Sandy always use lininer charge when racing . u can use flex if you need to wake up old cells .PS come see me sun and i will see if we can get that thing moving

Ken,thanx,much appreaciated.

linear. i also discharge them at 20 amps to 3.60 volts and let them sit like that untill the next week. i dead shorted one pack last year and i didn't like the results.

A quick update to what wev'e been doing , only flex at home , never on race day.
Charge at a 6 -7 amp linier and as soon your race is over discharge to 1.0 volt per cell @ 10 amps,,, give them a few minutes , they don't have to be cool and hit them again , I guess I'm assuming your running one pack all night , which you should , Spec racing is not having 6 battery packs in your
toolbox.
There's many articles on building a decent 10 amp discharger with either resistors or bulbs , I prefer using 6 , 1 ohm resistors.
Unplug when you hit the 1.0 volt mark , or something close is no big deal.

We've found that recharging with half a charge left makes the pack run flat

Hope this helps :thumbsup:

re-jump startin this thread...


How do you know when you discharge to 1.0 volts on a pack???

Eric L

re-jump startin this thread...


How do you know when you discharge to 1.0 volts on a pack???

Eric L With a multi meter or leave charger hooked to battery so you can moniter current load.
#83 Spec Sk.

My Spintech v.2 handles that for me :)

Man the Torpedo!

I was thinking about the fuss about the new SPEC packs, so why not insist on a change to:

GP3300 with a PCB protective circut.

With the change to a larger capacity cell SPEC racing could be better. As the cells age, they lose capacity. If a 1600cell loses 200mAh capcity you notice it right away and spend $30 for a new pack. If a 3300 pack loses 200mAh or even 1000mAh you still have a pack good enough to practice with and finish all the laps. Yes old cells have higher IR and lower voltage but you still can drive for 5 minutes.

Now to explain the why the PCB protective circut. Just like on LiPo's these circuts could be designed to have an AMP limiter, Low Voltage Cutoff, High Voltage Cutff or Equalization in Charging mode. GP3300's really don't need AMP limiters or high voltage cutoffs. What a TAMPER PROOF and SEALED SPEC pack needs is an on-board individual cell cutoff of .90V and equalization for charging. Pretty much when the race is over, hook the cells up to some 10A bulbs and one-by-one the PCB will cut off the cells at they hit .90V

Downside to this change, Cost would be about $10 to $15 dollars higher per pack and the onboard PCB will add about 80mOhm of resistance.

Goodside: Packs will have a longer lifespan justifying the extra $10 in cost. Less Voodoo in getting the packs to behave. And finally, old or new SPEC packs can still make a 5 minute race.

We changed one of our spec classes to the GP3300 cell only and what a difference. No body dumps and you can do just about anything to these
and not kill them. There's alot of cells still around and we found one warehouse that had new ones for $3.00 each. A few cycles to get them
going and your fine.:thumbsup:

The 1600's take all the fun out of spec to find some decent packs.:confused:

I've practiced with some old GP3300's I got off Ebay. .15-.2 secsonds a lap faster just due to the better voltage. The Murdock 3000 mah packs would be a great idea, but at our local track some wanna go brushless with spec packs, others thinking about Team Orion 2400 mah Lipo.

Just my opinion ,, but Lipo doesn't belong in Spec !

I know all the arguments , like only one battery , longer life , ect , ect.

Keep them out of Spec and you'll have more participants.

The Sanyo 1900 SCR's are a GREAT choice , run a pack a couple times per race day and dead short with a 10 ohm resistor,, can't beat it.

The GP3300's we run in the Pro-Spec class for more advanced drivers.

Like the old days.....haha....EricL will get a laugh out of that!

The GP3300 is a great battery. I used them with a 17.5 and they ran a good strong 4 min.

Sam

Their night and day better than most 3000 cells , the 3300 has the durability and was designed for RC use . Also has half the Internal resistance.

Like the old days.....haha....EricL will get a laugh out of that!

...I know u ain't callin me old!!!...are ya?!?

Well, you did run into the wall all by yourself :)

Well, you did run into the wall all by yourself :)

what happened was my switch came undone...came apart scrubin the floor

I wont tell ya how low I waz....fixed b4 the heats

...lookin through my stuff....I think I got way to many bad batteries....and not enough GP cell spec packs!!!lol

Eric L