While the consensus is they suck, what is the average Joe losing? I'm running two motors with them. Sarcasm unintended, what am I missing?fechter wrote:The one I dissected had 75NF75 FETs. These suck compared to 3077s.
WoodlandHills wrote:... the mechanical engineers that designed the hard parts left a significant amount of power headroom and the electrical engineers who designed the controller did not...
Same thing for me, If they made a phaserunner to bolt directly on the BBSHD housing, I'd also buy it a heartbeat. And if they can keep the PAS and the Bafang display to work with it I'd buy three at least !!WoodlandHills wrote:I am leaning towards the Grin Phaserunner, but if anyone came out with a 72v 45a controller that would bolt into the same place as the stock one I would buy two in a heartbeat! (Probably 3!) Will a Phaserunner fit under a gutted BBSHD controller housing? If it was under a cover, would it need its plastic potted housing and if it did not, would it be much smaller and then able to fit?
Agreed. The IRFB3077 MOSFETs are very robust. When other components are spec'd properly, and the traces are improved, the 3077's can pump out 15A per set of three. With 12, 60A is possible from the MOSFET's themselves. And their voltage limit is actually 75V, which means if you replace the caps with 100V versions, you can reliably run 16S (67.2V Hot) through them, assuming the controller's programming allows it. I use the 3077 MOSFET on our "smaller" controllers for this reason; More Current from a small package.fechter wrote:The 3077s will generate way less heat than the 75NF75s. They should survive way more current than the stator could take too. 3077s should handle 60A easily.
Yes, I'm sure that's possible if you find the right lead. It will likely cause a change in the battery meter as well.E-mil wrote:Forgive my naivety, but could it be possible that the system shutoff at +60V is controlled by a simple voltage sensor lead?
Would it maybe be possible to cheat this by means of a voltage divider or something similar?
You're missing on efficiency that would lead to better reliability (as the inefficiencies show up as heat). At stock power levels, you're not missing anything. The BBSHD is made well enough to handle all you can throw at it on stock levels. Start demanding more with modified shunts and your 75NF75 FETs may start to feel the burn. The fact that the controller is in the motor housing doesn't help with overall heat build up at the higher power levels either. Lower RDSon means less heat generation at the same power levels.tomjasz wrote:While the consensus is they suck, what is the average Joe losing? I'm running two motors with them. Sarcasm unintended, what am I missing?fechter wrote:The one I dissected had 75NF75 FETs. These suck compared to 3077s.
Could we solder the additionnal shunts in circuit with a switch to enable/desable some of them ?sather wrote:Location of shunts: Look at Ebikes4Reals photos above.
On the third photo down the two shunts are two little rectangles located at about 4 O'clock.
On the sixth photo down you will notice that a third shunt has been soldered on top the other two shunts.
The BBSHD has temperature sensors both in the windings and in the controller. The only reason for Bafang to put them there is to limit power when the temperatures get too high. It only seems prudent to wait and see if the stock lower power mosfets can hold the 45 amps before taking the risky and difficult step of replacing all of them.
It would be hard to make that work because the switch and the wires going to the switch would have enough resistance to be equal to or greater than the shunt resistance. The switch would also need to handle a good percentage of the shunt current (physically large switch).Matador wrote:
Could we solder the additionnal shunts in circuit with a switch to enable/desable some of them ?
I mean with the help of switch, we could do : 1) 2.5 mOhm (30A) ; 2) 1.667 mOhms (45A) ; 3) 1.25 mOhms (60A).
Even better if the switch was on the handlebar... Can even put a relay in controller to minimise impact of long wire resistance to handlebar switch (or use fat wire...).
Or we could make a custom wirewound resistor (see many youtube videos) using electromagnet wire or 10 gauge nichrome wire) with wire taps at different places to get different resistor value...