Many homeowners would want to try using different amperage against a voltage. Sometimes, they would get a positive result, and on other things, they would experience hitches.
If you have a 12v water pump, most people want to know, how do you power a 12v water pump?
You can achieve this in many ways. One of the ways is to try using a 24v motor. Although there are similarities between a 12v DC motor and a 24 volt Motor, there are also distinct differences.
Overall, both of these motors are designed to perform almost identically with the exception that a 12-volt motor draws twice the current from its 12-volt supply than what a 24-volt motor draws.
For a given mechanical load, the power supplied to both motors would be similar.
Table of Contents
Can you run 12V pump on 24V system?
You can use a 12V pump on your 24V system. However, the pump will run faster on 24 V than on 12 V. In addition, the overall energy spent to pump the same amount of water will still be higher at 24 V than at 12 V.
Can I use a 24V pump on a 12V battery?
This might work on a 24VDC fan but will run slower than at 24 VDC. Also, some fans can run at 50% of the proper voltage.
Can you run a 12V pump on 5v?
Yes, 5V might work but will stall if running too slow too.
How do you power a 12v water pump?
Understanding their similarities is just as important as knowing about the differences between 12v DC motors and 24 volt motors.
However, for the sake of example, some of the key comparisons between a 12v DC motor and a 24 Volt Motor are provided below.
- If 20 amps are required for a 12v DC motor to supply a particular mechanical power output, then only 10 amps would be needed by a 24 volt motor to achieve the same level of performance.
- For a simple type of DC motor, the rotation is at full speed on no-load, with speed determined primarily by applied voltage. Therefore, if 24 volts were applied to a 12v DC motor, it could cause some damage by running at twice the speed.
- In most cases, a 12v DC motor will be similar in price when compared to a 24 volt motor for the same application. The main reason is that the physical size of the motor can usually determine its power output.
- There is also a difference between wiring for a 12-volt motor versus a 24 volt motor. For example, at 24 volts, smaller wire can be used for delivering power efficiently, whereas for 12 volts, twice the size of wire is needed to provide the same amount of power.
12v Motors on 24v
Motor current rating
Motors are specified to run at a stated rpm at a particular applied voltage with a specified loading – that at which the motor takes its maximum continuous current.
If you run the motor under a lighter load than this ‘name plate rating’ its current consumption will reduce and its speed will increase slightly.
If you increase the load, then the motor’s current consumption will increase and its speed will reduce.
Obviously, you are now exceeding the motor’s continuous rating so it will start to get hotter than it should.
The greater the overload, the quicker the motor will heat so there is a time limit on such an overload.
However, it is usually safe to run a motor at a 300%-400% over current for, perhaps, a minute – although this will vary from motor to motor.
If you run a 12v motor from 24v its current drain and speed will still depend on the mechanical loading.
However, under no load, it will now run at twice the speed at which it originally ran with 12v.
Heating in the motor is still related to the current – so you can still run it at its full rated mechanical load/current.
However if the motor is badly balanced you may expect noise and vibration as the general construction may be inadequate for the faster speed.
There may also be a problem with brush wear since the brushes are being asked to switch the current twice as fast.
These effects are, however not very likely and usually, the speed increase is quite OK.
There is one caveat on this. The motor is an inductive device and the commutator and brushes are mechanical, switch.
Such a mechanical switching system will have a limit on the maximum rate at which is can work and if this is approached, the commutation breaks down
Motor speed limits
Limits on motor speed are not simply the bearing quality. If you rev a motor hard enough – centrifugal force will take over and the rotor will fly to pieces.
Also brush and commutator design is important. Depending on the design these will have a maximum switching rate and operating above this speed will cause tremendous brush arcing.
In extreme circumstances, this will generate severe noise transients which can destroy the controller.
This is unlikely: we have only ever seen one customer do this: he was running 12v motors on 36v and blew two controllers! These motor limits are not things a controller manufacturer can really comment on: you need to consult the motor manufacturer.
If you overload the motor, its current rises in the same way whether the motor is running from 12v or 24v.
However on stall the current from 24v could be twice that from 12v, so the motor could get four times as hot (heating is proportional to the square of the current).
This however won’t happen when you are using a good controller as the controller will limit the current to its designed value.
Also the controller varies the voltage on the motor so you are probably not going to use the motor at full voltage in any case.
Another consideration is that, if you put too much current through a permanent magnet motor, it is possible to slightly demagnetise the magnets.
This is cumulative: the motor’s performance will drop slightly each time you do it. However, for battery motors, is probably fairly safe to assume that, at the rated voltage, the current drawn when the motor is stalled will not reach this demagnetization level.
If you were to run a 12v motor off a 24v battery the stall current could then be excessive if it weren’t limited by the controller.
Therefore, provided you chose a controller suitable for the motor you use, you can usually run a motor 12v motor from a 24v battery with no effect except that full speed is doubled.
Motor stall current
Consider the stall current of a motor, for instance, the Sinclair C5 motor. On a freshly charged battery, its stall current can be 120 amps.
This is limited by the motor resistance, the resistance of the leads supplying it and on the internal resistance of the battery.
Adding anything else into this loop will increase the loop’s resistance. So, if you have a system that works nicely without a motor speed controller, adding a motor speed controller will inevitably reduce its peak performance.
Many 12v systems are simply not designed for operation with a speed controller and adding this will greatly reduce the performance.
The overheads on a 24v system are nowhere near as critical. The 2v drop, even 4v, will still take the battery supply nowhere near to the 9v rail. Motor resistances are also higher, so the extra effect of the controller and wiring is less noticeable.