New Products Flash Sale
Thread Tools
Old Apr 05, 2015, 10:28 AM
dimvasilk is offline
Find More Posts by dimvasilk
Team Hypoxia
dimvasilk's Avatar
United States, OH, Columbus
Joined Sep 2014
352 Posts
Discussion
Help with the switch from LiPo to Li-Ion

I'm planning to make the switch from LiPo to Li-Ion, and I was wondering if somebody could take a look at my plan just in case I missed something.

I was initially planning to use Panasonic NCR18650B's running in a 6s6p configuration, but then I found these batteries on eBay. I'm assuming they have the same discharge rate capabilities (let me know if this isn't something I can assume). I'll be running the quad with 4x Quanum MT Series 5008 335KV Brushless Motors with 17x5.5 props, which according to the product page each have a max amperage draw of 19.2 A. My guess is then that 4x19.2 or 76.8 A is the max amp draw I can see from all four motors. On this video, the man claims to have run the cells at 6A with "no problem". Because I'm running the 6p, 6x6=36 A. So I'd need another 6s6p pack to run in parallel with the other one for a max amperage of 72A, right?

This seems a bit like uncharted territory, so I'd love it if someone could give me some feedback. Thanks!
dimvasilk is offline Find More Posts by dimvasilk
Reply With Quote
Sign up now
to remove ads between posts
Old Apr 05, 2015, 11:38 AM
BigBadDogg is online now
Find More Posts by BigBadDogg
Registered User
BigBadDogg's Avatar
United States, MI, Wyandotte
Joined Dec 2014
834 Posts
you better look at the ebayers rating .. along with what I know those batterys are not 3200mah. more like 600 usable mah at best..purchased several 3000+ mah li-ion cell over past 6 months and none are at or even near 3200mah.. all Fake with small li-ion cell inside jacket filled with sand ..
BigBadDogg is online now Find More Posts by BigBadDogg
Reply With Quote
Old Apr 05, 2015, 12:12 PM
Jinkslynx is online now
Find More Posts by Jinkslynx
Registered User
Norway
Joined Jan 2008
104 Posts
Ecalc is a great tool for this. Here is an example to get you going. Also, Ultrafire batteries are trash.
Jinkslynx is online now Find More Posts by Jinkslynx
Reply With Quote
Old Apr 12, 2015, 11:50 AM
sas87 is offline
Find More Posts by sas87
Registered User
Joined Feb 2015
5 Posts
Ncr18650pf

Maybe you should try the NCR18650PF. They are rated for 10A discharge and internal resistance of less than 35mΩ. I've just bought some cheap ones from:aliexpress tested them to be actually 2700mAh and internal resistance less than 5mOhm. Haven't checked the C rate yet.
sas87 is offline Find More Posts by sas87
Last edited by sas87; Apr 12, 2015 at 02:37 PM.
Reply With Quote
Old Apr 12, 2015, 12:27 PM
hoppy is offline
Find More Posts by hoppy
Space Coast USA
hoppy's Avatar
Space Coast
Joined Oct 2000
21,725 Posts
Quote:
I'm assuming they have the same discharge rate capabilities (let me know if this isn't something I can assume)
Absolutely something you cannot assume.
hoppy is offline Find More Posts by hoppy
Reply With Quote
Old Apr 12, 2015, 03:40 PM
ggcrandall1 is offline
Find More Posts by ggcrandall1
Registered User
ggcrandall1's Avatar
USA, GA, Marietta
Joined Aug 2005
6,806 Posts
Quote:
Originally Posted by dimvasilk View Post
I'm planning to make the switch from LiPo to Li-Ion, and I was wondering if somebody could take a look at my plan just in case I missed something.

I was initially planning to use Panasonic NCR18650B's running in a 6s6p configuration, but then I found these batteries on eBay. I'm assuming they have the same discharge rate capabilities (let me know if this isn't something I can assume). I'll be running the quad with 4x Quanum MT Series 5008 335KV Brushless Motors with 17x5.5 props, which according to the product page each have a max amperage draw of 19.2 A. My guess is then that 4x19.2 or 76.8 A is the max amp draw I can see from all four motors. On this video, the man claims to have run the cells at 6A with "no problem". Because I'm running the 6p, 6x6=36 A. So I'd need another 6s6p pack to run in parallel with the other one for a max amperage of 72A, right?

This seems a bit like uncharted territory, so I'd love it if someone could give me some feedback. Thanks!
I don't understand why you would want to go to LiIon. They are much heavier than LiPo.

Glen
ggcrandall1 is offline Find More Posts by ggcrandall1
Reply With Quote
Old Apr 12, 2015, 05:53 PM
flypaper 2 is offline
Find More Posts by flypaper 2
Canadian Bacon
flypaper 2's Avatar
Kingston, Canada
Joined Jun 2004
14,144 Posts
Discharge rating is the big qualifier. The ones you get in power tools are the ones you want. These are the high discharge as you can see what they're put through. Long time ago when I was playing with them, I tried some that, at the time, I didn't know they were low discharge, Made a pack and put them in a plane and it would do a fast taxi but no where near enough to get off the ground.
They do have quite a voltage drop under load and I found I had to go to 4 cells in place of a 3 cell lipo to get the same performance. Wasn't really worth it having to carry the weight of an extra batt. Went back to lipo for that reason.
Here's a good website where this company out in BC makes them. Trouble is, they won't cell to the general public. I put it up so you can go through the specs that show the different purposes for low discharge and high discharge, sizes, etc.
http://www.molicel.com/ca/about_us.html

Gord
flypaper 2 is offline Find More Posts by flypaper 2
Reply With Quote
Old Apr 12, 2015, 06:46 PM
desertstalker is offline
Find More Posts by desertstalker
Registered User
Australia, VIC, Melbourne
Joined Feb 2010
2,013 Posts
Unless your quad is already very efficient with lipos dont bother.

The extra energy in high density cells is only useful if you can keep the discharge low.

Whats are you using currently for power, how long does it last.
desertstalker is offline Find More Posts by desertstalker
Reply With Quote
Old May 19, 2015, 08:36 AM
dimvasilk is offline
Find More Posts by dimvasilk
Team Hypoxia
dimvasilk's Avatar
United States, OH, Columbus
Joined Sep 2014
352 Posts
Quote:
Originally Posted by desertstalker View Post
Unless your quad is already very efficient with lipos dont bother.

The extra energy in high density cells is only useful if you can keep the discharge low.

Whats are you using currently for power, how long does it last.
I get about 20 minutes on my 5500 mAh. I was thinking about doing long range FPV, but the costs associated with that have currently put the project on the backburner.
dimvasilk is offline Find More Posts by dimvasilk
Reply With Quote
Old May 19, 2015, 08:36 AM
dimvasilk is offline
Find More Posts by dimvasilk
Team Hypoxia
dimvasilk's Avatar
United States, OH, Columbus
Joined Sep 2014
352 Posts
Quote:
Originally Posted by ggcrandall1 View Post
I don't understand why you would want to go to LiIon. They are much heavier than LiPo.

Glen
Higher energy density
dimvasilk is offline Find More Posts by dimvasilk
Reply With Quote
Old May 19, 2015, 08:37 AM
dimvasilk is offline
Find More Posts by dimvasilk
Team Hypoxia
dimvasilk's Avatar
United States, OH, Columbus
Joined Sep 2014
352 Posts
Quote:
Originally Posted by hoppy View Post
Absolutely something you cannot assume.
Okay, thanks!
dimvasilk is offline Find More Posts by dimvasilk
Reply With Quote
Old May 19, 2015, 08:38 AM
dimvasilk is offline
Find More Posts by dimvasilk
Team Hypoxia
dimvasilk's Avatar
United States, OH, Columbus
Joined Sep 2014
352 Posts
Quote:
Originally Posted by sas87 View Post
Maybe you should try the NCR18650PF. They are rated for 10A discharge and internal resistance of less than 35mΩ. I've just bought some cheap ones from:aliexpress tested them to be actually 2700mAh and internal resistance less than 5mOhm. Haven't checked the C rate yet.
Bookmarked. Thanks!
dimvasilk is offline Find More Posts by dimvasilk
Reply With Quote
Old May 19, 2015, 08:39 AM
dimvasilk is offline
Find More Posts by dimvasilk
Team Hypoxia
dimvasilk's Avatar
United States, OH, Columbus
Joined Sep 2014
352 Posts
Quote:
Originally Posted by flypaper 2 View Post
Discharge rating is the big qualifier. The ones you get in power tools are the ones you want. These are the high discharge as you can see what they're put through. Long time ago when I was playing with them, I tried some that, at the time, I didn't know they were low discharge, Made a pack and put them in a plane and it would do a fast taxi but no where near enough to get off the ground.
They do have quite a voltage drop under load and I found I had to go to 4 cells in place of a 3 cell lipo to get the same performance. Wasn't really worth it having to carry the weight of an extra batt. Went back to lipo for that reason.
Here's a good website where this company out in BC makes them. Trouble is, they won't cell to the general public. I put it up so you can go through the specs that show the different purposes for low discharge and high discharge, sizes, etc.
http://www.molicel.com/ca/about_us.html

Gord
Took a look. Thanks!
dimvasilk is offline Find More Posts by dimvasilk
Reply With Quote
Old May 19, 2015, 02:57 PM
abenn is offline
Find More Posts by abenn
Registered User
Letchworth, Great Britain (UK)
Joined Jul 2004
12,744 Posts
Quote:
Originally Posted by dimvasilk View Post
Higher energy density
To me "higher energy density" means more watt-hours per pound of battery weight. That being the case, LiPos beat Li-Ions hands down

I've used A123s -- one type of Li-Ion -- and I'm gradually moving over to LiPos to get longer flight durations. For example, a model that used to use a 5S A123 pack (2,300mAh, 16.5v nominal) now uses a 4S 3200mAh LiPo that weighs exactly the same. So that's a nominal 37.95 watt-hours for the A123 and nominal 47.36 watt-hours for the same-weight LiPo -- an increase of 25%. In practice I actually get 50% longer flights because of the fully charged voltages being greater.
abenn is offline Find More Posts by abenn
Reply With Quote
Old May 19, 2015, 04:06 PM
Race Miata is online now
Find More Posts by Race Miata
Registered User
Race Miata's Avatar
Vancouver, Canada
Joined Nov 2004
538 Posts
Exactly! For equivalent discharge rating, Lipo packs more energy per weight than LiIo. What tricks someone think otherwise is most likely because of lower discharge rating (real rating not manufacturer's rating) packs because they will be smaller and lighter regardless of the chemistry.
Race Miata is online now Find More Posts by Race Miata
Reply With Quote


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion How to build battery pack from li-ion Panasonic royalakshay Batteries and Chargers 18 Mar 22, 2015 12:56 PM
Discussion BMS for li ion and li mag?? Help out Wa7sh Batteries and Chargers 5 Feb 12, 2015 01:44 PM
Discussion can i charge Li--ion with max in lipo mood paktazh Batteries and Chargers 1 Aug 16, 2014 07:14 AM
Discussion can i charge Li--ion with max in lipo mood paktazh Batteries and Chargers 0 Aug 16, 2014 12:51 AM
Data The accurate flight time cutoff to know when switching LiPos --> Li-ions is optimal FilmedAboveWater Multirotor Talk 9 May 25, 2014 02:34 PM