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Old 04-08-2013, 12:12 PM   #121
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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.
Although this all may be true,

Most ruelebooks still say charge at max 1c. (This may be old fashioned and based on the limitedmexperience with lipo at the time, the rule is still there).

If charging at high c rate is beneficial for performance ignoring the above rule requires all serious about competition to invest in expensive charging technology (if the claim that cheap chargers are dangerous at high rate is true...)

In the end we end up with higher cost and an (maybe small) increased risk.

Wouldn't it make more sense to limit charge rates at 2c? That means no hot lipo's and as we are all doing it it makes no relative difference in performance.

Lipo used to be the holy grail as it was simple and easy to use. 1 charge scheme, no discharge required, heck you could even charge them at home....

Unfortunately the non conformation to simple rules, and the abscence of enforcing those rules has led us up sh.ts creek again....

Let me finish by mentioning, I do not doubt all of your intricat knowledge of lipo charging and behaviour. I just detest that there is a new technology race starting that is completely unnescessary, as the 'advantage' of high amp charging is only an advantage when the rest isn't. Unfortunately we will probably head the expensive way. Again....
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Old 04-08-2013, 12:42 PM   #122
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Although this all may be true,

Most ruelebooks still say charge at max 1c. (This may be old fashioned and based on the limitedmexperience with lipo at the time, the rule is still there).
ROAR hasnt updated their rule book since 2010, I was told it hasnt been enforced since then and would be removed with the rule book was updated.

If your rules dont allow higher than 1C charge rate then I would not charge higher than that and agree with you there.

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Old 04-08-2013, 12:45 PM   #123
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And yes we were all told that Lipo's were the Holy Grail and going to equalize everything in racing...just as BL motors would. All racers would now be on equal grounds and it would come down to driving....guess what.... Racers will always find ways to make things go faster. Manufactures will also find ways to make things go faster. Its why its called "RACING" and not "DRIVING". The competition will always drive racers to find ways to go faster than the next guy. Always have and always will.

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Old 04-08-2013, 12:58 PM   #124
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And yes we were all told that Lipo's were the Holy Grail and going to equalize everything in racing...just as BL motors would. All racers would now be on equal grounds and it would come down to driving....guess what.... Racers will always find ways to make things go faster. Manufactures will also find ways to make things go faster. Its why its called "RACING" and not "DRIVING". The competition will always drive racers to find ways to go faster than the next guy. Always have and always will.

EA
True.

However the question remains if this is a good road to be on. If i read comments in this thread by someone who claims to be a speed bump, but in the same sentence claims it makes sense to charge at 40 amps to get a 0,05v advantage I feel we have all gone mad.

I do not want to stop development. As a racer I have always sought to find things to improve, and I agree that if the rules allow, high rate charging is logical. But it could be a simple rule to prevent exploiting a potentally unsafe area.

Probably this is another argument that limiting motors to a point where each 0,01v matters is a bad idea as well...
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Old 04-08-2013, 12:59 PM   #125
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Originally Posted by Julius View Post
Although this all may be true,

Most ruelebooks still say charge at max 1c. (This may be old fashioned and based on the limitedmexperience with lipo at the time, the rule is still there).

If charging at high c rate is beneficial for performance ignoring the above rule requires all serious about competition to invest in expensive charging technology (if the claim that cheap chargers are dangerous at high rate is true...)

In the end we end up with higher cost and an (maybe small) increased risk.

Wouldn't it make more sense to limit charge rates at 2c? That means no hot lipo's and as we are all doing it it makes no relative difference in performance.

Lipo used to be the holy grail as it was simple and easy to use. 1 charge scheme, no discharge required, heck you could even charge them at home....

Unfortunately the non conformation to simple rules, and the abscence of enforcing those rules has led us up sh.ts creek again....

Let me finish by mentioning, I do not doubt all of your intricat knowledge of lipo charging and behaviour. I just detest that there is a new technology race starting that is completely unnescessary, as the 'advantage' of high amp charging is only an advantage when the rest isn't. Unfortunately we will probably head the expensive way. Again....
The problem is, this is racing. People are constantly pushing the envelope of what is legal and what is not. Whether it is improperly defined wire size, cut marks on VTA bodies, or high charge rates on lipos, it will always be something. My experience is no where near what others here have, but people seem to always be trying to find something for that little edge.

Mini is the new class of the month here. It started as a fun diversion from the serious TC and 12th scale racing. This past weekend, I watched someone doing some wiring mods to make a Tekin RS work. This is while another guy was dynoing his silver can motors and another was fitting his new 100c shorty pack into his car. These are $120 kits that now require $300+ in mods and $400+ in electronics to be competitive. By the way, Tekin RS is supposed to be good for 0.3 of a second improvement over the Tekin FX, which was good for some other amount over the stock ESC that comes with the kit.

Now the safety aspect is something else. But that being said, I have not heard of lipo fires due to high charge rates. I have heard of them due to overcharging (more then the 8.42v for 2s) and physical impacts/damage. While I see your point about this being just one more thing people will feel they need to chase to be fast, if it is not high charge rates, it will be something else.

100% my opinion here though.
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Old 04-08-2013, 01:05 PM   #126
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@ orcadigital

Well put. It takes only one to ruin a fun class and start the technology evolution war....
Specing is very difficult to achieve as well and often ends in people accusing each other of cheating.

There is no hope....
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Old 04-08-2013, 01:09 PM   #127
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True.

However the question remains if this is a good road to be on. If i read comments in this thread by someone who claims to be a speed bump, but in the same sentence claims it makes sense to charge at 40 amps to get a 0,05v advantage I feel we have all gone mad.

I do not want to stop development. As a racer I have always sought to find things to improve, and I agree that if the rules allow, high rate charging is logical. But it could be a simple rule to prevent exploiting a potentally unsafe area.

Probably this is another argument that limiting motors to a point where each 0,01v matters is a bad idea as well...
As I am referenced here I'd like to comment. I am a speed bump to EA. He is extremely quick and quite a marvel to watch drive. That is true for lots of pro drivers. I am mid pack A-Main club level in onroad, and even lower in offroad. That is what qualifies me as a speed bump to a sponsored pro-level driver. Yes, 0.05 volts is signifigant, and someone with better math skills then I could convert that to RPM, and with more information into speed. Also, in my earlier post, I stated that I charge at 10 amps and why. Just because I like learning about what others are doing, does not mean I am doing it. When I don't need to be corner marshalled with 5+ second delays, then I can worry about tenths here and there. That is me personally. I also understand that when I came in 4th place on Saturday in the TC main, it was due to the mistake I made and the overcorrection that followed...and not due to battery voltage, ESC of the month, motor with the hottest reviews, etc.
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Old 04-08-2013, 01:17 PM   #128
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As I am referenced here I'd like to comment. I am a speed bump to EA. He is extremely quick and quite a marvel to watch drive. That is true for lots of pro drivers. I am mid pack A-Main club level in onroad, and even lower in offroad. That is what qualifies me as a speed bump to a sponsored pro-level driver. Yes, 0.05 volts is signifigant, and someone with better math skills then I could convert that to RPM, and with more information into speed. Also, in my earlier post, I stated that I charge at 10 amps and why. Just because I like learning about what others are doing, does not mean I am doing it. When I don't need to be corner marshalled with 5+ second delays, then I can worry about tenths here and there. That is me personally. I also understand that when I came in 4th place on Saturday in the TC main, it was due to the mistake I made and the overcorrection that followed...and not due to battery voltage, ESC of the month, motor with the hottest reviews, etc.
Point taken.
As I don't kow your personal skill I could only go from your comment as written. i referenced it to illustrate a point, not to take a stab at you.
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Old 04-08-2013, 01:17 PM   #129
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@ orcadigital

Well put. It takes only one to ruin a fun class and start the technology evolution war....
Specing is very difficult to achieve as well and often ends in people accusing each other of cheating.

There is no hope....
Hehe there is one way to achieve it. It is in the mod touring thread.

Spec racing is a money sink. Same is true in 1:1 cars as well.
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Old 04-08-2013, 01:25 PM   #130
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Point taken.
As I don't kow your personal skill I could only go from your comment as written. i referenced it to illustrate a point, not to take a stab at you.
Point is valid, and there are people who definitely go that way, buying the newest and best because of what they read. I just wanted to point out that was not me. I immensely enjoy the technical aspects of RC, but besides not having the money or commitment level to push the envelope in so many ways, I know that track time will yield much greater dividends then 0.05 volts will.
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Old 04-08-2013, 01:36 PM   #131
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I don't know why ROAR isn't enforcing a written rule. I've seen a lipo catch on fire with a guy charging at 40 amps...... i'm not sure if it was the charge rate that caused the fire but he was the only one charging at that rate and the only time i've seen a battery catch on fire while charging.
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Old 04-08-2013, 01:45 PM   #132
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I don't know why ROAR isn't enforcing a written rule. I've seen a lipo catch on fire with a guy charging at 40 amps...... i'm not sure if it was the charge rate that caused the fire but he was the only one charging at that rate and the only time i've seen a battery catch on fire while charging.
First one Ive heard of. I know there were some guys using GFX's at the birds that had some fire on the spec packs due to power going off while charging and them not being there. When a GFX comes back on it sends full power to the battery from the power supply and can cause that issue.

The rule was taken out but rule book has not been updated. There are a lot of other things in there we would be using still if they went off of that rule book.

For example have you been racing at 1420 grams? If not why? Thats what the written rule is?


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Old 04-08-2013, 02:02 PM   #133
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First one Ive heard of. I know there were some guys using GFX's at the birds that had some fire on the spec packs due to power going off while charging and them not being there. When a GFX comes back on it sends full power to the battery from the power supply and can cause that issue.

The rule was taken out but rule book has not been updated. There are a lot of other things in there we would be using still if they went off of that rule book.

For example have you been racing at 1420 grams? If not why? Thats what the written rule is?


EA
Weight is always posted at race events along with body dimensions so that's a non issue. The rule book for ROAR shows 1c charge rating but no ammended post prior to race addressing it directly. I don't know what happened but I know that the guy that had his battery catch on fire was playing around with different chargers from week to week at the time. Good thing there were two alert racers who acted quickly and unpluged his power source and used a fire extinguisher right away. I know that guy that pitted next to him had to clean up his stuff since it was covered with resedue from the fire or extinguisher.
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Old 04-08-2013, 02:07 PM   #134
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Weight is always posted at race events along with body dimensions so that's a non issue. The rule book for ROAR shows 1c charge rating but no ammended post prior to race addressing it directly. I don't know what happened but I know that the guy that had his battery catch on fire was playing around with different chargers from week to week at the time. Good thing there were two alert racers who acted quickly and unpluged his power source and used a fire extinguisher right away. I know that guy that pitted next to him had to clean up his stuff since it was covered with resedue from the fire or extinguisher.
Well hopefully the guy was at least using a lipo sack. Any idea what type of battery it was and what charger? There are only a few that go to 40 amps that I know of.

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Old 04-08-2013, 02:12 PM   #135
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The cost of enforcement is high. There are rarely enough race directors to patrol voltages, weight, charging, mod rotors in stock stators, stock stators.

As for the hit of 300 to 200 cycles - as soon as my packs hit a certain range of IR they are relegated to practice packs. That is well over 100 cycles but dont keep packs beyond 140+ cycles.
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