for balancing, and the cheap ones do not.

[Ypedal]

I finally got myself a fluke, after messing with a " micronta " for a long long time.

biggest difference is the speed at wich it provides a reading.. 1 sec for the fluke.. 4 seconds on the micro..

this makes a difference when checking 24 cells every 10 minutes lol..

I got the 116.. works pretty damn good !
http://www.ebay.com/sch/i.html?_from=R4 ... Categories

[Farfle]

Agreed, my favorite dmm is a fluke 115. Has every feature I need, min/max logging, decent accuracy, and a 20a capable ammeter.

[amberwolf]

Mine is just an old 77-III, from several years back, when CompUSA shutdown the shop I worked at and sold everything off for nothing. It works very well, though the current part doesnt' work as the fuse was already blown and they cost too much to replace (and I have not yet gotten around to making an adapter for a "normal" fuse).

I've occasionally seen it's modern equivalents at Fry's Electronics for about $150-180, but that's still way beyond what I would recommend anyone spend for a meter for most ebike stuff. Typically it doesn't matter how accurate the meter is, just as long as it is consistent in it's readings and is linear, if you have a known voltage source to use for comparison. But for your purposes, it would be a lot easier to use a really good meter.

[bjosta]

I have 2 multimeters, one $10 cheap version bought locally at a radio shack equivalent and a cheap $37 china ebay model (Vichy VC99)
I have measured both against a true 5v reference (http://www.voltagestandard.com/DMMCheck.html)
The $10 version only reads 2 decimals at 5v but it consistently reads 5.00
The Vichy VC99 has 3 decimals at 5v and reads 5.005 and it's been consistently .005 high in all my reference measurements so far. (maybe even possible to open it and calibrate?)

For lipo balancing, do you really need better precision than that?

[NeilP]

For lipo balancing, do you really need better precision than that?

No not at all,

At present I only have cheap $1.99 chinese e-bay meters..3 or 4 of them and a £30 Sealey one. but all only read to two decimal places, so i ant one that goes to 3 places.

I now have 4 cellogs and an iCharger. All read differently, OK not by much, but just grabbing one set of figures from one cell read across the 4 different Celllogs and the iCharger. 4.142 - 4.164, so a 0.022 Volt spread across the devices.

As long as i can get a meter that reads accurately to 3 places, to check the cells and then calibrate the Celllogs and iCharger to those values then I will be happy. OK, I am probably being a bit fussy about it but it is a lot easier to be happy with your balance settings if you have confidence in the results you are getting from the kit. I would rather pay a bit more now for a good meter and have it for years and get it calibrated every few years as necessary

[amberwolf]

All read differently, OK not by much, but just grabbing one set of figures from one cell read across the 4 different Celllogs and the iCharger. 4.142 - 4.164, so a 0.22 Volt spread across the devices.

That's 0.022. This is pretty insignificant for most use-cases, and doesnt' represent much difference in SOC with even a single cell. At a guess, it would be good enough for ebike purposes, but if you do want more accuracy, a better meter like the Fluke would do that. Dunno which model would be best.

Since you only need it to do a calibration, perhaps you would want to check into test labs around your area, or places that do engineering, and see if any of them would be willing to rent out their equipment (even if you have to do your work there in the lab), so you don't have to spend as much money.

[NeilP]

Since you only need it to do a calibration, perhaps you would want to check into test labs around your area, or places that do engineering, and see if any of them would be willing to rent out their equipment (even if you have to do your work there in the lab), so you don't have to spend as much money.

Ah yes, just spotted the typo...I'll go and change it in the original text


Yea, I had thought of that and I have an old school friend that works at the local airport electronics facility, so that has always been an option..but I like my own kit.

As a difference in battery charge across the pack, I agree, not much difference, but when it is the kit that is balancing the cells to start with it all helps. When you think that often the iCharger finishes its balancing with cells showing 0.01 volts difference anyway at the end ..add that to the already different readings they are getting, you could end up with 0.03 or maybe more difference...all the little bits adding up. Generally not much to worry about..but as soon as the pack gets near the point where cells start dropping off 'the cliff' those few mV will make a difference...again only in extreme cases when trying to get the last few amps out the pack.

[Ykick]

Just be careful of those iCharger balance channels - I've had to recalibrate a couple different 106B+'s when they drifted over time. One day it simply decided to charge/balance cell #5 and #6 well above real world voltage although indicated voltage looked fine on the iCharger. I was just lucky to notice it when checking the brick with a cell log.

I found Junsi instructions to calibrate the balance port channels but it really freaked me out a bit. That's probably why I'm high on the compare, compare, compare meter principle...

[bjosta]

As long as i can get a meter that reads accurately to 3 places, to check the cells and then calibrate the Celllogs and iCharger to those values then I will be happy. OK, I am probably being a bit fussy about it but it is a lot easier to be happy with your balance settings if you have confidence in the results you are getting from the kit. I would rather pay a bit more now for a good meter and have it for years and get it calibrated every few years as necessary

Well then my suggestion is, in order of increasing cost and increasing quality (not necessarily accuracy)
Vichy VC99
Chinese Fluke model 17B
"real" entry level Fluke, I was going to say Fluke 117, but that might not be so god for ebike use, doesn't measure mA for example.

[NeilP]

Thanks for the recommendations

I did wonder about the 117, but was thinking if I was going to spend that sort of cash o a meter, spend a bit more and go up a stage

I found this after searching for the Vichy. I have not watched it all yet.it gets a bit much after a while

[NeilP]

If I was going to go for a entry level Fluke 117, then for a similar price I codl go for a Vichy bench meter?

same price..what do you reckon

http://www.ebay.co.uk/itm/VICHY-VC8145- ... 6444wt_974

[MitchJi]

Hi,

I'd shop for a good deal on a used fluke on ebay. It took me a few weeks of sniping and I got a nice fluke 73 III for $48 including shipping.

[NeilP]

Yea, i think that is the way to go. Going for a well known name has to be better when spending big money

[marty]

I wandered into a local electrical supply place and bought a Fluke 117. After looking at online prices I was surprised to see that I paid less. I am happy with this multimeter.

[NeilP]

Lucky...maybe it was older stock..bought before I price rise...or the retailer did not know what it was they were selling

[bjosta]

I wandered into a local electrical supply place and bought a Fluke 117. After looking at online prices I was surprised to see that I paid less. I am happy with this multimeter.

I heard it doesn't measure small currents like micro and milli amps, is that true? If so that's a shame, then you cant measure balance currents, drain currents of controllers etc.

[NeilP]

It does not go down to very small values, and its accuracy is not up there with its more expensive cousins, but I think for cell balancing accuracy it is enough. It is more than accurate enough for our needs .
The 6v range measures to single millivollts to within:

DC volts Range
Resolution: 6.000 V / 0.001 V
Range/Resolution: 60.00 V / 0.01 V
Range/Resolution: 600.00 V / 0.1 V
Accuracy: ± ([% of reading] + [counts]): 0.5% + 2


Amps
DC amps Range
Resolution: 6.000 A / 0.001 A
Range/Resolution: 10.00 A / 0.01 A
Accuracy: 1.0% + 3
20 A continuous overload for 30 seconds max

Their more expensice ones
like the 289
Voltage DC Accuracy 0.025 %
Range and Resolution
50.000 mV,500.00 mV, 5.0000 V, 50.000 V, 500.00 V, 1000.0V

Accuracy 0.06 %
Range and Resolution 500.00 µA, 5000.0 µA, 50.000 mA, 400.00 mA, 5.0000 A, 10.000 A



http://www.fluke.com/fluke/uken/digital ... ?PID=55996
http://www.fluke.com/fluke/uken/digital ... ?PID=56061

[Ypedal]

the 117 is more than adequate enough for our ebike needs... simple, rugged..

[zombiess]

I have a Fluke 123 Scope meter and love it, but I better love it since I paid $1300 for it about 8 years ago. It's my most accurate meter but I would like to check the calibration on it and that link posted to the precision voltage sources is nice.

I recommend buying a brand name meter. It doesn't have to be a Fluke, but get something decent if you want it to be accurate and precise. I do have some junky $1 Harbor Freight Cenotechs I keep around and in the car since they can come in handy in a pinch. I also have an old Radioshack meter that reads about 2% higher than the actual voltage measured by the Fluke.

Sometimes you can find a good deal on Ebay on used meters.

I think some of the Velleman scope meters which can be had for under $400. Scopes a very handy when trouble shooting problems on ebikes. Some can be had for less than $200.