Internal resistance tester

[999zip999]

I was looking for internal resistance tester. there was a thread about one but couldn't find it. If any one could help. i think it was 39.99usd . Thanks

[neptronix]

I'm thinking an expensive multimeter would work... am i right?

[Spicerack]

Maybe a real expensive multimeter- to measure the Ri it needs to send an AC pulse through the battery... most of the time it's a very expensive piece of equipment!

You can do a cheap and nasty test but it's not terribly accurate:

[Ykick]

Voltage drop and current will give you a ballpark but as Andy noted more accurate method uses pulses and another method with sine wave phase shift of V and I to determine resistance of single cells.

[neptronix]

Yeah, that will measure Ohm, but many lithium batteries will be in the mOhm range..
I know the iCharger and Hyperion chargers can do it; not the most accurate devices in the world, but they give you a general idea upon which to compare other batteries.

[IBScootn]

Check out the model 20R for around $50 out on eBay:
http://www.ebay.com/itm/20R-Internal-Ba ... 4636wt_922

I bought one to test out,

[999zip999]

Yes, I be scoot em. I think that be the one i'ave been thinking of. Does It work ? It has a kelvin 4 wire probe ? That one ? Thanks guys

[neptronix]

Ya know.. you could get an iCharger 106b+ for $80.. then.. you'd have an iCharger b+

Just sayin

[Doctorbass]

Check out the model 20R for around $50 out on eBay:
http://www.ebay.com/itm/20R-Internal-Ba ... 4636wt_922

I bought one to test out,

Yeah.. I aproove, I bought many of those for me and friends.

They work pretty well and accurate.. but they dont tolerate reverse polarity

So i modified them in two way:

- 4 wire kelvin measurement probe with seperate spring loaded pins for the current sens and the bleed

-I installed a relay that allow to contduct the tested cell and the tester only when the polarity is ok.. simple, cheap and save you from having blown tester!


I paid like 90$ for 3

I will post my review about it ( the SM8124)in the next hour.

Doc

[Doctorbass]

Doc

[IBScootn]

Thanks for the video doctorbass. Seems like it would be good to put this info into the ES wiki.

Could you also show how you made the modified test probe? I didn't see any dual pogo probes out on eBay, so assuming you just soldered the leads to the pogo pins and shrink-wrapped them up??

Mine is still on slow-boat from china - don't expect to see it anytime soon. But when I get it, I'll modify the leads to pogo; but sounds like I'll need to come up with another reverse polarity protection approach as I have lifepo cells. Dang, I hate products without reverse polarity protection. Anyways, thanks again for the heads-up.

[999zip999]

Thank's Doc that on target need to see again.

[999zip999]

Shippiing march 1. Couldn't find a faster way ? On ebay ?

[amberwolf]

They probably sell first, then when they have enough sold they manufacture them. (or order them from some other company).

[sangesf]

Doc

Where can I get one of those impotence meters?

LOL.. Gotta love yer accent.. That made my day..

[cassschr1]

Doc , when hooked up with reverse polarity just 1 time, say on 4.2 cell does it still blow?
What are the results...like does other functions still work, or does the screen go blank? I have one of these and about a year ago I thought something wasn't right,but didn't know what.

[Doctorbass]

Doc , when hooked up with reverse polarity just 1 time, say on 4.2 cell does it still blow?
What are the results...like does other functions still work, or does the screen go blank? I have one of these and about a year ago I thought something wasn't right,but didn't know what.

Yes it blow with low voltage too.

The result are that the reading on the LCD make non sense and the measured value is variating and not way from the real value.

no blank display.. just wront displayed value

[999zip999]

O.k. IBScootingn I order one to wonder if they come on the same boat as amberwolf quessed. Tell me when you get yours and i will tell you when i get mine. Ha Ha . Same boat ?

[Kin]

Hmm, so is this tester using some more accurate process than the "two resistors in parallel w/known load voltage drop" calculation?

Just wondering, because right now $40 seems like a substantial price to drop for it, if its not going to offer some sort of long term quality.

[SamTexas]

Maybe a real expensive multimeter- to measure the Ri it needs to send an AC pulse through the battery... most of the time it's a very expensive piece of equipment!

You can do a cheap and nasty test but it's not terribly accurate:

Thanks andynogo for the video. One question: What exactly is that cyclindrical blue load device you used?

[999zip999]

It's a coil of some kind of wire for resistance. But what kind and for how long ? Yes ?

[Spicerack]

Aaah sorree you misunderstanddeee!

Not my video. Shamelessly stolen from youtube, so no idea what value the load is. It's most likely enamelled winding wire. I'm not sure about his resistance value though- I hope he calibrated the multimeter first as quite often they will show about 4ohms just across the test leads....

A better way if you use this method would be to use a proper resistor with a low tolerance.

[IBScootn]

999zip999, my ship came in (ie 20R IR meter arrived today). Shipped Jan29, arrived Feb 8.

Seems to work fine, but need to install the pogo pins as it's too hard to get a good contact with standard probes. But with a little effort, I was able to verify my two new GBS 40AH cells were 2.5mOhms. Once I buy the pogos (yes I forgot to), and get them installed it will be interesting to see if my older 24 cells show any IR increase.

[IBScootn]

Doctorbass or anyone,

What pogo tips should I buy for the IR meter? I now remember why I didn't buy them earlier - too many choices: P50, P75, P100, pin only or pin & receptacle, etc. Can someone recommend an item off eBay to buy.

Thanks

[Doctorbass]

Doctorbass or anyone,

What pogo tips should I buy for the IR meter? I now remember why I didn't buy them earlier - too many choices: P50, P75, P100, pin only or pin & receptacle, etc. Can someone recommend an item off eBay to buy.

Thanks

These one seem perfect!

http://www.ebay.com/itm/10pcs-P75-E2-Dia-1-02mm-100g-Spring-Test-Probe-Pogo-Pin-/370580184485?pt=LH_DefaultDomain_0&hash=item56484cdda5#ht_2079wt_1396