### Author Topic: How much power?  (Read 1109 times)

0 Members and 1 Guest are viewing this topic.

#### catch22

• Beginner
• Posts: 5
##### How much power?
« on: January 31, 2011, 07:26:03 PM »
I am building a vehicle using wheelchair motors (PG8) I have two 12 v 18ah batteries that are fully charged.  The controller has two neg and positive leads, so I am figuring one set goes to each battery and the controller combines these to make 24 volts.

When I hook them up to the batteries, I get only one green bar and when I hit the joy stick, I get a click from the motor.   I tried hooking the two in parallel and using a car battery for the other lead. With this, I got the motors to run, but they only run a short time when they seem to cause a breaker of some kind to activate (power light starts flashing and motors stop.  Have to turn power off and then on again to get it to run again for a little bit).

I am going to try some large car batteries, but not sure why the motors are not working with the 18ah batteries.

Any thoughts?

#### rbtying

• Supreme Robot
• Posts: 452
##### Re: How much power?
« Reply #1 on: January 31, 2011, 07:29:15 PM »
Please provide an electrical schematic and/or picture of your setup, it is significantly easier to read than a block of text.

Moreover, please tell us what controller you are using - there are literally hundreds of them out there.

#### Soeren

• Supreme Robot
• Posts: 4,672
##### Re: How much power?
« Reply #2 on: January 31, 2011, 09:16:26 PM »
Hi,

The controller has two neg and positive leads, so I am figuring one set goes to each battery and the controller combines these to make 24 volts.
Loose assumptions can be a real circuit destroyer!
Find a data sheet on the controller and make sure.

When I hook them up to the batteries, I get only one green bar and when I hit the joy stick, I get a click from the motor.   I tried hooking the two in parallel and using a car battery for the other lead. With this, I got the motors to run, but they only run a short time when they seem to cause a breaker of some kind to activate (power light starts flashing and motors stop.  Have to turn power off and then on again to get it to run again for a little bit).
Again, find a data sheet. It sounds like you need to wire something different - Do the motors have brake wires that need to be connected up? Did the motors run full speed for however short the time was?
Perhaps the power terminals are for 24V main and 24V reserve battery (but do check the data sheet before you fry anything).
How many wires come from each motor?
Did you try wiring up a motor without the controller? (just try it on 12V first, it should move at reduced speed, but move it should).

I am going to try some large car batteries, but not sure why the motors are not working with the 18ah batteries.

Any thoughts?
About people just looking for a larger hammer when things doesn't work? Yes, but you wouldn't like them

What is written on each motor?
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Engineering is based on numbers - not adjectives

#### catch22

• Beginner
• Posts: 5
##### Re: How much power?
« Reply #3 on: February 01, 2011, 08:21:25 PM »
Thanks All

Motors are Penny & Giles with these numbers - D49305/3.   I have written to PG and they are looking for a diagram for this unit. (It apparently is an oldie.  They called it a PG8 when they responded to me.

Tried again tonight with two car batteries.  Motors run and seem to get to speed.  Just think that these motors may need just more amps than the smaller batteries provide.  Of course, the bigger amp batteries mean I have to figure out where to put them in the project.

The unit has two motors with factory wiring that connect to a single box that also has two battery plug in ports. This unit has another cable that goes to the controller with the power switch, speed control, indicator and joy stick.  All is factory and does not appear to have been changed.

#### Soeren

• Supreme Robot
• Posts: 4,672
##### Re: How much power?
« Reply #4 on: February 02, 2011, 09:48:56 PM »
Hi,

Motors are Penny & Giles with these numbers - D49305/3.   I have written to PG and they are looking for a diagram for this unit. (It apparently is an oldie.  They called it a PG8 when they responded to me.
Uh oh, if P&G don't know, what are our chances of knowing then.

Tried again tonight with two car batteries.  Motors run and seem to get to speed.  Just think that these motors may need just more amps than the smaller batteries provide.  Of course, the bigger amp batteries mean I have to figure out where to put them in the project.
You didn't measure the voltage on the smaller batteries while trying them?
I doubt that they shouldn't at least get it to run.

Once more...Did you try wiring up a motor without the controller?

The unit has two motors with factory wiring that connect to a single box that also has two battery plug in ports. This unit has another cable that goes to the controller with the power switch, speed control, indicator and joy stick.  All is factory and does not appear to have been changed.
Still, you should check a motor without the controller (at 12V).
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?