JayL

8.3.2.5.2 Li-Poly battery maximum charge voltage.
 1s Li-Poly batteries may be charged to a maximum of 4.20v.
 2s Li-Poly batteries may be charged to a maximum of 8.40v.
 3s Li-Poly batteries may be charged to a maximum of 12.6v
 4s Li-poly batteries may be charged to a maximum of 16.80v.
 2S LiFe batteries may be charged to a maximum of 7.40v.
 There will be no allowances for overages.

your 'rules' file is outdated

dayno

iTrader: (5)

Yes it is, I found one from 2008 it seems, thanks for the info / correction. I think we will stay with 8.44 tho for the reasons stated previously.

This is where I found what I was referencing.

http://www.roarracing.com/downloads/...ipo_Reader.pdf

jiml

iTrader: (3)

The problem with 8.44 is people who know what they're doing can adjust their chargers to 8.44, which is overcharging the battery. The original rule read 8.40 with a plus or minus tolerance of .04 volts to allow for variances in volt meters. Racers being racers read that as 8.44. Next thing you know batteries are coming up 8.45, 8.46, etc. I think ROAR even had an 8.50 rule, but people pushed that right up to the limit as well. That's when it became 8.40 absolute.

IMHO you should make the rule 8.40, and if someone comes up 8.41 give them the stink eye and let them race.

SWTour

iTrader: (9)

I was one of the 1st groups of racers who went LIPO and when we did the best cells on the market (stability wise) were the Korean Kokam Lipos that ORION was using. According to them at that time, a Properly charging LIPO Charger should STOP increasing battery voltage at 8.38v.

For my Brushless/LIPO classes we used the 8.38 as the MAX voltage with a +/- .07 volts (which really wasn't a -, just a +) for a NEVER OVER 8.45 for any reason.

Guys would come in at 8.46 and cry "We're only .01 over" -- to which they'd be told, NO You are .08 OVER - and .01 OVER the variant.

We did this in large part because w/o a "CALIBRATED" Voltmeter at EVERY Race...it was a hard thing to control...even if the chargers did their job correctly.

Cheap Meters, like a $9.99 one from Harbor Freight could vary .05 - .07 volts itself, compared to the "OFFICAL" Fluke we used in Tech.

(We were also told at that time, that a LIPO could be charged easily to 8.6 volts and that the discharge difference in 8.45 to 8.38 were minimal, but wen you went full .10s you could "FEEL" the difference... (Also at that time HEAT/BATTERY TEMP played a HUGE factor in how long Good Voltage stayed high -- a cold battery would fall below 8.00 volts under load very quickly..where a battery above 100 degrees would stay above 8.00 volts for nearly 1 minute. (NOTE: These were 2cell packs - TRUE 2cell 2s1p packs, not 2s2p (4c) packs -- those held their voltage a LOT longer)

Here is a voltage drop test I ran on one of my (at the time) Best 3300mAh 2c packs (which was our SPEC pack) THUNDER POWER 25c 3300 mAh.

T/P3300 25c 2c test - 5/26/2012
2nd test of a back to back charge/discharge/charge/discharge test.
static voltage after charge 8.42v
initial load test: (simulated Race Start)
@0:01 sec 8.09v @ 27.7a -
@0:15 sec 8.02v @ 22.5a -
@0:30 sec 7.95v @ 22.4a -
@2:00 min7.61v @ 21.8a -
@4:00 min7.41v @ 21.4a -
@5:00 min 7.34v @ 21.1a

nashrcracer

iTrader: (1)

what I heard was one of the reason for the 8.44 for the longest was the turbo charger, It was set to 4.22 per cell hard coded, couldn't adjust it. so as it was the most popular charger for pro racing at the time roar went with 4.22 per cell. in 2011 roar tried 8.50 with no variance. and even Joel Johnson got DQed for a race when he came up at 8.501 on the meter roar was using. so about 2012 I think roar went back to 8.40 no variance and has been there since.

could be worse TOUR oval guys had 4.22 and if you were over you had to burn it off to 4.20 putting heat in the motor before you even started.

JayL

if you are 8.44
you run your car in your hand 1/4 throttle for a min....super easy
use the time to warm your diff fluid up

dayno

iTrader: (5)

Has anyone tried ceramic bearings in there motor? Any benefit?

NutDriver

iTrader: (30)

Dayno,
I promise that I'm not picking on you, but the USVTA rules specifically address ceramic motor bearings.

dayno

iTrader: (5)

Lol no problem bud I appreciate any and all info, opinions etc. The way I read the rules was that using ceramic bearings makes you a dork, not that they couldn't be used. I actually wondered about there use because the wording seemed to imply you could use them but it was a dorky thing to do?

scirocco14

iTrader: (5)

I think it's more "not in the spirit of the rules" than anything else. But no one is going to stop you. I'd say it might be worth .001-.002 seconds per lap. Getting your gear mesh right is worth more than that, IMHO.

Mark

DARKSIDE

iTrader: (2)

the amount of time and effort to put them in the motor without damaging them is a waste....feel free to change them, but be careful....if the seat even a little off...its a lost

dayno

iTrader: (5)

Any opinions on whether putting wheel and drive train ceramic bearings in is worth it?

theproffesor

iTrader: (66)

Ceramic bearings may, I repeat may, be a benifit on the spur layshaft, the diff out drives, shaft drive bulkheads and possibly the inner bearings on the front and rear huns. The outer bearings take way too much abuse and would be damaged quickly.

But anything you might possibly gain will once again be destroyed by that wall in turn 4 that keeps jumping out in front you every 4th or 5th lap.

You are much better off working on fine tuning a setup and driving line than a couple hundred worth of bearings.

JEFFs SC10

iTrader: (15)

How do I become a USVTA member officially? I friggin Love VTA .

scirocco14

iTrader: (5)

Info here:

https://sites.google.com/site/nationalusvtapoints/home