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Old 02-04-2009, 08:55 AM   #1
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Default can you run 1/8scale electric on a 3s lipo

Will it still haul the mail, or will it be a dog.

I have RC8E, with MMM 2650.

Thanks,
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Old 02-04-2009, 09:13 AM   #2
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Yes but it's not recommend, this will suck a lot of amp and put lot stress on the battery.
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Old 02-04-2009, 09:19 AM   #3
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You can do it, but sooner or later you are going to puff your battery. The system will be pulling too many amps. Most 3s batteries are not going to be up to the challenge. You need 4s minimum to have a reliable setup.
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Old 02-04-2009, 09:37 AM   #4
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thanks, 4s it is then, case closed.
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Old 02-04-2009, 09:57 AM   #5
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It actually depends on what batter and motor you run. Just running on 3s doesn't automatically equal high amps and puffed packs. A lot of guys that have run 3s were also running stuff like 3300kv motors and small capacity packs.

If you run the 2650 on a good size 3s pack, it should be fine. A 4s 4500 pack would equal a 3s 6000 pack for example so you can go bigger capacity when you run fewer cells without adding weight/size.

Amp draw will drop going from 4s to 3s... if you don't change the gearing. But of course, you will gear the 3s taller so that will bring the amps back up. If you gear both setups for the same speed, then the 3s should be pulling more amps... that's not something I have actually checked. I am curious to see it first hand though... so that's a project I might do.
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Old 02-04-2009, 10:18 AM   #6
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Quote:
Originally Posted by glassdoctor View Post
It actually depends on what batter and motor you run. Just running on 3s doesn't automatically equal high amps and puffed packs. A lot of guys that have run 3s were also running stuff like 3300kv motors and small capacity packs.

If you run the 2650 on a good size 3s pack, it should be fine. A 4s 4500 pack would equal a 3s 6000 pack for example so you can go bigger capacity when you run fewer cells without adding weight/size.

Amp draw will drop going from 4s to 3s... if you don't change the gearing. But of course, you will gear the 3s taller so that will bring the amps back up. If you gear both setups for the same speed, then the 3s should be pulling more amps... that's not something I have actually checked. I am curious to see it first hand though... so that's a project I might do.
I did for a couple of race weekends using the 1.5d with a 3s 6000 25c PQ and a 3s 8000 max amps pack. The 3s 6000 puffed after a few races. The Maxamps packed performed quite well. The batteries were getting hot though so they were over taxed. This is geared for race speeds, so not like I was doing speed runs.

With the 35c packs that are out now, it might be possible to use 3s reliably but in my experience it didn't perform as well as 4s.

I have considered trying to rebuild an ultra-light buggy with a 1509 and 3s though if the 10 minute main becomes standard.
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Old 02-04-2009, 10:20 AM   #7
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Quote:
Originally Posted by glassdoctor View Post
It actually depends on what batter and motor you run. Just running on 3s doesn't automatically equal high amps and puffed packs. A lot of guys that have run 3s were also running stuff like 3300kv motors and small capacity packs.

If you run the 2650 on a good size 3s pack, it should be fine. A 4s 4500 pack would equal a 3s 6000 pack for example so you can go bigger capacity when you run fewer cells without adding weight/size.

Amp draw will drop going from 4s to 3s... if you don't change the gearing. But of course, you will gear the 3s taller so that will bring the amps back up. If you gear both setups for the same speed, then the 3s should be pulling more amps... that's not something I have actually checked. I am curious to see it first hand though... so that's a project I might do.


Any tips for the Fusion EX-1 Pro..??.......A good set up for mains.....
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Old 02-04-2009, 10:25 AM   #8
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In my opinion...

It is always better to run higher voltage rather than higher current. The batteries like it better, the controllers like it better, and the motors usually like it better too. Keep this in mind. If you double the current, the power lost due to resistance will go up by a factor of 4 not 2. So even though you have to go to higher winding motor, thus adding resistance, you will still have a more efficient system at higher voltage than lower voltage.

Since the controller builders are all making 6S the max, running on 5S is no sweat for those controllers.
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Old 02-04-2009, 03:20 PM   #9
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I have been running the Reedy 3s 3200 25C packs with zero problem for 4 months. I run on an indoor track and it has plenty of power and will run for 11-12 minutes. This set up makes the car very light and it handles the tight track better.
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