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Old 09-01-2006, 11:23 AM   #31
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Originally Posted by nutfluff
What are your practice packs truggy? I'm referring to todays newer cells...3700's and up. Does matched really equal power? Like I said, with these high capacity packs there are no problems with runtime and the power curves are so much higher that all of these cells have equivilant power througout the run regardless of the 3 hundreths of a volt. Maybe we should be matching IR instead of voltage for stock packs???? I have yet to get a pack with matching IR numbers...maybe we're on to something????
They are older SMC 3800.
I don't race anything over 3800 cannot really afford that plus I don't see the need. My practice times are about 5-10 min all depends on how well the set-up is working. They aren't matched and for some reason don't seem to have the same punch as my older Matched Axxis packs.
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Old 09-01-2006, 11:25 AM   #32
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hey fluff, can i get a website for slingshot. i only have 1 pack now because most of my stuff got stolen. i need to get some packs before next weekend and i want the best.

Matt
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Old 09-01-2006, 11:31 AM   #33
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Originally Posted by mat3833
hey fluff, can i get a website for slingshot. i only have 1 pack now because most of my stuff got stolen. i need to get some packs before next weekend and i want the best.

Matt
http://www.slingshotbatteries.com/
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Old 09-01-2006, 11:34 AM   #34
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thanks also have any of you bought the radioshack GP3700s? ive been thinking about buying a few packs and breaking them down and making stick packs out of them. for pratice of course

Matt
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Old 09-01-2006, 11:51 AM   #35
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His website is still being designed but you can contact him under the contact tab on that site. He can also be reached on this site. His user name is KWHIS.

Now what about matching IR's???
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Old 09-01-2006, 11:56 AM   #36
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Quote:
Originally Posted by nutfluff

Now what about matching IR's???

I dont think matching the IR would make a difference right? The reason why they match the packs is so that the batteries all discharge at the same time and dont get too far out of whack. (and to weed out bad cells)

Does the IR affect runtime?
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Old 09-01-2006, 11:57 AM   #37
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from my exp as long as the IR is close the pack will run great. i run mod 4wd buggy and i dont think ill run matched packs again.(the exception being 3800s im getting 2 for the mains) i think its overkill. unless youre running stock class of youre like the top driver in the world you wont gain any real benefit out of it. im shure someday we will be able to get IR voltage and runtime matched exactly but whats the real point?

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Old 09-01-2006, 12:29 PM   #38
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Quote:
Originally Posted by mat3833
thanks also have any of you bought the radioshack GP3700s? ive been thinking about buying a few packs and breaking them down and making stick packs out of them. for pratice of course

Matt
Several of the guys I race with have been running the GP3300 packs from Radio Shack made into side-by-side packs.They're fast enough to win and $25 a pack.We don't run any stock classes,just 19t and open mod.I didn't know Radio Shack had GP3700's but if they do I'm getting some-I don't want any of those "fragile" IB's and I'm ready for a couple new packs.Good high voltage matched packs will make a difference in stock,but I hate stock and I'll never run it again so it's just not an issue to me.

"Maximum efficency" just doesn't matter in off-road where the available traction limits the power you can use(unlike on-road).And run time is no longer an issue.If you can only put "X" amount of power to the ground,it doesn't matter how you get there.If an $80 battery pack and a new top of the line 15 turn mod motor and a $25 pack and a machine wound 13 turn motor both put the same amount of power to the wheels,and both make run time,that's a good thing.Keeping the cost of racing down means you will have more people to race with.
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Old 09-01-2006, 12:31 PM   #39
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it might only be 3300s but i think i saw a few 3700s

Matt
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Old 09-01-2006, 10:48 PM   #40
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Matching IR and Voltage does not make sense. These numbers are cumulative in the pack. That means you add up the numbers in all the cells. You do want all the IR's as low as possible though. Voltage is the same way but you want that high.
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Old 09-02-2006, 12:49 AM   #41
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I won't waste my money anymore for matched cells
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Old 09-02-2006, 10:48 AM   #42
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Originally Posted by Casper
Matching IR and Voltage does not make sense. These numbers are cumulative in the pack. That means you add up the numbers in all the cells. You do want all the IR's as low as possible though. Voltage is the same way but you want that high.
It seems like it would not but if you check Voltage and run time you will see a correlation their, IE: The more run time you have the Less voltage and higher IR you are going to have. To me on the matched packs with the larger capacity cells I'm Not looking at run time, I race stock so I'm only looking at Voltage and IR, On the IR the lower the better. I wish that the guys that I race with would Not buy matched packs... On the matched packs, Knowledge is power, if you don't think that lower IR and higher voltage mean anything then don't buy them, but do remember not all cells are the same. I am more of a on road racer and having good packs is more critical in this form of racing. So this affects my opinion on the matched packs...Plus if you suck as a driver more power is not your friend...
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Old 09-02-2006, 10:43 PM   #43
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I totally agree that lower IR and higher Voltage are important to a good performing pack in stock or 19T classes but my point is they are cumlative numbers. You want the IR as low as possible and the voltage as high as possible but matched batteries are matched by runtime first and then all the cells of similar runtime are made into packs with the highest voltage.
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Old 09-02-2006, 10:56 PM   #44
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Now since runtme isn't really a problem now and the point of matching runtime was originally so that the pack would dump at the same time...wouldn't matching IR be better as the batteries would all be releasing their energy at the same rate????
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Old 09-03-2006, 01:32 AM   #45
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Quote:
Originally Posted by nutfluff
Now since runtme isn't really a problem now and the point of matching runtime was originally so that the pack would dump at the same time...wouldn't matching IR be better as the batteries would all be releasing their energy at the same rate????
IR is the resistance against the Voltage release. The reason packs are matched runtime first, voltage second, is that when a full pack cycles as one (all cells in sync), given the voltage over the runtime, the voltage in each cell and each point during the discharge will be the same. For instance, if you match a pack based off voltage or IR, one cell could have a high runtime, and another low, so when the high cells are still running strong 4 minutes in, the low runtimes cell will have the voltage curve starting to fade. Since voltage adds up, if one cell is lower, it subtracts from the whole pack and will reduce total voltage and total punch....

Also, packs with higher, longer runtimes are better than their counterpart because in the 5th minutes, the pack will be at an earlier stage in the discharge cycle and at a higher point on the every decreasing voltage curve. So the difference isn't, I'll have 3 minutes of runitme left instead of 4, it will be I had more voltage output over 5 minutes.

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