9LikesAnyone every try data logging on their 1/8 e-buggy?
05-10-2019 | 07:53 PM
#16
Tech Master
Joined: Jul 2018
Posts: 1,011
From: Florida
There is a reason we don't make a 2 pole ROAR motor. The two pole design specified by ROAR is actually a rather poor design. All of our motors are 1, 1.5, or 2 turn motors and have 85-95% efficiency. We prefer adjust the kv of the motor by adjusting the length of the stator or the magnets. In 1/10th scale motors, we make between a 1900kv and a 7700kv motor with those 1, 1.5, or 2 turns configurations. Specifying a motor by turn count is almost meaningless because there are so many other factors that contribute to the actual RPM of the motor, but the 2 pole design has most of those locked down to keep motors as consistent between brands. When we developed our sensored motors we tested our 1406 4600kv motor vs a 7.5 turn motor on our dyno and put a 300 watt load on both. The 7.5 turn motor hit 300F in about 2 minutes and it stopped working. Our 1406 4600kv ran for 5 minutes and only got to about 230F.
In 1/8th scale there was no electric buggies until we came out with the original Mamba Monster and 1515 motor because there was no motors that could survive the load of 1/8th scale. We had to start the e-buggy class by making electric conversion kits for nitro buggies because no one made electric buggies at the time. In 1/8th scale, most of the other motor brands are similarly efficient because they have to be.
Also worth mentioning that the motor he has can do over 2hp and our 1/5th scale motor, the 2028, can peak over 10hp from a motor about the size of a soda can.
its good to hear that others are following because that drives the tech in the hobby. Are you running a model to determine output power or is it measured? Im not trying to get in to your IP. The reason I ask is because you can use acceleration rates (or toroids) to create a dynamic thermal time constant for peak and continuous power. With the thermal model you can damn near make it impossible to overheat the motor. The thermistors work great for chronic heat but the model can allow peaks of 4 times continuous torque. The model only applies to combos you build the model for meaning a castle motor and esc combo and or supporting partners.
05-10-2019 | 11:49 PM
#17
Tech Adept
Joined: Dec 2016
Posts: 192
From: Olathe, KS
I thought i saw somewhere you guys were catering to allot more than just RC so it makes sense that you are using methods I recognize to design. We had a line of motors that had glass wrapped rotors that i didnt care for but its good tech if you control the application.
its good to hear that others are following because that drives the tech in the hobby. Are you running a model to determine output power or is it measured? Im not trying to get in to your IP. The reason I ask is because you can use acceleration rates (or toroids) to create a dynamic thermal time constant for peak and continuous power. With the thermal model you can damn near make it impossible to overheat the motor. The thermistors work great for chronic heat but the model can allow peaks of 4 times continuous torque. The model only applies to combos you build the model for meaning a castle motor and esc combo and or supporting partners.
Output power is measured. Sometimes with current sense shunt resistors and sometimes with hall sensors. We don't do any limiting on output power to protect the motor or ESC because our customers tend to get very angry at us when we try to protect the hardware. We only measure it for data logging. We've tried to do some do some calculated temperature models to protect a set of capacitors in our 1/5th scale controller, but have never had luck getting them to work because the time constant on the current sense measurements are too slow to fully capture the data needed. Motor temperature is measured with the built in thermistors through the sensor wire.
05-12-2019 | 02:38 PM
#19
In 1/8th scale there was no electric buggies until we came out with the original Mamba Monster and 1515 motor because there was no motors that could survive the load of 1/8th scale. We had to start the e-buggy class by making electric conversion kits for nitro buggies because no one made electric buggies at the time. In 1/8th scale, most of the other motor brands are similarly efficient because they have to be.
Back in 2008 (possibly before your time with Castle?) I was running a E-8 with with a Castle Mamba Max (not "Pro") and a Neu (original Neu) 1512 2.5D motor.
People were using the Mamba Max with an external BEC on 4S and fans to keep it cool. The Neu 1512 series had no problems handing 1/8th buggy loads. After all, that design is what "Neu-Castle" motors are based on.
RC Product Designs electric 1/8th conversions were designed around the Mamba Max with a center diff top plate that had an extension behind the center diff to mount the ESC.
See: Mamba Max! The Neu motor is mostly hidden behind the ESC but you can see the tail end of it (just past the ESC Capacitors) with the RC-Monster Neu rear motor cover and the motor wires connected to the ESC wires. Battery tray is my custom contraption to hold two 2S hard case packs since there weren't any 4S hard case packs back then (AFAIK) but our club required hard case packs.
And BTW, this was my second electric 1/8th buggy. First one I had to make the motor mount myself.
05-13-2019 | 08:20 AM
#21
Tech Adept
Joined: Dec 2016
Posts: 192
From: Olathe, KS
Correct, I was referring to mainstream. AE, Losi, Kyosho, and X-Ray didn't make electric buggies at the time. There was aftermarket companies making kits to make buggies electric and people converting their own buggies, but no mainstream manufacture was building an e-buggy.
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
