help info about bmc v4t motor

ROG130 · Oct 17, 2013

hi all anybody give me there experience on the bmc v4t hub motor
as i am thinking of getting one for a carbon bike build i am doing
and looks small enough to make the bike look standard or stealth looking
but still have some go go in it
thinking of using a 10 or 16 ah pack about 48v to 72v
running a ca3 and lyen 12fet modded controller
please let me know if you have used one and what you think
thanks roger :mrgreen:

teklektik · Oct 17, 2013

I'm very happy with the V2S which is about the same as the V4C. I use Lyen 12 FET controllers and got all the stuff from Ilia at Ebikes SF - great guy and service. I have beat the crap out of the BMCs - over-volting them, over-amping them, running them submerged through streams, and seizing a bunch of clutches - basically lots of 'first build' experimentation. Having worked all that out, they now run day after day with no issues and pull like mules. 7300 miles and working like champs.

You will need to watch your voltage - these motors tend to eat the clutch much over 60v - unless you are using a CA V3 to limit things. Here's a post with some thoughts about setting up the controller (get a programming cable) and CA V3 (get a programming cable).

At the upper voltages you propose, your motor will run hot without too much coercion. Here's a thread on a sleazy quick means to add a thermistor to your motor without rewiring it (for CA V3 thermal rollback). I use this on one of my BMCs and it works very nicely.

ROG130 · Oct 18, 2013

teklektik said:
I'm very happy with the V2S which is about the same as the V4C. I use Lyen 12 FET controllers and got all the stuff from Ilia at Ebikes SF - great guy and service. I have beat the crap out of the BMCs - over-volting them, over-amping them, running them submerged through streams, and seizing a bunch of clutches - basically lots of 'first build' experimentation. Having worked all that out, they now run day after day with no issues and pull like mules. 7300 miles and working like champs.

You will need to watch your voltage - these motors tend to eat the clutch much over 60v - unless you are using a CA V3 to limit things. Here's a post with some thoughts about setting up the controller (get a programming cable) and CA V3 (get a programming cable).

At the upper voltages you propose, your motor will run hot without too much coercion. Here's a thread on a sleazy quick means to add a thermistor to your motor without rewiring it (for CA V3 thermal rollback). I use this on one of my BMCs and it works very nicely.

thanks for the info this is a big help
what voltage are you using

teklektik · Oct 18, 2013

65v nomial 73v HOC. I recommend you read the linked post above about my controller/V3 setup. It contains all the details and in turn links to a post about battery decisions.

My situation is somewhat different in that the two motors only carry half the load and so I can flog them harder. However, on some occasions I ran exclusively on a single BMC for some time -- the heating was much more substantial and the current limiting needed to be reduced so the clutch would hold on getaway.

help info about bmc v4t motor

ROG130

100 W

teklektik

100 MW

ROG130

100 W

teklektik

100 MW

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