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Old 07-29-2008, 09:22 AM   #16
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Thanks for the replies

The pack is stick, I did not know that made a diff, should I change it to side x side?

How do you discharge? the old light bulb rig?

I used to race back in the 80s and came back to get my kid into it, still assimilating the new tech.

The charger is peak, the packs get kind of warm is this bad for them?

Thanks
E
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Old 07-29-2008, 09:23 AM   #17
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Thanks for the replies

The pack is stick, I did not know that made a diff, should I change it to side x side?

How do you discharge? the old light bulb rig?

I used to race back in the 80s and came back to get my kid into it, still assimilating the new tech.

The charger is peak, the packs get kind of warm is this bad for them?

Thanks
E
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Old 07-29-2008, 09:24 AM   #18
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Thanks for the replies

The pack is stick, I did not know that made a diff, should I change it to side x side?

How do you discharge? the old light bulb rig?

I used to race back in the 80s and came back to get my kid into it, still assimilating the new tech.

The charger is peak, the packs get kind of warm is this bad for them?

Thanks
E
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Old 07-29-2008, 09:25 AM   #19
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Thanks for the replies

The pack is stick, I did not know that made a diff, should I change it to side x side?

How do you discharge? the old light bulb rig?

I used to race back in the 80s and came back to get my kid into it, still assimilating the new tech.

The charger is peak, the packs get kind of warm is this bad for them?

Thanks
E
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Old 07-29-2008, 11:15 AM   #20
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generally stick packs are more toy like and poorly assembled. Now before everyone goes getting excited, there are some good stick packs out there, and in some cases you need them due to your car/battery config.

Ultimately you should want to run side by side packs, with decent bars. They work in most cars and if you look at any good/fast racer they are all using them. Also in a side by side config, you can easily discharge/equalize your packs with an equalizer, and in the case that you direct solder, makes for a cleaner and easier install.

I think it would be a great idea to think about peaking your packs before you race, if you have that option. Im at the track for 8 hours on sundays, and 7 1/2 of those hours i have a pack on the charger. Think about it? if you shake up a soda bottle and open it right away, the pressue is crazy and you have soda all over, where as if you shake it and let it sit for 24 hours, odds are when you go to open the bottle its not going to explode. Think of your packs as a soda bottle, do you want them to be fast and have explosive power when your running them, or have them flat and not so explosive when your trying to become the fast guy at the track
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Old 07-30-2008, 12:48 AM   #21
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This was a big issue back in the day.. like 15 years ago with 1200mah & 1400mah SCR batteries. Mostly for runtime and off the line punch. Back then the batteries would barely make a 240second (4min) race geared for speed. We would have to set the car down on the line (not driving it at all) and wait for the tone! The old NiCads did have more punch from stepping on them hard while charging at 6 to 10amps.. Heat did not bother them like NiMh and LiPo.

A typical good matched pack like a 4200mah NiMh (EP Cell Pack) will have 60 to 100 seconds of "top charge" peak voltage (20amp typical stock motor at full speed). This is all but wasted these days with everybody driving practice laps before the race starts and driving the car to check in transponders..

This same 4200 NiMh also has about 600+ seconds (10min) of runtime on a stock motor at full speed! Now we all know that we don't run an offroad race except maybe for oval at full speed!

So in reality... are you really going to miss a top charge?

To see what I'm talking about look at the attached pdf.. It's a graph of a test I did on a 4200mah Slingshot Batteries NiMh pack. A 20 amp draw was placed on this pack and a computer attached meter took a reading every second until the pack reached 5.4v (6cell x .9v each).

The pack at 0 discharge time has 8.73v with no load.
At 120 sec in the pack starts to level off at 7.57v underload.
At 300 sec (5min race at full speed) the pack still is at 7.47v.

We have a whole lot of battery these days... nothing to worry about in racing...


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File Type: pdf Slingshot 4200 test.pdf (14.7 KB, 104 views)
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Old 07-30-2008, 07:49 AM   #22
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Very good info ! I guess I`m just stuck in my old ways of doing things .
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