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Old 04-16-2003, 04:09 AM   #1
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Default Is the need for matched cells becoming a myth?

I've just picked up two packs of supposedly "unmatched" GP3300's (Schumacher's 35 XVS jobbies). The match on both packs (according to the pro-trak) is around 90% (this is after about 3 cycles) - actually better than my "matched" 60 Reedy Extreme GP's. The runtime and voltage figures are virtually identical. They feel just the same on the track.

Here's my thinking - the cells are coming out of the factory with such close tolerances, that you don't need to fork out on matched cells.

When I had my 3000HV's, every pack of SMC's I saw had a runtime very close to 360secs, so I think Sanyo's cells were also close out of the factory gates.

Can anyone supply cell figures that are dramatically different to prove me wrong?
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Old 04-16-2003, 04:28 AM   #2
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Several guys at our track claims they cant tell the difference between matched and unmatched, when talking Sanyo HV. No numbers, it's purely based on track experience. So more and more people around here simply dont buy matched cells.
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Old 04-16-2003, 04:57 AM   #3
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i think that sometimes unmatch can be better...like my old 3000...th unmatched had a longer runtime than the matched...
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Old 04-16-2003, 05:27 AM   #4
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i'm a proponent of unmatched cells.
cells are already good enough out of the factory.
dont make much difference on my Pulsar
between an Orion V-Max 3000HV and a plain pack of 3000HV.
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Old 04-16-2003, 05:46 AM   #5
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i wanna ask a battery question and dun't wanna make a new thread. why are sanyo pack batteries bigger than the tamiya ones...i have 2 tamiya 3300's and they fit fine on my E3 but when i use sanyo's they don't fit well...you havto cut off the top bit....why don't they standardise the sizes?!
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Old 04-16-2003, 08:03 AM   #6
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From my experience, matched packs tend to last longer.

The reason for my opinion is this: Matched packs have similar runtime, IR and charge characteristics. This generally means that all cells in a matched pack will reach their peak charge in close proximity of the other cells. This reduces the risk of over charging cells, which causes damage. They will also discharge at a rate similar to the other cells. This reduces the risk of reversing cells, which causes damage.

I agree that the manufacturing tolerances on cells has really reduced the number of truely bad cells. I think that purchasing loose unmatched cells and building packs will definitely give you all the battery you need for normal weekend club racing. The need for high dollar packs for weekly racing is way over-rated.

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Old 04-16-2003, 08:34 AM   #7
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The GP3300's are great. I run one pack all day, every race day. I bought it 6months ago and it still has plenty of guts. I figure I'll buy one pack and just wear it out. NiMH's don't like sitting about anyway. And I always have time to charge them back between heats. Granted, running stock isn't nearly as hard on the cells as mod. So my tactic wouldn't work for everybody. But given that cells have a life span, it didn't make sense to stock up on them.
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Old 04-16-2003, 09:23 AM   #8
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gotpez:
ur spot on.on both accounts.
there will always be those with big bucks who HAVE to spend on the best cells , but i'll never be one of them.
davioh:
i dont understand u...
cos i remember that Tamiya 3300 stick packs ARE Sanyo 3300HV's..
is there really a dimensional difference in their packing?
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Old 04-16-2003, 09:27 AM   #9
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Default Is the need for matched cells becoming a myth?

In my experience, Matched Cells are a MUST if you are racing. Especially in Stock Class. UN-Matched packs will not handle the abuses of higher charge rates that are needed to be competetive in Stock. For Mod you need run-time more than anything and a pack is only as good as the weakest cell.
For Bashing, the question would be WHY would you spend the money on Matched packs?
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Old 04-16-2003, 11:04 AM   #10
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Quote:
Originally posted by lee82gx
gotpez:
ur spot on.on both accounts.
there will always be those with big bucks who HAVE to spend on the best cells , but i'll never be one of them.
davioh:
i dont understand u...
cos i remember that Tamiya 3300 stick packs ARE Sanyo 3300HV's..
is there really a dimensional difference in their packing?
the tip of the sanyos (not tamiya ones) stick out.....like the casing....so it doesnt' fit....i'd show u a comparison...but i cut the other ones cuz they didn't fit...
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Old 04-16-2003, 11:17 AM   #11
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Quote:
In my experience, Matched Cells are a MUST if you are racing. Especially in Stock Class. UN-Matched packs will not handle the abuses of higher charge rates that are needed to be competetive in Stock. For Mod you need run-time more than anything and a pack is only as good as the weakest cell.
What charge rates do you need if you are running 3300's in stock? I am relatively new at this but I have had plenty of punch in my 3300s following recommended charge rates. All the matchers I know of recommend 5 amps and definitely no more than 6 amps for their matched 3300 packs. I charge my 2400s, matched and unmatched at 6.5 amps and have no problems (but I equalize the 2400s after every race).
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Old 04-16-2003, 11:40 AM   #12
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I charge my NiMH batteries at 7 amps with a .05 cutoff. I repeak at 7 amps with a .03 cutoff. I do this with the Sanyo 3000HV and GP3300 cells.

This is defnitely an agressive charge rate. Unmatched packs would take it, but not for long. The weakest cell would soon destroy itself.

Jeff Gilligan
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Old 04-16-2003, 11:46 AM   #13
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Quote:
Originally posted by davioh
the tip of the sanyos (not tamiya ones) stick out.....like the casing....so it doesnt' fit....i'd show u a comparison...but i cut the other ones cuz they didn't fit...
Hi Davioh,

I think your pack was soldered together with to much play between the batteries. You can put a pack of tamiya and one of those longer types together. You will see the gap between two batteries are different. That's why you need to shave of the top.

Did you buy those in "Yan On Building" MK ? Are these matched with a white label and black printing ?
If so these "matched" are indeed less runtime then unmatched.
That's why they were quite cheap compared with real matched.

But as already said on this thread, if you are only bashing around, there is no need to buy matched. But when you race it is a must.
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Old 04-16-2003, 11:52 AM   #14
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i think i do hav a white with black lableing batt...but it didn't say matched...i got it in sham sui po...ap lui gai...but i don't bash and i don't go to the track alot, i just go up and down the street and 3300's seem to last longer than 3000's
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Old 04-16-2003, 12:11 PM   #15
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Quote:
I charge my NiMH batteries at 7 amps with a .05 cutoff. I repeak at 7 amps with a .03 cutoff. I do this with the Sanyo 3000HV and GP3300 cells.
What I find interesting about charge rate is that rates of charging are so much lower than discharging yet it causes damage to the cells.

It's also funny how you are supposed to race stock to avoid the costs of mod but it seems you have to torch your batteries in the charging process to be "competitive". I think the rules need to be reworked for stock to level the playing field. I personally cannot wait for brushless motors to become the standard.
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