R/C Tech Forums

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

Reply
 
Thread Tools Search this Thread
Old 07-19-2010, 04:42 AM   #1
Tech Apprentice
 
Join Date: Jun 2010
Location: Fussa, japan
Posts: 76
Trader Rating: 1 (100%+)
Default LIPO charge rate, ive searched no answer

Hey guys I'm new to LIPO's I've got a Yokomo 3000mah 25C saddle pack and i was wondering what Amp to charge at? I'm charging it at 2A right now balanced charged, 2cell. People keep saying 1C so i assumed that meant current so 1A per cell which is what im charging at. So my question is should LIPO's be charged at max 1A per cell? Or am i wrong there, sorry guys i just cant find any clear cut answers.
__________________
Yokomo DMAX - Daily drifter!
HPI SPRINT 2 - Wife's
Tamiya F104W
I drift at CHANCE CIRCUIT!!!!! And SPEEDWAYPAL!!!
I live in japan pm me if you need something hard to find, I'm paypal verified!
Jdmpurest is offline   Reply With Quote
Old 07-19-2010, 05:07 AM   #2
Tech Champion
 
Matt Howard's Avatar
 
Join Date: Aug 2001
Location: Abilene TX
Posts: 5,952
Trader Rating: 6 (100%+)
Default

Quote:
Originally Posted by Jdmpurest View Post
Hey guys I'm new to LIPO's I've got a Yokomo 3000mah 25C saddle pack and i was wondering what Amp to charge at? I'm charging it at 2A right now balanced charged, 2cell. People keep saying 1C so i assumed that meant current so 1A per cell which is what im charging at. So my question is should LIPO's be charged at max 1A per cell? Or am i wrong there, sorry guys i just cant find any clear cut answers.
Charging a 3000mah pack at 1C would equal 3 amps. The C is equal to the capacity of the pack, to charge a 4000mah pack at 1C would be a 4 amp charge rate, a 5500mah pack would be a 5.5 amp charge rate, etc.
__________________
Official member of The Guild of Calamitous Intent and proud supporter of Conjectural Technologies.
Serpent S411 LE kit #192
RCTech #361
Matt Howard is offline   Reply With Quote
Old 07-19-2010, 05:12 AM   #3
Tech Apprentice
 
Join Date: Jun 2010
Location: Fussa, japan
Posts: 76
Trader Rating: 1 (100%+)
Default

Quote:
Originally Posted by Matt Howard View Post
Charging a 3000mah pack at 1C would equal 3 amps. The C is equal to the capacity of the pack, to charge a 4000mah pack at 1C would be a 4 amp charge rate, a 5500mah pack would be a 5.5 amp charge rate, etc.
So it would be safe to charge 2cells at 3A or 3A per cell?
__________________
Yokomo DMAX - Daily drifter!
HPI SPRINT 2 - Wife's
Tamiya F104W
I drift at CHANCE CIRCUIT!!!!! And SPEEDWAYPAL!!!
I live in japan pm me if you need something hard to find, I'm paypal verified!
Jdmpurest is offline   Reply With Quote
Old 07-19-2010, 05:23 AM   #4
Tech Master
 
FREAKAH's Avatar
R/C Tech Elite Subscriber
 
Join Date: Jan 2002
Posts: 1,389
Default

1C: C = capacity/1000. (capacity divided by 1000)


Your battery's capacity is 3000mah so..

3000/1000 = 3 amp charge rate

....Or 1 amp per 1000mah

For 2C you just multiply the 1C charge rate by 2: 3 X 2 = 6 amp charge rate
For 3C you just multiply the 1C charge rate by 3: 3 X 3 = 9 " "
And so on.........

You determine charge amp rate by the capacity of the battery, not the cell count. But you do have to input the proper pack voltage into the charger.
__________________
Second-Hand Racing
RACE WORLD HAWAII
Losi Type-R |Tamiya F104 PRO | Tamiya F103 | Mugen MTX-4R | AE FT GT2

Last edited by FREAKAH; 07-19-2010 at 05:36 AM.
FREAKAH is offline   Reply With Quote
Old 07-19-2010, 05:56 AM   #5
Tech Adept
 
Join Date: Oct 2009
Location: AUSTRIA
Posts: 233
Send a message via ICQ to vitomon Send a message via Skype™ to vitomon
Default

the safest bet is to always charge the lipo with 1C. if it has 5000maH, 5A would be ok to charge with. some packs you can charge with more up to 3c but unless the lipo manufacturer is allowing that its not good and unsafe. so 1c charge rate is the normal way to go.
vitomon is offline   Reply With Quote
Old 07-19-2010, 06:52 AM   #6
Tech Elite
 
LMRacing's Avatar
 
Join Date: Nov 2008
Location: Rome, GA
Posts: 2,739
Trader Rating: 27 (100%+)
Default

I always charge at 2c, I race every weekend and I've never had a problem in 2 years.

I use SMC, Thunder Power, Speed Power, and IP packs. All Roar approved hardcase packs and I spend a little more on them though. I've not heard good things about Venom and some other packs and would probobly shy away from charging more than 1c on a pack like that. As well smaller packs like TX and RX packs or 1/18th packs I charge at 1/2c Mostly because the smaller wires I dont want to put too much heat in and melt the insulation. The chargers know when to start knocking down the amperage.

Really charging at 1/2c 2c 1c, theres not much difference other than how fast it gets the pack to 8.4V. The battery won't feel any more "punchy" charging it at a higher amp like a NIMH would
LMRacing is offline   Reply With Quote
Old 07-19-2010, 07:51 AM   #7
Tech Initiate
 
Join Date: Mar 2010
Posts: 35
Default

I always use 10A to charge, no matter how many C and capacity..
teamsanwa is offline   Reply With Quote
Old 07-19-2010, 09:09 AM   #8
Tech Elite
 
rough512's Avatar
 
Join Date: May 2002
Posts: 3,454
Trader Rating: 12 (100%+)
Default

Quote:
Originally Posted by teamsanwa View Post
I always use 10A to charge, no matter how many C and capacity..
How are your packs so far? How long have you been doing that?
rough512 is offline   Reply With Quote
Old 07-19-2010, 09:49 AM   #9
Tech Regular
 
Join Date: Aug 2003
Location: England
Posts: 257
Default

Quote:
Originally Posted by teamsanwa View Post
I always use 10A to charge, no matter how many C and capacity..
Remind me not to pit near you...
TraceRacing is offline   Reply With Quote
Old 07-19-2010, 10:22 AM   #10
Regional Moderator
 
CarbonJoe's Avatar
 
Join Date: Jul 2006
Posts: 2,661
Default

Quote:
Originally Posted by teamsanwa View Post
I always use 10A to charge, no matter how many C and capacity..
If you race at any ROAR sanctioned events, you'll be DQ'ed if caught. ROAR rules mandate a maximum 1C charging rate.
__________________
*** The Gate - Celebrating 8 years at the same location ***
The difference between genius and stupidity is that genius has its limits. - Albert Einstein
Understeer is when you hit the wall with the front of the car and oversteer is when you hit the wall with the rear of the car
CarbonJoe is offline   Reply With Quote
Old 07-20-2010, 03:40 PM   #11
Tech Elite
 
LMRacing's Avatar
 
Join Date: Nov 2008
Location: Rome, GA
Posts: 2,739
Trader Rating: 27 (100%+)
Default

Quote:
Originally Posted by CarbonJoe View Post
If you race at any ROAR sanctioned events, you'll be DQ'ed if caught. ROAR rules mandate a maximum 1C charging rate.
No acctualy Roar mandates following the battery manufactures suggested charge rate but no more than 2C

Edit: nope looked it up again, I was wrong it is 1c, I remember it being 2 for some reason
LMRacing is offline   Reply With Quote
Old 07-20-2010, 06:56 PM   #12
Registered User
 
UltegraSTI's Avatar
 
Join Date: Jul 2005
Posts: 7,171
Trader Rating: 20 (100%+)
Default

just do 1c. its club racing and its meant to be fun. guys with batt deals and $ to burn can tell ya different. honestly if u run mod, who cares. charge it up and go. balance up and if u dont burn the battery down to its near dead, u dont need to balance charge it all the time. balance charge always leaves a stock class racer flat that charge, its the subsequent charges that are real nice. if u follow good etiquette u'll be fine. it has to be 8.40v, so what does it matter how quick u get the batt back up to that voltage. thats all u accomplish-a faster charge.

while folks talk bout being creative, some dirt oval guys figured out with lipos they didnt already care about after some use/abuse. was to rip them hard on the charger in nickel mode. such that the voltage was 8.8-9v even. discharge them down to the 8.4 limit (usually by runnin the car, or a motor fan), go thru tech legal then when the batts rested waitin for race the voltage in the pack would creep up again naturally. and there was an advantage. well track got a whiff of that and i believe later in season they were tech'g voltages twice before heats at big races. crazy stuff. but hey i like my house (and the tracks i race at) as they are, not burned down in a fire.

R
UltegraSTI is offline   Reply With Quote
Old 07-20-2010, 07:53 PM   #13
Tech Elite
 
COBRARACING's Avatar
 
Join Date: Nov 2007
Posts: 3,318
Default

My advice is charge at 1-2c max and to be honest once the battery is reaching its capacity the current always drops away .even if you tried to charge the battery say at 15 amps or 20 amps you would see the current drop to 7 amp anyway as the battery cannot handle the charge current you are pushing through it even at the beginnning of the charge cycle

Most important always balance the lipos some say its not needed and they charge them without balancing them to get a quick charge and back on the track but from my study you need to always balance the cells eveytime without fail .
__________________
Email : [email protected] or [email protected]
Repair service Address
Hobbywing Technology Co., Ltd.
4th Floor, 3rd Building, KeLunTe Industrial Park, ShangLiLang, BuLan Road, LongGang District, ShenZhen, China
COBRARACING is offline   Reply With Quote
Old 07-20-2010, 08:36 PM   #14
Tech Initiate
 
Join Date: Mar 2010
Posts: 35
Default

Quote:
Originally Posted by rough512 View Post
How are your packs so far? How long have you been doing that?
i used around 1 year, no any problem~!
teamsanwa is offline   Reply With Quote
Old 07-20-2010, 08:39 PM   #15
Tech Initiate
 
Join Date: Mar 2010
Posts: 35
Default

Quote:
Originally Posted by TraceRacing View Post
Remind me not to pit near you...
Dont worry, this is the trend of using a higher charge rate..
teamsanwa is offline   Reply With Quote
Reply



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 02:12 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