Advice please : Quick voltage and amps question + speed control

[A_Camera]

Ok I have 3 x 18v 3a motors to run in parallel. I was thinking of using a 24v 10 amp battery charger..will I die ?
And can I add a potentiometer somewhere easily to it or do I need a PWM with pot?

Here’s what I was thinking:
10AMP 12V/24V HEAVY DUTY BATTERY CHARGER ELECTRICAL CAR VEHICLE VAN TRUCK LORRY

That is only a 24V/5A so it will not work, at least not with any significant torque, if at all. You get 10A out only if you flip the switch to 12V out.

No, you will probably not die if you connect it, but of course, no guarantee is given by me. Anyway, why would you buy that to run motors? I mean, as far as I know, lead battery chargers pulse the output, which means that you need to modify the charger to get constant voltage and current out of it, and based on your questions, you can't do that. Why not buy a proper power supply? OK, more expensive... but there is a reason.

[Fivetide]

That is only a 24V/5A so it will not work, at least not with any significant torque, if at all. You get 10A out only if you flip the switch to 12V out.

No, you will probably not die if you connect it, but of course, no guarantee is given by me. Anyway, why would you buy that to run motors? I mean, as far as I know, lead battery chargers pulse the output, which means that you need to modify the charger to get constant voltage and current out of it, and based on your questions, you can't do that. Why not buy a proper power supply? OK, more expensive... but there is a reason.

I thought it was 5 - 10 amps ? Anyway I rechecked the values and each motor pulls 1.7 Ah so I was thinking about 24v 5a 120w or I could go for the 24v 10A 240w ? there's only £5 difference. Couple that like magicniner suggested to the 10-50V 40A PWM DC Motor Speed Controller CW/CCW Reversible Pulse Driver TE535 and hopefully it will have the power.. what do you think ?

[cropwell]

First of all, forget potentiometers. You would need f**cking great big wirewound ones to handle the power.

Also for 18v motors I would use an 18v supply. PWM controllers give you full voltage, but vary the on/off ratio. This means you get full torque, but the power is in bursts, which regulates the speed. If you are using 24v then you could burn out the motors.

I look forward to the time you show your balls to the forum !

Cheers,

Rob

[A_Camera]

I thought it was 5 - 10 amps ? Anyway I rechecked the values and each motor pulls 1.7 Ah so I was thinking about 24v 5a 120w or I could go for the 24v 10A 240w ? there's only £5 difference. Couple that like magicniner suggested to the 10-50V 40A PWM DC Motor Speed Controller CW/CCW Reversible Pulse Driver TE535 and hopefully it will have the power.. what do you think ?

It's 12V/10A or 24V/5A you can not select the ampere, only the voltage. Get a proper power supply like this instead of a charger:

http://www.ebay.com/itm/272388436734...%3AMEBIDX%3AIT

You are better off with those than a battery charger designed for charging lead batteries.

[Fivetide]

It's 12V/10A or 24V/5A you can not select the ampere, only the voltage. Get a proper power supply like this instead of a charger:

http://www.ebay.com/itm/272388436734...%3AMEBIDX%3AIT

You are better off with those than a battery charger designed for charging lead batteries.

Ok it seems I need to think a bit more about this.. this is what I'm trying to replicate for my Uncle. But we have managed to gather 3 x 18v 1.7aH drills so far between us.

[Clive S]

How about three steppers

[Fivetide]

How about three steppers

Yeah Clive I have 3 Nema 17 high torque but I wasn't sure if running them constantly for 20 mins would be ok ?

[Clive S]

Yeah Clive I have 3 Nema 17 high torque but I wasn't sure if running them constantly for 20 mins would be ok ?

Nema's can run for hours think router and 3d printers, they can also run very hot in access of 60C without problems.

They also have the better torque at lower speeds

[A_Camera]

Yeah Clive I have 3 Nema 17 high torque but I wasn't sure if running them constantly for 20 mins would be ok ?

Sure it's OK to run them constantly for hours also, but you need a driver for each and a motion controller also. So it is a bit more complicated. Even if you don't want a driver for each motor, just want to connect all three in parallel it is a fair bit more complicated to do what you are showing in the video.

[magicniner]

Get the 24V PSU and a single PWM controller rated to run all three motors, check the specification of the motors for current draw, you've just referred to the motor ratings as aH (amp hours) which is a battery charge capacity not a motor current draw.
If you don't have one get a multi-meter so you can check voltages and currents once you have something to fiddle with.