MuttDriver
1 µW
- Joined
- Nov 17, 2011
- Messages
- 2
Hello,
First post here, so please correct me if I am posting in the wrong place or breaking any rules.
I’ve recently got my hands on an old 24V electric forklift, and I’m planning to turn it in to two winter projects on a budget. Sadly there are no batteries, and the electronics has been picked apart with parts missing and cut wires everywhere, but the engines are working and seem to be in good condition.
I’m going to use the lift tower and hydraulics to make a stationary goods elevator for the first floor in my barn. The motor driving the hydraulics isn’t marked, but I’m guessing it is about 300 amps (24VDC). The hydraulic valve lever has a micro switch build in, that closes when you lift the forks. I could drive the motor with a contactor, but I haven’t found one for less than about 70 usd, and I'm hoping I can build something a lot cheaper. I’m thinking of using Mosfets for this. I have proposed a schematic for this below. I’m going to power the elevator with two car batteries in series.
Project number two is an electric lawn tractor conversion. I’m planning to use the forklift’s drive motor for the tractor’s drive motor coupled to the tractor’s transmission, which also means that I don’t need electric reverse. It is 24 VDC 2000W (about 83A). I’m thinking of using the Kelly KDS36200 controller for the drive motor. For the grass cutters I’m thinking of using a car alternator converted to a brushless DC motor controlled by a cheap 120A esc, as I don’t need precise speed control or start-up under load for the cutters. For this setup I also need an expensive contactor, but I can’t even propose how to do it with Mosfets. The “contactor” needs to be on the positive side, and the Kelly controller activates it by connecting to ground. I’m planning to use two 12V 100ah deep cycle batteries for the tractor, maybe more depending on runtime.
For both designs, I will be using a main switch for safety and to avoid any battery drain. Although I haven’t includes fuses in the schematics, I will be using those as well.
I have no background in electronics and my abilities doesn’t go far beyond soldering and reading simple diagrams, so I need some help on this.
Elevator schematic:
Will it work?
What Mosfets could be used? I was thinking of 5 of these http://www.nxp.com/documents/data_sheet/PSMN4R5-40PS.pdf in parallel, but can’t interpret the values well enough to say for sure.
What do I need for the “flywheel” diode if any?
What values should R1 and R2 be, to fully drive the Mosfet without damaging it?
Lawn Tractor:
Is my choice of controller appropriate? And if not, then do you have any suggestions?
Can anybody help me out with a schematic and components list for a cheap alternative for a heavy duty contactor for this setup?
The specs. and wiring diagram for the Kelly controller is herehttp://kellycontroller.com/mot/downloads/KellyKDSUserManual.pdf.
I know I’m asking a lot, but hopefully somebody finds it fun to do the “math”, and maybe it could be useful to some other novices on this forum
Cheers, Peter
First post here, so please correct me if I am posting in the wrong place or breaking any rules.
I’ve recently got my hands on an old 24V electric forklift, and I’m planning to turn it in to two winter projects on a budget. Sadly there are no batteries, and the electronics has been picked apart with parts missing and cut wires everywhere, but the engines are working and seem to be in good condition.
I’m going to use the lift tower and hydraulics to make a stationary goods elevator for the first floor in my barn. The motor driving the hydraulics isn’t marked, but I’m guessing it is about 300 amps (24VDC). The hydraulic valve lever has a micro switch build in, that closes when you lift the forks. I could drive the motor with a contactor, but I haven’t found one for less than about 70 usd, and I'm hoping I can build something a lot cheaper. I’m thinking of using Mosfets for this. I have proposed a schematic for this below. I’m going to power the elevator with two car batteries in series.
Project number two is an electric lawn tractor conversion. I’m planning to use the forklift’s drive motor for the tractor’s drive motor coupled to the tractor’s transmission, which also means that I don’t need electric reverse. It is 24 VDC 2000W (about 83A). I’m thinking of using the Kelly KDS36200 controller for the drive motor. For the grass cutters I’m thinking of using a car alternator converted to a brushless DC motor controlled by a cheap 120A esc, as I don’t need precise speed control or start-up under load for the cutters. For this setup I also need an expensive contactor, but I can’t even propose how to do it with Mosfets. The “contactor” needs to be on the positive side, and the Kelly controller activates it by connecting to ground. I’m planning to use two 12V 100ah deep cycle batteries for the tractor, maybe more depending on runtime.
For both designs, I will be using a main switch for safety and to avoid any battery drain. Although I haven’t includes fuses in the schematics, I will be using those as well.
I have no background in electronics and my abilities doesn’t go far beyond soldering and reading simple diagrams, so I need some help on this.
Elevator schematic:
Will it work?
What Mosfets could be used? I was thinking of 5 of these http://www.nxp.com/documents/data_sheet/PSMN4R5-40PS.pdf in parallel, but can’t interpret the values well enough to say for sure.
What do I need for the “flywheel” diode if any?
What values should R1 and R2 be, to fully drive the Mosfet without damaging it?
Lawn Tractor:
Is my choice of controller appropriate? And if not, then do you have any suggestions?
Can anybody help me out with a schematic and components list for a cheap alternative for a heavy duty contactor for this setup?
The specs. and wiring diagram for the Kelly controller is herehttp://kellycontroller.com/mot/downloads/KellyKDSUserManual.pdf.
I know I’m asking a lot, but hopefully somebody finds it fun to do the “math”, and maybe it could be useful to some other novices on this forum
Cheers, Peter
