the big rc

iTrader: (40)

Yup, they just had a 4 race point series here and my son won it and i took 2nd with box stock cars, $80 reedy stock motors and average batteries with no special charging or discharging done. I'm sure that stuff works for guys that are consistent and don't wreck, but for the average racer money would be better spent at the track practicing imho

WillS

iTrader: (32)

Seriously though, did we not just watch the ROAR Nationals? 1 wreck = 1 position lost

Socket

iTrader: (61)

Most of the races were so painful to watch. That track had literally one passing zone at the end of the straight and that was it. Smart move was to relax, hit your marks, don't push and let everyone else bomb themselves.

Unfortunately, that's how most tracks are built now. Super tight, single lined, and fast.

WillS

iTrader: (32)

Mostly indoor med to high bite tracks. I think its a track size issue. You see this same issue with Arenacross in comparison to Supercross and Motocross.

thecman26

iTrader: (112)

Its' funny because the ROAR nats were at the Hobbyplex and its HUGE! Race on a small track! Maybe that's why Dustin Evans, Matt Chambers, and the rest of the MOHR crew are wicked fast. Small track teaches you to drive!

The real trick to a stock motor is finding the sweet spot of the motor: Each motor has it's own sweet spot (gearing/timing) and ya just gotta figure it out on your own unless you have the money to buy all the electronic gadgets to help.

captain stacker

iTrader: (10)

I've built a discharger hooked up to a wattmeter, and here is a quick look at the results. Voltage sample taken every minute from 1 to 5min.

.....................1min 2min 3min 4min 5min
saddle 6000, 7.94 7.87 7.80 7.69 7.63
shorty 5000, 7.89 7.80 7.69 7.61 7.54

shorty 3800, 7.76 7.64 7.52 7.45 7.37

so as you can see, the saddle pack at one stage, at the 3min in particular is 0.11volt higher than the shorty. I've also added a low profile shorty for comparison. Both shorty's are 5 cycles old, saddles are 20-25 cycles old. So the difference may have been even greater considering all things equal.

is 0.11volt going to make a difference? who knows what it's worth?

so I'm thinking if you can run saddles and not be disadvantaged by the extra weight, why not.....

WillS

iTrader: (32)

Are you doing a constant dump? If thats the case then your numbers would correlate that. If you change loads up and down you will see very little change until after 5mins. Resistance will also play a factor in that equation as well as the battery manufacturer. We can race with numbers all day, but at the end of the day, those numbers don't win races.

Socket

iTrader: (61)

What is the discharge amps? Why not use the discharge data on the icharger?

How hot were the packs? Did you charge at 70 amps?

wyd

iTrader: (51)

I take it this is in offroad? It depends on your track but at ares in offroad you could do that as we don't have too many hard core off road stock guys but on are oval well that is a different story and that would never work. Deends where your at and how hard core the guys are in your area. It is one of the reasons are off road class is growing and are oval is slowly fading. Too many hard core win at all costs type guys on are oval. Unless you have good batteries that you cycle to always have the best voltage and lowest resistance and then you need one of the high power I Chargers to charge your packs. Its crazy what they do to gain that almighty tenth or two.

captain stacker

iTrader: (10)

yes constant dump. An ideal rig would involve an rc car dyno, or even tekins data logging feature on track.

Yes these are just numbers, however I'm not 100% certain shorty lipos are the best lipos to use, even though it seems to be the most popular!

my lower spec icharger only discharges at a rated 7amps, however the actual discharge is more like 2-3 amps.

My discharge unit is just under 20amps. I primarily built it to discharge lipos at the track, however I can use it to to compare lipo vs lipo, and track my lipos deterioration over time.

packs were not hot, just at a constant room temperature of 18degrees

charged at only 1C

yes I know about discharging at 30amps/40amp charging cycles, get the lipo hot to reduce internal resistance. However that's not what I'm looking for here. Just after some data from a consistent test bed.

Socket

iTrader: (61)

Eh. That data doesn't mean much to me because it doesn't match the real world at all. I'm dumping at 40 amps to 3.1, then charging at 70 amps to 4.35.

Tommygun1

iTrader: (16)

Actually, it matches the real world very closely. A stocker pulls about 20 amps average in a 5 minute run. Discharging a battery at 20 amps for 5 minutes replicates it. No it's not exact, but a good indication. I have no idea what dumping at 40 then charging way over voltage at 70 has to do with anything.

Captain, your numbers are a good indication of what best batteries are. I'd want to check them all when new though and same brand (maybe they are same brand?).

Socket

iTrader: (61)

If you don't know, then respectfully, you don't belong in the conversation. Sorry.

RC*PHREAK

iTrader: (146)

i would imagine that he means it wouldn't make a difference if you used the same discharge/charge procedures for both packs.

Socket

iTrader: (61)

I think it does. Different batteries and capacities take 70 amp charging and heat differently, in my experience. I've tried them, I've mapped them.