Help us build a solar powered washing machine
Budget: €12 – €18 EUR
We are making a 24V DC solar powered washing machine for us in offgrid villages in developing countries. We have already made some progress ourselves on converting an AC voltage semi-automatic washing machine to DC. Such a machine has as separate washing machine/compartment and separate spinning machine/compartment to remove the water from the washed clothes, and is sometimes known as a "twin tub" machine.
The focus of this project is on the washing machine part only, not the spinning machine.
When we remove the 100-150W 1250 rpm AC motor from the washing machine and replaced it with a similar 24V 250W 1500rpm DC motor, it worked fine, except that instead of alternating the direction during the agitation cycle (clockwise-pause-anticlockwise-pause) it always went the same way (clockwise-pause-clockwise-pause). If we reversed the polarity of the connection to the battery, we got a reversed direction. Therefore, the clockwork wash timer was reversing the polarity of the AC motor ok, but was not reversing the polarity of the DC motor.
We require an electronic circuit that allows the DC motor to reverse. The cycle is something like
- 10 seconds clockwise
- 5 seconds pause
- 10 seconds anti-clockwise
- 5 seconds pause
which is repeated until the time allocated by the user (up to 15 minutes) comes to an end.
The existing clockwork wash timer could be used by modified by a circuit to work properly, or it could be completely replaced by the circuit. Doesn't worry us which is chosen.
This would give us a basic solution for a semi-automatic "twin tub" solar DC washing machine.
----------------------------------------------------
Beyond this stage, we would also like to look at converting a single-tub fully-automatic washing machine. The same swap of an AC motor for DC would be done, but the circuit would need to no only do the wash agitation, but also control the water pumps that bring water into the machine, and pump water out of the machine. It would also then have to control the spin cycle - a more powerful motor is probably going to be used for this, maybe 500W instead of 250W, because spinning takes more power. We have tested this ourselves and a 500W DC motor works ok. 1500rpm is a pretty typical spinning speed. The control cycle for the full washing program would be something like this:
- 5 minutes ON for water-in pump to fill the washing machine, then turn OFF
- 15 minute main motor ON for washing cycle with agitation as described above
- 5 minutes ON for water-out pump to empty the washing machine, then turn OFF
- 5 minutes ON for water-in pump to fill the washing machine for 1st rinse, then OFF
- 5 minute main motor ON for rinse agitation cycle, as washing agitation
- 5 minutes ON for water-out pump to empty the washing machine, then turn OFF
----option for 2nd rinse cycle
- 5 minutes main motor ON for spinning, then OFF
End of cycle
Please quote separately for Phase 1 of the project, to fix the directional problems of agitation in the washing cycle only of a semi-automatic twin-tub machine, which is our most pressing issue, and a separate quote for Phase 2 of the project which is the more complicated circuit for the automatic machine.
We are willing to buy you a low cost ($100-200) 6-10kg capacity washing machine and 250-500 DC motor(s) from Amazon to allow you to convert a machine similar to what we are working on, and other parts as needed such as water pumps. There is no need to include such costs in your offer, as labour costs will dominate the project.
We expect a functional prototype in less than 1 month, and a circuit diagram and PCB board to allow us to manufacture the solution in the future in small volumes for field testing.
Thank you.
You can email me if you have further questions.
The focus of this project is on the washing machine part only, not the spinning machine.
When we remove the 100-150W 1250 rpm AC motor from the washing machine and replaced it with a similar 24V 250W 1500rpm DC motor, it worked fine, except that instead of alternating the direction during the agitation cycle (clockwise-pause-anticlockwise-pause) it always went the same way (clockwise-pause-clockwise-pause). If we reversed the polarity of the connection to the battery, we got a reversed direction. Therefore, the clockwork wash timer was reversing the polarity of the AC motor ok, but was not reversing the polarity of the DC motor.
We require an electronic circuit that allows the DC motor to reverse. The cycle is something like
- 10 seconds clockwise
- 5 seconds pause
- 10 seconds anti-clockwise
- 5 seconds pause
which is repeated until the time allocated by the user (up to 15 minutes) comes to an end.
The existing clockwork wash timer could be used by modified by a circuit to work properly, or it could be completely replaced by the circuit. Doesn't worry us which is chosen.
This would give us a basic solution for a semi-automatic "twin tub" solar DC washing machine.
----------------------------------------------------
Beyond this stage, we would also like to look at converting a single-tub fully-automatic washing machine. The same swap of an AC motor for DC would be done, but the circuit would need to no only do the wash agitation, but also control the water pumps that bring water into the machine, and pump water out of the machine. It would also then have to control the spin cycle - a more powerful motor is probably going to be used for this, maybe 500W instead of 250W, because spinning takes more power. We have tested this ourselves and a 500W DC motor works ok. 1500rpm is a pretty typical spinning speed. The control cycle for the full washing program would be something like this:
- 5 minutes ON for water-in pump to fill the washing machine, then turn OFF
- 15 minute main motor ON for washing cycle with agitation as described above
- 5 minutes ON for water-out pump to empty the washing machine, then turn OFF
- 5 minutes ON for water-in pump to fill the washing machine for 1st rinse, then OFF
- 5 minute main motor ON for rinse agitation cycle, as washing agitation
- 5 minutes ON for water-out pump to empty the washing machine, then turn OFF
----option for 2nd rinse cycle
- 5 minutes main motor ON for spinning, then OFF
End of cycle
Please quote separately for Phase 1 of the project, to fix the directional problems of agitation in the washing cycle only of a semi-automatic twin-tub machine, which is our most pressing issue, and a separate quote for Phase 2 of the project which is the more complicated circuit for the automatic machine.
We are willing to buy you a low cost ($100-200) 6-10kg capacity washing machine and 250-500 DC motor(s) from Amazon to allow you to convert a machine similar to what we are working on, and other parts as needed such as water pumps. There is no need to include such costs in your offer, as labour costs will dominate the project.
We expect a functional prototype in less than 1 month, and a circuit diagram and PCB board to allow us to manufacture the solution in the future in small volumes for field testing.
Thank you.
You can email me if you have further questions.