How do you get the internal resistance of a pack to come down? These are the Trinity spec packs.

Best I could tell you would be to cycle them several times using a turboflex charge and then use a single bulb to take them down to nothing as slow as possible after you discharge to .90 when cycling.

Some more people with more spec racing background could maybe add some tricks to this but this is how I always kept mine fresh!

Are these the new Speed Spec packs ?? If so , you have to be carefull
compared to the original yellow label pack.
I'll try and make this short----

They're a Nicad hybrid cell , very diff from old cell
They hate being flexed , just like nimh's
They need a low delta peak setting .02- .03
They like being discharged but not to 0.0 , maybe to 2-3 volts for the pack.
The bummer with a stick is you really can't equalize properly , oh well
The high IR is a characteristic of the cell so only time or cycling will help
Keep your charge and discharge rates reasonable , 4-5 chg , 8-10 disc.
You try and tug 20 amps from these and temps go thru the roof.
Run a couple times race day and see if the second run is better.

Hope this helps

Yep these are the Speed Spec 06 packs. When I cycle them on my GFX, the IR seems to be fairley high, but I'll try cycling them a different way to get the IR down.

Not flexing is going to help the most , but these packs are still going to show about 10 points higher than the original ones.

When you bring the pack down to 2 or 3 volts do it at a low discharge rate like 1-2 amps.

Take one pack and cycle it every other day and record the data , it should improve to a certain point and stabilize , then its as good as it's going to get.

Good Luck

Hey Jack,

Give me a call later when get a chance, we'll talk about your "high" IR's. I just got done cycling our Spec Packs so we can compare numbers.

What are you seeing for #'s ? How high are you calling high ?
Hopefully your not comparing these to a modern nimh cell.
Think of these cells like the old Sanyo SCE cells , no matter what
you did to them they would not discharge like an SCR cell.
If your rules permit , play with your gearing a little to see if
that helps OR FIND SOME ORIGINAL SPEC PACKS THAT ARE STILL
GOOD.

Is there anyway to check IR with a ohmmeter?

NO , It has to calculated during a discharge cycle.

This is built into the GFX computer circuit of the charger.

I don't have the numbers in front of me right now, but I plan on cycling some this weekend and I'll post the numbers I get.

You'll probably have IR's of 32 to 38 and average voltage at 10 amps of 4.5 or so.
The runtime for a 1600 pack is pretty high , like 670-700 sec's at 10 amps.

The original Spec packs had IR's of 25 , slightly higher voltage and shorter run time, if you can find any ??


We built our own Spec packs for our track this year " 50 packs " from SANYO 1900 SCR cells and their GREAT !! Leave them in a 0.0 tray for days and charge and go , we even recharge the same pack all race night.
These have an IR of 19 to 22 and have an av voltage at 10 amps of 4.78

use a integy torpedo booster for spec packs!!! it will extend your run time and increase your voltage and lower IR. I have noticed a big difference when using the booster. Just another idea to try!!!

JP

Runtime 425 426 467 420 460 505 523 496
Voltage 4.44 4.48 4.51 4.48 4.52 4.51 4.45 4.43
@1 V 4.47 4.51 4.55 4.50 4.55 4.56 4.50 4.48
IR 36.2 35.6 32.5 36.4 32.9 29.7 31.3 32.1

The numbers above are the numbers I got today. These are at a 5 amp charge and a 15 amp discharge.

These numbers are pretty much in line with what I've seen for the new Speed Spec packs ,

THEY JUST ARE NOT A HIGH DISCHARGE CELL AND WHEN YOU TRY AND PULL 15 AMPS FROM THEM THE VOLTAGE FALLS.

Hopefully your track your racing at is running something close to a spec motor as this will help drastically , a #2226 spec motor with 4383 brushes and red springs with pull 2.8 to 3.4 amps @ 5 volts without a fan @ 16,000 rpm's . With this said your Spec pack should see around 10 amps average discharge. KEEP STOCKS OUT OF SPEC RACING !!!!

NO , It has to calculated during a discharge cycle.

This is built into the GFX computer circuit of the charger.

If you watch during the discharge cycle, the GFX suddenly stops discharging at the full amperage when it takes the resistance measurement. That always happens at 120 seconds and lasts for three seconds.
As for measuring internal resistance, the way it is done, applies Ohms law. You already know the discharge current (I), and you need to measure the voltage across the pack while it being discharged (V), then apply Ohms law V=IR

So the inverse of this would read... R = V/I
In laymans terms, divide the voltage by the discharge current.

#2226 spec motor with 4383 brushes and red springs with pull 2.8 to 3.4 amps @ 5 volts without a fan @ 16,000 rpm's .

My Spec motors pull 3.5-4.0 amps at 1.5 volts. If I ran them at 5 volts they may shut off my GFX! lol

My Spec motors pull 3.5-4.0 amps at 1.5 volts. If I ran them at 5 volts they may shut off my GFX! lol


I agree with what he Said

My Spec motors pull 3.5-4.0 amps at 1.5 volts. If I ran them at 5 volts they may shut off my GFX! lol

Something is wrong with this picture , sounds like you power supply to your GFX is faulty .

Amp draw ''WITH OUT " a fan usually goes down slightly as you increase the voltage.

We built 25 of these for our track and all the amperage's @ 5 volt , no fan , were between 2.8 to 3.4 amps, there's no way this motor will kick off a GFX with a 20 plus amp power supply !!!!!!!

We raced last night and after checking our battery's after the feature, I guestimate we were pulling about 15 amps for 4 min , the motors were barely warm with 1.88 rollout.

Let me know if I can help , but something doesn't add up , our fixed 19's with stout springs / brushes only pull about 10-11 amps @ 5 volt and the GFX runs them fine.

Back to the resistance subject real quick ,

Gear your car so it runs close to the same lap times the entire race and you'll be fine .

What I saw the first night with a Low resistance pack , and again this is premature judgement , they ran real strong at the beginning but fell off the last minute where a higher resistance pack ran more even and we turned more laps, work in progress , we used up about 1100-1200 mah of a 1900 pack in 4 min.

Something is wrong with this picture , sounds like you power supply to your GFX is faulty .

Amp draw ''WITH OUT " a fan usually goes down slightly as you increase the voltage.

We built 25 of these for our track and all the amperage's @ 5 volt , no fan , were between 2.8 to 3.4 amps, there's no way this motor will kick off a GFX with a 20 plus amp power supply !!!!!!!

We raced last night and after checking our battery's after the feature, I guestimate we were pulling about 15 amps for 4 min , the motors were barely warm with 1.88 rollout.

Let me know if I can help , but something doesn't add up , our fixed 19's with stout springs / brushes only pull about 10-11 amps @ 5 volt and the GFX runs them fine.

My spec motors pull 3.5-4.0 amps at 1.5 volts with a fan. I was just kiddin' when I stated they would shut off my GFX. Our ARCOR 19 turns pull 13-14 amps at 1.5 volts with a fan on our GFX with no problems.

When you stated 2-3 amps at 5 volts I was givin' ya a hard time as ours pull 3.5-4.0 at 1.5 volts (1/2 amp less without a fan).

You're mean Tony!!!

I used to use a Pyramid 10 amps supply with my GFX, mainly because I had it from the old days. I wasn't paying attention and while breaking in a motor I burned it out. That is pretty much the only time you can get a power supply to max out. (too small a PS and running a motor that draws close to ten amps) I replaced it with a dura-comm 25 amp supply. I charge, or run in motors and can run my lathe at the same time, no problemo~ The radio shack regulated power supply looks just like the dura-comm and works real good too. :thumbsup:

My Spec motors pull 3.5-4.0 amps at 1.5 volts. If I ran them at 5 volts they may shut off my GFX! lol

Thanks again Tony for helping a kid out and giving him the HP to get the win 2 weeks in a row.:thumbsup: