R/C Tech Forums

Go Back   R/C Tech Forums > General Forums > Rookie Zone

Reply
 
Thread Tools Search this Thread
Old 11-21-2009, 11:18 AM   #1
Moderator
 
roadrashracing's Avatar
 
Join Date: Nov 2005
Location: Green Bay, Wi
Posts: 12,858
Trader Rating: 76 (100%+)
Default Lipo charge times

right now I have a a 2s 4600 lipo and my charger only charges up to 3 amps. I don't want to get a new charger but would like to get a larger voltage battery. Does a 3s take longer to charge then a 2s with the same mah rating or does the #of cells does not make a difference on charge time.
roadrashracing is offline   Reply With Quote
Old 11-21-2009, 12:11 PM   #2
Tech Lord
 
Join Date: Jul 2008
Location: Houston, TX
Posts: 11,530
Trader Rating: 21 (100%+)
Default

As long as your charger can deliver a 1C charge, charge time won't be any longer for a 2C or 5C lipo. Should be about an hour.

However long your 2S is taking now, should be about same timer for a 3S of the same mah assuming your charger can charge at 3amps for the higher voltage. This is where the chargers power output comes into things - as long as 3amps and 12.6volts (~38watts) is within the chargers output power raticng, it'll charge at 3amps.
Duster_360 is offline   Reply With Quote
Old 11-25-2009, 07:33 AM   #3
Tech Apprentice
 
xnitrorc's Avatar
 
Join Date: Oct 2009
Location: Nottingham
Posts: 90
Send a message via Skype™ to xnitrorc
Default

You can work out charge times of a battery and charger by looking at the mah of the battery that will be written on it and the mah OUTPUT of the charger that will be written on the charger.

Dividing the mah of the battery by the mah of the charger will give the charge time in hours. For example, if the output on the charger was 300mah and the battery was a 650mah then 650 divided by 300 would give 2 hours and 10 minutes.
__________________
Have you got the X in X Nitro RC?
http://www.xnitrorc.co.uk
Schumacher Racing - http://www.xnitrorc.co.uk/~xnitrorc/127-schumacher
xnitrorc is offline   Reply With Quote
Old 11-25-2009, 08:43 AM   #4
Tech Lord
 
Join Date: Jul 2008
Location: Houston, TX
Posts: 11,530
Trader Rating: 21 (100%+)
Default

That works and provides an approx for NiMh or NiCd, but since lipo charging is a two step charge, (CC/CV), it won't be close. I've charged everything from 800mah to 5000mah, 2S to 6S and roughly it takes 45-60min for a significant charge (discharge was+/-80% of capacity).

You can get the same kind of estimate by dividing capacity in mah by the charge rate in millamps (amps x 1000) and get hours for charging. This ignores any capccity left in batt and IR (internal rsistance) of the batt itself.

If you're just topping on off (discharge < 10-20% capcity), charge times ar shorter, but still longer than you'd expect. This shortens the CC part of the charge, but doesn't affect the CV part which is where the most time is taken.
Duster_360 is offline   Reply With Quote
Old 11-26-2009, 10:46 PM   #5
Tech Champion
 
BuggyKing's Avatar
 
Join Date: Oct 2006
Location: Huntington Beach, Ca
Posts: 7,919
Trader Rating: 17 (100%+)
Default

having a good power supply also will help in reducing charge time.
__________________
Our government is a #$%$ joke, from the head jester on down
RIP Mike M
BuggyKing 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 10:12 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