Best motor for my project

[clarkdef]

Hi all I signed up to this forum to get good advice on which motor to use on my project.

I am building a rwd hill climber my goal is to climb a certain dirt mountain section post a time then try and beat it every year.

I have a plan of using 6 Large motors using two battery packs per 3 motors, but the thing is I don't know how many motors my batteries can actually power properly, the batteries are 1.2v 2100mah, < can 6 of these power 3 large motors?

Or am I best to go with 4 XL motors? Or though I don't know if my batteries can power two of those either...

I am fairly new to this new type of technics my last set before the new stuff was 8880 supercar

So in conclusion: 3 large motors powered by 6x 1.2v 2100mah batteries, left rear wheel. 3 large motors powered by 6x 1.2v 2100mah, right rear wheel. Total 12x 1.2v 2100mah batteries and 6 large motors.

Hope I make sense...

[AndyCW]

Welcome to the forum and good luck with your project.

On to your questions.

It is not the batteries that are in the battery packs that matter as much as the battery packs themselves. The battery packs have a built in current limiter of sorts and so do the IR receivers. The PF motors are designed for the most part not to exceed the strength of the lego components and with this in mind they do not put out an enormous amount of power.

Six large motors would require 4 IR receivers and 4 battery backs to power them at their full potential. You may as well go with 8 large motors, because they would require the same battery and rx support.

The problem in my eyes is that as you scale up power, you also scale up weight and the increased weight ussually ofsets the majority of the gains. The overwhelming majority of fast and agile MOCs on here are fairly small in size.

You should check out this webpage. It details the properties of the different Lego motors. This can be used to help make educated decisions.

http://www.philohome.com/

The best Lego motor with regards to power output is the RC Buggy motor. It is motor number 5292 on Philo's website. It requires one rx and one battery pack per motor to allow it to "breath".

v/r

Andy

[clarkdef]

Wow thanks for this info I nearly spent a lot of money on bricklink my friend! Yes 4 battery packs is way too much weigh and space, it wouldn't get up the hill!

My limit for battery packs is 2.

According to 'Lego Motor's Chart' This is what I worked out and you are spot on my friend.

1x Buggy Motor: Power output 4.96, cost high - 55grams - one battery/rx + 496 divide 55 p/w ratio of 9.01

2x XL Motor: Power output 5.30, cost moderate - 138 grams - one battery/rx = 530 divide 69 p/w ratio of 3.84

2x L Motor: Power output 4.28, cost high - 84 grams - one battery/rx = p/w ratio of 5.09

I have built the chassis and I am very proud of it, took 2 weeks.. Buggy motors are the way, I do have another idea to avoid this computed limitation muhahahahaaaaa