R/C Tech Forums

Go Back   R/C Tech Forums > International Forums > Australian Racing

Reply
 
Thread Tools Search this Thread
Old 02-19-2009, 04:25 PM   #1
Tech Apprentice
 
Join Date: Jan 2009
Location: Sydney
Posts: 63
Default Lipo Low Voltage Cut-off

Hi,

I just got my first brushless system (Hobbywing 35A ESC & 3000kV Motor) and 3200mah 20C Lipo pack. The ESC come by default with no LVC protection but can be set from 2.6V to 3.4V /cell. I'm thinking of setting it to 3V /cell, as I dont want to kill the Lipo, is this to low? is most of the capacity gone already @ 3V? Or under high load will the voltage drop cause the esc to cut out if I set it to 3V?

What do other with the same combo set the LVC at?

Regards

Ric

Last edited by Ricardo40; 03-26-2009 at 01:55 PM.
Ricardo40 is offline   Reply With Quote
Old 02-19-2009, 04:57 PM   #2
Tech Elite
 
lookieaefanboi's Avatar
 
Join Date: Jan 2009
Location: Touring Japan baby!
Posts: 2,848
Trader Rating: 31 (100%+)
Default lipo cutoff

Lipos die if lowered to below 6v I would recommend setting the cutoff higher say around 6.8v.
__________________
Associated T4.1, Tamiya Mini M05 fully hopped up, Atomic VMII Lipo and Serpent S411 2.0 x 2 ;) All Powered by Team Orion,Hobbywing, Futaba, Savox, Fantom and Team Powers :)
lookieaefanboi is offline   Reply With Quote
Old 02-19-2009, 05:02 PM   #3
Tech Fanatic
 
RaZz0R's Avatar
 
Join Date: Oct 2008
Posts: 766
Trader Rating: 12 (100%+)
Default

I set mine to 3.2 per cell - had it cut off & on charge the correct amount of Mah was put back in so I figured its about right, thats for a 25c 3800 IP lipo. so thats 6.4v in total.

But I guess it depends on the esc as to what options you have
__________________
All toys going - left wrist going under the knife
RaZz0R is offline   Reply With Quote
Old 02-19-2009, 05:04 PM   #4
Tech Apprentice
 
Join Date: Jan 2009
Location: Sydney
Posts: 63
Default

Quote:
Originally Posted by lookieaefanboi View Post
Lipos die if lowered to below 6v I would recommend setting the cutoff higher say around 6.8v.
Thanks, I'll set it to 3.4V /cell and see if I get any problems with voltage drop under load.

Ric
Ricardo40 is offline   Reply With Quote
Old 02-20-2009, 05:53 PM   #5
Tech Elite
 
Drifting101's Avatar
 
Join Date: Oct 2007
Location: Melbourne, Aus
Posts: 2,199
Trader Rating: 8 (100%+)
Default

Quote:
Originally Posted by lookieaefanboi View Post
Lipos die if lowered to below 6v I would recommend setting the cutoff higher say around 6.8v.
5.4v is absolute cut off, 6v is just to make shore that the cheap ones are ok

Dad took his down to 5.6v touched it to a car battery and it is fine
__________________
::Mi4::17.5::::::M03R::HW 3000kv::::::T4::7.5::::::HB Cyclone D4::5.5::

"Why follow, when you can lead?"
Schumacher
Drifting101 is offline   Reply With Quote
Old 02-21-2009, 10:15 AM   #6
Tech Regular
 
MattWebb's Avatar
 
Join Date: Jan 2006
Location: Perth, Western Australia
Posts: 320
Trader Rating: 3 (100%+)
Default

Quote:
Originally Posted by Drifting101 View Post
5.4v is absolute cut off, 6v is just to make shore that the cheap ones are ok

Dad took his down to 5.6v touched it to a car battery and it is fine

He did what?
And this worked?
Could you go into more detail?
__________________
www.teamadrenaline.net - your home for West Australia r/c race results and gossip
MattWebb is offline   Reply With Quote
Old 03-03-2009, 05:13 PM   #7
Tech Initiate
 
Jack Gibson's Avatar
 
Join Date: Mar 2009
Posts: 24
Default

Quote:
Lipos die if lowered to below 6v I would recommend setting the cutoff higher say around 6.8v.
Comments from the Super Coach...
__________________
The Original Super Coach - impersonators will be punished!
Jack Gibson is offline   Reply With Quote
Old 03-03-2009, 08:01 PM   #8
Tech Regular
 
Number09's Avatar
 
Join Date: Jun 2008
Location: Adelaide
Posts: 302
Trader Rating: 8 (100%+)
Default

Quote:
Originally Posted by MattWebb View Post
He did what?
And this worked?
Could you go into more detail?
I have accidentally dropped a lipo to 5.9 volts, which meant my charger wouldn't charge it, so I put it on charge on nicd mode at 1 amp for 5 seconds, and that was enough to bump it over 6 volts so it could charge normally in lipo mode. Obviously I DONT RECOMMEND IT THOUGH
Quote:
Originally Posted by Drifting101 View Post
5.4v is absolute cut off, 6v is just to make shore that the cheap ones are ok

Dad took his down to 5.6v touched it to a car battery and it is fine

Touching it on a car battery is absolutely nuts!!! Does'nt he have any lipo knowledge???
__________________
I am in fact a very humble person. I am WAY more humble than anyone. Help me spread the word
Number09 is offline   Reply With Quote
Old 03-04-2009, 04:57 AM   #9
Tech Regular
 
Join Date: Nov 2008
Posts: 331
Trader Rating: 21 (100%+)
Default

I dropped a lipo to 3.3 volts (yes 2s). Put it on the lowest nicad charging current for 5 seconds charge. Did this about 30-40 times as the charger cut out 5 seconds into the charge saying the battery had an error. Then finally exhaustively reached over 6 volts and was able to charge normally. Damm gtb wasnt set for lipo cut off and I was driving around waiting for it to cutt out. Lipos works fine now, but wont be doing that again.
fastbynature is offline   Reply With Quote
Old 03-04-2009, 03:06 PM   #10
Tech Elite
 
Drifting101's Avatar
 
Join Date: Oct 2007
Location: Melbourne, Aus
Posts: 2,199
Trader Rating: 8 (100%+)
Default

Quote:
Originally Posted by Number09 View Post
I have accidentally dropped a lipo to 5.9 volts, which meant my charger wouldn't charge it, so I put it on charge on nicd mode at 1 amp for 5 seconds, and that was enough to bump it over 6 volts so it could charge normally in lipo mode. Obviously I DONT RECOMMEND IT THOUGH



Touching it on a car battery is absolutely nuts!!! Does'nt he have any lipo knowledge???
Yes I do, should of explained it more it was basically just a spark. I learned this method from some one who assembles them and owns a company that makes them
__________________
::Mi4::17.5::::::M03R::HW 3000kv::::::T4::7.5::::::HB Cyclone D4::5.5::

"Why follow, when you can lead?"
Schumacher
Drifting101 is offline   Reply With Quote
Old 03-05-2009, 12:52 PM   #11
Tech Champion
 
Join Date: Feb 2003
Location: Sydney, Australia
Posts: 5,310
Trader Rating: 1 (100%+)
Default

By touching to a car battery I guess you mean "bumping" up the voltage. I guess if you know what you are doing but I would recommend it. Other wise it will be the 1st thing someone does when their battery won't charge!

Under AARCMCC rules you are required to have a operating lipo cutout of no less than 3.0v per cell (when using a lipo pack). The lower the power you use the higher you should run this as it helps to protect the weaker cells in you pack. I assume by 300k you meant the mini motor (3000kv) which can easily be used at 3.4v per cell. The voltage drop on lipo is rapid at the end of their charge so you only need a low setting if you are loading up the battery (10.5-2.5t motors). Note that no two batteries are the same so one of your two cells in any pack will run out of power before the other.
__________________
Blade: Andro Treiber H 79g AN
FH: Donic Bluefire M3 Max Blk
BH: Donic Bluefire M2 Max Red
Powered by Falco
Dragonfire is offline   Reply With Quote
Old 03-25-2009, 09:34 PM   #12
Tech Rookie
 
Join Date: Mar 2008
Location: Trangie,central west,NSW.
Posts: 7
Default

I had once a lipo that had cut out with the lipo safe set to 6 volts.When i went to re charge the battery,one cell had 2.5volts and the other had 3.5 volts !!!!
I have also had to use the nicad for 5 seconds,10 times in a row trick to get a cell up to the voltage where the charger would charge it on lipo settings.
Lately i have been running NO lipo cutoff,just run `till it stops.If you pull the battery out of the car and try to charge it straight away it won`t charge.But if you wait a few hours or`till the next day the lipo will be back up to 3.5V per cell and it will charge no worries .I know this is definately not recommended but SO FAR no problems.
trangieboy is offline   Reply With Quote
Old 03-25-2009, 09:34 PM   #13
Tech Rookie
 
Join Date: Mar 2008
Location: Trangie,central west,NSW.
Posts: 7
Default

I had once a lipo that had cut out with the lipo safe set to 6 volts.When i went to re charge the battery,one cell had 2.5volts and the other had 3.5 volts !!!!
I have also had to use the nicad for 5 seconds,10 times in a row trick to get a cell up to the voltage where the charger would charge it on lipo settings.
Lately i have been running NO lipo cutoff,just run `till it stops.If you pull the battery out of the car and try to charge it straight away it won`t charge.But if you wait a few hours or`till the next day the lipo will be back up to 3.5V per cell and it will charge no worries .I know this is definitely not recommended but SO FAR no problems.
trangieboy is offline   Reply With Quote
Old 12-27-2011, 06:44 PM   #14
Tech Rookie
 
Join Date: Dec 2011
Posts: 1
Default Lipo Low Voltage Cut-off

Hi, I got for Xmas a HPI Savage flux xs car and a few 2s Lipo. Do you know if this car have a low voltage cut off or I have to install one on it? What would you recommand?

Thanks
MKibanez is offline   Reply With Quote
Old 12-27-2011, 10:04 PM   #15
Tech Regular
 
tazmadman's Avatar
 
Join Date: Jun 2009
Posts: 460
Trader Rating: 14 (100%+)
Default

Quote:
Originally Posted by Drifting101 View Post
5.4v is absolute cut off, 6v is just to make shore that the cheap ones are ok

Dad took his down to 5.6v touched it to a car battery and it is fine
Are you serious my advice to anyone is NEVER do that to do that is totally stupid and if your dad does that i hope he has a good life insurance and car insurance policy that is the most ridiculous and dangerous statement i have heard in a long time that a fast way to give the hobby a bad name

to anyone starting out DO NOT EVER TOUCH A LIPO TO A CAR BATTERY
__________________
Bodies painted by - DSCustom RC Paint ... for Racers ...
Durango DEX210 DEX410V3
tazmadman is offline   Reply With Quote
Sponsored Links
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 -8. It is currently 04:38 PM.



Search Engine Optimization by vBSEO 3.5.0