335i

iTrader: (14)

In general yes, this is true. But it this particular case, I still I'm not convinced one setup would run that much cooler than the other setup.

Edumakated

iTrader: (19)

I've run pretty much every single combination you can think of in electric 8th scale from 2s - 6s. There is a very noticeable drop in temps when you go from 3s/4s to 5s/6s setups. The motors generally don't run significantly cooler regardless of voltage if you are within the 28-35k rpm range, but the ESCs and batteries do in fact run cooler as you go up in voltage.

My 6s packs with a 1400kv-1500kv motors come off the track at ambient temps. I haven't run a fan on any of my speed controls in more than two years. I stopped regularly checking temps three years ago when I switched to 5s and 6s permanently. I don't recall the last time I had a speedo run more than 120 degrees in the middle of the summer.

High voltage is definitely better in my real world experience - especially with truggies. However, unless you are consistently running longer than 10 minutes, 4s is good enough in a buggy these days as the batteries a bit stronger than they were three and four years ago when it was common to use 15-25c packs versus the 40-60C packs that are out now.

I just like my stuff to have a significant margin of error versus just being on the edge of working well. To me 4s is on the edge. It is good enough for government work...

Muggydude

iTrader: (92)

After running my 6s 3600mah 1400kv motor setup this weekend, I have these results:

ESC was never over 135 F. Lipo was never over ambient.
the motor ran about 160 F for the 7 minute qualifiers with 2 minutes practice. For the 15 minute main, it came off at 172 F, so overall I'm pretty happy. The track was fairly large and had quite a few stretches of full throttle.

Dave H

Reason efficiency is so important to some, is they are trying to run with nitros. Nitros have traditionally ran longer mains, with refueling. But these long mains stretches an electric vehicles capability without needing battery changes, which are clumsier than refueling, or using really heavy batteries, which make the car a pig to drive.

Fans and airflow will have very little impact on the efficiency or power loss. Fans only move the lost power, they do not fundamentally reduce the underlying power loss. (other than impact of temps on general conductivity)


A long time office wall decoration:

chiro972

iTrader: (10)

Agreed. My track does 12 minute mains in e-buggy and I can run a few warmup laps and make 12 minutes and keep on running for another 5 as I did one night when we were the last race and a few of us just kept going when the main was done.

I went with 4S because these buggies are heavy already and adding two more cells was just out of the question for my liking. Clearly there are some engineers answering questions here and I'm sure they are absolutely right. Heat and run time won't ever be as good as with an optimally setup 6S system, but for my racing needs the 4S is the best choice for me.

I think there are pros and cons to each.

Edumakated

iTrader: (19)

I would run a 6s 2650mah for a 12 minute main. It would be quite a bit lighter than a typical 4s 5000 pack. If 4s is working, no need to change though.

Pulse_

What are your runtimes in 6S 1400kv 3300mah generally?

Edumakated

iTrader: (19)

Around 20 minutes. Most 6s setups in buggies seem to burn about 150-175/minute depending on driver & track.

6s 3300 = 5s 4000 = 4s 5000

Mr RCTech

iTrader: (2)

This information is all good but gets throw out the window when you program
your speedo with torque limiting, punch control, etc.. LOL!

You can run a hotter motor and program the speedo for any number of cells.

Gearing plays a big roll.

I seen higher gearing ratios with higher advance timing and
Lower gearing ratios and less advance timing.
Both just as fast!

335i

iTrader: (14)

Yea it seems everyone has there own version of that saying these days. Its pretty funny.

audriusv

iTrader: (12)

Tekin RX8 + 1900kv motor, Caster 1.5R E-Buggy with 2X LiPo 5200mAh 35C batteries (~265gr one). Total racing weight 3.6kg. LVC at 3.5V, limiter in ESC ~80%. Hard clay track, length ~290m. Ambient temperature 20-25C. After 3 minutes warm up, 10 minutes main and 1 minute additional run put back to batteries +/- 3000-3100mAh (in balancing mode).

Already have 4400mAh 35C ~235gr LiPo batteries. Will be testing this weekend. And looking for not expensive shortie 3800mAh 200gr batteries... Eager to try these as with them I can change significantly front/rear weight bias...

Muggydude

iTrader: (92)

They are perfect comparisons-Same vehicle, same gearing (top speed) same esc settings, same type of motor (tekin buggy) bateeries were pretty close in capacity, 4s 5200mah 30c, and 6s 3600mah 30c

Nogas

iTrader: (7)

I run 1/8 buggy and truggy, both on 4s at the moment but looking into a 6S set up for the truggy to get through 20 minute mains.

One thing that is clear from my experience is runtimes vary massively depending on driver level and smoothness and track size / layout.

I run on a large outdoor track and it seems we (all the same pace guys at my track use around the same) use alot more battery than alot of you guys in the US and this seems mainly to be due to track size and design.

In my mbx6 buggy running 1900 tekin geared 15 / 46, i use around 3500 - 3600 mah for a 10 minute race with 1 warm up lap. Which is around 340 - 350 mah / minute.

In my mbx6T running a HW 2000 / 150A xerun combo geared 15 / 46 i'm using around 4500 - 4600 mah for a 10 minute main, with no warm up laps. 450 mah / minute.

Unless some one makes a super light 10000mah 4S i'm never gonna make a 20 min main on 4S.

Now everyone keeps banging on about how efficient 6S set ups are but it seems that everyone forgets they have more cells, which makes them weigh more, so they are potentially consuming the same amount of power (maybe marginally less due to lower temps). I think a good comparison would be weight of pack / runtime.

What i'm trying to work out is what size 6S pack i'm going to need to make 20 minutes as i know a 3600 mah as someone quoted earlier simply will not be enough.

So basically if you've run both 4S and 6S in the same car what were your pack weights / runtimes (to LVC) or if you haven't run to LVC, mah used / minute (so i can work out a theoretical runtime to LVC).

Mine for my truggy on 4S 5000mah are 580 grams / 12 minutes (to LVC). 580 divided by 12 = 48 grams of pack per minute.

I think this is probably the easiest way to fairly compare the 2 options

stevo90630

hello all,

I recently purchased a new 1/8 buggy, and I wasn't sure what motor and batteries to purchase. So I decided to get some help from a well known hobby shop in SoCal.

long story short.....

Based on recommendation, I purchased the following parts.

DYNP4001D Platinum Speedpack, 11.1 Volt 5200mAh 3S 50C Lipo Battery w/Deans

and

Tekin T8 2650 with an RX8 gen 2 esc.

18 tooth pinion and 46 tooth spur gears.




Now.......



Tekin has suggested that I buy an entirely new set up, batteries and motor.


15 tooth pinion and 46 tooth spur

t8i 1950 kv

and

ProTek-R-C-4S-Supreme-Power-Li-Poly-100C-Hard-Case-Battery-Pack-148V-3700mAh

or

ProTek-R-C-4S-Supreme-Power-Li-Poly-100C-Hard-Case-Battery-Pack-148V-4700mAh For longer run times.


I only run at OCRC as of yet, but will be trying out some of the other tracks in SoCal when I get some more time.

what are the advantages and dis-advantages of each set up?

Will I be ok with what I currently have, or should i go to the t8i immediately?

Thoughts?
Comments.
Questions.

Thank you!