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Old 08-04-2019, 08:29 PM
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Default Question about LiHV batteries...

Hi all - I'm in the process of coming back after a near 20 year hiatus. As I'm currently getting equipment together, I'm obviously looking at batteries. It seems like most LiPo providers are replacing their line with newer LiHV batteries, which have a slight voltage bump at 7.6 volts (3.8V/cell). Now of course, I've seen the articles about how you can easily use these by just charging them at the customary 4.22 peak voltage that older 7.4V LiPos are charged at to remain "legal".

So my question is, how exactly is Tech at sanctioned races actually ensuring that no one is bumping their packs to full capacity? Is this setting one up for additional scrutiny by using one of these packs?

The reason I ask is that I'm probably going to run in a Stock 17.5 TC class, and I still remember very well that there's nothing stock about Stock Racing. Stock back then was all about batteries (aside from the insane bushing break-in and magnet zapping techniques), where the best combination of voltage and IR was king. Good IR is still subject to luck of the draw and good charging techniques, but I just want to make sure that rogue over-charging to get an edge won't be a problem. I may as well pick up where I left off 20 years ago and just race Mod if this is a problem. It might just be easier if all the sanctioning bodies can just agree to allow 7.6V charging for competition... Someone please correct me if I missed any details about allowing 7.6V charging for sanctioned competition.

Thanks.
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Old 08-04-2019, 09:24 PM
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Most tech inspections will check voltage, with 8.40 being the max allowable, 8.41 will get you bumped out until you reduce the voltage.
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Old 08-05-2019, 12:32 AM
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Originally Posted by TurnNBurn View Post
So my question is, how exactly is Tech at sanctioned races actually ensuring that no one is bumping their packs to full capacity? Is this setting one up for additional scrutiny by using one of these packs?
Only someone who plans to flout the rules would ask that question. By the same logic, if they only checked voltages for suspect packs, wouldn't you have better chance of success at modifying your 2 cell LiPo battery to have LiHV cells or >2 cells?

Just buy a better LiPo battery and stick to the rules instead of asking 'what if'.
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Old 08-05-2019, 02:49 AM
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Originally Posted by nbTMM View Post
Only someone who plans to flout the rules would ask that question. By the same logic, if they only checked voltages for suspect packs, wouldn't you have better chance of success at modifying your 2 cell LiPo battery to have LiHV cells or >2 cells?

Just buy a better LiPo battery and stick to the rules instead of asking 'what if'.
You're making a lot of assumptions.
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Old 08-05-2019, 02:55 AM
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Originally Posted by belewis01 View Post
Most tech inspections will check voltage, with 8.40 being the max allowable, 8.41 will get you bumped out until you reduce the voltage.
Max allowable voltage varies slightly from track to track and race to race. I've seen everything from 8.4 to 8.44v. And not every track/race will let you simply bring the voltage down and then run your race. If you're over voltage in tech at a ROAR race, you don't get to run that qualifier/race.

@ the OP. They tech the voltage of everyones battery, LiHV or not. So you're not going to have any extra eyes on you if you do. Now club racing where there is rarely any tech at all.... that's a different story.
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Old 08-05-2019, 09:16 AM
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Thanks for the information all - and NO, I’m not asking because I was planning on cheating. As mentioned above, I already lived having to deal with the “skirting of the rules” back in the 90’s. It’s what drove me to Mod in the first place. While stock class motors had their restrictions, there were no rules to stop people from buying the $200 magnet boosters, or the $150 packs of “top voltage, minimal IR” batteries, which actually cost them less if they were sponsored.
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Old 08-06-2019, 10:35 AM
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Originally Posted by TurnNBurn View Post
Thanks for the information all - and NO, I’m not asking because I was planning on cheating. As mentioned above, I already lived having to deal with the “skirting of the rules” back in the 90’s. It’s what drove me to Mod in the first place. While stock class motors had their restrictions, there were no rules to stop people from buying the $200 magnet boosters, or the $150 packs of “top voltage, minimal IR” batteries, which actually cost them less if they were sponsored.
Actually there is nothing different today. Although the technology is different people are stll searching the lowest IR batteries and they do get them with discharging and charging on 40A or even more (I even had heard of 70A charging). Numbers you do not want to sit close by, for sure whan no good LiPo bag is used.
Motors are also hot. Not only by optional rotors but also with motor analyzers and moving sensors to get the maxumum and equal timing. And not to mention people who run stock with a stock ESC but managed to place a FET board of a more powerfull ESC or who are into electronics with hot air soldering do replace the FET's by one with better specs so I have seen once.....
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Old 08-06-2019, 09:00 PM
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Originally Posted by Roelof View Post
Actually there is nothing different today. Although the technology is different people are stll searching the lowest IR batteries and they do get them with discharging and charging on 40A or even more (I even had heard of 70A charging). Numbers you do not want to sit close by, for sure whan no good LiPo bag is used.
Motors are also hot. Not only by optional rotors but also with motor analyzers and moving sensors to get the maxumum and equal timing. And not to mention people who run stock with a stock ESC but managed to place a FET board of a more powerfull ESC or who are into electronics with hot air soldering do replace the FET's by one with better specs so I have seen once.....
Modifying ESCs like that is blatant cheating. It's no longer ROAR/EFRA/BRCA approved with those modifications.
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Old 08-06-2019, 11:10 PM
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Originally Posted by gigaplex View Post
Modifying ESCs like that is blatant cheating. It's no longer ROAR/EFRA/BRCA approved with those modifications.
True, moving sensors isn't legal either in several stock classes, but which technical controll can or will check that?
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Old 08-07-2019, 09:59 AM
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Wow - does it really matter what ESC one is using if it has. a “blinky” mode? Then again, if the ESC has been modified, what good is the mode other than to make the LED blink? 😒

Ugh, this is making me just want to jump straight back into Modified.
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Old 08-07-2019, 10:11 AM
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If theres a will theres a way to cheat..as 1 can see from above..I put in as many hours as I can on tracks to improve my skills in driving.Its all fun .it will catch up to those that slide the rules no biggy I never charge at more than 2.5 c ..I charge in a ammo can with fireproof cloth and a smoke detector attached to lid..
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Old 08-07-2019, 11:01 AM
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Well, just look up "the best" topics, all are searching for the best motor, ESC, battery, chargerr, car and even radio.
Also read the iCharger X6 topic where people are busy to create the 30A dischage bank as also in the iCharger 406 topic the 40A discharge. And why??? A hot LiPo has a low resistance. Heating is not alowed but heating the battery by high current discharging and charging is alowed, how stupid and unsafe that sounds..... (over here in Holland we have a 2C max 12A charge and max 20A discharge rule)

There are topics about re-aligning sensors to get them equal, If you know how to resolder a sensor it is very easy to move them to the end of the solder pads giving 5 to 10 degrees timing extra.
Again, people do go far to go fast, I have seen plenty of tricks, even up to cheating with FDR limits by using different pulleys and other numbers engraved in gears.
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Old 08-07-2019, 11:32 AM
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almost every race I have been at in the last 4 years has done a thermal check on battery in car b4 race if its 10 degrees F over room temp U are no Disqualified..
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Old 08-07-2019, 11:34 AM
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Originally Posted by TurnNBurn View Post
Wow - does it really matter what ESC one is using if it has. a “blinky” mode? Then again, if the ESC has been modified, what good is the mode other than to make the LED blink? 😒

Ugh, this is making me just want to jump straight back into Modified.

Don't let it scare you. Things are much more even now than they were back in the 90s. Yes a few questionable things have popped up from time to time but it's far less common and the internet usually calls it out fairly quickly when it does happen.
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Old 08-07-2019, 12:43 PM
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True.

More and more is done to prevent cheating, over here with the ENS the new Muchmore ESC has a RPM limiter so there is no need to find more RPM. and more tools are invented to check on stuff, a few years ago with a large event they used a simple 2 channel oscilloscope to meassure the sensor and the motor coil to see if they are in phse as a real zero timing.

Only the intensity of tech control depends the kind of race.

But there are some legal speed tricks you have to do or otherwise you will be noticable slower. Stuf like shimming the rotor close to the sensors, minimise the rotor play, oil the bearings and use a torque screwdriver to screw the 3 motor can screws.
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