Moving to Lithium

[typhoon_driver]

Re: Moving to Lithium

Drill motors work fine. Used them in the featherweight typhoon bot and used two in the light weights. They won't give you the instant spin up from more powerful motors but will do the job.

Ratio out the gearbox you might wanna actually gear it up, the output from a standard drill gearbox is around the 800rpm mark, little bit slow in my book!

Good point Dave, I don't run my batteries until they're dead but there have been times that I haven't been able to charge them between battles so it's nice to know that I can run them again and still get a full fight from them.

[PJ-27]

Re: Moving to Lithium

My plan was to take take the gear box off the motor and then do a 10:1 reduction.

[typhoon_driver]

Re: Moving to Lithium

cool, only issue i could see you having with that is attaching something to the output shaft of the motor as they are tiny (only a few mm). You might as well look at getting a speed 900, decent power and a 6mm shaft. Not too expensive either.

[Mouldy]

Re: Moving to Lithium

For wire/connections I use silicon/wet noodle wire purchased from robotmarketplace.com I think robochallenge are also starting to stock wet noodle wire now though... Drop grant a pm.

Connectors I use deans connectors, there rated upto 70a contin, you can pick them up cheaply of eBay/robochallenge

As Gary said a speed 900 would be a good alternative... But if uve got a bit more weight spare you could go for a car fan motor. On 24v there really good. And better yet cheap of eBay/scrap yard

[PJ-27]

Re: Moving to Lithium

Would you say the car fan motor would be better than the 24v Drill motor? Car fan motor is pretty much in the Bitza spirit!

[Mouldy]

Re: Moving to Lithium

Id say so yeah, there quite powerful and high speed, I think some are around the 1hp mark. A lot of people who build spinners started of with car fan motor powered weapons

[RogueTwoRobots]

Re: Moving to Lithium

I've never used car fan motors but they'd be infinitely better than a drill motor.* If I remember correctly, some of them can chuck out close to 1hp (which, for comparison, is what a Bosch 750 produces). they've got nice thick shafts as well thus minimising the risks of bending from impacts.

*(NST uses a 24V drill motor but that's one of the good quality Dewalt drill motors that are far superior to run-of-the-mill drills)

EDIT: What Dave said

[PJ-27]

Re: Moving to Lithium

That's a really neat idea, I'll have to see if we an get hold of one....

[RogueTwoRobots]

Re: Moving to Lithium

This is a spin-up test of Tony Booth's robot DragonStrike, using a car fan motor from a Ford Mondeo. Cost him £5 out the scrappy:

http://www.youtube.com/watch?v=lV9oBPDI1so

Couldn't find any decent footage of DragonStrike fighting, but The Toonimator uses a similar setup and is very effective:

http://www.youtube.com/watch?v=dXzfHuTfibM

Just to give you an idea of what potential there is

[PJ-27]

Re: Moving to Lithium

Looks like we'll be making a trip to the scrappy then!

[PJ-27]

Re: Moving to Lithium

Just to confirm, are we talking about the motor that drives the engine cooling fan in most FWD cars or the motor that drives the cockpit air vents?

[typhoon_driver]

Re: Moving to Lithium

engine cooling motor

[PJ-27]

Re: Moving to Lithium

Cheers!

[Danjr1]

Re: Moving to Lithium

considering my 24v nimh pack has for some reason decided to die on me, I'm looking at lipo. what do people use for a voltage cut-off in the robot?

[typhoon_driver]

Re: Moving to Lithium

Damaging the writing of your nimh pack might have something to do with that. In that case I would think twice about moving to lipo considering the higher currents involved.

Anyway back to the question, most people don't. Just over size the pack and charge after every battle.