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:

https://www.amazon.es/gp/product/B089QPHT12/ref=ox_sc_act_title_1?smid=A11TPN66ALC6DO&psc=1

https://www.amazon.es/gp/product/B09F3J45FW/ref=ox_sc_act_title_2?smid=A1HB8ND62I2K1Q&psc=1

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

 

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

 

Can't you bring the 12V power closer to the shaker? Or, buy a dedicated 12V 20A power supply that runs from AC?
Boosting to 24V then losing that voltage over a cable run means your 12V supply will have to supply 40A to the booster at 12V to get 20A at 24V, probably more than 40A because nothing is 100% efficient. Can your 12V battery/supply handle 40A load? Then, you will be wasting 240W of power as heat through the cable, it will get warm possibly.
If running from a car battery while the car is charging it, means your alternator may have to charge at 40A steadily. Can your alternator handle that load for long periods of time?
It might be easier to buy a larger gauge wire instead, to minimize the voltage drop

 

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:

https://www.amazon.es/gp/product/B089QPHT12/ref=ox_sc_act_title_1?smid=A11TPN66ALC6DO&psc=1

https://www.amazon.es/gp/product/B09F3J45FW/ref=ox_sc_act_title_2?smid=A1HB8ND62I2K1Q&psc=1

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

DC-DC converters are not generally used for application involving a motor. To understand why that is the case, you need to start with a basic calculation of the required input power for a given output power. Taking an output power of 480 watts and assuming an efficiency of 80% gives a required input power of 600 watts, which at 12 volts is 50 Amperes. Looking at the wires on the A11TPN... I'm wondering if it can safely operate at those power levels.
I'm also wondering why you need to use the battery in your vehicle. Doesn't that run the risk of not being able to start the engine so you can return home? Can't your vehicle transport two batteries in series in addition to the one required by the vehicle?

 

You will do better by investing in a cable with larger diameter conductors. Also, eliminating any voltage drops at connections. Any point with a voltage drop now will be getting hot, and so will be easy to locate.
15 Meters is about 47 feet and that is quite a distance for a power cable. Reducing losses will provide a greater benefit.
If the "car battery" is actually in a tractor then it may be possible to drive an alternator from the tractor PTO connection and have an adjustable voltage source. That might be a possibility.
The amazon site wanted to infest my computer with amazon cookies and so I did not visit the site. But before purchasing any electronics from amazon, be aware that they do not provide any customer support at all. Not one bit, and they are unable to answer any questions.

 

Hello sagor, it is not possible to have the battery close to the machine. You need at least 10 to 15 metres of cable. Because of the power of the motor I had thought of a 2.5mm cable (14awg), but I could put up to a 4mm section cable (12awg), even so the motor would not get the 12v and it would probably not work. The supply can handle a 40 amp load but I'm worried it might overheat or break.

 

Hello Papabravo and MisterBill2, the thing is that this type of machine works hooked to a 12 volt battery of approximately 70 amps. I have seen them hooked to cars, tractors or independent batteries and I was wondering if I could make a machine with similar characteristics. I have already made the machine and it is working properly. I have it hooked up to a 2 metre cable to do the tests but to use it in the field these machines have about 15 or 20 metres of cable (usually 1.5 mm section or 16 awg) and the motors have a power of 250 watts. How is it possible for them to work taking into account the voltage drop?

 

This is a very dificult solution, but is something I remember from the 80's:

An ambulance has a large electrical load, sometimes more that the standard alternator can handle. One company put a 2nd alternator on the engine. If you did this, and adjusted the 2nd alternator up to around 16 V, that would be high enough so that there would be 12 V at the motor under full load. This means the engine would have to be idling whenever the motor is running.

Again, not a great solution, but one I have seen work.

ak

 

Hi alaska, I have read your alternative but I don't understand what you are proposing.

 

To make my own machine I was watching videos like these:

and I don't see that these machines have any special parts.

Sorry but I am not an engineer although I like to do these things and I am a beginner.

 

Would it be possible to colocate the battery with the motor and make the longer leads a control circuit?

 

@40A You need #8AWG wire minimum. For flexibility you might look into welding lead wire. And as to alternators, 100A alternators are fairly common and should be available through any parts supply house for your vehicle.

 

I thought you were talking about a whole tree shaker, not a rake. Why do you have to power it from so far away? Are you trying to use a vehicle to power it?

 

@Yaakov I don't understand your proposal. What is a control circuit? The motor has to go in the machine because it moves the connecting rod and generates the movement, while the battery is heavy and usually goes at the other end.

I have to power it from so far away because the trees are big and the batteries are heavy, it is not comfortable to move them all the time. The machines I've seen are powered by a long cable like this.

 

The reach of the rake is limited to a few meters from the ground. The cables powering those examples are not very large. I have seen backpack power units which means they are not hauling around car batteries. I think you need to consider a different battery source, possible an SLA type which which can be smaller and lighter but sufficient to power the shaker.

If what you are proposing was necessary, these couldn't be commercial products.

 

I could put up to a 4mm section cable (12awg),

4mm cable has a resistance of 4.6mΩ/metre per conductor, so a 15 metre length has a go-and-return resistance of 138mΩ. That will drop 2.76V at a current of 20A. If you use two lengths in parallel you would halve the voltage drop to just 1.38V.

 

@Yaakov I have also seen some machines powered by a battery in a backpack, but most of them have a small cable that connects to a 15 meter extension cord, and I have seen them running on batteries like car or tractor batteries.

 

@Alec_t You mean connect two cables from each pole (positive and negative) of the battery to the motor?

 

I would go with a large (welding) cable.
That will be the simplest and most efficient.

 

Because of the length and the resistance of the wire, size #14 is not close to adequate for a distance of 15 M, about 47 feet. I suggest at least #10 wire, although #8 would provide even less voltage drop. With wire that size and length the problem of flexibility certainly exists, and so "welding cable" is one option, and I have cone across wire listed as "Boat wire" or "Boat cable" that is also much more flexible, and probably costs much less than welding cable because it does not need to have weld-spatter resistant insulation..
ONE cable for positive, one cable for negative, with #10 or #8 cables.