R/C Tech Forums

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

Reply
 
Thread Tools Search this Thread
Old 02-19-2008, 08:06 AM   #106
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

We appreciate you being a guinea pig. But I really hope your taking precautions with doing all that. Sounds extremely dangerous.

What about using a heat lamp over a salad bowl wrapped in aluminum foil with a grill placed on top. Put the lipo on the grill. Maybe use a small fan just to move the hot air around more evenly.

At least then you can watch it out in the open. Plus allowing another experiment. Keeping it hot while charging.
oXYnary is offline   Reply With Quote
Old 02-19-2008, 08:11 AM   #107
Tech Elite
 
glassdoctor's Avatar
 
Join Date: Aug 2006
Posts: 2,250
Trader Rating: 4 (100%+)
Default

Danny we told you so, LOL.

Anyway... IMO 180*F+ is too hot by anyone's standards. You need to do some research into what the mfg state about max temps and safety etc. I agree that it's ok to get them warm... there must be a limit. I will bet that the performance will continue to improve right up until the battery goes nuclear. But that doesn't mean it's ok to push it that far.... at some point it becomes grossly irresponsible for a guy to do, and especially for a mfg/reseller to recommend. So we might be right back to where the other thread went if we aren't careful.

BTW, I tried to tell you I have a lipo-warmer that would help... and it won't get to irresponsible temps like 180-190... it maxes out around 140-150*

But I would recommend and be happy with @100-120 range for good performance without hurting the pack.

Dustin
glassdoctor is offline   Reply With Quote
Old 02-19-2008, 09:19 AM   #108
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 or8ital View Post
Danny, could you post some avg laptimes based on your charging methods and vs other packs on back to back runs? Unfortunately my charging #'s dont win me prizes Id like to see how your packs can help me on the track.
Once again please read some of my posts. My info is only for those who are looking for the best performance out of there packs and can actually benefit from a pack that runs at its best. If your not one of those then don't worry about all of this and just keep repeaking your Lipos and enjoy RC.

I have many years of racing experience and have been matching cells for many years as well and I know how racers are always looking for that little extra. My concerns about Lipos not being any simplier than NiMh seems to be correct.
Danny/SMC is offline   Reply With Quote
Old 02-19-2008, 09:27 AM   #109
Tech Champion
 
Join Date: Oct 2005
Location: Cincinnati, OH
Posts: 5,360
Trader Rating: 38 (100%+)
Default

Quote:
Originally Posted by Danny/SMC View Post
Once again please read some of my posts. My info is only for those who are looking for the best performance out of there packs and can actually benefit from a pack that runs at its best. If your not one of those then don't worry about all of this and just keep repeaking your Lipos and enjoy RC.

I have many years of racing experience and have been matching cells for many years as well and I know how racers are always looking for that little extra. My concerns about Lipos not being any simplier than NiMh seems to be correct.
What is your judge of "best performane"? Certain #'s on a charger or laptimes? I judge performance on the track. Thats what Im trying to determine. Best Performance pack/methods for racing. If there was a contest on battery #'s then it sounds like you win. I want to know if that translate on the track.
or8ital is offline   Reply With Quote
Old 02-19-2008, 09:32 AM   #110
Tech Master
 
billjacobs's Avatar
 
Join Date: Sep 2004
Location: Rockville, MD
Posts: 1,264
Trader Rating: 54 (100%+)
Default warming LIPO's

Putting a lipo in an oven or on a heating pad just seems too slow. Have you tried putting the LIPO into a microwave???

We need exact times to heat up the pack, and the point at which the pack catches fire.

This is important to try, because we all know that pushing the extra .03v out of a pack makes all the difference in the world when racing. Race results can't possibly be largely based on driver skill, or else 1/2 the r/c industry would be out of business.

Keep up the good work. Oh, and by the way, the best charger for lipo is the fma scorpian charger, the only true balance charger on the market (doesn't bleed balance like every other balance charger.) And it's only $70.
billjacobs is offline   Reply With Quote
Old 02-19-2008, 10:02 AM   #111
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

Umm Bill.. You ever put metal in a microwave?

EDIT:
I'm wondering for the electric gurus out there. Would a series of infrared leds put out enough heat to warm a pack to 150 degrees or so? Say like in a small box with a entire inner surface covered in infrared leds.

If that would be possible, that could be something easy to port and power at the track.
oXYnary is offline   Reply With Quote
Old 02-19-2008, 10:03 AM   #112
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 glassdoctor View Post
Danny we told you so, LOL.

Anyway... IMO 180*F+ is too hot by anyone's standards. You need to do some research into what the mfg state about max temps and safety etc. I agree that it's ok to get them warm... there must be a limit. I will bet that the performance will continue to improve right up until the battery goes nuclear. But that doesn't mean it's ok to push it that far.... at some point it becomes grossly irresponsible for a guy to do, and especially for a mfg/reseller to recommend. So we might be right back to where the other thread went if we aren't careful.

BTW, I tried to tell you I have a lipo-warmer that would help... and it won't get to irresponsible temps like 180-190... it maxes out around 140-150*

But I would recommend and be happy with @100-120 range for good performance without hurting the pack.

Dustin

Please don't attempt any of the tests I'm performing or use a charge rate higher than 1C. Never warmup your Lipo packs. Doing any of this can result in a fire and can be dangerous


Just because I'm doing some tests to actually figure out what helps and doesn't help doesn't mean I reccomend this but I do feel I can post my findings.

Some of you have stated that charging any higher than 1C will not yield any benefits. I did some tests and posted the results which seem to prove that a higher charge rate helps.

Then some said that if you get the pack warm/hot prior to charging it the results would be the same as charging it back up immediately after a 35 amp discharge cycle. This was correct but I decided to push the temp up and got better results.

So now we know that a 35 amp discharger is not necessary but I still feel it's the easiest way to get the temp up especially considering that your sure the inside of the cells/pack will be warm/hot by doing this.


After doing all these tests if I would be attending a Lipo race and wanted to extract the most out of my Lipos I would charge at 12 amps and get the pack to be atleast 140 degrees before I charge it back up. This can be done by using some kind of heating device or by discharging a fully charged pack at 35 amps.

Last edited by Danny/SMC; 02-19-2008 at 11:29 AM.
Danny/SMC is offline   Reply With Quote
Old 02-19-2008, 10:05 AM   #113
Tech Fanatic
 
Join Date: Jun 2007
Location: Adrian, MI
Posts: 823
Trader Rating: 1 (100%+)
Default

Danny...... or anybody

Is it possible that ??... If there is any change in the resistance in the load (IR of battery) on any volt meter.... Will you get different volt readings ??

What would happen if all volt readings were done with the volt meter at the same temperature as the battery as in the first volt readings ??

I am trying to understand how accurate all these readings are.

I hope you can understand what i am trying to ask you
Lazer Guy is offline   Reply With Quote
Old 02-19-2008, 10:12 AM   #114
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 or8ital View Post
What is your judge of "best performane"? Certain #'s on a charger or laptimes? I judge performance on the track. Thats what Im trying to determine. Best Performance pack/methods for racing. If there was a contest on battery #'s then it sounds like you win. I want to know if that translate on the track.

Racers have been using a T35 for years now and when a pack gives better results on a GFX it gives better results on the track. It may not be a huge improvement but trust me when the hardcore racers start using Lipos they will want to have any advantage even if it's a small one.

When I was at the Snowbirds you should of seen how many racers were bringing over multiple Brushless rotors and cans to the Novak pits to have the rotors gaussed out and the cans measured for IR to try and build the best possible BL motor. That is just the nature of the hardcore racer and that is in every type of racing not only RC racing.
Danny/SMC is offline   Reply With Quote
Old 02-19-2008, 10:17 AM   #115
Company Representative
 
Danny/SMC's Avatar
 
Join Date: Oct 2001
Location: Elkton, VA
Posts: 3,097
Trader Rating: 2 (100%+)
Default

Bill Jacobs: As I have to prove everything I say on this message board I would like you to show me your test results that claim the FMA charger is the best charger for RC car racing ?
Danny/SMC is offline   Reply With Quote
Old 02-19-2008, 10:19 AM   #116
Tech Champion
 
Join Date: Oct 2005
Location: Cincinnati, OH
Posts: 5,360
Trader Rating: 38 (100%+)
Default

Quote:
Originally Posted by Danny/SMC View Post
Racers have been using a T35 for years now and when a pack gives better results on a GFX it gives better results on the track. It may not be a huge improvement but trust me when the hardcore racers start using Lipos they will want to have any advantage even if it's a small one.

When I was at the Snowbirds you should of seen how many racers were bringing over multiple Brushless rotors and cans to the Novak pits to have the rotors gaussed out and the cans measured for IR to try and build the best possible BL motor. That is just the nature of the hardcore racer and that is in every type of racing not only RC racing.
Yes the battery is one of many items that determine performance. As you have said multiple times things are new with lipo as you are learning. Such as the C rating having a possible impact on performance. Brushless is new too. As we have seen you cant always apply an old way of thinking to these new technologies. Now what Im trying to determine is if your pack is .01 faster on a 10 second lap in general vs a Orion 3600 or is .1 faster. Or is it -gasp- slower. The charger #'s dont give me this info. I dont really want to invest in every brand to see which is best on the track. Not trying to be a thorn. Just saying thats how I want to base my decision (Ive sold all my lipo packs so Im shopping again).
or8ital is offline   Reply With Quote
Old 02-19-2008, 10:20 AM   #117
Company Representative
 
Danny/SMC's Avatar
 
Join Date: Oct 2001
Location: Elkton, VA
Posts: 3,097
Trader Rating: 2 (100%+)
Default

Lazer Guy: Not sure what your getting at ?

A GFX will charge the pack until it peaks then it will go into a discharge which you set the amp rate. It can go up to 35 amps which is what I use. The discharge will be a constant discharge from full charge to 6 volts then it will stop. You will then have the packs discharge time in seconds and mAh , average voltage and the packs internal resistance.
Danny/SMC is offline   Reply With Quote
Old 02-19-2008, 10:27 AM   #118
Company Representative
 
Danny/SMC's Avatar
 
Join Date: Oct 2001
Location: Elkton, VA
Posts: 3,097
Trader Rating: 2 (100%+)
Default

or8ital; Our 22C pack has been tested on the track and is faster than the Orion packs in actual laptimes. The test was done with an Orion 4800.

I did test a 3600 pack and the average voltage and IR was not really better than the 4800.

Our new 28C packs have a better average voltage than our 22C pack and the IR is 4 milliohms lower. Once again this is the info were getting on a GFX which should translate to better laptimes. If it doesn't then we just spent money on tooling and better materials for nothing.
Danny/SMC is offline   Reply With Quote
Old 02-19-2008, 10:35 AM   #119
Tech Lord
 
syndr0me's Avatar
 
Join Date: Dec 2004
Location: 5280 Raceway
Posts: 13,140
Trader Rating: 32 (100%+)
Default

Danny, with your higher charge rates, are you certain the "benefit" you're seeing isn't also due to increased temperature in the cells? There is a lot of hard data to prove that anything above 1C is deeply detrimental to cell life, and can possibly lead to degradation in the cells that would make them more prone to fire. I know you say your cells can handle it, but you really should do some long-term testing and let people also know how it affects other aspects of the battery's life. I know some guys don't care, because they get packs for free, but for the rest of the world, knowing the potentially severe drawbacks to 3C charging would be useful. You're kind of throwing the advice out there like it's no big deal, but the effects are cumulative, not instant. How about doing 50 3C cycles compared to 50 1C cycles, and showing us how things like voltage and capacity hold up over time.

My understanding is that some LiPo manufacturers won't even sell you their batteries (to re-sell) if they don't feel comfortable with how you're using them. How does your supplier feel about recommending 3C charging? Are they okay with that? Have they told you it's "no problem?" And why don't they have a web page? Doesn't China have the internets yet?
syndr0me is offline   Reply With Quote
Old 02-19-2008, 10:38 AM   #120
Tech Master
 
jag88's Avatar
 
Join Date: Nov 2003
Posts: 1,075
Trader Rating: 1 (100%+)
Default

I'm wondering why you haven't been balancing your packs in any of your tests ? Is the life of the pack cut so short that balancing isn't an issue?
jag88 is offline   Reply With Quote
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
* * * BRAND NEW * * * FTB4, SMC 5000 28c Hardcase 7.4 Lipo, JR Z8800s jpeck R/C Items: For Sale/Trade 12 10-26-2008 04:03 AM
FOR SALE: SMC 4000 28C HARDCASE LIPO'S commander Australia For Sale/Trade 4 10-20-2008 11:08 AM
SMC 4000 mah Hardcase Lipos 28C NIB rraden R/C Items: For Sale/Trade 11 09-12-2008 11:20 AM
SMC 28C 4000 hardcase lipo fred kellner R/C Items: For Sale/Trade 0 04-09-2008 08:31 AM
New SMC Lipos 7.4v 2s 4000 and 5000mah HardCase IOwNMkeG R/C Items: For Sale/Trade 4 03-30-2008 01:54 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 12:05 AM.


Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net