[mendoza]

Hello everyone, I am trying to make an olive shaker. The shaker has a 12v dc motor and works between 15 and 20 amps. Due to the voltage drop it needs a cable with a large section or a voltage booster to 24v 20 amps dc so that after 15 metres of cable the motor gets the 12v it consumes. I am considering a booster like these from Amazon:

#N/A Convertidor DC-DC 12V De Calidad (10V-23V) Módulo Step Up 24V 20A 480W : Amazon.es: Electrónica

Amazon.es: Convertidor DC/DC Regulador Incrementador 12V Step Up to DC 24V 20A 480W Convertidor de Refuerzo a Prueba de Agua con Puerto USB Funda Protectora para Auto Car Truck

Comprar Convertidor DC/DC Regulador Incrementador 12V Step Up to DC 24V 20A 480W Convertidor de Refuerzo a Prueba de Agua con Puerto USB Funda Protectora para Auto Car Truck en la tienda de Coche y moto de Amazon.es.

www.amazon.es

but I do not know if they are designed for intensive use or not (I have read in some comments that this type of boosters after using them for many hours can burn). I would use them for about 6-8 hours a day. Any suggestions? Any ideas are welcome

 

[mendoza]

The machine is connected to a car battery, so using two batteries in series to have 24v is not an option for me.

 

[piotrsko]

Sure it is an option, but you cant direct connect the second battery to anything else but the 24v olive shaker and recharging will be tedious

 

[brian_]

It's hard to say whether the linked converter can handle continuous operation, since the specifications are not really complete. They should include a duty cycle definition, or specify that the rated output is "continuous".

I haven't used them, but Victron Energy is well-regarded by many people, and has a range of DC-to-DC converters. They have various types, including 12 V in / 24 V out models with at least 25 amp output ratings in three series:

• Orion DC-DC Converters Non-isolated, High power (model: Orion 12/24-20) would require sheltered location
• Orion IP67 24/12 and 12/24 DC-DC Converters (model: Orion IP67 12/24-50)
• Buck-Boost DC-DC Converter 25A / 50A / 100A (50A or 100A model)

Each series has a datasheet which can be downloaded, and none of them specify a duty cycle, but they do list continuous output current (and in some cases a higher "maximum" current) which suggests that for current under the "continuous" rating they should be suitable for this application.

I'm sure the Victron products are excessively expensive, but they do suggest that what you're looking for should be available. I just used them for examples because I knew that that they would have a selection of converters, and would likely be well-constructed.

Since you don't really need 24 volts - you only need 12 volts at the shaker motor - a converter which allows you to adjust the output voltage, or one which regulates the output at the motor using a separate sensing wire, would be better than simply a 12 V to 24 V converter.

15 metres (each way) at only 20 amps should only be a couple of volts of drop even with relatively light (10 AWG, 5.3 mm2) conductors. Wouldn't this work well without a voltage converter, just by using larger cable?

 

[mendoza]

The problem is that because of the design I have made, the housing and the tube I can't use a 10 awg section wire, that's why I had thought about a voltage booster.

@brian_ What do you mean by this? I don't understand it very well: "Since you don't really need 24 volts - you only need 12 volts at the shaker motor - a converter which allows you to adjust the output voltage, or one which regulates the output at the motor using a separate sensing wire, would be better than simply a 12 V to 24 V converter."

 

[mendoza]

Looking for information on internet I have read that DC motors consume "X amps" for starting, but once they are running they can consume much less.

In the specifications of my motor it says that the rated current is between 10-20A, but the motor is 12V and has a power of 360W How is it possible?. Shouldn't it consume 30A?, does the motor have less power than indicated and that is why it consumes less?
Finally, could it be that the 10-20 amps are consumed at begining but then it consumes much less?

In the specifications it also says that the motor can work between 12-24V, in both cases the power is the same, the difference is that at 12V you have 6000rpm and with 24v you have 12000rpm.

I'm sorry I didn't tell you the engine specifications earlier

 

[brian_]

The problem is that because of the design I have made, the housing and the tube I can't use a 10 awg section wire, that's why I had thought about a voltage booster.

@brian_ What do you mean by this? I don't understand it very well: "Since you don't really need 24 volts - you only need 12 volts at the shaker motor - a converter which allows you to adjust the output voltage, or one which regulates the output at the motor using a separate sensing wire, would be better than simply a 12 V to 24 V converter."

You said:

The shaker has a 12v dc motor and works between 15 and 20 amps. Due to the voltage drop it needs a cable with a large section or a voltage booster to 24v 20 amps dc so that after 15 metres of cable the motor gets the 12v it consumes.

So, the motor needs to get 12 volts... not 24 volts. You're only considering the voltage booster to overcome the voltage drop in the cable, so if that voltage drop is only (for example) 3 volts, you only need to put about 15 volts into the cable to get 12 volts to the motor.

 

[remy_martian]

I don't understand why there's 15m of motor cable. Fruit tree shakers operate less than a meter off the ground.

 

[goingjag]

I think the problem is related to the cable size. if you need 10 amps at 12 volts with a 15 meter cable it needs to be 7 awg or thicker. I'm guessing you don't have that. You can go here to calculate yourself or look for others DC Cable Size Calculator | Fabhabs I believe you are dealing with too much of an electrical loss for the cable you have chosen. I doubt that increasing the voltage will help, even if it does work short term, I suspect you will burn out whatever you are using to boost the voltage or burn up the cable.