New BMS frame battery controller

[bikeonfire]

Here's the new kit: http://www.bmsbattery.com/battery-pack/680-bottle-ebike-battery.html

I had a live chit chat with a rep from bms and asked about buying a spare of one of the included 20a sine wave controllers. Bin Li said it was not possible because it comes together. I said that if the controller fails or I need to change a cell I'll be opening up the case. I asked if this controller will be available in the future. He said of course. I asked if I could order it now since there's long shipping times to Canada. He asked someone, apparently. Nope. This kit comes with the LCD3 which I'm quite interested in, so I asked if this controller supports all the functions of the LCD3. He 'hung up' on me. Way to go, BMS.

So I look at the other sine wave controllers supplied by BMS and I don't see one that pulls 20a continuous. I see 15a and 25a but not 20a. Before Bin Li ran off I asked if I could use another controller, say the s12s, which pulls a max 25a. I asked if I could limit the amp draw from this controller. He said no. But I wonder if that's actually true? What if I never used level 5 on the LCD3, would that effectively limit the max amps to 20a or under? I have a few friends following my foray into electric bikes closely so I want to be able to help them with a 'fool proof' setup, which I'm attempting to build for myself. Willing to bend a few 'rules' for my own setup.

I'm happy that BMS is providing a kit around their battery instead of a built wheel since it makes a lot of sense to order a bare hub. And the frame case is quite a lot more elegant than a rack battery or a big bag all velcroed in, but it needs to be serviceable. Any thoughts?

 

[Samd]

A few of use have tested these in other threads. Looks good, doesn't rattle. But the USB and charge port can be susceptible to water ingress...

 

[mlt34]

Here's a closer look at that battery you're talking about: http://endless-sphere.com/forums/viewtopic.php?f=3&t=61994
I'm waiting as well for specs on the controller.

 

[Samd]

Try this:
http://endless-sphere.com/forums/viewtopic.php?f=14&t=58928

 

[bikeonfire]

while I really like the format of this battery pack the limitations are rather limiting. If something were to go wrong it (er, when) then there's not a lot of room to move. Looks like a rack battery will be the way to go. And can go with 25 or 30amps instead for the bafang CST.

thanks for the link!

 

[d8veh]

So I look at the other sine wave controllers supplied by BMS and I don't see one that pulls 20a continuous. I see 15a and 25a but not 20a. Before Bin Li ran off I asked if I could use another controller, say the s12s, which pulls a max 25a. I asked if I could limit the amp draw from this controller. He said no. But I wonder if that's actually true? What if I never used level 5 on the LCD3, would that effectively limit the max amps to 20a or under? I have a few friends following my foray into electric bikes closely so I want to be able to help them with a 'fool proof' setup, which I'm attempting to build for myself. Willing to bend a few 'rules' for my own setup.

If you switch the S12S to "Torque simulation mode", it uses current control rather than speed control. I'm not sure whether the current limit set on the display is only for the PAS or global. I would guess only for PAS, but if that's what you use, there should be no problem.

IIRC the S12S used to have a 23A label on it. I don't know if they've changed that recently. Whatever it's set to, it's very easy to adjust the current upwards by adding solder, and downwards by crimping it because the shunt is accessible directly behind the end-plate. You can make a rudimentary ammeter by connecting your voltmeter about 6" to 12" apart on one of the battery wires. Run the motor at full current by applying the brake to slow it right down while at full throttle. Note the number of mV on the meter. Crimp a couple of "V"s in the shunt with some side-cutters, then repeat the test and note the new mV. The % difference between the two readings is the % difference in the current. e.g. 20mv = 23A, 18mV = 20.7A