R/C Tech Forums

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

Reply
 
Thread Tools Search this Thread
Old 03-31-2009, 08:58 AM   #1
Tech Fanatic
 
Join Date: Oct 2008
Posts: 946
Trader Rating: 46 (98%+)
Default Lipo Battery Myth's

Ok so airplane guys have been using Lipo battery technology for some time now. It's a new era now for 1/8 scale buggies. I have a few questions about the batt's

1. I use a hyperion duoII charger. I balance and charge my pack after every discharge. I am running zippy 4S 5000mah packs. I also am charging it at 5amps (1amp per 1,000MAH) My packs peak out at 16.78

Is that right? I had a guy telling me at the track his losi pack get over 18. I have a losi pack it it sucks.

2. How long should you wait to recharge a pack after you have ran it?

3. Would running a 1500kv motor with a 6S battery with the same 5000mah last longer than the 4S 5000mah in a MM 2200kv.

4. using a zippy 4S and Mamba Monster 2200kv is only getting me about 15min run times. Sound right?
__________________
Losi 8ight 2.0 sirio evoIII
Losi 8ight T 2.0 .21 vpec-t
Associated SC8
Jammin Crt.5 .12 Picco
everyjuangohome is offline   Reply With Quote
Old 03-31-2009, 09:45 AM   #2
Tech Regular
 
Billetboy's Avatar
 
Join Date: Apr 2008
Posts: 319
Trader Rating: 49 (100%+)
Default Lipos

Your 4S lipos should peak at 16.8 volts, so the guys at the track must have a 5s or something. lipos are 4.2 volts per cell.

Lipos can be charged right after discharge unless they are really hot. You are suppose to let them cool-down to room temp, but I never do, but my packs are never over 100 degrees anyway.

Voltage and Amperage is inversely proportional. More voltage = less amperage. So, Yes, A 6S setup take less mah to do the same work as the 4s setup, therefore you will get considerably longer runtimes from a 6S setup of the same Mah as the 4s setup. Also, Amperage generates heat, so the 6s setup will run cooler than the 4S.
Billetboy is offline   Reply With Quote
Old 03-31-2009, 09:48 AM   #3
Tech Fanatic
 
Join Date: Oct 2008
Posts: 946
Trader Rating: 46 (98%+)
Default

Quote:
Originally Posted by Billetboy View Post
Your 4S lipos should peak at 16.8 volts, so the guys at the track must have a 5s or something. lipos are 4.2 volts per cell.

Lipos can be charged right after discharge unless they are really hot. You are suppose to let them cool-down to room temp, but I never do, but my packs are never over 100 degrees anyway.

Voltage and Amperage is inversely proportional. More voltage = less amperage. So, Yes, A 6S setup take less mah to do the same work as the 4s setup, therefore you will get considerably longer runtimes from a 6S setup of the same Mah as the 4s setup. Also, Amperage generates heat, so the 6s setup will run cooler than the 4S.
What would an average runtime be with a 1500kv motor and a 6S 5000MAH pack?
__________________
Losi 8ight 2.0 sirio evoIII
Losi 8ight T 2.0 .21 vpec-t
Associated SC8
Jammin Crt.5 .12 Picco
everyjuangohome is offline   Reply With Quote
Old 03-31-2009, 10:05 AM   #4
Tech Addict
 
crazyjr's Avatar
 
Join Date: Jul 2005
Location: middle georgia
Posts: 613
Default

Quote:
Originally Posted by Billetboy View Post
Your 4S lipos should peak at 16.8 volts, so the guys at the track must have a 5s or something. lipos are 4.2 volts per cell.

Lipos can be charged right after discharge unless they are really hot. You are suppose to let them cool-down to room temp, but I never do, but my packs are never over 100 degrees anyway.

Voltage and Amperage is inversely proportional. More voltage = less amperage. So, Yes, A 6S setup take less mah to do the same work as the 4s setup, therefore you will get considerably longer runtimes from a 6S setup of the same Mah as the 4s setup. Also, Amperage generates heat, so the 6s setup will run cooler than the 4S.
5S packs peak at 21v, so if he is getting 18, he either has an undercharged 5s, or a waaaaaaaay overcharged 4s, either way that's not good.

On the 6s thing, you only get better runtime, if you gear for the same speed as the 4s setup. for instance, if you are geared for 40mph on 4s, you need to re-gear for 40 on the 6s to see any real improvement in runtime
crazyjr is offline   Reply With Quote
Old 03-31-2009, 10:07 AM   #5
Tech Regular
 
Billetboy's Avatar
 
Join Date: Apr 2008
Posts: 319
Trader Rating: 49 (100%+)
Default

Not sure, I run 5S on a 1700kv Neu and I get 26 minutes on 5000mah
Billetboy is offline   Reply With Quote
Old 03-31-2009, 11:05 AM   #6
Tech Elite
 
y2kgtp's Avatar
 
Join Date: Sep 2008
Location: Deltona, FL
Posts: 2,559
Trader Rating: 35 (100%+)
Send a message via AIM to y2kgtp Send a message via Yahoo to y2kgtp
Default

Quote:
Originally Posted by Billetboy View Post
Your 4S lipos should peak at 16.8 volts, so the guys at the track must have a 5s or something. lipos are 4.2 volts per cell.
I thought they were 3.7V per cell?
__________________
"Yes my car is technically illegal, but still its either just as fast or slower than any other car on the track so whats the issue with it being illegal?"
y2kgtp is offline   Reply With Quote
Old 03-31-2009, 11:19 AM   #7
Tech Champion
 
Jason Pelletier's Avatar
 
Join Date: Jul 2007
Location: New York
Posts: 8,820
Trader Rating: 33 (100%+)
Default

#1 myth is that noobs think to run lipo you need brushless.
__________________
Island Raceway & Hobby
Jason Pelletier is offline   Reply With Quote
Old 03-31-2009, 12:10 PM   #8
Tech Lord
 
Join Date: Jul 2008
Location: Houston, TX
Posts: 11,530
Trader Rating: 21 (100%+)
Default

Quote:
Originally Posted by y2kgtp View Post
I thought they were 3.7V per cell?
Lipo "nominal" voltage is 3.7v/cell. Max voltage is 4.2v/c, minimun voltage is around 3v/c. Nominal voltage is supposed to be the voltage the lipo will hold when its discharged.
Duster_360 is offline   Reply With Quote
Old 03-31-2009, 12:33 PM   #9
Tech Fanatic
 
Heavy B's Avatar
 
Join Date: Jan 2006
Location: Lincoln, NE
Posts: 857
Trader Rating: 18 (100%+)
Default

Quote:
Originally Posted by y2kgtp View Post
I thought they were 3.7V per cell?

Yes, but when charging the peak voltage is 4.2v per cell.
__________________
Brian Bernt
2013 9th Annual HobbyPLEX Enduro Open Class Co-Champion
2011 ROAR Region 8 Mod 2wd SCT Champion
2010 & 2007 Summer Series at the Plex Modified 2wd Buggy Champion
2009 Summer Series at the Plex Modified 2wd Stadium Truck Champion
Heavy B is offline   Reply With Quote
Old 03-31-2009, 12:34 PM   #10
Tech Elite
 
y2kgtp's Avatar
 
Join Date: Sep 2008
Location: Deltona, FL
Posts: 2,559
Trader Rating: 35 (100%+)
Send a message via AIM to y2kgtp Send a message via Yahoo to y2kgtp
Default

Quote:
Originally Posted by RB FIVE View Post
#1 myth is that noobs think to run lipo you need brushless.
you just like to use the word N(.)(.)bs....
__________________
"Yes my car is technically illegal, but still its either just as fast or slower than any other car on the track so whats the issue with it being illegal?"
y2kgtp is offline   Reply With Quote
Old 03-31-2009, 02:14 PM   #11
Tech Fanatic
 
Join Date: Oct 2008
Posts: 946
Trader Rating: 46 (98%+)
Default

Quote:
Originally Posted by Billetboy View Post
Not sure, I run 5S on a 1700kv Neu and I get 26 minutes on 5000mah
26mins? That is a really long runtime. What are your motor and ESC temp's after 26mins of straight running.
__________________
Losi 8ight 2.0 sirio evoIII
Losi 8ight T 2.0 .21 vpec-t
Associated SC8
Jammin Crt.5 .12 Picco
everyjuangohome 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 06:35 AM.


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