dnmun
1 PW
you won't believe how small the individual winding wires are but usually there are 9 wires in each phase, and they add up to a little larger cross section than the 18G though. but just barely.
BMC V3 -- Infineon Build
- Thread starter Muad'dib
- Start date
BVH
1 kW
- Joined
- Mar 26, 2009
- Messages
- 411
So if I do the partial upgrade to the axle, leaving maybe a 3 inch pigtail, the remaining estimated 8-10 inches of 18 GA going to the windings really is choking down current flow at the higher Amp conditions. But maybe in reality, it really doesn't matter and I'm just over-thinking this whole thing.
dnmun
1 PW
by doubling up the phase wire, you just increase the conductivity, so more power gets to the motor. the voltages on the phase wire side of the controller are low so the currents are higher and in fact the little short sections may get hotter than before at the same speed, but just marginally hotter. that is why the little bitty connectors can eat up so much power in a short space, because the current is flowing through high resistance, very tiny contact patches between the metal faces of the clips. soldering up the connector, from stranded wire from the controller to stranded on the motor leads, eliminates the problem of high resistance in the phase wire. that alone could double your conductivity and increase reliability since the wires wouldn't loosen up later over time like the connectors do. then add another 3 wires in parallel.
or you can move the controller closer to the motor. if you can move it halfway and then cut the phase wires in 2 and double them up you have 2 wires now and half the length so the conductivity is increased 4 fold. and since soldering(removing the connectors) can add 50-100% to conductivity, then you could end up 6-8X higher in conductivity, but just to that point on the wire above the axle where you tie them together.
or you can move the controller closer to the motor. if you can move it halfway and then cut the phase wires in 2 and double them up you have 2 wires now and half the length so the conductivity is increased 4 fold. and since soldering(removing the connectors) can add 50-100% to conductivity, then you could end up 6-8X higher in conductivity, but just to that point on the wire above the axle where you tie them together.
grandmasterE said:
The V3 has plenty of low end torque. A couple of times I have taken off from a stop and accidentally lifted the front wheel off the ground. Really strong acceleration. So far my highest top speed is 39.1 mph going down a slight hill. Going up that same hill I was doing 34 mph. Both speeds without pedal assist. The motor is very quiet as well. Just a slight hum from take off to top speed.
Bike specs:
1000W V3 motor
48V 10ah LiFePO4 battery
BMC 30amp controller
26" rim
Muad'dib
10 W
This last week I got around to working on those wires, and am sad to say I'm giving up and putting the 14 gauge back in. I spent 5 hours tonight trying to make those wires fit and it was close, but no cigar. The "wet noodle" high strand count wires were just a bad idea, because the insulation is so big it might as well have been 10 gauge wire. Tonight I tried some flat copper braid sold as speaker wire (supposedly 14 gauge, but looked like more copper than that), following the example of Geoff's thread. With the outer shrink tubing there was no way it was going into that axel, and without it it still didn't happen. I think the design has changed since Geoff's motor, because my V3 doesn't seem to be able to break down to the point of being able to see the upward angling hole in the middle of the axel. The hole comes up through an inch or inch and a half of some other piece of the motor that doesn't appear to be removable. I got some nice thin and long pliers to stick in there, but it was too tight to pull everything through.
I guess I'll run big wire down to the axel and then hope the 14 gauge doesn't melt and short. Maybe I'll have to limit to 20 amps or something.
Anyone else with BMC motors having similar issues? How many amps are you running and do you get wire insulation melting ever?
I guess I'll run big wire down to the axel and then hope the 14 gauge doesn't melt and short. Maybe I'll have to limit to 20 amps or something.
Anyone else with BMC motors having similar issues? How many amps are you running and do you get wire insulation melting ever?
dnmun
1 PW
it really is a bitch to get the phase wires in there if you go over 14AWG. if i had not bot the little picks the week before at harbor freight, i don't think i coulda got the 12G into the motor. and that was a goldenmotor with larger hole than the BMC i think. pushing without everything binding in the hole was tough, but redirecting and then pulling the phase wires out of the hole inside was the hardest part. 4 tries, 3 hours total?
i tore the hall wires inside the axle too at the same time i was pushing the new phase wires in, and now i don't have the rubber sheath around the wires either, gonna have to silicone it to death.
it was 18G in the stock phase wires and i got a factor of 10 increase in conductivity going to 12G and 1/2 length, but i doubt if it is that important. 14G from the fork into the axle seems totally fine, imo. they won't melt, the motor winding wires are smaller so those are the ones you need to worry about overheating, imho.
i tore the hall wires inside the axle too at the same time i was pushing the new phase wires in, and now i don't have the rubber sheath around the wires either, gonna have to silicone it to death.
it was 18G in the stock phase wires and i got a factor of 10 increase in conductivity going to 12G and 1/2 length, but i doubt if it is that important. 14G from the fork into the axle seems totally fine, imo. they won't melt, the motor winding wires are smaller so those are the ones you need to worry about overheating, imho.
nicobie
100 MW
Just so you stuck with teflon coated wire I don't think you will have any trouble.
On my 600w BMC I've pushed over 1500w (with 2600w bursts) for 10 miles at a time and have had no trouble at all, and this was with the stock wire too.
However, I must add that I blew out the freewheel because of the crap Kewin controller that was mostly either on or off. I tried two of them and got the same results with both. Take it from me that the older Infineons don't work well on the 600w BMC. I just put on a Clyte analog 72v/35a and now all is well.
On my 600w BMC I've pushed over 1500w (with 2600w bursts) for 10 miles at a time and have had no trouble at all, and this was with the stock wire too.
However, I must add that I blew out the freewheel because of the crap Kewin controller that was mostly either on or off. I tried two of them and got the same results with both. Take it from me that the older Infineons don't work well on the 600w BMC. I just put on a Clyte analog 72v/35a and now all is well.
Muad'dib
10 W
I wonder if the melting wire insulation I experienced had anything to do with the controller. I am now using a Crystalyte 48v48amp digital controller. I had heard that only analog controllers work with BMC, but this one does work. Limiting it to 30 amps with the Cycle Analyst, I still had smoking wires after only a minute or two of hill climbing. First the dealer said it is "amp hungry" but later he said it should be given less than 30. I wonder if somehow the way it is wound inside is different than the V2, because it certainly sounds like Nicobie is not having this problem.
Is the insulation on the teflon wire pretty thin? Where is it available? The problem isn't getting good wire--the silicon wet-noodle wire is great and rated for very high heat resistance--the problem is getting good wire that is thin enough to fit in that tiny hole. Well, I'll report back when I have it running again.
Is the insulation on the teflon wire pretty thin? Where is it available? The problem isn't getting good wire--the silicon wet-noodle wire is great and rated for very high heat resistance--the problem is getting good wire that is thin enough to fit in that tiny hole. Well, I'll report back when I have it running again.
nicobie
100 MW
Now I'm running a stock Clyte 35a analog controller. But when I was running the 72v infineon with a soldered up shunt I ran it at 40a all the time with no smoking problems. I was doing 30 seconds of 50a also with no problem. The controller would get hot and the motor warm but that's about it. I couldn't pull more than 50a or my Ping battery's BMS would pop. This was at 72v too. I must add that when climbing long and steep hills I would try to keep the amps at 25 or a bit less.
The insulation on teflon wire is a lot thinner than normal wire. It handles heat better too. The wire on my 600w BMC motor was teflon coated.
You can do a search for "teflon wire" or check out this site;
http://www.surplussales.com/wire-cable/Wire4.html
Their minimum order is 25 feet, but it's relatively cheap and you will need quite a bit anyway to do the 3 hall and 2 phase wires.
The insulation on teflon wire is a lot thinner than normal wire. It handles heat better too. The wire on my 600w BMC motor was teflon coated.
You can do a search for "teflon wire" or check out this site;
http://www.surplussales.com/wire-cable/Wire4.html
Their minimum order is 25 feet, but it's relatively cheap and you will need quite a bit anyway to do the 3 hall and 2 phase wires.
Sacman
10 kW
Muad'dib said:
Yes I'm running the same Crystalyte 48amp digital controller with my V2-T, only I'm using the 72V version. It worked fine on the road for 3 weeks up until until I really pushed it hard on my ride in the mountains http://endless-sphere.com/forums/viewtopic.php?f=4&t=11767&p=178836&hilit=Sacman+%3D+mountain#p178836
I have verified (at least in my case) that the weak link is definitely in the thin phase wires of the BMC motor. They just can't handle that kind of current and mine melted. I'm going to rewire the BMC motor similar to the way Jeoff did and I finally got all the materials to do it ... even the braided ground straps and heat shrink needed to use for the new phase wires. But for now it will have to wait. Right now I'm busy trying to assemle two 72V Headway battery packs.
Muad'dib
10 W
Bad news. I got the 14 gauge wires in there and fixed it all up and it worked fine for a couple of days. The wires still got hot on hills, but I expected that since I didn't increase the wire size (by much if at all). Having it all soldered together and bigger wire to the axle didn't seem to make a big difference with the heat.
Anyhow, I had done a few trips across town the other day and it was working great, then I decided to try going up a fairly steep but short hill while pedaling as hard as I could. Current was limited to "30 amps" with an uncalibrated Cycle Analyst. I had a 40 amp fuse inline anyway, and that didn't blow so that should have been *not a problem* for the new 18fet Digital Crystalyte controller. I got up the hill, but then it just stopped working. Turn throttle, nothing. I hoped it was an overheating thing that would reset in a minute or two, but no. Then I hoped I had somehow drained the batteries, but no. I was at 53v and they charged up fine. Nothing worked. I opened the controller (twice now), and everything in there looks good, no evidence of anything gone wrong. I opened up the motor to see if my wiring had gone wrong somehow, but it also looks good. I have exhausted testing what I can think of. Any ideas?
I'm off to Germany in about a week, for a year, and I was going to bring my new transportation with me. Now I'm thinking I have to sell my parts. I've got 34 brand new Headway cells that I haven't even had a chance to try yet.
The wires still got hot on hills, but I expected that since I didn't increase the wire size (by much if at all). Having it all soldered together and bigger wire to the axle didn't seem to make a big difference with the heat. Anyhow, I had done a few trips across town the other day and it was working great, then I decided to try going up a fairly steep but short hill while pedaling as hard as I could. Current was limited to "30 amps" with an uncalibrated Cycle Analyst. I had a 40 amp fuse inline anyway, and that didn't blow so that should have been *not a problem* for the new 18fet Digital Crystalyte controller. I got up the hill, but then it just stopped working. Turn throttle, nothing. I hoped it was an overheating thing that would reset in a minute or two, but no. Then I hoped I had somehow drained the batteries, but no. I was at 53v and they charged up fine. Nothing worked. I opened the controller (twice now), and everything in there looks good, no evidence of anything gone wrong. I opened up the motor to see if my wiring had gone wrong somehow, but it also looks good. I have exhausted testing what I can think of. Any ideas?
I'm off to Germany in about a week, for a year, and I was going to bring my new transportation with me. Now I'm thinking I have to sell my parts. I've got 34 brand new Headway cells that I haven't even had a chance to try yet.
TPA
10 kW
Can you get spare parts for this motor?
If you could, you might get another axle and try drilling out the hole slightly. I don't know how much stock you have in the axle to play with, but since the drop out shoulder right up against a larger diameter there is no cantilevering of the smaller diameter. The smaller diameter is in pure shear
Tau=V/A Divided by 2 since there are 2 dropouts.
Steel = about 400Mpa yield, safety factor say 5, so 80Mpa
V=80Mpa*(10mm^2-7mm^2*pi/4)
V=80Mpa*.00004
=3200+kg load allowable
Safety factor for bumps
Axle should not be the weak link
How big is the hole dia? I guessed a 10mm axle with an enlarging of the hole to 7mm
If you could, you might get another axle and try drilling out the hole slightly. I don't know how much stock you have in the axle to play with, but since the drop out shoulder right up against a larger diameter there is no cantilevering of the smaller diameter. The smaller diameter is in pure shear
Tau=V/A Divided by 2 since there are 2 dropouts.
Steel = about 400Mpa yield, safety factor say 5, so 80Mpa
V=80Mpa*(10mm^2-7mm^2*pi/4)
V=80Mpa*.00004
=3200+kg load allowable
Safety factor for bumps
Axle should not be the weak link
How big is the hole dia? I guessed a 10mm axle with an enlarging of the hole to 7mm
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