Giant Scale Aircraft - General Discuss all other giant scale aircraft here.

LiIon batteries

Reply

Old 10-01-2018, 02:46 PM
  #1  
jetmech05
Thread Starter
 
Join Date: Jul 2005
Location: Jacksonville, FL
Posts: 4,853
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default LiIon batteries

For those of you running LiIon batteries when do you charge your flight batteries?
jetmech05 is offline  
Reply With Quote
Old 10-02-2018, 05:45 PM
  #2  
jetmech05
Thread Starter
 
Join Date: Jul 2005
Location: Jacksonville, FL
Posts: 4,853
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default ??

This isnít a fishing deal. Iím curious as to what voltage do you guys recharge LiIon batteries
jetmech05 is offline  
Reply With Quote
Old 10-03-2018, 04:55 AM
  #3  
speedracerntrixie
My Feedback: (29)
 
speedracerntrixie's Avatar
 
Join Date: Jun 2010
Location: Sacramento, CA
Posts: 6,135
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default

No particular voltage. Most will do 2 or 3 flights on a full charge then track how much it takes to bump them up to a full charge. Do this a few times and you can get a fairly accurate estimate of how much current is consumed per flight. This will give you a good idea of how many flights are safe on a charge.
speedracerntrixie is online now  
Reply With Quote
Old 10-06-2018, 08:30 AM
  #4  
BillyJ
 
Join Date: May 2007
Location: Houma, LA
Posts: 90
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default

Duralite charger that comes with packs you cannot charge more than 1 amp through yellow leads on these
BillyJ is offline  
Reply With Quote
Old 10-09-2018, 07:11 AM
  #5  
Appowner
 
Join Date: Nov 2017
Posts: 419
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default

Originally Posted by jetmech05 View Post
This isnít a fishing deal. Iím curious as to what voltage do you guys recharge LiIon batteries
You sure you mean voltage and not amperage?
Appowner is offline  
Reply With Quote
Old 10-09-2018, 10:33 AM
  #6  
speedracerntrixie
My Feedback: (29)
 
speedracerntrixie's Avatar
 
Join Date: Jun 2010
Location: Sacramento, CA
Posts: 6,135
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default

Back in the days of Nicad and Nickel Metal we would charge at a certain voltage due to progressive voltage drop during use. Wonít work with Lithium chemistry due to rapid voltage drop off.
speedracerntrixie is online now  
Reply With Quote
Old 10-09-2018, 10:43 AM
  #7  
krzy4rc
My Feedback: (2)
 
krzy4rc's Avatar
 
Join Date: Jun 2003
Location: LA
Posts: 65
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default

I monitor my consumption and fly to 50% of rated mAh.
krzy4rc is offline  
Reply With Quote
Old 10-10-2018, 04:49 PM
  #8  
CK1
My Feedback: (60)
 
CK1's Avatar
 
Join Date: Apr 2002
Posts: 1,313
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default

I fully charge and fly a 10 minute flight . Recharge to track mA put back in after the 10 minute flight and this gives you the actual mA's used per 10 minute flight . This way I can figure how many 10 minute flights I can get in before reaching the 50% use of pack capacity mark I set before recharging again . 50% gives you a wide safety margin
CK1 is online now  
Reply With Quote
Old 10-10-2018, 05:33 PM
  #9  
jetmech05
Thread Starter
 
Join Date: Jul 2005
Location: Jacksonville, FL
Posts: 4,853
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default Sorry

i guess Iím not making myself clear....at what voltage of the pack do you recharge. Iíve been using 7.1 volts under 1 amp load I recharge. But then if youíre at 7.4 volts before first flight do you go ahead and charge?
This is a curiosity thing just wondered what you all are doing
jetmech05 is offline  
Reply With Quote
Old 10-10-2018, 06:06 PM
  #10  
speedracerntrixie
My Feedback: (29)
 
speedracerntrixie's Avatar
 
Join Date: Jun 2010
Location: Sacramento, CA
Posts: 6,135
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default

I thought you were quite clear. Perhaps it is us that are not being clear. Charging any lithium based batteries based on voltage is a bad idea! The voltage drop off as the battery reaches the end of its capacity is very steep and it is not a good indicator of how much capacity it left. To know how much capacity is left you need to figure how much is being used. That is why a few of us suggested you do a couple flights on a fully charged battery and take note of how many ma it takes to top off the battery. That information can be used to determine how many safe flights you can do between charges.
speedracerntrixie is online now  
Reply With Quote
Old 10-10-2018, 06:20 PM
  #11  
CK1
My Feedback: (60)
 
CK1's Avatar
 
Join Date: Apr 2002
Posts: 1,313
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default

Using your method I would stay with the 7.1v cut off point and definetly go no lower than 7.0v before recharging. I would also always top off before the first flight of the day regardless of voltage drop if using your method . If using the method in my previous post I would have more confidence of the residual capacity in the pack . Reading a voltage drop in my opinion isn't as informative as knowing the calculated mA capacity remaining based on previous useage data .
CK1 is online now  
Reply With Quote
Old 10-14-2018, 04:32 AM
  #12  
dhal22
 
Join Date: Aug 2006
Location: Roswell, GA
Posts: 5,586
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default

I know very little about battery chemistries but the above recommendations work for me. My larger planes use two 5200 mah Fromeco batteries (plus ignition on some) and I burn 300 mah or so per battery per flight. Or so the charger says after refilling the batteries.
dhal22 is offline  
Reply With Quote

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


Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service