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Old 08-07-2005, 11:11 PM   #1
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Default Difference between matched/ normal cells

How big is the real difference between a matched pack and a normal pack made by loose cells? I'm not talking about some super high voltage/long runtime pack that only team drivers like Hara, Masami..etc can obtain. But those pack we can buy from the matcher for a reasonable price. I'll give one more specifc example:
1. Pack A - GP3300 410+ 1.175-1.179 from a reputatable battery matcher
2 Pack B - a normal GP3300 pack that you build from random loose cells

I know the performance Pack B would be really depends on your luck but lets assume we are not super lucky nor did we get any bad cells in our pack. And i know why/how match packs work better. But i'm interested in the real life difference. So imy question is, if you compare these two packs, how big is the difference in performance?

1. What would be the normal average voltage and runtime from a random GP3300 pack?
2. how much faster/longer runtime would a matched pack like Pack A give us over the pack B?

Thanks.
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Old 08-08-2005, 02:08 AM   #2
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The main advantage of getting macthed batteries is that all the cells perform the same (or near the same).
That means that you will dump when all cells dump.

Nick
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Old 08-08-2005, 02:28 AM   #3
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At my level (decent club driver), and with the new generation of high-capacity cells, I have found almost no difference between a pack of matched and unmatched cells. This is running 19t or stock, where I'm never close to dumping the cells or pushing them to their limits.
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Old 08-08-2005, 04:06 AM   #4
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Since packs are wired in series, your pack is only as good as your weakest cell. Matched packs are much more reliable, if anything, because you don't have to worry about one cell crapping out. With unmatched packs, who knows? Wait till you get one bad cell in the main, then you'll get matched packs.
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Old 08-08-2005, 03:51 PM   #5
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thanks for your reply. My background is Electrical and elctronics engineering so i do understand the "weakest link" problem. But what i want to know is apart from all the theories, what's the real world difference between a matched and non-matched pack.

E.g. How much faster lap time you can get? (what sort of track)
How much faster top speed you can get?
How much longer run time you can get when racing a 8 min race?
What is the average voltage/runtime of your non-matched pack vs matched pack?

I know the performance of the non-matched pack can be really different depend on our luck but if we can all post what we found.. then maybe we can see an overall picture of how big the real world difference is?
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Old 08-08-2005, 04:25 PM   #6
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One of the analogies that I tend to use when trying to explain the difference between matched and unmatched packs is to imagine that they are like rowing teams. You can go out and find six random girls (okay realisticly guys) but chances are they won't have the same strength (voltage) or endurance (runtime). Now put them against a matched olympic rowing team and see who wins Kind of makes it simple like that don't ya think.
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Old 08-08-2005, 04:29 PM   #7
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When Rod said rowing teams he means mud wrestling teams. The matched ones are like hot supermodels, and the others are like...... uhhhh........ yeah........ how bout those super models errrr.... I mean matched packs

-Korey
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Old 08-08-2005, 04:30 PM   #8
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Quote:
Originally Posted by Sushi Boy
When Rod said rowing teams he means mud wrestling teams. The matched ones are like hot supermodels, and the others are like...... uhhhh........ yeah........ how bout those super models errrr.... I mean matched packs

-Korey
EXACTLY!
werd Korey hehe
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Old 08-08-2005, 05:26 PM   #9
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Quote:
Originally Posted by nnick
The main advantage of getting macthed batteries is that all the cells perform the same (or near the same).
That means that you will dump when all cells dump.

Nick
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Old 08-08-2005, 05:57 PM   #10
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anyone got some result from real world experience?

Quote:
Originally Posted by yellow15
But what i want to know is apart from all the theories, what's the real world difference between a matched and non-matched pack.

E.g. How much faster lap time you can get? (what sort of track)
How much faster top speed you can get?
How much longer run time you can get when racing a 8 min race?
What is the average voltage/runtime of your non-matched pack vs matched pack?
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Old 08-08-2005, 06:35 PM   #11
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The most helpful thing I can add is something that was passed along by Danny as SMC. He says that over a four minute race, a +0.01 diference in voltage per cell will yield approximately 0.5 - 1.0 seconds... if you drive a perfect race.

I would guesstimate that on average, your worst 3300 or 3700 cell would register around 1.15-1.16, so an unmatched pack would cost you, on average, up to a few seconds versus a matched pack.
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Old 08-08-2005, 06:50 PM   #12
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Quote:
Originally Posted by grazianos
The most helpful thing I can add is something that was passed along by Danny as SMC. He says that over a four minute race, a +0.01 diference in voltage per cell will yield approximately 0.5 - 1.0 seconds... if you drive a perfect race.

I would guesstimate that on average, your worst 3300 or 3700 cell would register around 1.15-1.16, so an unmatched pack would cost you, on average, up to a few seconds versus a matched pack.
Thanks for your reply. So that's a few seconds over a four min race? So for an average racer, just one tiny mistake is enough to offset the benefit from a matched pack?

Or even with no mistakes/crashes, since most of us average racer won't do perfect laps every single lap so it means we'll probably see almost no difference in performance when switching between matched and non-matched pack? (unless you got a very bad cell in your non-matched pack)
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Old 08-08-2005, 08:14 PM   #13
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it's not only track time to consider, but also pack life... I was reading a link from another post and ran across this:

Cell Balancing In multi-cell battery chains small differences between cells due to production tolerances or operating conditions tend to be magnified with each charge / discharge cycle. Weaker cells become overstressed during charging causing them to become even weaker, until they eventually fail causing premature failure of the battery. Cell balancing is a way of compensating for weaker cells by equalising the charge on all the cells in the chain and thus extending battery life.

Kill 2 birds with one quote... hehehe
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Old 08-09-2005, 10:22 AM   #14
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Quote:
Originally Posted by Big Rigg
it's not only track time to consider, but also pack life... I was reading a link from another post and ran across this:

Cell Balancing In multi-cell battery chains small differences between cells due to production tolerances or operating conditions tend to be magnified with each charge / discharge cycle. Weaker cells become overstressed during charging causing them to become even weaker, until they eventually fail causing premature failure of the battery. Cell balancing is a way of compensating for weaker cells by equalising the charge on all the cells in the chain and thus extending battery life.

Kill 2 birds with one quote... hehehe

thats why orion and reedy match there cells using the up charge method..you want tight match packs use the charge up ,not discharge method, thats old school....word mackeral
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