1st bot

lol. Does anyone know how i can measure how long a battery would last at a certain wattage and voltage etc.

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so what weapon are we going to put on it
May I suggest using a gerbil so that it can gnaw your opponents into submission..... eventually :)

Not exactly Chompalot, more like Chewabit :proud:

Can someone please tell me how i calculate how long a battery will last

Heres how Id do it.

Volts= Joules/Coulomb
Amps= Coulombs/second.

For a 5 amp hour battery, that would be 5 * 3600 (secs in an hour) = 18000 coloumbs

at 30 amps 18000 Couloumbs (storage)/ 30 (rate) = 600 secs. Roughly 10 minutes.

Thats how Id do it anyway. Some1 is now bound to bring in an complex efficiency factor on the battery, but thats the basic physics.

Though its not that easy with the hamster.. :mrgreen:.

You cruel buggers. How can you expect a hamster wheel to spin at a 10:1 gear ratio? Even Im not that cruel to animals!

On the plus side, It appears to be the energy source of the future. According to Star Trek: The Next Generations engineering panels, a hamster powers the Enterprise Ds warp drive...

i love gerbils

Ok say i was gonna use four windscreen wiper motors what could i expect to get out of them e.g. speed rpm torque and what voltage etc. i need to use. Lets not have a discussion about weight etc.

I think they are about 150rpm when ran at 24volts, with a decent amount of torque. You would also need fairly large wheels (minimum of 200mm) and still would be slow.

so basically you wouldnt expect to get much speed out of them but a reasonable amount of torque. How much torque would you expect roughly. Can they be safely run at 24v?

mark you can get some decent speed out of them if you do what i am doing. Ive tore off the gearbox and am using cogs and chains to regear the motor. they can be safely run at 24v.

If you send me an email i can give you some pics and more info on what I am up to.