SMC 28C 4000/5000 Hardcase Lipo part 2
11-30-2008, 04:21 PM
#1426
have someone walking thru the pits checking your charger..
we all had lipo sacs and agreed to charge at 1c, any one cought not doing so was asked to leave and not come back!
we all had lipo sacs and agreed to charge at 1c, any one cought not doing so was asked to leave and not come back!
11-30-2008, 04:23 PM
#1427
To tech for heating just follow my suggestions as I think it's a fair way to do it.
For overcharging this is done in Tech prior to the run. Just put a voltmeter on the pack and it shouldn't be over 8.44 as this is the allowed margin of error as not all chargers have the same calibration. If a racer has a pack that is above 8.44 he shouldn't be allowed to make his run and you tell him to stop overcharging. Overcharging should never be tolerated and should be considered cheating.
For overcharging this is done in Tech prior to the run. Just put a voltmeter on the pack and it shouldn't be over 8.44 as this is the allowed margin of error as not all chargers have the same calibration. If a racer has a pack that is above 8.44 he shouldn't be allowed to make his run and you tell him to stop overcharging. Overcharging should never be tolerated and should be considered cheating.
So charger problems can happen also.
11-30-2008, 04:25 PM
#1429
I agree with the cheating part. However I purchased a new Core UDC 20 when they came out at the Carpet Nats this March. It turned out it was a bad charger and charging above the 8.44 volts. When I went to tech the packs voltage was 8.49 volts. I went back to using my Orion Advantage charger and the voltage was never above 8.44 the rest of the week.
So charger problems can happen also.
So charger problems can happen also.
Yes chargers aren't all calibrated the same and should be checked. In your case it was not an attempt to cheat and can be proven.
11-30-2008, 04:30 PM
#1430
And apparently some chargers are being calibrated beyond 8.40 (I'm looking at you CE) to try and leverage the margin of error and go right to 8.44. It seems like most chargers are pretty good at getting it right to 8.40 or a little lower. Why not lower that limit to something like 8.41 and do away with this? It's not like it's hard to scrub off .01, I've seen guys do it with a few seconds of throttle.
11-30-2008, 04:36 PM
#1431
Don't blame CE for doing what there customers ask plus it's within the established Lipo rules. Like I mentioned in one of my posts above you can calibrate the LRP to be at 8.44.
If a racer thinks he's getting beat by a pack that is charged at 8.44 then so be it but I know it will not make much of a difference if any.
Lets follow the current rules and keep things simple like no heating of the packs and just race and have fun.
If a racer thinks he's getting beat by a pack that is charged at 8.44 then so be it but I know it will not make much of a difference if any.
Lets follow the current rules and keep things simple like no heating of the packs and just race and have fun.
11-30-2008, 04:39 PM
#1432
11-30-2008, 04:59 PM
#1433
Don't blame CE for doing what there customers ask plus it's within the established Lipo rules. Like I mentioned in one of my posts above you can calibrate the LRP to be at 8.44.
If a racer thinks he's getting beat by a pack that is charged at 8.44 then so be it but I know it will not make much of a difference if any.
Lets follow the current rules and keep things simple like no heating of the packs and just race and have fun.
If a racer thinks he's getting beat by a pack that is charged at 8.44 then so be it but I know it will not make much of a difference if any.
Lets follow the current rules and keep things simple like no heating of the packs and just race and have fun.
This isn't a knock on you or SMC, Danny. It's just something that's been nagging at me for a while now, and this seemed like a decent time to bring it up. My apologies for mucking up your thread with it.
Last edited by Adam?; 11-30-2008 at 05:22 PM.
11-30-2008, 05:39 PM
#1434
No problem as this is what these boards are for. Trying to help and udnderstand these things. The problem is that some chargers aren't well calibrated and others like the LRPs offer a way for you to clibrate them yourself. So if you own a charger that goes to 8.43 and the rule is 8.41 this means you need another charger which makes no sense. If the rule is 8.41 and some chargers are at 8.38 there is still a difference and the hardcore racers will use the charger that has 8.41
I get your point but I think 8.44 is fine and if somone thinks he needs to use an LRP charger ot get CE to calibrate there GFX so be it as I doubt that will make them win races. If you looked at the Cleveland race lap times this weekend you would see that most racers are turning there fastest laps not in the first couple of laps.
If a racer thinks he needs to have the extra .04 volts all you have to do is to top off your pack with a regular charger until it reaches 8.44 and if by mistake you overshot by a few hundreths just turn on your car and hit the throttle until your at 8.44.
I get your point but I think 8.44 is fine and if somone thinks he needs to use an LRP charger ot get CE to calibrate there GFX so be it as I doubt that will make them win races. If you looked at the Cleveland race lap times this weekend you would see that most racers are turning there fastest laps not in the first couple of laps.
If a racer thinks he needs to have the extra .04 volts all you have to do is to top off your pack with a regular charger until it reaches 8.44 and if by mistake you overshot by a few hundreths just turn on your car and hit the throttle until your at 8.44.
Last edited by Danny/SMC; 11-30-2008 at 06:46 PM.
11-30-2008, 06:40 PM
#1435
Tech Master
iTrader: (13)
V=I*R that's voltage equals current*resistance, so if you are charging on you charger with charge leads that havetheir own resitance then the voltage is going to read higher on the charger due to the leads so the charger will need to charger to lets say 8.44 on the charger to reach an actual 8.40 on the battery correct?? so if you check your battery with a good voltmeter with low resistance leads to get an accurate reading at the battery then the voltage should read lower so in affect you are calibrating your by raising the voltage in the charger to account for the charge leads and the charger internal resistance.
Now i'm sure that i'll get some $%#$ somewhere for having a $500 charger (that cost me $270, 200 on ebay then 50 to update and 10 to ship each way) and for having a $330 fluke to just check the voltage of my battery but i would rather buy good equipment when i can afford it
Now i'm sure that i'll get some $%#$ somewhere for having a $500 charger (that cost me $270, 200 on ebay then 50 to update and 10 to ship each way) and for having a $330 fluke to just check the voltage of my battery but i would rather buy good equipment when i can afford it
11-30-2008, 06:47 PM
#1436
Volt meters are calebrated at the leads ,, not at the corcuit board .. same as your charger. Volts is Volts is Volts . But for that matter it all depends on the unit the calibrator is using to calibrate it with now doesnt it! For the most part , You are correct but, theres always nothing that is perfect. Just think of it like this , NEVER and ALWAYS are the two longest words in the dictionary.
11-30-2008, 06:52 PM
#1437
I just cycled one of my 5200/24C packs. I charged it up to until the voltage was at 8.44 while the charge was off. So the pack had 8.44 resting voltage.
Here are the numbers:
Regular charge which the pack has a resting voltage of 8.39
529 - 7.38 - 6.1
8.44 resting voltage:
544 - 7.40 - 6.3
So if you think 15 seconds of runtime with .02 higher average voltage will give you much better lap times then charging at 8.44 is the solution. I doubt that this can make a big difference on the track.
For those who see an increase in IR that is surely caused by the pack not being cycled for a few days. The last cycle numbers I had for this pack it had been cycled a few times that day.
Here are the numbers:
Regular charge which the pack has a resting voltage of 8.39
529 - 7.38 - 6.1
8.44 resting voltage:
544 - 7.40 - 6.3
So if you think 15 seconds of runtime with .02 higher average voltage will give you much better lap times then charging at 8.44 is the solution. I doubt that this can make a big difference on the track.
For those who see an increase in IR that is surely caused by the pack not being cycled for a few days. The last cycle numbers I had for this pack it had been cycled a few times that day.
11-30-2008, 06:56 PM
#1438
Tech Master
iTrader: (13)
Volt meters are calebrated at the leads ,, not at the corcuit board .. same as your charger. Volts is Volts is Volts . But for that matter it all depends on the unit the calibrator is using to calibrate it with now doesnt it! For the most part , You are correct but, theres always nothing that is perfect. Just think of it like this , NEVER and ALWAYS are the two longest words in the dictionary.
11-30-2008, 07:03 PM
#1439
It just seems strange that the most accurate charger on the market is going to be used to charge batteries to 8.44, rather than the 8.40 intended by the rules. I suppose the "calibration" argument is okay, but who are we kidding? You yourself said racers "demanded" it, and we know it wasn't because it had problems getting to 8.40 each time.
I just don't think it's right to take the high road on the one hand, and say we should abide by the rules, and then make thinly-veiled excuses for CE with the calibration argument, when it's obvious what they're really doing.
I just don't think it's right to take the high road on the one hand, and say we should abide by the rules, and then make thinly-veiled excuses for CE with the calibration argument, when it's obvious what they're really doing.
11-30-2008, 07:04 PM
#1440
I just cycled one of my 5200/24C packs. I charged it up to until the voltage was at 8.44 while the charge was off. So the pack had 8.44 resting voltage.
Here are the numbers:
Regular charge which the pack has a resting voltage of 8.39
529 - 7.38 - 6.1
8.44 resting voltage:
544 - 7.40 - 6.3
So if you think 15 seconds of runtime with .02 higher average voltage will give you much better lap times then charging at 8.44 is the solution. I doubt that this can make a big difference on the track.
For those who see an increase in IR that is surely caused by the pack not being cycled for a few days. The last cycle numbers I had for this pack it had been cycled a few times that day.
Here are the numbers:
Regular charge which the pack has a resting voltage of 8.39
529 - 7.38 - 6.1
8.44 resting voltage:
544 - 7.40 - 6.3
So if you think 15 seconds of runtime with .02 higher average voltage will give you much better lap times then charging at 8.44 is the solution. I doubt that this can make a big difference on the track.
For those who see an increase in IR that is surely caused by the pack not being cycled for a few days. The last cycle numbers I had for this pack it had been cycled a few times that day.