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Old 09-19-2006, 06:22 AM   #16
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Quote:
Originally Posted by M2Racing
I'm no expert but ...
You get what you pay for.
Thats not always true. People have paid a lot for utter rubbish and will do so again in the future.
Bang for buck, its a decision between a mid range matched pack or a top line unmatched pack. I think unmatched packs are risky, but there is only a small probability of getting an honestly bad pack. With a matched pack, you know exactly what you've got.
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Old 09-19-2006, 09:05 AM   #17
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May I know which would give a better performance:

A matched Gp3300 cells or unmatched IB3800 ???
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Old 09-19-2006, 10:11 AM   #18
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Originally Posted by Tpg racer
May I know which would give a better performance:

A matched Gp3300 cells or unmatched IB3800 ???
unmatched IB3800
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Old 09-19-2006, 01:08 PM   #19
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Tom (SPC), Thankyou for your reply. I want you to know that I am NOT against the role of the matcher in the RC industry. From reading a few other threads, I see that the matcher not only qualifies the cells but also qualify and package the cells for RC usage.

Its just that from my understanding of matching, the original purpose was that the pack would charge and discharge in unison which is suppose to yield better performance and life of the pack.

Then there was the fact that batteries needed to be discharged individually, hence equalized, such that they all result in the same ending voltage. (no over dischaging, like you say).

Then there was the fact that batteries needed to be charged individually such that all cells are peaked rather that the strongest cell peaking before the rest. This now being done by chargers such as the Spintech ICC and the soon to come Much-More unit.

So now if I were to start with a fully charged pack with each cell fully peaked to its own capacity and then discharge it within a finite amount of time say 6min and that the discharge curves of every cell are similar and then finish the charge by equalizing the pack to a set per cell voltage, would I get the same performance of a matched pack?

Of course this is given the condition that there are no bad cells.

On that subject (bad cells), I had mentioned that modernized and improved methods of manufacturing cells of late should yield better quality and consistent cells far from the old days of the yellow label Sanyo 1200s. I am quite surprised to hear from a few of you (matchers) that the likelyhood of a "bad" cell is quite often. It would be interesting to hear from someone at IB or GoldPeak on the quality and consistency of their cells in terms of the statistic of the "bad" cell occuring.
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Old 09-19-2006, 01:37 PM   #20
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Originally Posted by YR4Dude
Then there was the fact that batteries needed to be charged individually such that all cells are peaked rather that the strongest cell peaking before the rest. This now being done by chargers such as the Spintech ICC and the soon to come Much-More unit.
Where could I find info on this new Much-More unit?
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Old 09-19-2006, 01:41 PM   #21
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Just a random thought. There is a possibility that a bad cell to a matcher may not be a bad cell to a manufacturer. It depends on what criteria they use. Maybe the matchers have a lower tolerance for deviation from certain numbers.
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Old 09-19-2006, 01:48 PM   #22
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I built 2 unmatched 4200 packs for a buddy. Cycled them and I couldnt believe how much better one pack was than the other. Huge difference in run time and voltage. Unfortunately I didnt have a matched 4200 for reference as I am sure it would have made the gap between good and bad even larger.
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Old 09-19-2006, 02:04 PM   #23
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Quote:
Originally Posted by YR4Dude
...So now if I were to start with a fully charged pack with each cell fully peaked to its own capacity and then discharge it within a finite amount of time say 6min and that the discharge curves of every cell are similar and then finish the charge by equalizing the pack to a set per cell voltage, would I get the same performance of a matched pack?
Isn't that a partial definition of a matched pack? "Hypothetically if I had a pack with similar enough cells and charged/discharged them as a pack, wouldn't it behave like a matched pack?"
I guess I'm beginning to miss your point. Matched packs perform inherently better and there are great matched packs available at prices close to that of unmatched ones. I apologize if this sounds forward, but why is this issue??
Quote:
Originally Posted by YR4Dude
...On that subject (bad cells), I had mentioned that modernized and improved methods of manufacturing cells of late should yield better quality and consistent cells far from the old days of the yellow label Sanyo 1200s. I am quite surprised to hear from a few of you (matchers) that the likelyhood of a "bad" cell is quite often. It would be interesting to hear from someone at IB or GoldPeak on the quality and consistency of their cells in terms of the statistic of the "bad" cell occuring.
I purposely did not quantify the number of bad cells I personally see. In no way am I criticizing IB, GP or any other cell manufacturer. In manufacturing, quality control is always an ongoing battle. I only mentioned there are some bad cells to make the point of "value added" service; the matchers sort and catch those cells during the grading process. Again, I don't know of any battery supplier selling unmatched packs who pre-tests all of the cells they sale. Do you?

Last edited by SPC; 09-19-2006 at 04:18 PM.
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Old 09-19-2006, 05:25 PM   #24
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I'm sorry. I didn't mean to put anyone on guard here. This is not meant to bash matched packs or the service of battery matching.

Please allow me to rephrase my point.

If I were to use the new individual cell chargers with bulk cells then run the unmatched pack for a finite amount of time less than the capacity of an average pack. Then finish the charge with an individual cell discharger like a Much-More or Teamwave. Would I get about the same performance as an average "matched" pack?

And also would I get some good life out of it since it is being charged and discharged to each cells own ability? In other words no cell is overcharged or over-discharged.

Thanks to everyone who have posted so far.
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Old 09-19-2006, 06:33 PM   #25
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Quote:
Originally Posted by EddieO
.....if thats 426 seconds.....than thats what you will get, which won't give you optimal performance if the rest of the pack has 440 cells....

Later EddieO
that brought a thought into my head. What determines what makes a cell better than others? Meaning why do some have high runtime but lower voltage. Some have great numbers all around. Others all low.

Or is that the burning question all the battery manuf are trying to capitalize on?

Most matchers that I talk to now are saying that IB cells are more consistent than the old sanyo's and GP per case. I know my one buddy who used to match said that some cases of GP3300's might all be 1.15's and he couldnt sell any of them, then the next case all 1.17's.

So has IB they just caught onto something to make the cells more consistent?

If a cell is rated at 1.2v then why are they not all 1.2volts even?
Another question is if the cells capacity is 1.2 how are we seeing 1.23 at amps 35 now ?

Sorry if these questions sound dumb but I have no idea how a rechargeable cell really works
Are they really more like a 1.3v ?
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Old 09-19-2006, 07:04 PM   #26
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Cells will always have fluctuations in voltage, capacity and IR. There is no way for a cell manufacturer to produce cells that all have the same specs.

The resting voltage of a discharged cell is what is used for rating it. So if you take a nicad or nimh cell the resting voltage will be around 1.2volts. The reason why the average voltage has improved is due to the IR being dropped which means there is less voltage drop under load.
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Old 09-20-2006, 12:23 AM   #27
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I guess there are many others out there who have general questions about battery numbers and battery matching. The way the service of matching has been described so far seems to be more like they are "qualifed" by the service rather than matched.

Again I want to redirect back to the use of the newer charging and discharging electronics doing individual cells in a pack. Given that no cells are overcharged or over-discharged, if an unmatched pack is used certain amount prior from any cell passing its cut-off voltage, would it yield the same performance as a "matched" pack of similar voltage?
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Old 09-20-2006, 12:41 AM   #28
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If the cells aren't matched they will never have the same voltage or capacity thus they will not perform equally.

If you want the maximum performance then zapped and matched cells are the way to go. Like I said in my earlier post most companies mid level packs sell in the 45-55 dollar range. Loose cells are in the 6.50-7.50 range so the savings aren't that great.
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Old 09-20-2006, 06:28 AM   #29
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Quote:
Originally Posted by YR4Dude
I guess there are many others out there who have general questions about battery numbers and battery matching. The way the service of matching has been described so far seems to be more like they are "qualifed" by the service rather than matched.?
The cells are first qualified FOR service then matched.
Quote:
Originally Posted by YR4Dude
Again I want to redirect back to the use of the newer charging and discharging electronics doing individual cells in a pack. Given that no cells are overcharged or over-discharged, if an unmatched pack is used certain amount prior from any cell passing its cut-off voltage, would it yield the same performance as a "matched" pack of similar voltage?
The answer to your question is dependent upon numerous operating parameters that must be identified. You must first define those parameters along with your definition of "same performance as matched." However, within these limits I believe your question has already been answered.

Last edited by SPC; 09-20-2006 at 07:09 AM.
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Old 09-25-2006, 01:42 PM   #30
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Okay, its been a while but Yes my questions have been answered both directly and indirectly.

Thanks to all those who have commented especially Tom of SPC. I now have a better understanding of battery conditioning and care.

I want everyone to know that this wasn't about being against battery matching. It was more a discussion why it is still necessary despite all the technololgy built into the cells and all the technology available to manage and condition the cells at the invidual user''s level.
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