discus18

I noted that whenever I discharge my pack to 5.4v and store it for the next race day, the less punch I would get from the pack. If I don't discharge it after the race day and store it "as-is", the pack would give me more "punch" the next time I use it. It may sound crazy to most of you, but that's what I have been experiencing. Actually why do we want to discharge it to 5.4v and store it? If I put the battery on tray just before charging it, would it decrease the battery "punch" ?

Thanks!

itchynads

Traying your cells should increase run-time at the cost of voltage. If you need punch its best not to tray your cells.

antoniop

Huummm,

What cells are you using?
I assume you are talking about GP3300 last generation.

According to the testing SMC made (and I can confirm it, coz I did the same thing) if you bring your packs down to 0V in discharge, run time will go down but punch will go up (Internal Resistance gets lower) with discharge up to 0V.

Honestly, from my experience I can't find a difference in punch if I equalize at 5.4V or just charge as it is.

PitCrew

Interesting.

If I just discharge to 5.4, the charge mAh is generally lower, as in its done around 3000 mah. If I tray before charging the mah usually reaches 3600+ and peaks at only 9.1-9.2 They perform awesome on the track.

But it depends on the tray. I use two trays, a Trinity which discharges at around 10 amps, and I have an Integy tray thats old: it discharges around 1 amp.

I use the Trinity tray first, the go to the integy tray to take the cells down slow and steady: before charging.

antoniop

Ok,

That's easy explained. If you discharge a pack after a run at 30 or 20 amps with cut off at 5.4, what happens is that the voltage depression caused by the high discharge current will almost immediatly bring the pck down and the charger will cutt discharge.

However there's a lot of charge in the pack that can be drained at lower currents.

If you put that same pack on a a tray with cutoff and discharge it at 1 A the voltage depression is almost insignificant and the charge will be drained slowly before the cutt off works.

What you did was to remove 300mAh or 500mAh "slowly". After that your batteries will probably accept more mAh, hence the 3600 you are talking about.

In the case of GP the closer you get to 0V per cell the more you will be decreasing IR (internal resistance) and you pack will peak lower (that's a good thing) and the punch will be better.
This will happen at the expense of some lost run time, but even in mod that was never a problem for me. For the stock racers that's even better, they need punch and lower IR (that translates in lower voltage depression when you pull the trigger and that equates to more volts to the motor and faster spin).

I hope I got it right... after I while even I was confused

EddieO

iTrader: (6)

Umm, not sure what latest testing you are reading regarding the SMCs....their current testing, which has been going on for a while now is to DEADSHORT them. Bringing them down to zero volts alone won't do much for voltage or IR.

check smcs site, if you have the new generation 2 or 3 of the gp3300 cell, then you can deadshort and you will potentially gain, however you WILL lose some runtime. No big deal for stock or 19t.....critical for most mod classes.


Later EddieO

UCHEATULOSE

dead short for stock and 19 turn racing! it's a must!

TexRacer

iTrader: (70)

Guys deadshorting is the way to go with GP3300's.
After more than 8 months of doing this I have had nothing but great performance from my packs.
I charge at 6.0amps with a .05 cutoff.
If the pack sits more than 10-12 minutes before my race I peak at 6.0amps at a .01cutoff to get the pack warm again.
I run the pack on the track,discharge the rest with 30 amps down to 5.4volts.I then put the pack on 3 made trays.
These are the ONLY 3 trays at this time that will take the packs to 0.0
Trinity Realtime 2 or 2.5
Integy Octane 2
When the lights go out I let the pack sit for about 2-3 minutes afterward and then solder a wire from positive to negative and store them this way.
Now the 1st batches of cells I had were 1.15's at 30 amps and like 390-397 runtime.These cells have lost a total of about 20 seconds but voltage is up and resistance is very low and punchy as hell.
***Note the NEW generation of ShorterGP3300 cells dont have the voltage of the last one's but MORE runtime and lower resistance on average.
With this extra runtime being in the 415-430 area deadshorting will be great.The ONLY classes that i dont see deadshorting are hard core 1/12th scale mod,Sedan mod and Oval mod.
In all other classes it can only benefit you.

antoniop

You're right. Bring them to 0V and THEN dead short. That's the way to improve IR.

PitCrew

NO.

Deadshort while they are charged. That way you are zapping them at the same time...


JUST KIDDING

vtl1180ny

Weren't we just told a few months back NOT to dscharge to zero or dead short GP3300 NiMh batteries??????

I've put the voltmeter on a cell while using my Trinity 2.5, when the light goes out it still isn't at .09v, you need to let them sit longer...

SOuthernFRIED

iTrader: (21)

I am wondering too.Pro-Match says not to dead short the 3300's.So what gives?Should we short or not?

Calvin Ng

this question is about solderin the wire from posative to negative of the battery

how long do you leave that way for?

EddieO

iTrader: (6)

SMC recommends to leave it there until you use it again. HOWEVER, if you plan on running the battery again the same day, they DON'T recommend deadshorting in between the charges.

ALL the details are on the SMC site, check it out....

Every battery matcher is different, they rarely agree.....the biggest issue out there is to NOT deadshort the generation 1 Gp3300 cells(the ones that were .1.12 to 1.15 voltage). Generation 2(1.14-1.18 voltage) and Generation 3(1.15-1.17 with the short button head) can be deadshorted with positive results if done properly.

Later EddieO

Calvin Ng

whats the way to do it properly