Hi,
I have a Kollmorgen brushed hub motor that is spec'd at 24V. I have no other specs on the motor and don't know where to get them...bought it about 5 years ago and it seems like it's a 200W or maybe 250W...
Question: I also have a 48V/16ah Ping LifePO4, which seems to top out at around 60V on charge. I'd like to take the Kollmorgen for a test ride, to see if I want to keep it, etc. It's a rear-wheel hub. I don't have a controller and plan on just "flipping the switch" when I'm up to around 10mph or so. If all works well, I'll invest in a controller.
I don't want to hurt the hub. Any advice on if this is relatively safe for the Kollmorgen. How much is too much for a brushed motor? I know people overvoltage all the time. Any advice is appreciated. Thanks!
I haven't done this so take it with a large grain of salt...
I have read of many people taking a motor to 33-50% more volts (24 over-volted to 36 is +50%) and (36 OV to 48 is +33%). The results have been that the motor gets pretty warm on a hill climb, then cools off during cruise mode on level ground or downhill.
If the up-hill is too steep or too long, the motor and/or controler will fry.
Several people I've read have doubled the rated voltage, leading to significant heat. They often attached a surface-glued temperature probe to the motor case that activated a switch which turned on an extra air-cooling fan when it got too hot.
This extra complexity decreases range depending on how often and long the fan runs off the battery pack, but raises top speed and can get you "X" power from a smaller/cheaper motor.
Whatever you try, please post the results for the benefit of future questions. Best of luck!
I used a heavy duty push button to run my 24 volt brushed motor on 48 volts of SLA to see what it would do. It did warm up a little from a couple of short test runs. When I ran motor at 36 volts it did not warm up.
It takes a little bit of time for the heat to work it's way out from the windings to the case, so if you do run it, give it some short bursts of power and wait a few minutes to see how hot the case gets.
I came to the conclusion that I would have to run a fan if I wanted to have a reliable 24V motor running a 48V. These motors are designed to be safe from water and dirt damage, they sacrificed getting rid of heat efficiently like they do on other electric motors with built in fans.
Deron.
it's true, overvolting from 24v to 48v is a bridge too far for a brush motor unless you can keep the heat within limits, but if you are in a hilly area, pretty impossible. If you live in the netherlands why not. In the US geography 36v stands a better shot at lasting the course.
You're kidding about putting a fan on the hub motor...er...right?
I haven't noticed any heat build up either, so I guess I'm ok at 48V. I ordered a brushed controller and throttle from ecrazyman and I'll let you know how it goes.
Have most of it captured in a blog if you're interested "Ping - Brushed Kollmorgen Tests"
HA! I didn't catch that either. I often skim postings instead of read them slowly. Whenever I see "Kollmorgen" I immediately think that its a separate motor connected to the wheel by a chain/belt.
E-Bikers with a hub-motor have sometimes put a thermostat-controlled fan/duct on their controller, But I assumed you were talking about something like a "Peltzer" configuration.
"You're kidding about putting a fan on the hub motor...er...right?"
They have water cooled computers, water inside a computer, who would have figured?
Most motors have fans to cool them, with the exception of bike motors. Come up with a good way to cool a bike motor and you could: make the motor smaller, or more powerful, or more reliable.
One pound, five thousand watt, helium cooled bike motor :)
Deron.