1st Mountain Ride with BMC V2-T Motor + 18FET 48A Crystalyte

[Sacman]

I'm using a 600W BMC V2-T motor and a 18fet 48A digital Crystalyte controller. This Sunday morning I got to do some riding in the mountains for the first time with my latest ebike setup. As I was riding up the hills to my brother's house I saw 2 geared up mountain bikers moving quickly past me going the opposite direction. I knew there was an entrance to the Cleveland National Forest not too far away from us and I knew they were headed there. So I turned around and caught up with them.

We chatted while riding. They seemed like friendly and pleasant people. They were surprized when I told them I was riding an ebike and they said they couldn't tell. They looked like good strong riders and they said they've been riding up the mountains along the fire roads mostly every weekend for the past year. I've never been in the national forest riding on the fire roads so I asked them if I tag along so they could show me the fire roads routes... and they said yes. Great!

I'm using 2.5-inch Hookworm tires that didn't have the knobbies their tires had. So I told them I'll try to hang with them on the ride as long as I could. They just looked at my tires and said "you should be okay". We entered the national forest and started climbing. The fire road was mostly hard pack but had lots of loose slough and gravel on the bends. My dual suspension bike and tires were doing okay as long as I didn't lean too hard on the turns.

Most of the climb was on about 10% -20% grade, with some steepest parts as high as 25% grade. It was a fairly hot late morning with the temperature already at about 98 degrees Farenhiet. My 2 fellow riders were pedaling fairly hard and were averaging 7-8 mph up the mountain. Immediately I could see what a tremendous advantage I had with the ebike. I was keeping up with them with fairly little effort from the motor. I dropped down in gears and was pedaling but was only using between 250-350 watts climbing at that speed. I have my ebike setup for a more upright and comfortable riding position for the road and so I actually had more trouble keeping the bike upright going over bumps and turns at that slow speed.

After 20 minutes the road got even steeper and our climbing speed got even slower. We were moving only at about 5 mph by now and it was getting more and more difficult for me to keep the bike upright going that slow. I told my friends and they said to go ahead up the road a half mile to a level spot with a great view. I told them okay and I'll wait for them and maybe take my camera out and get some pictures. So off I went.

I punched up the throttle to a more comfortable speed of 10 mph and burning about 800-900 watts and kept it there most of the way up. The BMC motor definetly sounded like it was working now. A couple of times I opened it to WOT just to see what it could do and I was seeing 1600 watts but the motor really sounded strained and I didn't want to toture it so I backed off. I stopped at the clearing and took some pictures and waited for my friends. We continued thru the national forest up the mountains for about 40 minutes and I continued to go ahead to the next level clearing and stop to wait for them. These guys were good. They only stopped and took a 2 minute breather and continued up the mountains.

After probably the 5th or 6th time stop I was still in my tourist mode busy taking pictures so I told them to go ahead and this time I'll catch up. Well when I got back on my ebike and tried to catch up with them I was using WOT most of the way. After about 4 minutes the motor lost power and the ebike just quit. The Cycle Analyst display was still on and showing I had decent battery power left. I jumped off the bike, took off my gloves and felt the motor and controller. Motor was cool but the controller was hot. :? I turned off the controller, waited 5 minutes and turned it back on but still no power. Looks like I wasn't going to catch up to my friends so I decided to decend back down the mountain alone.

So I rode down the mountain averaging 14 mph. I was on my brakes most of the time and It took me about 25 minutes to get back to the entrance to the national forest. When I got back to the city streets I had only about 3 miles of pedaling to get back home. Good thing that BMC motor freewheels because it made that ride home not difficult. When I got home I checked the system and was relieved to find out that I had just melted the thin 16 gauge wires I had used for temporary phase wire connections. No wonder the motor was no longer getting power. Whew! I'll replace those wires soon but it was a hot day riding and so I just relaxed after that.

 

[Sacman]

UPDATE: Here's a pic of the melted wires and the connections.

So looking back now ... I was actually doing WOT burning 1600W continuous for 4 minutes trying to catch up to my friends on the trail ahead of me when the wires melted and i lost power. And I guess it was a pretty hot day of 98 degrees F. The wires that melted were temporary to convert the Anderson connections on the motor to the automotive connectors on the controller. I'm really hoping the controller is okay but I'm too tired to look at it right now.

 

[dnmun]

the dreaded trailer connectors.

inside the molded plastic is a puny crimp capable of handling maybe 10A max. that's where your heat came from. i thought these were outlawed already.

cut them out and go solder everything together. when you cut off the trailer connector then you can run your new phase wire directly from there to the outside of the axle.

just adding 14G on top (parallel) of your 16G will let you run 40A continuous, but solder all the joints, then see if you can get them to overheat.

 

[torker]

Beautiful pics, except that last one :x Always good to find the limits without major damage. I wonder if that would be a good place for a fuse?

 

[dnmun]

that's his phase wire connector, jumper from factory installed trailer connector to andersons with the small wires. current here can be much higher than in the power cable itself, just lower voltage.

 

[Fishmasterdan]

Sounds like fun Sacman.

I have been riding off road here is PNW for a little while. I have burned motors speed controls melted wires ect....

Take my advise and if you plan on riding in the mountains get some sort temp sensors on your electronics. I am running a Puma that is similiar to your motor. I have never ran in the mountians and not had to stop to let everything cool.

 

[nicobie]

Hey Sacman,

Looks like you found your weakest link

I hope your controller is still ok.

Nick

 

[dogman dan]

Nice Pics 8) , but mind those mountain lions! It takes awhile to learn to balance at 5 mph. Being in the right gear is part of it, I find I can balance better if the feet are spinning faster. At 5 mph, you can enjoy the scenery better anyway, but at 98F, some speed is nice for the cooling wind.

Next time, feel the axle, geared motors can get real hot inside and still have pretty cool covers. The axle, that is more directly connected to the inner motor is a good place to monitor temp with a cheap automotive indoor outdoor thermometer. Mabye the controller too, or with a switch, one thermometer could be looking at both, with two sensors. Or get an infared thermometer and just check when you stop. Beats frying expensive stuff. Ya'll have seen my melted the motor threads, and I agree, in the mountians you have to stop and cool off at some point, even in cooler weather.

I bet you do some more of this stuff, once you fix the wiring. In a way, that wire was a fuse. Cut off the bullet connectors and if the wire is too short, make a lengthener with fat wire and andersons for that kind of wattage. Those trailer connectors are far to skinny for a real motor.

I have found dirt road riding not too bad on city tires, as long as they aren't slicks or semi slicks. My favorite city tire has just enough tread to grab some in dirt, but not send my flying when I hit a bit of loose sand on pavement. The tire I like is the bell kevlar comfort bike tire found at wallmart. $15 and good for 3000 miles or more. The center rib gives em a good roll, while the edge tread makes moderate off road, like fire roads, tolerable.

 

[Sacman]

cut them out and go solder everything together. when you cut off the trailer connector then you can run your new phase wire directly from there to the outside of the axle.
just adding 14G on top (parallel) of your 16G will let you run 40A continuous, but solder all the joints, then see if you can get them to overheat.

I'll definitely be losing those lousy trailer connections and soldering up thicker wires. I notice the Anderson connectors were perfecly fine tho. :| So those are pretty good to handle high current. I'm still wondering about how to get thicker wires thru the axle tho.

 

[Sacman]

It takes awhile to learn to balance at 5 mph. Being in the right gear is part of it, I find I can balance better if the feet are spinning faster. At 5 mph, you can enjoy the scenery better anyway, but at 98F, some speed is nice for the cooling wind.

Next time, feel the axle, geared motors can get real hot inside and still have pretty cool covers. The axle, that is more directly connected to the inner motor is a good place to monitor temp with a cheap automotive indoor outdoor thermometer. Mabye the controller too, or with a switch, one thermometer could be looking at both, with two sensors. Or get an infared thermometer and just check when you stop. Beats frying expensive stuff. Ya'll have seen my melted the motor threads, and I agree, in the mountians you have to stop and cool off at some point, even in cooler weather.

I bet you do some more of this stuff, once you fix the wiring. In a way, that wire was a fuse. Cut off the bullet connectors and if the wire is too short, make a lengthener with fat wire and andersons for that kind of wattage. Those trailer connectors are far to skinny for a real motor.

If I ever do get hooked on climbing these mountains with and ebike I'll definitely make another ebike specifically for that purpose (lower COG, knobby tires, lower number teeth on front cranks,... etc.). But for now I'd like to keep the comfy "street commuter" more or less the way I have it right now.

And you're probably right about getting some sort of temerature motitoring sensor to keep check on the equipment. Boy gone are the worry-free days when I used to run only a 20A controller. Stepping up to higher current and higher torque really takes some getting used to ... to keep an eye on your equipment. :wink:

 

[dnmun]

no problem, you don't have to push new phase wires. getting close to the axle with doubled up phase wire will give you almost everything you can otherwise do. wait until you twist off the wires and then you can push new phase wires through the axle, like everybody else does.

i think your problem really would be solved with parallel (14G/stock16G) from the controller to the axle. the axle is metal and can soak up some heat if they get hot inside, but i worry about the motor itself getting too hot since it is geared. most of the resistance in all these phase wires is in the connections, they get loose too. they have to make it as a kit so it can be assembled by the DIYer, but a real solution involves soldering all the connections, even down to soldering the ground of the battery to the controller. but keep one disconnect on the hot side for an emergency, and out where you can reach it when it smokes.

but that's imho.

 

[grimbasement]

I have that same motor and I can vouch for it's ability to climb the hills while remaining relatively cool. I did blow my 35 A BMC v2 controller last week when the controller blew a cap (and other things) but the motor was still cool. Seems the cheap trailer connector acted like a fuse. Maybe I missed it but what is your battery setup?

 

[dnmun]

i have caps. i have some 100V1000uF caps for upgrading to 72V ($.30) and a buncha used 63V470uF caps($.02). you can fix it.

 

[dogman dan]

Feeling the covers is not as good a way to judge the internal heat of a gearmotor. Check the axle next time, I bet it feels a bit warmer than the covers.

 

[Sacman]

Feeling the covers is not as good a way to judge the internal heat of a gearmotor. Check the axle next time, I bet it feels a bit warmer than the covers.

Yeah especially if the wires were melting inside the axle.

I'm gonna take the BMC motor apart and upgrade the wires. I wanted to the first time I got the motor but I ended up just wanting to get the motor installed and running to see how it worked. I went to the local electronics warehouse store and got me some good braided battery straps, colored 20 gauge stranded wire, and lots of heatshrink tubing. I'm gonna try something like what Geoff did in his thread upgrading the wires to the PUMA motor.

I still haven't had a chance to check on my controller yet tho.