Go Back  R/C Tech Forums > General Forums > Electric Off-Road
Losi 1/8 8ight E 4wd Thread >

Losi 1/8 8ight E 4wd Thread

Losi 1/8 8ight E 4wd Thread

Reply

Old 08-30-2008, 02:21 AM
  #61  
Tech Master
iTrader: (19)
 
*Chrominator*'s Avatar
 
Join Date: Feb 2006
Location: Living in a Van down by the river.
Posts: 1,146
Trader Rating: 19 (100%+)
Default

Originally Posted by air8 View Post
So let's see if this sounds about right:


Can we assume the higher the Kv of motor, the smaller the battery needed? If so then,

2100Kv = 3s
1700Kv = 4s
1300Kv = 5s

And the larger the battery the less work it needs to do so it will run cooler, as well as the ESC will run cooler?
I like what this guy is suggesting , and the chart that he gives is pretty helpful as well. I found it in the 1/8 Electric Conversion Thread.


Originally Posted by Edumakated
I would go with the 2.5d or 3d on 5s lipos. You will get substantially longer run times as the setup will be more efficient.

The motor speed is KV x voltage = rpms. So if the motor runs at 3300kv on a 4s lipo (14.8 volts) it will spin at about 49,000 rpms. A typical nitro only spins at 30-38,000 rpms.

It is important to keep in mind that lower kv motors and higher voltage run cooler and more efficient (longer run times). They are also just as fast as higher kv setups with the appropriate gearing and voltage.

the 1.5d is brutally fast on 4s and so is the 2d. However, they are not the most efficient and can be hard on your ESC and batteries. Great motors in the right hands, but you are limiting your future voltage options and run time.

Impaktrc.com has a great chart to show suggested voltage and kv for RPMs.

http://www.impaktrc.com/popup_image.php?pID=3076

The 1512 motors and their KV:

1512 1.5d (3300kv), use on 3s or 4s
1512 2d (2700kv), use on 4s
1512 2.5d (2050kv) use on 4s, 5s, or 6s
1512 1y (1850kv) use on 5s or 6s
1512 3d (1700kv) use on 5s or 6s

#s, means the number of cells in a lipo pack at 3.7 volts per cell, so

3s = 11.1 volt (3 x 3.7, etc)
4s = 14.8 volt
5s = 18.5 volt
6s = 22.2 volt

The higher voltages run cooler with lower kv motors. A 1512 1.5d on 3s spins at about 36,000 rpms which is a tad faster than an nitro. A 1512 1y on 5s spins about 34,000 rpms which is similar to the above setup. However, it will run significantly longer and cooler as less amps for the same amount of power.

In other words, a 1512 1.5d you need 3s 8000 mah battery... where as you can run a 5s 4000mah battery with a lower kv motor for the same speed and much more run time.

Confused yet?

If you plan on racing, pick a motor and voltage that allow you run around 30-40,000 rpms. My suggestion is the 2.5d or 3d on 5s. You can get 20-25 minutes of run time under race conditions.
*Chrominator* is offline  
Reply With Quote
Old 08-30-2008, 05:49 AM
  #62  
Tech Elite
iTrader: (86)
 
jhautz's Avatar
 
Join Date: Jan 2006
Posts: 4,263
Trader Rating: 86 (100%+)
Default

1700kv is a perfect racing setup on 5s. I currently run a 1700kv motor on 5s in my conversion and it is perfect. For 4s I would go for 2100kv. This seems right in the wheelhouse for what most are finding to be good racing setups.

Not sure anyone will really be happy with 3s and these kv motors IMO.
jhautz is offline  
Reply With Quote
Old 08-30-2008, 06:17 AM
  #63  
Tech Lord
iTrader: (81)
 
Davidka's Avatar
 
Join Date: Oct 2004
Posts: 10,426
Trader Rating: 81 (100%+)
Default

3s should be a non issue at this point. It seems to me that nobody running 1/8 electric is using 3s any longer. With Losi, MaxAmps and others packaging ready made 4s batteries this will likely become the standard in 1/8 similar to the way 7.2v has been the standard for 1/10.
Davidka is offline  
Reply With Quote
Old 08-30-2008, 09:14 AM
  #64  
Tech Regular
 
Join Date: May 2008
Location: Toronto, ON, Canada
Posts: 265
Default

I would prefer using a 5s setup over 4s, as it's higher voltage/less amps and thus more efficient (in theory).

The problem is that there are less (if any) hard-cased 5s batteries avaliable compared to 4s, and the 5s batteries will be slightly wider than ones with an even number of cells (because the plus and minus ends will be on the opposite ends, so you'll need to run one of the discharge wires along the entire length of the battery).

But going up to 6s seems like a little too much (not to mention Monster is the only ESC that officially supports that high of a voltage), and you'd need a really low kV motor to stay in efficient motor RPM range.

Compromises... :\
shurcooL is offline  
Reply With Quote
Old 08-30-2008, 10:07 AM
  #65  
Tech Legend
iTrader: (255)
 
Cain's Avatar
 
Join Date: May 2002
Location: West Fargo, North Dakota
Posts: 31,349
Trader Rating: 255 (100%+)
Default

if the demand is there, don't be suprised if losi makes a hardcased 5s battery pack.

As far as I know, losi is the only one with a hardcased 4s pack on the way right now
Cain is online now  
Reply With Quote
Old 08-30-2008, 02:21 PM
  #66  
Tech Elite
iTrader: (22)
 
Drift_Buggy's Avatar
 
Join Date: Dec 2004
Location: Australia
Posts: 2,661
Trader Rating: 22 (100%+)
Default

Originally Posted by Cain View Post
if the demand is there, don't be suprised if losi makes a hardcased 5s battery pack.

As far as I know, losi is the only one with a hardcased 4s pack on the way right now

I hope so, I would get the 5S hardcase but depending on what size. Most 5S packs are pretty tall and don't fit under the buggy body.

Impakt/Tekno RC have a chart out for a little guide

Drift_Buggy is offline  
Reply With Quote
Old 08-30-2008, 05:27 PM
  #67  
Tech Regular
 
Join Date: May 2008
Location: Toronto, ON, Canada
Posts: 265
Default

Originally Posted by Drift_Buggy View Post
Most 5S packs are pretty tall and don't fit under the buggy body.
You do realize you don't need the same mAh when you're going up in cell count, right? I hope you're not looking at 5s 5000 mAh packs vs. 4s 5000 mAh packs.

4 cells * 3.7v/cell * 5000 mAh = 74 Watt*hour (total power avaliable to be delivered)
5 cells * 3.7v/cell * 4000 mAh = 74 Wh

I'm sure a 4000 mAh 5s battery will be pretty similar in size (volume) as a 4s 5000 mAh one. Although 5s usually tends to be taller and shorter.

Just wanted to throw that out there.
shurcooL is offline  
Reply With Quote
Old 08-31-2008, 12:15 AM
  #68  
Tech Addict
iTrader: (32)
 
Join Date: Mar 2004
Location: west side, Mi.
Posts: 698
Trader Rating: 32 (97%+)
Thumbs up

Originally Posted by Cain View Post
Runtime can vary. I know badassrevo on his converted losi 8ight was running almost 25 minutes with a 5000mah pack, then on a track change, couldn't make 20. I would say a 5000mah should be good for 15 minutes.

If you must make 20 minutes, give a 6000mah pack a look. I did this with my rc8 by using a PolyRC 6000mah 4S 25C pack. its heavier of course, but not really noticeable in the RC8. as the weight is more centerd on the losi, could work out quite well.

i can only make 13 minutes on my Neu Energy 5000 30c/60c packs, i run RC8, mamba monster, Neu 1512 2.0 d/f (2550 kv), 15/46. but i race very hard. so it really depends on the track surface/grip, size of track, and youre driving style to figure runtime.

i really like the looks of the losi EIGHT, i have driven one and they are sweet. GJ Losi
Apl Hed is offline  
Reply With Quote
Old 08-31-2008, 12:37 AM
  #69  
Tech Addict
iTrader: (32)
 
Join Date: Mar 2004
Location: west side, Mi.
Posts: 698
Trader Rating: 32 (97%+)
Default

Originally Posted by trdsupra88 View Post
good point although Ive never seen an 8th scale race on an electric track but Im guessing theres not alot of room...
been there.......done that. electric 8 is fun anywhere, my RC8-E turns on a dime and gives up change. i have abolutely no probs on a 1/10 scale track.
Apl Hed is offline  
Reply With Quote
Old 08-31-2008, 06:53 AM
  #70  
Tech Master
iTrader: (37)
 
Racerx336's Avatar
 
Join Date: Nov 2007
Location: Allen, Tx.
Posts: 1,449
Trader Rating: 37 (100%+)
Default

Originally Posted by Apl Hed View Post
been there.......done that. electric 8 is fun anywhere, my RC8-E turns on a dime and gives up change. i have abolutely no probs on a 1/10 scale track.
You are correct, I run faster times with my RC8E than I do with my zx5/gtb/5.5 combo at our local 10th scale indoor track.
Racerx336 is offline  
Reply With Quote
Old 08-31-2008, 12:26 PM
  #71  
Tech Legend
iTrader: (255)
 
Cain's Avatar
 
Join Date: May 2002
Location: West Fargo, North Dakota
Posts: 31,349
Trader Rating: 255 (100%+)
Default

Originally Posted by Apl Hed View Post
i can only make 13 minutes on my Neu Energy 5000 30c/60c packs, i run RC8, mamba monster, Neu 1512 2.0 d/f (2550 kv), 15/46. but i race very hard. so it really depends on the track surface/grip, size of track, and youre driving style to figure runtime.

i really like the looks of the losi EIGHT, i have driven one and they are sweet. GJ Losi
The 2.0 1512 is more of a pig on runtime than the 2.5D . The 1512 2.5D is actually quite thrifty.
Cain is online now  
Reply With Quote
Old 08-31-2008, 01:04 PM
  #72  
Tech Elite
iTrader: (19)
 
Join Date: Dec 2007
Location: Chicago, IL
Posts: 2,854
Trader Rating: 19 (100%+)
Default

Originally Posted by Apl Hed View Post
i can only make 13 minutes on my Neu Energy 5000 30c/60c packs, i run RC8, mamba monster, Neu 1512 2.0 d/f (2550 kv), 15/46. but i race very hard. so it really depends on the track surface/grip, size of track, and youre driving style to figure runtime.

i really like the looks of the losi EIGHT, i have driven one and they are sweet. GJ Losi
Yup. This is why I moved to the 2.5d and lower kv setups. I could barely get 12-13 minutes with my 1.5d with a 4s 5000. With a 4s 5000 and the 2.5d, you should be able to get right at 20 minutes. I run 15 minute mains with a minute or two of warm up laps and have no problems. I always have a little extra left at the end of the race too. Bump up to 5s and 20 minutes is no problem with a 5s 4000 battery. A 5s 5000 should get you right at 25 minutes or so.

1512 1.5d (135 amps)
1512 2d (120 amps)
1512 2.5d (78 amps)
1512 3d (70 amps)

The fuel efficiency is obvious...
Edumakated is offline  
Reply With Quote
Old 08-31-2008, 01:20 PM
  #73  
Tech Elite
iTrader: (19)
 
Join Date: Dec 2007
Location: Chicago, IL
Posts: 2,854
Trader Rating: 19 (100%+)
Default

I hope there isn't a motor or voltage "standard." What I love about this class is that people are free to experiment with what works best for them. In addition, electric 1/8th setups are so fickle, a simple track change could mean the difference between being able to make a 10 minute main vs a 20 minute main.

Personally, I like going with the lower kv/higher voltage stuff as it is more versatile and you can always be assured you will be able to run long enough.

IMHO, 4s and 5s are the way to go.

3s works but you need to run a minimum of 8000 mah to get any kind of decent run time. The motors are too demanding as well. No one really makes a 3s battery that can withstand the strain a Neu 1512 1.5d puts on it. I puffed a 25c Polyquest 3s 6000 pack after a couple of races. I had good luck with a 3s 8000 maxamps battery, but the setup is not efficient enough for hard racing.

4s works if the motor isn't drawing much more than say 80amps. The Neu 1512 1.5d and 2d are amp hungry motors. I suspect this is why Losi only has a 2100kv motor. Anything more is going to be very demanding and limit run time.

5s is the best for run time. I am never going back down to 4s. The batteries are a tad heavier, but not so heavy that the balance of the car is thrown off. From what I have seen having race quite a few different setups, a < 2000kv motor on 5s is perfect. Long run time and still faster than nitro top end. The batteries fit great under the body as well (at least on with my rc8 body).

6s is probably great for long run times. The problem with 6s is that you need high end chargers. The batteries are also pretty heavy and tall. Althought, you shoudl be able to get away with a 6s 3500mah pack for most situations.
Edumakated is offline  
Reply With Quote
Old 09-01-2008, 07:00 AM
  #74  
Tech Elite
iTrader: (86)
 
jhautz's Avatar
 
Join Date: Jan 2006
Posts: 4,263
Trader Rating: 86 (100%+)
Default

Originally Posted by air8 View Post
Anyone know who's producing the electronics for this buggy?

And did I hear right, that there is a limited production at first?
Originally Posted by rocketron View Post
neither are true
Originally Posted by tyhodge07 View Post
i heard it was hacker or novak
I got it from a couple reliable sources that the electronics for this esc is made by hobbywing in china and the esc hardware design is basically a rip off of the Novak circuits but with sensorless software.

I am not holding out to much hope that this is going to be very good. Hobbywing is the same people that make all of the other low end stuff like the venom, speedpasion, orion. They are basically a no name company that produces escs and then labels them any way another company wants them. Basically cheap stuff labeled any way you want. I guess we will see when it actually comes out out I'm not holding out to much hope at this point. I had one on pre-order, but at this point I canceled it after finding this out. I'll let someone else waste some testing money on this before spending mine on it. Not sure on the motor manufacturer yet.

Here is the website for hobbywing
http://www.hobbywing.com/english/Pro...em%20for%20Car

EDIT: Pretty lame of Losi to basically copy its competitors stuff too IMO.

EDIT AGAIN: If you look at the Hobbywing website it has a section for 1/8 car brushless systems, but nothing is listed yet. I'm betting that in the near future, we will be able to buy the same controller as the Losi but with a hobbywing sticker on it and save some money.

Last edited by jhautz; 09-01-2008 at 07:13 AM.
jhautz is offline  
Reply With Quote
Old 09-01-2008, 07:40 AM
  #75  
Tech Regular
 
Join Date: Jul 2008
Posts: 477
Default

hmmmm there are a couple racers at my track that have the losi esc/motor combo in 10th scale rigs and they havent had any problems with their stuff. i think the losi motors are made by the same factory that makes the mamba/tekin motors. not sure about the esc but the guys that have them around here like them and have had good luck with them so far. im not gonna worry about it. heck 99.9% of all rc crap is made over sea anyway.
charly71 is offline  
Reply With Quote

Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service