Trucks- power consumption...
08-15-2019, 05:59 PM
#1
Thread Starter
Trucks- power consumption...
I'm a relative newby when it comes to larger electric powered trucks. As you see from my other thread I've been working on the
Kaelble Z6W2A 130 heavy tractors. I've been testing the 2nd truck and fixing things as they come up. The diesel 'motor'
failed while testing- there's a reduction gearing inside and I had gone to a wonky solution to line up the motors with the output which
originally relied on a tiny 'idler' gear. This poor thing got the beejezzus kicked out of it and failed altogether bending the shaft it was on.
I rebuilt the motor to have a more robust, simpler gear train.
The aspect of these systems is power consumption. The two 55 turn motor just running as a pair draw about 1 amp with no load.The
best I can get my motor to do, without a load is about 2.5 amps. This is twin 55 turn performance motors turning a common drive gear.
and overall going through about a 10:1 reduction to the output. Just coupled to the transmission (using light air tool oil) in neutral the load now requires
between 4-5 amps and with various gears selected, driving just the two rear axles without lockers engaged the draw
goes up to 7+ amps.with lockers engaged driving all four rear wheels I'll often blow an 8 amp( fast acting) fuse...
I have to say that the power sent to the rear wheels in this model is impressive, I have already learned not to get my hands in the way..
I recognize a lot of these components are new, likely needing some break in but I figure if I'm actually driving and pulling a load the power requirements
will be even greater.
This why I like glow/ gas powered models! The logistics in many ways are simpler. Also it's not easy keep this thing cool!
I'd appreciate thoughts, insights on similar projects, size and weight wise. Your experience with heavier trucks would be appreciated.
Light trucks, 1/16 scale machines, buggies while I'm sure have their own challenges won't have a lot in common...
Jerry
Kaelble Z6W2A 130 heavy tractors. I've been testing the 2nd truck and fixing things as they come up. The diesel 'motor'
failed while testing- there's a reduction gearing inside and I had gone to a wonky solution to line up the motors with the output which
originally relied on a tiny 'idler' gear. This poor thing got the beejezzus kicked out of it and failed altogether bending the shaft it was on.
I rebuilt the motor to have a more robust, simpler gear train.
The aspect of these systems is power consumption. The two 55 turn motor just running as a pair draw about 1 amp with no load.The
best I can get my motor to do, without a load is about 2.5 amps. This is twin 55 turn performance motors turning a common drive gear.
and overall going through about a 10:1 reduction to the output. Just coupled to the transmission (using light air tool oil) in neutral the load now requires
between 4-5 amps and with various gears selected, driving just the two rear axles without lockers engaged the draw
goes up to 7+ amps.with lockers engaged driving all four rear wheels I'll often blow an 8 amp( fast acting) fuse...
I have to say that the power sent to the rear wheels in this model is impressive, I have already learned not to get my hands in the way..
I recognize a lot of these components are new, likely needing some break in but I figure if I'm actually driving and pulling a load the power requirements
will be even greater.
This why I like glow/ gas powered models! The logistics in many ways are simpler. Also it's not easy keep this thing cool!
I'd appreciate thoughts, insights on similar projects, size and weight wise. Your experience with heavier trucks would be appreciated.
Light trucks, 1/16 scale machines, buggies while I'm sure have their own challenges won't have a lot in common...
Jerry
08-16-2019, 06:22 AM
#2
Hello Jerry
From my experience with industrial motors:
Without seeing your exact setup, I would venture the dual motor without a limited slip would create motors sometimes fighting each other, thus creating more amp draw.
I would advise one motor, if even larger to drive it.
From my experience with industrial motors:
Without seeing your exact setup, I would venture the dual motor without a limited slip would create motors sometimes fighting each other, thus creating more amp draw.
I would advise one motor, if even larger to drive it.
08-16-2019, 06:31 AM
#3
Also don't be too concerned for heat buildup
It is common for motors to run hot, the insulation of the windings is the critical part, which is probably at least 60 deg C
(Have you ever touched a hot vacuum cleaner motor when clogged?)
It is common for motors to run hot, the insulation of the windings is the critical part, which is probably at least 60 deg C
(Have you ever touched a hot vacuum cleaner motor when clogged?)
Last edited by heavyaslead; 08-16-2019 at 06:55 AM.
08-16-2019, 04:00 PM
#4
Thread Starter
Thanks heavyaslead. I imagined that there could be some competition between motors but hoped these are matched closely enough
so as to keep that to a minimum. Heat wise the enclosed nature of the implementation works against it. I will say that I used these motors
on purpose because of their power and should have realized that power isn't free. The original maker of these models Stehr in Germany sells
this same diesel engine set with twin mabuchi type 540 motors that he advertises as 12volt motors. I don't know if they truly are 12 volt which could account for less current draw or if he's just pushing them at 12 volts. His printed documentation states 0.9 amp no load 5 amps running( driving) and if I read if correctly
a maximum load of 33 amps (!!). Since the truck weighs around 35 pounds and he says it can tow 200kg: again that kind of power doesn't come for free.
I wanted to post this on the RC Truck and Construction forum however my ID over there is on the fritz again..
I'm going to see if I can experiment with other types of motors and also invest in a amp/watt meter to see what's watt....
Jerry
so as to keep that to a minimum. Heat wise the enclosed nature of the implementation works against it. I will say that I used these motors
on purpose because of their power and should have realized that power isn't free. The original maker of these models Stehr in Germany sells
this same diesel engine set with twin mabuchi type 540 motors that he advertises as 12volt motors. I don't know if they truly are 12 volt which could account for less current draw or if he's just pushing them at 12 volts. His printed documentation states 0.9 amp no load 5 amps running( driving) and if I read if correctly
a maximum load of 33 amps (!!). Since the truck weighs around 35 pounds and he says it can tow 200kg: again that kind of power doesn't come for free.
I wanted to post this on the RC Truck and Construction forum however my ID over there is on the fritz again..
I'm going to see if I can experiment with other types of motors and also invest in a amp/watt meter to see what's watt....
Jerry
08-16-2019, 04:29 PM
#5
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Ever looked at the 1/10 scale crawlers? They have some tremendous torque and may draw less. Just a thought. I know the one i have is heavy and will crawl over just about anything. It only uses 2 regular batteries like the 1/16 takes. Just an idea.
08-17-2019, 12:33 AM
#6
Thread Starter
they are clever and equipped with good solid engineering we're talking apples and oranges. This truck is very beefy in the construction department
and very heavy much different than most crawlers.
I didn't choose the twin motor approach. Take a look: Simulated Diesel motor
A simple translation give these specs:
(Per motor) Nominal voltage 14.4 V No-load speed 14500 min
At 12 V 12000 min
Current consumption 0.9 A
Current consumption at max. Efficiency 5 A
Blocking current consumption 33 A
It's stated as "per motor" but I don't know how far down the list that extends. Excluding the stall current those numbers are more or less what I saw
with the motor without a load. I'm beginning to think I need to take the truck off of my workbench test power supply and begin testing using a robust 60 amp ESC.
I should move this thread to another forum as it really doesn't belong here, I apologize for that. The admin over in the other truck and construction forum
has not answered my ID problem questions so I'm sort of stuck. Once that is resolved I'll move this thread.
Jerry
08-19-2019, 04:22 AM
#7
Keep in mind Jerry
The Mabuchi 545 would be the equivalent 12V version
The peak current would only be experienced under initial low RPM torque generation or if the load stalls the motor. Otherwise the nominal would be appropriate.
An ESC twice to three times that rating is a great idea, because its actually the driver that will likely burn up before the motor.
Again, my experience the 540 motors do heat up, especially the one driving my 30 lb. Maus
The Mabuchi 545 would be the equivalent 12V version
The peak current would only be experienced under initial low RPM torque generation or if the load stalls the motor. Otherwise the nominal would be appropriate.
An ESC twice to three times that rating is a great idea, because its actually the driver that will likely burn up before the motor.
Again, my experience the 540 motors do heat up, especially the one driving my 30 lb. Maus
Last edited by heavyaslead; 08-19-2019 at 04:26 AM.
08-19-2019, 06:57 AM
#8
Could you post us a few pics of the motor and spur gear? I watched the video on the other thread (VERY clean drivetrain btw) but didn't see the dual motors. I used to have a dual motor 550 RC car but found a single 775 motor ended up with more power through out the whole band. I would suggest something like a Sabertooth to run that thing, it is super tough and will have the low speed control you want on that guy while having over current/temperature protection on it too.
If you are open to brushless I would be happy to help there. ESCs for brushless operations are dirt cheap even for high performance ones and offer lots of adjustments. There are tons of RPM/KV options as well as brushless motors are much better labeled and spec'd than brushed motors. One of the cons of brushless is you can't run dual motors off one ESC, you do need two ESCS, however with the right gearing you may only need one.
If you are open to brushless I would be happy to help there. ESCs for brushless operations are dirt cheap even for high performance ones and offer lots of adjustments. There are tons of RPM/KV options as well as brushless motors are much better labeled and spec'd than brushed motors. One of the cons of brushless is you can't run dual motors off one ESC, you do need two ESCS, however with the right gearing you may only need one.
08-19-2019, 07:40 AM
#9
Even smaller brushed motors like the 775 can sometimes pull upwards of 130A of current at stall. It's better to burn out a motor than an ESC as the high amp ESCs are more expensive than the motors. With brushed motors heat and use can kill the brushes, but that is where brushless shines. There are no brushes to wear out or be killed by heat. They make brushless motors that have more torque and spin slower if you are not looking for race car speeds. I would think that a dual motor setup might fight itself. Also keep in mind that the higher the voltage you use, the more efficient the motor becomes. For example with my 1/6th scale tanks I use some geared brushed motors at 24V. At that voltage the motor draws 18A nominally. Running the same motor at 12V means the motor pulls more like 24-30A nominally under the same load.
08-19-2019, 08:01 AM
#10
Even smaller brushed motors like the 775 can sometimes pull upwards of 130A of current at stall. It's better to burn out a motor than an ESC as the high amp ESCs are more expensive than the motors. With brushed motors heat and use can kill the brushes, but that is where brushless shines. There are no brushes to wear out or be killed by heat. They make brushless motors that have more torque and spin slower if you are not looking for race car speeds. I would think that a dual motor setup might fight itself. Also keep in mind that the higher the voltage you use, the more efficient the motor becomes. For example with my 1/6th scale tanks I use some geared brushed motors at 24V. At that voltage the motor draws 18A nominally. Running the same motor at 12V means the motor pulls more like 24-30A nominally under the same load.
08-19-2019, 08:07 AM
#11
Thread Starter
Erik thanks for your kind offer. The twin electric motors are buried within the simulated diesel motor, not sure if I have photos of them but I will look.
I thought about making my next one using brushless motors but balked at the restriction on running two as the brushed ones
and as you said theorized I may not need to. Unfortunately part of the appeal of this thing is the motors concealed within the engine
shell so the configuration is fairly set. True a test could be rigged with a brushless to see what happens using a simpler mount but
I'd like to stay with the original configuration.
I don't recall if I was clear on the original intent on the previous thread but my work on this project is to replicate components already made
but it's just me trying to keep costs down by making my own. The simulated diesel motor is sold by Stehr already but at 800 or 900 Euro
per unit I prefer to make my own. As part of pre-owned partial kits and parts I have two sets of the unfinished castings for these diesel motors
so the results of the first attempt at building one out are what you see. I made the internals using 48 pitch gearing used in buggies/ crawler
types as I wanted to use standard parts as much as practical. As I've done more research and receive feedback I'm beginning to believe
the current levels I'm seeing may not really be really too far out of line. It's just that I've not dealt with higher powered electrics before..The source
of concern was based on blowing successively higher rated fuses on my old bench mounted power source which is rare but it isn't really designed to
pump out gobs of current. either. I need to switch further testing to ESCs designed to support higher loads. I will not rule out that the system needs
to be redesigned or a fundamental flaw fixed but I won't kno that until I can do further tests. My number one truck has a complete and original drive
line and simulated diesel so I need to try to run it once I check it out to see what it draws by comparison... I suspect I may have been a bit of an
alarmist due to my inexperience with models like this. I only make metal bits, I'm not an electronics guy. My dad who was an electronics whiz would
be shaking his head right about now...I can just about hear him...
Jerry
I thought about making my next one using brushless motors but balked at the restriction on running two as the brushed ones
and as you said theorized I may not need to. Unfortunately part of the appeal of this thing is the motors concealed within the engine
shell so the configuration is fairly set. True a test could be rigged with a brushless to see what happens using a simpler mount but
I'd like to stay with the original configuration.
I don't recall if I was clear on the original intent on the previous thread but my work on this project is to replicate components already made
but it's just me trying to keep costs down by making my own. The simulated diesel motor is sold by Stehr already but at 800 or 900 Euro
per unit I prefer to make my own. As part of pre-owned partial kits and parts I have two sets of the unfinished castings for these diesel motors
so the results of the first attempt at building one out are what you see. I made the internals using 48 pitch gearing used in buggies/ crawler
types as I wanted to use standard parts as much as practical. As I've done more research and receive feedback I'm beginning to believe
the current levels I'm seeing may not really be really too far out of line. It's just that I've not dealt with higher powered electrics before..The source
of concern was based on blowing successively higher rated fuses on my old bench mounted power source which is rare but it isn't really designed to
pump out gobs of current. either. I need to switch further testing to ESCs designed to support higher loads. I will not rule out that the system needs
to be redesigned or a fundamental flaw fixed but I won't kno that until I can do further tests. My number one truck has a complete and original drive
line and simulated diesel so I need to try to run it once I check it out to see what it draws by comparison... I suspect I may have been a bit of an
alarmist due to my inexperience with models like this. I only make metal bits, I'm not an electronics guy. My dad who was an electronics whiz would
be shaking his head right about now...I can just about hear him...
Jerry
08-19-2019, 08:16 AM
#12
With brushed systems the current consumption is going to be much higher than a BLDC motor. 8A is really nothing honestly. It never hurts to over spec on the ESC though. One of the things we found with multirotors and wings for that matter is that even though a smaller ESC may be able to drive that motor fine, larger ESCs drive the same motor (bigger mosfets) much smoother even if temperature is not a factor. The higher the quality the ESC the better it is going to drive. The motor you can go cheap on but the ESC really makes a difference in operation. I would be more than happy to help here if you have any electrical questions on motors or ESCs btw, just ask away!
