BPM kit build thread

[Deleted member 4366]

If you get a battery from ebay or buy the cells and make up packs like some members do .... do they have to buy the BMS pcbs and then wire them in?

Yes and no.
If you buy a ready-made Lifepo4 pack, they normally have BMS pre-installed inside the pack. Everything is automatic, so no worries, but relatively expensive.
Lipo packs don't come with BMS, so, If you're going to use them, you need to do a bit of studying first, as there are safety risks. Do a google search on "lipo safety" or whatever and see what comes back. Basically, you need a lipo charger, which tend to be automatic and safe provided you set them up right, and after that you need to make sure the battery doesn't go down below a certain voltage, which depends on the pack.
Lipos are better if you need to provide a lot of current because you have a motor bigger than 250w, or if you want to build a super-light-weight bike. Lifepo4s are better for normal applications.

 

[wings]

350w BPM motors in the UK

I have rung ecosmobile who advertise kits on ebay. I was told that the 350w BPM motors will be available UK end of June. Only a three month warranty. I think Alien offer a one year warranty on everything, does anyone have experience of the "Magic Pie"from golden motor?

 

[peasjam]

I've tracked down the problem. Looks like there is a issue with my battery.

If I connect the charger, battery and controller in series to force voltage into the system then the control unit and motor all work perfectly. Still getting a massive voltage drop from 48.3 to 5.1 at the power lines when just the battery is connected to the controller. Not sure what the problem with it is. Going to have to get in contact with BMS and try to get it sorted. I'm really not looking forward to this....

 

[Bikemad]

Magic Pies

does anyone have experience of the "Magic Pie"from golden motor?

I'm still using one of the original Pies which I modified to get the tyre correctly centred, and it has been running fine until I recently tried a dual controller mod for more power. I ended up blowing the additional controller and all three hall sensors in the process, but it's happily running in sensorless mode back on the original internal controller at the moment, but I'm sure it won't last much longer, as I've beefed up the shunt so that it now draws just over 2.9kW!

If anyone's interested, more details and pictures of my unsuccessful dual controller mod can be found here.

Alan