An Unusual Configuration

geterdone · 07-11-2009, 01:37 PM

I'm trying to do something a bit odd, and was wondering if anybody thinks it's a bad idea as I'm not an EE.

I have a '94 36v resister cart with a 1012191 2HP 2800RPM @ 36V motor.

It's mainly just for moving heavy tools around a flat piece of land; don't really ever go more than 5-10 MPH.

The 7 yr old Trojan T-105's are starting to finally give up the ghost, to the point they won't go much more than a mile. At $600-800 for a new set of batteries, I'm trying to find a cheaper and more permanent way to run the cart longer distances. One of the things that the cart is ALWAYS carrying around is a 3500 watt / 25 amp generator for the other tools. So I was thinking about getting a DC speed controller, hooking it up to the generator, and keeping the batteries for just short trips.

The only thing I'm not sure about is the fact that most AC powered DC speed controllers put out either 90V or 180V DC. Since many others are running 90V+ on this motor, can I just use a 1 HP @ 90 V / 12A speed controller and connect it up? Is the fact I'm not fully powering the motor going to present any issues? Will it work with the existing resister-cart speed voltage controller? Would I need to isolate the battery bank from the higher voltage?

Any advice would be appreciated.

dock98 · 07-11-2009, 01:39 PM

welcome to BGw.geterdone.i am sure one of the "toaster" gurus will be along to help.

be patient.its the weekend.

roady89 · 07-11-2009, 02:26 PM

No, simply not going to happen. The generator will have to be the size of a large welding machine. 25 amps won't even get it rolling.

You could run charger off the generator but you won't gain much if anything at all. Actually, you'll burn more money in fuel than if you would just buy a set of batts.

Nate · 07-11-2009, 02:33 PM

The problem with a controller that takes AC in and gives you a DC out is it won't be able to handle the impedance of your golf cart motor. The golf cart motor has way too low impedance and will quickly over amp the controller you suggested.
You could have the generator operate your battery charger to help keep the batteries toped off but your start current (start from dead stop) could blow the charger fuse if it is still plugged in when you go.
This can be done but you would need to control current from the generator either with a step down transformer in the 2KW range or a large switching device, neither cheap and the transformer would be heavy.
Feel free to ask any more questions you might have or point out something I may have overlooked.

geterdone · 07-11-2009, 03:32 PM

Yeah that's along the lines of what I was thinking would be an issue.
I know there are aircraft dc supplies that will put out 32V @ 100amps, but unfortunately they weigh in at 200+ lbs, and I'm not even sure if that's an appropriate amount of umph.

Nate · 07-11-2009, 06:28 PM

To give you an idea of what you are up against:
Bone stock 36V cart can surge 250 amps at start then settle down to about 50 amps for cruising.

Fleck · 07-11-2009, 06:44 PM

Could that size generator power a regular cart charger? Often thought about bringing a small generator when I go wheelin.

dougmcp · 07-12-2009, 11:44 AM

Quote:

Originally Posted by Fleck

Could that size generator power a regular cart charger? Often thought about bringing a small generator when I go wheelin.

Yes, the Honda 3000 is the bare minimum I would use. The Honda 2000 will go into overload and not do anything to charge a cart.

Nate · 07-13-2009, 07:22 PM

If you are talking about supplementing power while the cart is running you would need a bigger charger or some kind of power supply. 30 amps are the most you can put in the pack while removing at least 50 amps.

Fleck · 07-13-2009, 09:19 PM

Quote:

Originally Posted by Nate

If you are talking about supplementing power while the cart is running you would need a bigger charger or some kind of power supply. 30 amps are the most you can put in the pack while removing at least 50 amps.

Nate; if you are talking about my last post. I'm talking about just having the charger and generator along in case the buggy needs a little more "Gas" to get back home, I have yet to see any charger ports while in the woods

07-11-2009, 01:37 PM	#1
geterdone Not Yet Wild Join Date: Jul 2009 Posts: 3	An Unusual Configuration I'm trying to do something a bit odd, and was wondering if anybody thinks it's a bad idea as I'm not an EE. I have a '94 36v resister cart with a 1012191 2HP 2800RPM @ 36V motor. It's mainly just for moving heavy tools around a flat piece of land; don't really ever go more than 5-10 MPH. The 7 yr old Trojan T-105's are starting to finally give up the ghost, to the point they won't go much more than a mile. At $600-800 for a new set of batteries, I'm trying to find a cheaper and more permanent way to run the cart longer distances. One of the things that the cart is ALWAYS carrying around is a 3500 watt / 25 amp generator for the other tools. So I was thinking about getting a DC speed controller, hooking it up to the generator, and keeping the batteries for just short trips. The only thing I'm not sure about is the fact that most AC powered DC speed controllers put out either 90V or 180V DC. Since many others are running 90V+ on this motor, can I just use a 1 HP @ 90 V / 12A speed controller and connect it up? Is the fact I'm not fully powering the motor going to present any issues? Will it work with the existing resister-cart speed voltage controller? Would I need to isolate the battery bank from the higher voltage? Any advice would be appreciated.
geterdone Not Yet Wild Join Date: Jul 2009 Posts: 3

07-11-2009, 01:39 PM	#2
dock98 doin it in the desert Join Date: Dec 2008 Location: Sonora Desert,Az Posts: 5,603	Re: An Unusual Configuration welcome to BGw.geterdone.i am sure one of the "toaster" gurus will be along to help.be patient.its the weekend.

07-11-2009, 02:26 PM	#3
roady89 nimda Join Date: Jun 2007 Posts: 13,022	Re: An Unusual Configuration No, simply not going to happen. The generator will have to be the size of a large welding machine. 25 amps won't even get it rolling. You could run charger off the generator but you won't gain much if anything at all. Actually, you'll burn more money in fuel than if you would just buy a set of batts.
roady89 nimda Join Date: Jun 2007 Posts: 13,022

07-11-2009, 02:33 PM	#4
Nate Gone Wild Join Date: Dec 2006 Posts: 679	Re: An Unusual Configuration The problem with a controller that takes AC in and gives you a DC out is it won't be able to handle the impedance of your golf cart motor. The golf cart motor has way too low impedance and will quickly over amp the controller you suggested. You could have the generator operate your battery charger to help keep the batteries toped off but your start current (start from dead stop) could blow the charger fuse if it is still plugged in when you go. This can be done but you would need to control current from the generator either with a step down transformer in the 2KW range or a large switching device, neither cheap and the transformer would be heavy. Feel free to ask any more questions you might have or point out something I may have overlooked.
Nate Gone Wild Join Date: Dec 2006 Posts: 679

07-11-2009, 03:32 PM	#5
geterdone Not Yet Wild Join Date: Jul 2009 Posts: 3	Re: An Unusual Configuration Yeah that's along the lines of what I was thinking would be an issue. I know there are aircraft dc supplies that will put out 32V @ 100amps, but unfortunately they weigh in at 200+ lbs, and I'm not even sure if that's an appropriate amount of umph.
geterdone Not Yet Wild Join Date: Jul 2009 Posts: 3

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07-11-2009, 06:28 PM	#6
Nate Gone Wild Join Date: Dec 2006 Posts: 679	Re: An Unusual Configuration To give you an idea of what you are up against: Bone stock 36V cart can surge 250 amps at start then settle down to about 50 amps for cruising.
Nate Gone Wild Join Date: Dec 2006 Posts: 679

07-11-2009, 06:44 PM	#7
Fleck Gone Crazy Join Date: Nov 2008 Location: Pine Hill NJ Posts: 560	Re: An Unusual Configuration Could that size generator power a regular cart charger? Often thought about bringing a small generator when I go wheelin.

07-13-2009, 07:22 PM	#9
Nate Gone Wild Join Date: Dec 2006 Posts: 679	Re: An Unusual Configuration If you are talking about supplementing power while the cart is running you would need a bigger charger or some kind of power supply. 30 amps are the most you can put in the pack while removing at least 50 amps.
Nate Gone Wild Join Date: Dec 2006 Posts: 679

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