R/C Tech Forums

Go Back   R/C Tech Forums > General Forums > Electric On-Road

Reply
 
Thread Tools Search this Thread
Old 11-30-2008, 05:21 PM   #1426
Tech Master
 
Join Date: Jul 2004
Location: MI
Posts: 1,544
Trader Rating: 1 (100%+)
Send a message via AIM to John St.Amant Send a message via MSN to John St.Amant Send a message via Yahoo to John St.Amant
Default

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!
John St.Amant is offline   Reply With Quote
Old 11-30-2008, 05:23 PM   #1427
Tech Champion
 
Join Date: Jun 2004
Location: St Louis
Posts: 7,868
Trader Rating: 198 (100%+)
Default

Quote:
Originally Posted by Danny/SMC View Post
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.
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.
__________________
Please become an organ donor.
www.donatelife.net
Custom decals and Sno-Tee'z, T-Shirts by Sno Camel
dodgeguy is offline   Reply With Quote
Old 11-30-2008, 05:24 PM   #1428
Tech Champion
 
Join Date: Jun 2004
Location: St Louis
Posts: 7,868
Trader Rating: 198 (100%+)
Default

Quote:
Originally Posted by John St.Amant View Post
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!
This sounds like a waist of time. 1C 2C does it really matter? There is no performance increase on the track. It just saves time.
__________________
Please become an organ donor.
www.donatelife.net
Custom decals and Sno-Tee'z, T-Shirts by Sno Camel
dodgeguy is offline   Reply With Quote
Old 11-30-2008, 05:25 PM   #1429
Company Representative
 
Danny/SMC's Avatar
 
Join Date: Oct 2001
Location: Elkton, VA
Posts: 3,097
Trader Rating: 2 (100%+)
Default

Quote:
Originally Posted by dodgeguy View Post
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.

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.
Danny/SMC is offline   Reply With Quote
Old 11-30-2008, 05:30 PM   #1430
Tech Addict
 
Adam?'s Avatar
 
Join Date: Sep 2008
Location: ohhh, that guy...
Posts: 639
Default

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.
Adam? is offline   Reply With Quote
Old 11-30-2008, 05:36 PM   #1431
Company Representative
 
Danny/SMC's Avatar
 
Join Date: Oct 2001
Location: Elkton, VA
Posts: 3,097
Trader Rating: 2 (100%+)
Default

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.
Danny/SMC is offline   Reply With Quote
Old 11-30-2008, 05:39 PM   #1432
Tech Master
 
Join Date: Jul 2004
Location: MI
Posts: 1,544
Trader Rating: 1 (100%+)
Send a message via AIM to John St.Amant Send a message via MSN to John St.Amant Send a message via Yahoo to John St.Amant
Default

Quote:
Originally Posted by Danny/SMC View Post
Lets follow the current rules and keep things simple like no heating of the packs and just race and have fun.
AMEN!
John St.Amant is offline   Reply With Quote
Old 11-30-2008, 05:59 PM   #1433
Tech Addict
 
Adam?'s Avatar
 
Join Date: Sep 2008
Location: ohhh, that guy...
Posts: 639
Default

Quote:
Originally Posted by Danny/SMC View Post
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.
I agree. I think the 8.44 rule should be revised to 8.41, though. It's clearly encouraging questionable behavior amongst racers, and some charger manufacturers. If the average (non-adjustable) charger comes off around 8.39, and these adjustable guys are coming off at 8.44, something isn't right. We can say it doesn't matter on the track, and for most of us that's probably true. But you can't deny that in the past, people were willing to pay almost any price for more voltage, and that it obviously matters to many of us, no matter how misguided.

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 06:22 PM.
Adam? is offline   Reply With Quote
Old 11-30-2008, 06:39 PM   #1434
Company Representative
 
Danny/SMC's Avatar
 
Join Date: Oct 2001
Location: Elkton, VA
Posts: 3,097
Trader Rating: 2 (100%+)
Default

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.

Last edited by Danny/SMC; 11-30-2008 at 07:46 PM.
Danny/SMC is offline   Reply With Quote
Old 11-30-2008, 07:40 PM   #1435
Tech Master
 
Join Date: Jan 2006
Location: Kansas City, MO
Posts: 1,260
Trader Rating: 13 (100%+)
Send a message via AIM to HenBeav
Default

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
__________________
[URL]http://www.fastlanehobby.com[/URL]

Support your local Lowe's, Walmart and Layne Machine Works INC.
HenBeav is offline   Reply With Quote
Old 11-30-2008, 07:47 PM   #1436
Tech Master
 
Join Date: Jul 2004
Location: MI
Posts: 1,544
Trader Rating: 1 (100%+)
Send a message via AIM to John St.Amant Send a message via MSN to John St.Amant Send a message via Yahoo to John St.Amant
Default

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.
John St.Amant is offline   Reply With Quote
Old 11-30-2008, 07:52 PM   #1437
Company Representative
 
Danny/SMC's Avatar
 
Join Date: Oct 2001
Location: Elkton, VA
Posts: 3,097
Trader Rating: 2 (100%+)
Default

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.
Danny/SMC is offline   Reply With Quote
Old 11-30-2008, 07:56 PM   #1438
Tech Master
 
Join Date: Jan 2006
Location: Kansas City, MO
Posts: 1,260
Trader Rating: 13 (100%+)
Send a message via AIM to HenBeav
Default

Quote:
Originally Posted by John St.Amant View Post
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.
so for higher voltage i should cut my leads really short
__________________
[URL]http://www.fastlanehobby.com[/URL]

Support your local Lowe's, Walmart and Layne Machine Works INC.
HenBeav is offline   Reply With Quote
Old 11-30-2008, 08:03 PM   #1439
Tech Addict
 
Adam?'s Avatar
 
Join Date: Sep 2008
Location: ohhh, that guy...
Posts: 639
Default

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.
Adam? is offline   Reply With Quote
Old 11-30-2008, 08:04 PM   #1440
Tech Addict
 
Adam?'s Avatar
 
Join Date: Sep 2008
Location: ohhh, that guy...
Posts: 639
Default

Quote:
Originally Posted by Danny/SMC View Post
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.
That's good data, thanks Danny.
Adam? is offline   Reply With Quote
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
* * * BRAND NEW * * * FTB4, SMC 5000 28c Hardcase 7.4 Lipo, JR Z8800s jpeck R/C Items: For Sale/Trade 12 10-26-2008 04:03 AM
FOR SALE: SMC 4000 28C HARDCASE LIPO'S commander Australia For Sale/Trade 4 10-20-2008 11:08 AM
SMC 4000 mah Hardcase Lipos 28C NIB rraden R/C Items: For Sale/Trade 11 09-12-2008 11:20 AM
SMC 28C 4000 hardcase lipo fred kellner R/C Items: For Sale/Trade 0 04-09-2008 08:31 AM
New SMC Lipos 7.4v 2s 4000 and 5000mah HardCase IOwNMkeG R/C Items: For Sale/Trade 4 03-30-2008 01:54 PM



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off



All times are GMT -7. It is currently 02:09 PM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net