Go Back  RCU Forums > RC Helicopters > Electric RC Helis > Helimax
Reload this Page >

!!HELP!! lipos & chargers !! OH MY!!

Notices
Helimax This is for all your Helimax questions and comments.

!!HELP!! lipos & chargers !! OH MY!!

Old 03-16-2007, 12:21 PM
  #1  
javiwood
Junior Member
Thread Starter
 
Join Date: Jun 2006
Location: rock island, IL
Posts: 9
Likes: 0
Received 0 Likes on 0 Posts
Default !!HELP!! lipos & chargers !! OH MY!!

can some one help me understand how lipos and chargers work? ive been looking at the duratrax ice and the orion charger. but they dont look like they just plug in to the wall?? im lost ihave a pirahna peak charger for my truxs & bugs. but i dont know anything about lipos and the chargers. can someone give advice on how they work and the best buy for my $$, and whats the best way to go for my helimax axe cp. thanks all!![sm=confused.gif]
Old 03-16-2007, 02:58 PM
  #2  
hobbimaster
Senior Member
 
Join Date: Feb 2005
Location: west palm beach, FL
Posts: 244
Likes: 0
Received 0 Likes on 0 Posts
Default RE: !!HELP!! lipos & chargers !! OH MY!!

Honestly, there's nothing to fear. The lipo's must be charged by a lipo charger at 1C. what that means is if you have a 1000MaH pack you can chage at 1 amp, a 2000MaH pack at 2 amps ect. Basically instead of the usual 3X the capacity of a NiMh, you only go 1X the capacity for a lipo. As for chargers I use 2 ice chargers set up to do my transmitters, RX packs, glow igniter, lipos and, NiMh packs. its the best bang for the buck! All my packs are Thunder power, most 3 cells (11.1), and some 2 cell orion (7.4v) for my onroad cars. I have a Thunder power 1320Mah in my axe CP and if flies wonderfly. Its a little longer than the stock pack, but a few rubber bands will hold it in place just fine. Check your LHS to see what they have in stock, the ice runs around $120-$130, and the lipo's around $50.
Old 03-16-2007, 10:26 PM
  #3  
VBDave
Member
 
Join Date: Jan 2007
Location: Virginia Beach, VA
Posts: 50
Likes: 0
Received 0 Likes on 0 Posts
Default RE: !!HELP!! lipos & chargers !! OH MY!!

What C rating LiPo's does the stock Axe CP need anyway?
Old 03-16-2007, 11:04 PM
  #4  
Heliko
Senior Member
 
Heliko's Avatar
 
Join Date: Jan 2007
Location: Colorado Springs, CO
Posts: 591
Likes: 0
Received 0 Likes on 0 Posts
Default RE: !!HELP!! lipos & chargers !! OH MY!!

ORIGINAL: VBDave

What C rating LiPo's does the stock Axe CP need anyway?
I'm not sure that question has a direct answer. This is what I do know. I took volt and amp readings on both motors. I did this in an effort to come to some common ground between brushed and brushless motors.

I took these readings at maximum load. I increased the throttle to just before the blades reached critical angle of attack on the main motor and used right full rudder on the tail motor.
Here's what I found:
At 9.92 volts the main motor draws 11 amps which equals 109.12 watts.

At 9.1 volts the tail motor draws 2.4 amps which equals 21.84 watts.

That's 13.4 amps altogether.

I use 11.1v, 1350ma DN Power Li-Po's with a 15C rating. This means it's safe continuous discharge current is 20.25 amps.

Helimax recommends the Electrifly 11.1v, 910ma Li-Po with a 15C rating, but it's safe continuous discharge current is 13.65 amps.

I've also heard of someone using a battery with an 8C rating, but I believe it was 11.1v, 2100ma Li-Po which despite the 8C rating gives it a safe continuous discharge rate of 16.8 amps.

The best answer I can give is do the math and make sure the batteries discharge rate is 13.4 or better. I would say that the Electrifly's 13.65 CDA would be the minimum so you can allow at least a small safety margin.

BTW to find out the current discharge rate take the Li-Po milliamp rating and turn it in to amps (to turn milliamps into amps move the decimal point 3 spaces to the left) then multiply it by the "C" rating.

Here's the equation:
(ma x .001) x C rating= Continuous Discharge Amperage

Here's an example:
My DN Power 11.1v, 1350ma 15C Li-Po
(1350 x .001) x 15= 20.25

Hope this answers your question.
Old 03-17-2007, 02:30 AM
  #5  
VBDave
Member
 
Join Date: Jan 2007
Location: Virginia Beach, VA
Posts: 50
Likes: 0
Received 0 Likes on 0 Posts
Default RE: !!HELP!! lipos & chargers !! OH MY!!

More than enough info, thank you! Guess I'll just look for 15C packs then...
Old 03-17-2007, 11:14 AM
  #6  
AirforceRcks
Senior Member
 
AirforceRcks's Avatar
 
Join Date: Nov 2005
Location: ABQ, NM
Posts: 257
Likes: 0
Received 0 Likes on 0 Posts
Default RE: !!HELP!! lipos & chargers !! OH MY!!

the thunder power 1320mah lipo is probably your best bet.
lots of people have them and it seems to be the best for it.
Old 03-17-2007, 03:13 PM
  #7  
Heliko
Senior Member
 
Heliko's Avatar
 
Join Date: Jan 2007
Location: Colorado Springs, CO
Posts: 591
Likes: 0
Received 0 Likes on 0 Posts
Default RE: !!HELP!! lipos & chargers !! OH MY!!

ORIGINAL: AirforceRcks

the thunder power 1320mah lipo is probably your best bet.
lots of people have them and it seems to be the best for it.
It's true the TP packs are among the best out there, but they're also expensive. At two-thirds the price DN or Mega Power packs may be slightly heavier, but work really well too.

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 -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.