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Old 04-07-2013, 09:14 AM   #106
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Originally Posted by MC112b View Post
I think we're reaching the upper limit of practicality. We will be needing 36v or 48v systems in a few years.
How many of these 24v 1400w systems will your race facility's 15A electric services going to support? Voltage will have to go up to keep the current down.
If you are talking about rc cars where 2S and 4S packs are used, 12V and 24V power supplies is all you need. Race track electrical services are fine.

It is the heli and planes that are using 12S (6S x 2) and 14S (7S x 2) that are charging parallel on the PowerLabs that need that higher input voltage for the high cell counts. A single 3D heli flight on a 12S pack will last only 5min or less, thus the need for parallel charging of large packs at fast times.

Here is a guy charging twelve 6S 4000mAH packs at once on his PL8.
http://www.youtube.com/watch?v=JVsLfKgT50k

Most chargers that racers use won't have that capability unless it is a PL6/8 or iCharger 4010 Duo. http://www.youtube.com/watch?v=W9MrGF-W4tM
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Old 04-07-2013, 06:16 PM   #107
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watts = volts x amps

1400/120v = 11.6 amps on the AC circuit. Most commercial buildings will be 20A circuits anyway. It really just depends how many pit spots are on a circuit, and how many guys are charging at these rates.
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Old 04-07-2013, 10:59 PM   #108
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For tc Racing, these chargers are perfect ,but charging all these cells at once is incredible, although dangerous.....
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Old 04-08-2013, 04:59 AM   #109
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For tc Racing, these chargers are perfect ,but charging all these cells at once is incredible, although dangerous.....
Dangerous on cheap chargers, but not on the PowerLab or iCharger.

PowerLab were designed for parallel charging at high currents on large packs. The software and hardware has all the safety features to allow it. TC cars don't have the demand for this, whereas in large helis and planes, 12S and beyond are used.
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Old 04-08-2013, 06:06 AM   #110
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I am sure the chargers are up to the task, but if One of these packs go sour, the whole setup will go up in flames... I guess if you purchased One of these chargers already, you better be charging at higher than 20amps to justify the extra dollars spent, even if alot of pressure is put on the packs.... I'll have to give it a try since I already have a TP 1430C and a Trackpower 25Amp power Supply. I guess I can charge(after discharge) my TP 5300 65C safely at 23amps max , and see what that does... I am curious though to know if my Tp3300 65C wouldn't yield better results since they will heat up more than the 5300's ... I'll have to test and see....
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Old 04-08-2013, 06:12 AM   #111
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So some think it is OK for say a Mod oval car to race with a 1S lipo and pull an average of 80 amps on the track, heat up to 120 degrees under that load, not swell and hurt it at all but its unsafe to charge one at 40 amps, temp reaches 90 degrees?

Just like the rest of your useless post on here make no sense at all. I am really starting to see why so many people have you on the ignore list now.

Continue on with your useless propaganda that you seem to really know no true facts about. Only what you have "read" on the internet......which everyone knows if its on the internet it must be true.

EA
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Old 04-08-2013, 06:23 AM   #112
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Originally Posted by bertrandsv87 View Post
I am sure the chargers are up to the task, but if One of these packs go sour, the whole setup will go up in flames... I guess if you purchased One of these chargers already, you better be charging at higher than 20amps to justify the extra dollars spent, even if alot of pressure is put on the packs.... I'll have to give it a try since I already have a TP 1430C and a Trackpower 25Amp power Supply. I guess I can charge(after discharge) my TP 5300 65C safely at 23amps max , and see what that does... I am curious though to know if my Tp3300 65C wouldn't yield better results since they will heat up more than the 5300's ... I'll have to test and see....
PowerLab chargers are beyond those chargers you mention. Do some research on them. They have been around for years. The software have safety features incorporated as well as fuses on power cables and polyfuses on the parallel boards. I have charged six 6S packs at a full 40A all day without any issues for years. If a Lipo goes bad, a fuse will go but the software will detect that during charging and manage it. I don't see RC car chargers in the pits with that level of software/fuse protection.
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Who charging 20+ amps or more now??-mpa.jpg  
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Old 04-08-2013, 06:27 AM   #113
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Originally Posted by bertrandsv87 View Post
I am sure the chargers are up to the task, but if One of these packs go sour, the whole setup will go up in flames... I guess if you purchased One of these chargers already, you better be charging at higher than 20amps to justify the extra dollars spent, even if alot of pressure is put on the packs.... I'll have to give it a try since I already have a TP 1430C and a Trackpower 25Amp power Supply. I guess I can charge(after discharge) my TP 5300 65C safely at 23amps max , and see what that does... I am curious though to know if my Tp3300 65C wouldn't yield better results since they will heat up more than the 5300's ... I'll have to test and see....

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Old 04-08-2013, 07:53 AM   #114
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I suppose some are not here to exchange opinions, but rather to win a popularity contest !!! I'll still read and post regardless... Good luck selling your products !!!
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Old 04-08-2013, 08:05 AM   #115
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Originally Posted by EAMotorsports View Post
So some think it is OK for say a Mod oval car to race with a 1S lipo and pull an average of 80 amps on the track, heat up to 120 degrees under that load, not swell and hurt it at all but its unsafe to charge one at 40 amps, temp reaches 90 degrees?

Just like the rest of your useless post on here make no sense at all. I am really starting to see why so many people have you on the ignore list now.

Continue on with your useless propaganda that you seem to really know no true facts about. Only what you have "read" on the internet......which everyone knows if its on the internet it must be true.

EA
Glad someone finally said it...

I am content with my GFX at 10 amps. I can't even time putting tire compound on reliably at the right time before a race, not going to try and complicate it with timing discharge and charge times. This has been an interesting read though. I am curious if anyone has done the math or experimenting to compare the IR change between charge rates and how that equates to end RPM at the beginning and end of a 6 or 8 min run.
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Old 04-08-2013, 08:58 AM   #116
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I suppose some are not here to exchange opinions, but rather to win a popularity contest !!! I'll still read and post regardless... Good luck selling your products !!!
I think it is less of lack of interest in exchange but historically you seem to have a divergent opinion that mostly uses analogies of years old products and technologies.

I am sure that in some circles the 68 mustang is still the fast car.... Just to be fair I like to hear different approaches but you seem to always look for the powder keg instead of helping put out fires.
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Old 04-08-2013, 09:07 AM   #117
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Originally Posted by EAMotorsports View Post
So some think it is OK for say a Mod oval car to race with a 1S lipo and pull an average of 80 amps on the track, heat up to 120 degrees under that load, not swell and hurt it at all but its unsafe to charge one at 40 amps, temp reaches 90 degrees?

Just like the rest of your useless post on here make no sense at all. I am really starting to see why so many people have you on the ignore list now.

Continue on with your useless propaganda that you seem to really know no true facts about. Only what you have "read" on the internet......which everyone knows if its on the internet it must be true.

EA
bertrandsv87's advice is really good and helpful...




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Old 04-08-2013, 10:41 AM   #118
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Originally Posted by orcadigital View Post
Glad someone finally said it...

I am content with my GFX at 10 amps. I can't even time putting tire compound on reliably at the right time before a race, not going to try and complicate it with timing discharge and charge times. This has been an interesting read though. I am curious if anyone has done the math or experimenting to compare the IR change between charge rates and how that equates to end RPM at the beginning and end of a 6 or 8 min run.
I by no means claim to know everything but I do know with my racing experience and working with the factory that makes my lipo's what I have learned seems to be true thus far. I tried to not reply but when people keep taking jabs at my integrity they are going to get a reply eventually....

I have not done any test like you mention but I know the voltage after a 4 minute run in oval is higher when charged at 40 amps versus 10, 15, or 20 amps. Meaning you charge the pack to 4.22 (Legal voltage in oval racing) race a 4 minute race (no warm up laps no extra laps) and the voltage will be say 3.80. If you do the exact same routine with a 40 amp charge when you come back your voltage will be at 3.85 or so and this is with possibly an extra lap from performance. Which means the battery is holding its voltage curve longer.

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Old 04-08-2013, 10:51 AM   #119
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The key takeaway from all of this is;

1 - Nothing beats a quality lipo pack except an equally good stick
2 - Good battery chargers (ICharger, PowerLab...) make good lipos better
3 - Dont attempt high C-rate charging unless you have quality sticks, a quality charger, lipo bag and knowledge
4 - What might work for others may not apply to your setup, driving style or equipment
5 - Regardless of how top-notch your power package is - nothing replaces car setup!

There is some good reading on batteries & chargers outside of RCTECH. Nothing replaces knowledge and experience.

Thanks for sharing EA.
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Old 04-08-2013, 11:59 AM   #120
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Originally Posted by EAMotorsports View Post
I by no means claim to know everything but I do know with my racing experience and working with the factory that makes my lipo's what I have learned seems to be true thus far. I tried to not reply but when people keep taking jabs at my integrity they are going to get a reply eventually....

I have not done any test like you mention but I know the voltage after a 4 minute run in oval is higher when charged at 40 amps versus 10, 15, or 20 amps. Meaning you charge the pack to 4.22 (Legal voltage in oval racing) race a 4 minute race (no warm up laps no extra laps) and the voltage will be say 3.80. If you do the exact same routine with a 40 amp charge when you come back your voltage will be at 3.85 or so and this is with possibly an extra lap from performance. Which means the battery is holding its voltage curve longer.

EA
That .05 volts can be fairly signifigant especially in spec racing. I personally appreciate the info. Hope we can come up and run with you guys at Thunder again this year. Since I am running TC along with 12th now, I can be a speed bump to you in 2 classes instead of just 1. Just tell Dirla to stop hitting me!

Quote:
Originally Posted by MDawson View Post
The key takeaway from all of this is;

1 - Nothing beats a quality lipo pack except an equally good stick
2 - Good battery chargers (ICharger, PowerLab...) make good lipos better
3 - Dont attempt high C-rate charging unless you have quality sticks, a quality charger, lipo bag and knowledge
4 - What might work for others may not apply to your setup, driving style or equipment
5 - Regardless of how top-notch your power package is - nothing replaces car setup!

There is some good reading on batteries & chargers outside of RCTECH. Nothing replaces knowledge and experience.

Thanks for sharing EA.
Only thing I would add that was from EA's first post was the shortening of the Lipo's life (200 cycles vs 300 cycles as an example) when charging at higher rates.
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