R/C Tech Forums

Go Back   R/C Tech Forums > General Forums > Electric On-Road

Reply
 
Thread Tools Search this Thread
Old 01-30-2012, 04:01 PM   #31
Company Representative
 
Danny/SMC's Avatar
 
Join Date: Oct 2001
Location: Elkton, VA
Posts: 3,097
Trader Rating: 2 (100%+)
Default

Quote:
Originally Posted by COBRARACING View Post
The biggest battery factory for lipos and lifep04's is based in china and uses material imported from japan it is also Government funded with an unlimited budget and some of the best chemical engineers in Asia.

The highest they have reached is 6000mah for a 7.4v 5200mah for a 14.8v and 5500 for a 3.7v and that is from november of last year and a cont racting of 60c

No more comments id let you figure out the rest about others who claim these rediculous ratings we see today .

Have you personally tested a 3000mAh cell at 180amps ? If the info comes from the factory you should do your own tests as I got fooled by the factories claims. I think they understand that very few people have the equipment to test at these high rates so they will claim what they feel will sell more packs.
Danny/SMC is offline   Reply With Quote
Old 01-30-2012, 04:03 PM   #32
Tech Apprentice
 
Join Date: Jan 2011
Posts: 73
Default

I totally agree with you.
Still would it not be useful for the end user to also know the C rating of the assembled pack?
While the C rating of the cells speak lots of the battery's capabilities the rest of the battery should be up to par with proper connectors, wires etc.
taz00 is offline   Reply With Quote
Old 01-30-2012, 04:15 PM   #33
Company Representative
 
Danny/SMC's Avatar
 
Join Date: Oct 2001
Location: Elkton, VA
Posts: 3,097
Trader Rating: 2 (100%+)
Default

The meter we use can give the IR of the pack or the cells in the pack. We will rate the C rate on our own equipment pictured in this thread. C rate will be based on the cells used in the pack. Once we know the IR range of a given cell we can make sure every pack we sell will be withing the IR range. This is way better than just selling packs based on a factories rating and shipping them out as we get them.

The problem with doing C rate for the entire pack is the connector and wires can't handle enough amps without getting to hot.

I personally believe this can be a game changer as the customer will know exactly what he's paying for as each pack will come with the IR of each cell marked inside the packaging.

I'm also considering checking the match of the cells for mAh as I have seen this can also be a problem. Everyone claims there packs are matched but once again are they really matched ?
Danny/SMC is offline   Reply With Quote
Old 01-30-2012, 06:15 PM   #34
Tech Lord
 
wingracer's Avatar
 
Join Date: Nov 2007
Posts: 12,861
Trader Rating: 24 (100%+)
Default

Quote:
Originally Posted by Danny/SMC View Post
Thought some of you might like to see my C rate tester. I'm able to pull over 200 amps with this setup. All tests are done on one single cell.
Nice. Had any good fires with that thing?

Quote:
Originally Posted by Danny/SMC View Post
I'm also considering checking the match of the cells for mAh as I have seen this can also be a problem. Everyone claims there packs are matched but once again are they really matched ?
I'm surprised it took this long for someone to look into it.
__________________
Sean. Certified speed crazed mowron.
Team Shepherd USA
www.ashfordhobby.com
wingracer is offline   Reply With Quote
Old 01-30-2012, 06:22 PM   #35
Tech Champion
 
oXYnary's Avatar
 
Join Date: Dec 2003
Posts: 6,301
Trader Rating: 4 (100%+)
Send a message via AIM to oXYnary Send a message via Yahoo to oXYnary
Default

Quote:
Originally Posted by martymiller View Post
Besides the CE gfx, what meter can measure the IR of a cell. Just curious.

Thanks
http://www.progressiverc.com/esr-meter.html


EDIT: Also in example, the Thunder Power TP820CD charger does, as many other do. Not that new fangled Orion though..
__________________
www.3drcracing.com <<RC Video Game.
Kyosho Mini-Z Buggy, Moto Racer | Losi Micro SCT, 8ight Mini
oXYnary is offline   Reply With Quote
Old 01-30-2012, 08:32 PM   #36
Company Representative
 
Danny/SMC's Avatar
 
Join Date: Oct 2001
Location: Elkton, VA
Posts: 3,097
Trader Rating: 2 (100%+)
Default

No fires to report of yet. When you try a cell at to high of load it just cuts off right away.

I do believe our packs are well matched as I have tested some but with the new rating system I want to push it to another step and check every pack and most likely include a graph showing each cell within the pack.

I do have some graphs on our FB page.
Danny/SMC is offline   Reply With Quote
Old 01-30-2012, 09:39 PM   #37
Tech Master
 
Magnet Top's Avatar
 
Join Date: Dec 2008
Location: Seattle
Posts: 1,966
Trader Rating: 4 (100%+)
Default

Danny,

In my testing internal resistance changes depending on the battery temperature. Will you be providing specifications that include the temperature of the battery when tested ?

Thanks,
Jake D.
Magnet Top is offline   Reply With Quote
Old 01-30-2012, 09:49 PM   #38
Company Representative
 
Danny/SMC's Avatar
 
Join Date: Oct 2001
Location: Elkton, VA
Posts: 3,097
Trader Rating: 2 (100%+)
Default

Yes the complete method that we use will be listed. Unlike the current C rate system that no one lists how they get there results. My goal is to have an accurate system to rate our packs which can be verified by anyone who uses the same meter we do and follows the method we list.
Danny/SMC is offline   Reply With Quote
Old 01-30-2012, 10:35 PM   #39
Tech Regular
 
Join Date: Jan 2002
Posts: 302
Default

Quote:
Originally Posted by COBRARACING View Post
The biggest battery factory for lipos and lifep04's is based in china and uses material imported from japan it is also Government funded with an unlimited budget and some of the best chemical engineers in Asia.

The highest they have reached is 6000mah for a 7.4v 5200mah for a 14.8v and 5500 for a 3.7v and that is from november of last year and a cont racting of 60c.
What are you talking about? What you're saying doesn't make sense.
Nominal voltage for a lipo cell is 3.7V.
3.7V is one cell
7.4V is two cells in series
14.8V is four cells in series
They all can use the same cell, which would have the same capacity. If the highest single cell capacity available is 6000mAH, then putting them in a series would have the same pack capacity (1S, 2S, 4S). There's no distinction between 3.7V, 7.4V, 14.8V.

Last edited by Potato; 01-31-2012 at 12:32 AM. Reason: cell count math fail
Potato is offline   Reply With Quote
Old 01-30-2012, 11:02 PM   #40
Company Representative
 
Danny/SMC's Avatar
 
Join Date: Oct 2001
Location: Elkton, VA
Posts: 3,097
Trader Rating: 2 (100%+)
Default

14.8V is 4 cells in series not 3.

To sell any pack above 5000mAh they need to be built as 2P or higher. Shipping regulations require that no cells be higher than 5000mAh to be considered as a small LiPo and not be classified as class 9 Hazmat shipping.

In the case of a 6000/60C it needs to be 2S2P but you are right where you can use the 3000mAh cells and make a 4S2P to get 14.8V or 3S2P to get 11.1V.
Danny/SMC is offline   Reply With Quote
Old 01-31-2012, 12:25 AM   #41
Tech Addict
 
Matthijs's Avatar
 
Join Date: Sep 2008
Location: Uithoorn, The Netherlands
Posts: 716
Trader Rating: 1 (100%+)
Default

Quote:
Originally Posted by RC MARKET View Post
unknow why they are mark up label C rate ?

in this moment battery factory in China , some material is from Japan ,
can made 60C , around 6500-6800 mah only !

But market had 65C 70C 75C & 90C Now !!
The server from your online store could use some more C...I'll bet loading with 90C will get you more customers instead of the 20C you've got now.....
__________________
Exotek F1R3 // Tamiya TRF101
Matthijs is offline   Reply With Quote
Old 01-31-2012, 12:34 AM   #42
Tech Regular
 
Join Date: Jan 2002
Posts: 302
Default

Quote:
Originally Posted by Danny/SMC View Post
14.8V is 4 cells in series not 3.

To sell any pack above 5000mAh they need to be built as 2P or higher. Shipping regulations require that no cells be higher than 5000mAh to be considered as a small LiPo and not be classified as class 9 Hazmat shipping.

In the case of a 6000/60C it needs to be 2S2P but you are right where you can use the 3000mAh cells and make a 4S2P to get 14.8V or 3S2P to get 11.1V.
You're right, I fixed my post. I just didn't understand that post. There are two parts, one is an issue of cell chemistry (C-rate), the other is a matter of pack configuration.
Potato is offline   Reply With Quote
Old 01-31-2012, 01:15 AM   #43
Tech Master
 
Magnet Top's Avatar
 
Join Date: Dec 2008
Location: Seattle
Posts: 1,966
Trader Rating: 4 (100%+)
Default

Quote:
Originally Posted by Matthijs View Post
The server from your online store could use some more C...I'll bet loading with 90C will get you more customers instead of the 20C you've got now.....
lol !

Not to hijack the thread... but yeah, I believe that RC Market has the slowest web "server" in the world. I'm not even joking. They have a lot of stuff but glacial performance !

it probably runs on a 1200 baud modem !
Magnet Top is offline   Reply With Quote
Old 01-31-2012, 02:05 AM   #44
Tech Fanatic
 
daleburr's Avatar
 
Join Date: May 2010
Location: Oxfordshire, UK
Posts: 862
Default

Quote:
Originally Posted by Magnet Top View Post
lol !

Not to hijack the thread... but yeah, I believe that RC Market has the slowest web "server" in the world. I'm not even joking. They have a lot of stuff but glacial performance !

it probably runs on a 1200 baud modem !
Wo...rst we...b...si...te e...ver
__________________
Team Xray
RC-Timing Software - http://www.rc-timing.com
Mercedes AMG F1 - http://www.mercedes-amg-f1.com/
daleburr is offline   Reply With Quote
Old 01-31-2012, 02:34 AM   #45
Tech Champion
 
RC MARKET's Avatar
 
Join Date: Feb 2007
Location: HK
Posts: 6,172
Trader Rating: 12 (100%+)
Default

Quote:
Originally Posted by Matthijs View Post
The server from your online store could use some more C...I'll bet loading with 90C will get you more customers instead of the 20C you've got now.....
We not have 90C battery to sale !
but saw why too many co. mark up C Rate to sale !
RC MARKET is offline   Reply With Quote
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
(WTS)EXtra Unit Vista Power EV-622A 10A C 5A D&Giant Power 7.4V 5200 50C Hardcase Lip sangyi41 Malaysian Forsale-Trade 12 06-27-2011 01:12 PM
Thunder Power Rc 40C 5000 Lipo ThunderPowerRC Electric On-Road 439 02-25-2010 04:35 PM
C Rating battery craze! True or untrue!! Bulldawg RC Electric Off-Road 236 03-11-2009 01:44 PM



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 10:48 PM.


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