Phillip F

iTrader: (43)

I was at the track yesterday setting up my buggy when i see this other guy running his buggy super fast. I asked him what motor he was running. He was running the a 17.5 T. NOW.... I run a Reedy 17.5 T and it doesnt go fast like that guys buggy. I asked him how he charges his battery. He said he has been charging all his batts at 20 amps. I have been charging mine at 9.2 amps which is a good charging rate according to a tech I talked to in Promatch batteries. Promatch , however , said yiu can charge the batts up to 20 amps.. but it will affect the life of the battery . OK... now we are talking. I am going to try charging my batts at 20 amps next time im going to the track. But now my question is... FYI i have an iCharger 308duo.... after I charge the batts at 20 amps... run the car. Can I charge the batts again at 20 amps without discharging? Should i get a discharger just to do this "high charging technique". Btw... this is just for club racing. For now... I dont have any ambition to race at big events.... yet.

Matt Trimmings

iTrader: (170)

It's not a night and day difference like you are making it sound. Gearing, timing, corner speed, track conditions, driving ability etc equates to a fast lap.

Andy Koback

iTrader: (280)

Yes, you can just re-charge @ 20A after a run without dis-charging. One cell guys will dis-charge after a run and then re-charge just to get a little heat in the battery to help lower I.R. Like Matt mentioned, gearing, set-up and other things can make a big difference too.

LAGuy

iTrader: (5)

Cars being equal. He's either discharging at a high rate to lower the IR (high charge rate simply keeps the pack warm) or simply over volting the pack. Isn't legal, yet a lot of stock racers seem to be doing it. You'll need a quality charger for either method. The 308 is good for over volting, but you'll need the 406 for high discharging into a resistor bank.

Phillip F

iTrader: (43)

I absolutely agree. I do have experienced racing a few years ago in nitro 1/10 1/8 on road and 1/8 off road buggy. Anyways... i already have my gearing and suspension setup done to my style of driving... all i need is a bit of power.

Phillip F

iTrader: (43)

Thank you.

Slotmachine

iTrader: (4)

Higher amp charge may not always charge tge pack fully. I charge at a high rate then rechage tge pack at 3 amps to top it off. I always get about 10 more minutes of charge on the battery.

Phillip F

iTrader: (43)

what battery and charger do you do this with?

Phillip F

iTrader: (43)

OKAY.... UPDATE on what happened to me today at the track.

I usually charge my Lipo at 2c only which is 9.2 amps. It takes me 25 minutes to charge the battery. My average lap times (22 secs.) with that charge considering my gearing is perfect for the track ( Im getting good speed in the straights and clearing the jumps easily). Now, I tried charging at 15 amps. By charging 15 amps, it took me 15 minutes to have my Lipo fully charged. And I am getting a lot of punch which made my average lap times at 19 sec....wow. I shaved off 3 secs from my average lap times . This is in the span of 5 minutes without making any mistakes in the track. Now... just to make it interesting.... how about charging 20 amps for my last run then I pack up..... Now, of course I let my pack rest 10 minutes in between ..... I was averaging at 18 secs. for a 5 minute run. My Lipo wasn't even warm while it was being charged at 20 amps. I was monitoring it like a hawk.

WOW... no wonder these people are charging at 40 amps...then discharging at 40 amps too. Imagine how much punch and speed one can get.

Now... I already ordered the 40A discharger resistor bank from one of the members of this forum and he will give me instructions on how to use it. I am pretty excited to try it out now.

DirkW

iTrader: (1)

3-4s per lap...? So overall 2-3 more laps in 5 minutes...? Sorry, but I don't buy it.

Not that your times didn't maybe improve dramatically, I'll give you that. But that it was just because you added another 5-10A on charging is not credible. After all, that's a world of difference you're claiming here. Sorry, but it really is much more likely that you actually simply drove differently (=much better) for some reason - and if you had had the same good run with a battery charged at 2C, it would not have been a 22s per lap average either, but up there with the times you got.

Do you really believe that doing this 40A charge/discharge method will cut down lap times by ~25%??? (You claim to be close to 20% already, and you seem to expect another major jump from your 18s times) IMHO that's just wishful thinking - it's simply not how it works. Hell, stepping up the motor one category (e.g. 17.5T to 13.5T) would most likely not give near as much of an advantage per lap as you claim, let alone just charging the battery a little differently... It may give you a few(!) tenths of a second, but certainly not several seconds (especially at such a short track). It's still physics, not magic.

Phillip F

iTrader: (43)

I don't know... all I did differently there is charging at higher amp... driving style is still the same ...setup the same. I use to be a nitro guy and it felt like running from a .12 engine with a .15 power engine. It just made my buggy accelerate faster and punchier to clear the jumps. And with all the faster momentum in the corners ...it just shaved seconds in my average lap time. The dramatic difference is when I was charging from 9.2A to 15A. Plus I also like the faster charging times too. ... from 22 sec to 19 sec average lap time. I am pretty happy right now with all that power . Which is pretty cool since the Lipo batt mfg informed me that 15A is the highest you can charge to get more of the battery. I don't want to charge at 20 A ...that was just a "one run" deal.

So I don't have any plans yet on charging at 40A since I already have plenty of power, I already ordered the 40A discharger and was wondering if I discharge at higher amp rate and stick to charging at 15A.... would it make a difference?

Matt Trimmings

iTrader: (170)

Santa Clarita.....SCVRC? That track changes quite a bit depending on how much water is put down. It's also fairly small so lap times are usually pretty low, in the 16-18 second range depending on layout. It is quite possible you crashed less....but 3 seconds per lap is not going to be something that anybody else is going to claim based on charging at 9.2 to 15 amps.

Phillip F

iTrader: (43)

yes that's the track. The "expert" guys average 16-17 sec.

I drove for 5 minutes without crashing and was trying to be consistent. Battery charged at 9.2A... my average lap was 22 sec.

Now, when I charged my batts at 15A.... my average lap was 19 sec ...again driving for 5 minutes without crashing.

BTW.... experience wise... this is my 3rd time at the track after 15 years .

Matt Trimmings

iTrader: (170)

Good for you...I'm just saying that charging at 15 amps is not the reason for those 3 seconds gained. You might have gained a tenth or two. There are too many other variables.

JAE

iTrader: (30)

I was the guy driving the buggy very fast slowly around the track...my new xb2 I was trying to figure out sliding all over the place... It's possible your motor was over geared for scvrc too. 72/31 is the sweet spot. Track is all bottom end. Maybe the extra punch enabled you to drive a lot tighter while still carrying the jumps... There is a really tight 180 that goes into an elevated crossover that you need some punch to clear if you take the turn super tight. Not 3 seconds tight but if your new b5m is pushing, or you are taking that turn wide, missing your line after clearing the jump, you'll lose a second there. In any event, it's not the 20 amp charge. Also, the fantom motors have a ton of bottom end rip. Don't notice much of a difference on bigger tracks, but on the super tight tracks like scvrc I noticed about a 20 percent increase in punch coming from my reedy 17.5. I still think the reedy's are badass motors especially for the price but can't say enough about the bottom end on. My certified fantom... At bigger tracks though, the difference was minor