Cell internal resistance meter

[Miles]

Just came across this: http://www.rcgroups.com/forums/showthread.php?t=980290

Not sure if it's been referred to before, or not....?

 

[fechter]

That's pretty cool. I think it would come in handy when building packs from used cells.

 

[Doctorbass]

Great find!!

i'm contacting him for more info on the accuracy.

That would be interesting to have it in my lab!

I just still wonder.. WHY he still use 2 wire measurement instead of 4 (sensing and current seperated)

I found 3 additionnal RI meter: the RIM1000 (0.1miliohm resolution) 99$ usd

http://www.elv.de/output/controller.aspx?cid=74&detail=10&detail2=7916

And these ri meter on ebay: (0.01mohm resolution !)199 usd

http://cgi.ebay.com/ws/eBayISAPI.dl...sid=m37&satitle=120330643378&category0=&fvi=1

And thisone that also measure the Ah with a DC clamp (199usd) not 299...

http://cgi.ebay.com/ws/eBayISAPI.dl...o=CRX&its=S%2BI%2BSS&itu=ISS%2BUCI%2BSI&otn=4

Doc

 

[biggs]

Great find!!

I just still wonder.. WHY he still use 2 wire measurement instead of 4 (sensing and current seperated)

I found 3 additionnal RI meter: the RIM1000 (0.1miliohm resolution) 99$ usd



Doc

hy doc,

i know why he is using only 2 wires:
he measures only 0.5 ohm and 1 ohm!!!
maybe for measuring resistance of cells for pairing it, thats ok but if you want to know the Ri of the cells absolute i don't think that this is ok.

with the rim 1000 the current goes up to 12A!!

i use the rim1000 with 4 wire setup and this works ok


bg
alex

 

[Doctorbass]

Great find!!

I just still wonder.. WHY he still use 2 wire measurement instead of 4 (sensing and current seperated)

I found 3 additionnal RI meter: the RIM1000 (0.1miliohm resolution) 99$ usd



Doc

hy doc,

i know why he is using only 2 wires:
he measures only 0.5 ohm and 1 ohm!!!
maybe for measuring resistance of cells for pairing it, thats ok but if you want to know the Ri of the cells absolute i don't think that this is ok.

with the rim 1000 the current goes up to 12A!!

i use the rim1000 with 4 wire setup and this works ok


bg
alex

I thought the Ri 2 wire meter had 1ohm and 0.5ohm LOAD and not these value as the acuracy mof measurement...

If you read carefully you will see that the meter have 2 different load that it apply to measure the current drop.. and i think these loiad are the 0.5 and 1 ohm.. not the accuracy..


You said you have the RIM1000??

have you any pics that show the botton pad on it with english translation?

I contacted Conrad and they dont sale it to Canada.

only ELV.com confirmed me that they can sale it.. it's like 160usd equivalent from euro and shipping...

can you do a favor for me?

to post a video of a measurement with it... i want to see how fast and how the reading display work...

do you know if the pulse current they say is a 1000hz pulse?.. like any other Ri meter...

or is it just a single pulse?

thanks

Doc

 

[Miles]

From the manual: http://nqrc.com/manuals/irm-005.pdf

Cell resistance minimum: 4 milliohms.
Cell resistance precision: +/- 2 milliohms.

 

[Doctorbass]

From the manual: http://nqrc.com/manuals/irm-005.pdf

Cell resistance minimum: 4 milliohms.
Cell resistance precision: +/- 2 milliohms.

Yeah.. it's not the 4 miliohm that make me uncertain... it's the +/-2 miliohm!!! .. it's like 33%error on the best cell Ri i have! (6 miliohm)

It wouold be just perfect if it could be modified for better accuracy!.. I mean all the data it can calculate is really interesting... but the only cons is the +/-2 miliohm!!!

Doc

 

[biggs]

You said you have the RIM1000??

have you any pics that show the botton pad on it with english translation?

I contacted Conrad and they dont sale it to Canada.

only ELV.com confirmed me that they can sale it.. it's like 160usd equivalent from euro and shipping...

can you do a favor for me?

to post a video of a measurement with it... i want to see how fast and how the reading display work...

do you know if the pulse current they say is a 1000hz pulse?.. like any other Ri meter...

or is it just a single pulse?

thanks

Doc

hi,

i have no camera for a video but i can send you a pic and the manual.
the english part starts on page 22. and the france part on page 41.
i think the france part is yours.

at conrad it costs about 76,95 Euro
i don't know how much the shipping costs from vienna to you.

bg
alex

View attachment RIM1000_de-en-fr.pdf

 

[Doctorbass]

You said you have the RIM1000??

have you any pics that show the botton pad on it with english translation?

I contacted Conrad and they dont sale it to Canada.

only ELV.com confirmed me that they can sale it.. it's like 160usd equivalent from euro and shipping...

can you do a favor for me?

to post a video of a measurement with it... i want to see how fast and how the reading display work...

do you know if the pulse current they say is a 1000hz pulse?.. like any other Ri meter...

or is it just a single pulse?

thanks

Doc

hi,

i have no camera for a video but i can send you a pic and the manual.
the english part starts on page 22. and the france part on page 41.
i think the france part is yours.

at conrad it costs about 76,95 Euro
i don't know how much the shipping costs from vienna to you.

bg
alex

View attachment 1

Hello,

Alex,

Thanks for these precious infos!!

I think this device is the one i need!

Do you know if it pulsate at 1000hz?

Are you living in Europe? (does anyone here live in Europe and have acces to Conrad store?)

I would appreciate if someone would accept to buy one for me and to ship it to Canada I can send money in advance for that including shipping, the Ri meter and for the help you provide me. I need one!

German RI device seems enough accruate for me instead of chinese device.

doc

 

[biggs]

Hello,

Alex,

Thanks for these precious infos!!

I think this device is the one i need!

Do you know if it pulsate at 1000hz?

Are you living in Europe? (does anyone here live in Europe and have acces to Conrad store?)

I would appreciate if someone would accept to buy one for me and to ship it to Canada I can send money in advance for that including shipping, the Ri meter and for the help you provide me. I need one!

German RI device seems enough accruate for me instead of chinese device.

doc

i live in vienna 10 minutes away from the next conrad store

bg
alex

View attachment rim2003_V3.pdf

 

[Doctorbass]

Hello,

Alex,

Thanks for these precious infos!!

I think this device is the one i need!

Do you know if it pulsate at 1000hz?

Are you living in Europe? (does anyone here live in Europe and have acces to Conrad store?)

I would appreciate if someone would accept to buy one for me and to ship it to Canada I can send money in advance for that including shipping, the Ri meter and for the help you provide me. I need one!

German RI device seems enough accruate for me instead of chinese device.

doc

i live in vienna 10 minutes away from the next conrad store

bg
alex

Alex, did you reed your PM?

 

[Doctorbass]

Today i found two new Internal resistance meter !!

One is cheap and use the 4 wires sensing technic.

Here is the website of the manufacture : http://www.chinasampo.cn/Digital-Multimeter/SM8124.htm

INCREDIBLE !

30$ for this one:

I'll order two for me(two to chheck their accuracy! :wink:

and thisone that i found while searching on ebay for 100A 3.3V psu and i found this guy saling alot of A123 for cheap and that he use this RI meter to show the value of the cell he sale:

http://cgi.ebay.com/10-A123-3-3V-23...ryZ34056QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

The cell he test show 7.9mohm at 1000hz

and i found it on the alibaba website:

http://www.made-in-china.com/showro...-Inner-Resistance-Testing-Meter-RBM-200-.html

The RBM-200

I asked for the price.

Doc

 

[Miles]

Good finds Doc

 

[oatnet]

Today i found two new Internal resistance meter !!

One is cheap and use the 4 wires sensing technic.

Here is the website of the manufacture : http://www.chinasampo.cn/Digital-Multimeter/SM8124.htm

INCREDIBLE !

30$ for this one:

I'll order two for me(two to chheck their accuracy! :wink:

Hey Doc, great find, where did you order it from? I would find that downright handy - if it is reasonably accurate.

-JD

Found an expensive one here:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=350183922047

 

[deVries]

Ok, It's been a year and a half+ *& no one has updated this thread!!!

Doc or anyone in the know... PLEASE UPDATE these meters or newer and better ones. Many battery builder want-a-bees should be in the market for one of these, but I/we don't know a darn thing about what to look for...

Please help the electric battery builder dummies like me! :lol:

Today i found two new Internal resistance meter !!

One is cheap and use the 4 wires sensing technic.

Here is the website of the manufacture : http://www.chinasampo.cn/Digital-Multimeter/SM8124.htm

INCREDIBLE !

30$ for this one:

I'll order two for me(two to chheck their accuracy! :wink:

and thisone that i found while searching on ebay for 100A 3.3V psu and i found this guy saling alot of A123 for cheap and that he use this RI meter to show the value of the cell he sale:

http://cgi.ebay.com/10-A123-3-3V-23...ryZ34056QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

The cell he test show 7.9mohm at 1000hz

and i found it on the alibaba website:

http://www.made-in-china.com/showro...-Inner-Resistance-Testing-Meter-RBM-200-.html

The RBM-200

I asked for the price.

Doc

 

[Doctorbass]

Ok right..

Some updates:

I got 3 of these SM8124… since I know they are generally polarity sensitive.. I thought it would be better to have spare one…

I found they are pretty accurate but if you reverse polarity they BLOW !

So I installed a relay into mine that connect the probe only if the right polarity is connected… it’s a 2PST 5V relay. The relay 5V coil is connected in serie with a diode and directly connected to the probe input. So when you connect the probe, the battery under test will supply the relay coil only if the polarity are OK. The disadvantage is that you can only measure from 3.2V ( the minimum voltage that can activate the relay) to around 20V for a bried moment)

I also modified single connection probe into dual point ( Kelvin probe) to bypass the resistance loss of the connection of the probe to the cell. It’s stupid but the probe wire are already dual wire ( Kelvin).. but they connect together inside the probe to a single point.. making the advantages of the dual point useless…

When I’ll have time I’ll post pics of that mod.

This SM8124 is really good for the measurement but you must modify it to make it last the time you want!

Doc

 

[HypnoToad]

Hey Doc, I know this is an old thread, but I ordered a SM8124 today and I was wondering if you had any pics of your relay mod.

I sounds like a good thing to do and also do you need to use a certain type of relay to switch on at 3.2v?

Thanks.

 

[deVries]

Doc, can you recommend a better low priced RI meter than these? What is your choice for low cost now???

Thanks.

 

[Doctorbass]

Doc, can you recommend a better low priced RI meter than these? What is your choice for low cost now???

Thanks.

Ir meter require accurate electronic components and a re a bit more complicated than a simple DVM. the one i found that are the SM8124 are the cheapest you can find that are accurate at 0.1 miliohm.. but they blow easy if you reverse the polarity or ... even... look at them too much time!

Finding one that is under 30$ is nearly impossible.. we normally pay like 150-300$ for a good DVM ( multimeter) and we have to pay like 500-2000$ for an accurate and bulletproof Internal Resistance meter.

The Hioshi are very good but $$$$

Doc

 

[BatteryMooch]

Doc, can you recommend a better low priced RI meter than these? What is your choice for low cost now???

Thanks.

I'm not the expert Doc is on these things but Wayne Giles has designed a very nice IR meter which has worked well for than one person I personally know.

The construction details are here: http://www.giantshark.co.uk/forum/viewtopic.php?f=121&t=3396
It's available from ProgressiveRC for $85: http://www.progressiverc.com/esr-meter.html

[Edit] Additional Info and specs: http://www.rcgroups.com/forums/showthread.php?t=1323465

 

[999zip999]

Is this just for lipo ?

 

[BatteryMooch]

Is this just for lipo ?

No, any chemistry up to, IIRC, 5V/cell at less than 250mOhms for the pack ESR (forgot the cell ESR max). It was labeled as a LiPo ESR meter because of the big debates at the RCGroups forum over the ESR of different LiPo cells that prompted Wayne to design the meter.

 

[megacycle]

Appears to handle up to 5Ah do you know if they can do or be modded for bigger.
This would be good.

 

[BatteryMooch]

I would contact Wayne Giles with that question to be sure of the correct answer but I don't think any mods would be needed. The meter applies a 16A pulse for 15mS to do the ESR measurement, regardless of the capacity of the cells. I can't see any reason why the meter wouldn't work with any cell that could handle the 16A pulse.

The meter's development was prompted by the need to sort out very conflicting R/C car/plane/boat LiPo performance and ratings claims and those packs topped out at about 5Ah (when the meter was created). I think this is the reason why it's labeled as being for 500mAh to 5000mAh cells.

Best to ask Wayne though.

 

[megacycle]

Thanks for the info.
Might be wrong in my thinking about its operation.
Will have to read Wayne's right up on that.
If it measures volt drop for its operation
there might be a reason like needing a larger pulse current for resolution or something hmm

Would be valuable piece of gear to have would say almost compulsory.