Power supplies 12v (not really a car)

[Tigercubrider]

So, I am building a “thing” that is going to hopefully revolve, and the motor is a 12v 150w kids scooter motor.
By my reconning a 12.5A PSU should be ok?
I might bung up the capacity to 15A if I can find something cheap

 

[flameport]

12.5A is theoretically correct.
In reality it will require a much larger power supply as the starting current will be considerably more than the running current.

 

[carmanmemoranda]

No connection to theses people but they do have interesting features, news and technical advice for pretty much anything 12volt related

Auto and Marine Electrical Components Knowledge Centre 12 Volt Planet

Welcome to our Knowledge Centre! Here you can find useful information, tips and guidance on various topics related to vehicle electrics. Auto and Marine Electrical Components - 12 Volt Planet. Useful guides and resources vehicle and marine electrics

www.12voltplanet.co.uk

 

[big-all]

is it geared down or direct drive and speed controlled electronically or a mixture off both ??
gearing is much much better at controlling heavy slow loads than electronics
as in gearing to give maximum required speed with electronics out[least restriction/resistance ]with electronics plus gearing change off gear][to reduce speed efficiently
whilst electronics can fully cover the function off gearing in modern high-powered motors it needs to be within a specific range that cruder setups may not get near to

 

[RandomGrinch]

I might bung up the capacity to 15A if I can find something cheap

If you want something cheap to start playing with, you could look at a 2nd hand PC power supply?
Dead cheap, with plenty of current available, although there may be some load balancing issues to be aware of.

 

[Tigercubrider]

Thanks all
I did wonder about a gearbox, I have a new 150w 12v scooter motor and a maybe 5" or so scooter wheel, connected by belt drive (toothed)
my logic was that if it can be powerful enough to shift a kids scooter it should do for my needs.
I was going for an electronic speed control as that is what they seem to use.

I have a couple of old PCs destined to be scrapped and also have a car jump starter/compressor pack that should have the amps

 

[magicmushroom666]

Are you using the electronics from the scooter? that would be sensble as it might not be a DC motor that you can just connect 12V directly to. With the scooter electrics you can connect the supply to where the battery was assuming the battery was 12V.

 

[Tigercubrider]

I don't have the control as the bits are new (and cheaper than a broken scooter)

it is a DC motor

 

[martygturner]

12.5A is theoretically correct.
In reality it will require a much larger power supply as the starting current will be considerably more than the running current.

Not really as the starting current will depend on the motor load present at start up and the maximum amps drawn will be at the stall load of the motor. In a 12v battery operated dc motor the amps drawn will discharge the small battery very quickly at stall , which will to a degree limit the amps drawn by the motor, however most have either a) the battery thermal cut out or b a motor one or c an over draw circuit ( a motor stall circuit...amps rising off she switches.)...I would suggest a and c in a child's scooter. I would suggest that you calculate the load first on the 150w motor, and then see what size power supply you need to drive that load, don't go over size, the right size for the load and make sure you pop some for of over load circuit in - good old fuse will do.

 

[mattylad]

Old server power supplies are often converted to 12v/13.8v for ham radio use because they can deliver lots of amps.

Although for this a simple 12v 8A PSU should suffice, usually plenty on ebay.