When you make a statement like that, wether you like it or not, people hear "No one is checking, so if I can get away with it, I'm going to cheat"
Originally Posted by captain stacker
besides the duo3 and pulsar 3, which other chargers that are cheaper that can charge a 2s lipo to 8.44 volts? My track does not tech batteries.
If that alone didn't piss you off, please read on......
In the early days lipo batteries were poorly understood by the RC industry and racers. No one really understood about graded cells or chemistry generation.
Preheating of cells and packs was originally thought to be safe, but that proved false, even when done by people who understood WHY, HOW, and WHEN to do it.
The ROAR standard was ALWAYS 4.20vdc/cell +.02vdc/cell to COMPENSATE for voltmeter tolerance
. RACERS incorrectly made 4.22vdc/cell the standard. With Gen 1 and 2 chemistry Lipos, 8.44 was thought to be safe even with tolerances in the voltmeters, but that was really only for grade A and B cells. Usually only the most expensivie packs are/were made with A/B cells. Few of the early packs were put together with matched cells (capacity, discharge curve, charge curve, and internal resistance). Many of the Gen 3 and newer chemistry packs are much closer in overall tolerance, and it's much faster and easier to match cells for packs, which is part of what makes 2S2P packs possible.
That's before we even get into the discussion of charge rates! Heck, some super high select grade A cells now can be charged at 3C+. DON'T try that with budget D/E cells from Hong Kong, though, they'll puff with a quickness.
Preheating + overcharging of low grade cells = LOTS of lipo fires. Since a lipo fire is an alkaloid fire, adding water instead of using a dry chemical fire extinguisher = BIGGER fire. Most people see FIRE and react with water, so all it takes is one newbie for things to turn really bad really fast.
Gen 3 and successive chemistry Lipos are much more thermally stable, effecient, and SAFE at 8.40 volts due to the way that they're formulated.
The early experience with equipment damage from lipo fires, coupled with better chargers, better batteries, lipo charge sacks, and a better general understanding of lipos has lead to the generally accepted max safe charge for all single lipo cells at 4.20 volts per cell. 4.20 volts DC per cell pretty much maximizes effeciency and safety, balanced with longevity for the racer. Thus, the current ROAR standard, 2S packs at 8.40 volts MAX, +0, -whatever you want. Thus, the "voltmeter tolerance" was removed from the rules and brought the wording and working of the voltage rules in line with the intent.
The primary purpose of end voltage adjustable chargers is to be able to fine tune the instrument so as to compensate for circuit tolerance and component quality to ensure that, when confirmed with a high grade voltmeter, that you're actually getting to 8.40 volts DC for a final charge vice 8.3something instead, NOT for overcharging.
RTFM, it'll tell you the same thing.
.04 volts total in a pack might not seem like much, but it removes your safety margin, puts your equipment and other people at risk, especially if you have an older, or damaged, or cheaper quality, or charge abused cell pack. Gen3+ cells are much more tolerant of overcharging and overdischarging, but if there's anything suspect in the cell or the pack, that will reveal the weakest link, usually quickly and dramatically.
In any case, I would think that you would WANT to have a legal car, in all aspects, wether anyone is looking or not, but that's your morallity. If you win, you still have to face yourself and wonder if it's because you're the better driver with the better equipment, or because you cheated. If someone figures out that you're cheating with battery voltage (no matter how slight), it calls into question EVERYTHING else that you're doing at the track, no matter where you finish.
Bottom line, it's a safety issue. You may get lucky and nothing will ever happen, or you may strike it rich and burn down the whole facility.
Personally I own several ProTek branded iChargers. One I have to adjust to 4.23 to get 4.20, the other 4.21 to get 4.20, verified with a calibration checked Fluke 77BN.