Controller Upgrade

[awol]

Can anyone tell me if I can upgrade my controller for one which will work with my lcd display and capable of about 22amps? The one I have is a 14amp with shunt soldered up to 16amp and it gets warm now. In the future I will be using higher power batteries so may as well make use of the extra amps if I can. I know I could get an S12S and LCD from BMSB but I really like this display.

 

[Deleted member 4366]

Conhismotor do controllers with the same display, but they don't have a speed sensor connector, which means a bit of jiggery pokery to get it to display the speed correctly.

 

[jonathan75]

I've got the same display, elifebike call it the 861 series display, which this company seems to also, who claim to be a manufacturer (the website is posh so i think they are..). They list 350w controllers with 18a and 450w with 22a. It might be worth emailing them to see if those controllers work with your display, and if they can supply singly or (more probably) know of a supplier who can.

My only concern (and this applies for myself too as my 15a controller seems not much for hill cycling), is whether 350w and 450w are too much for my 250w motors, and what it means exactly when a controller has that figure on it, and whether it can be adjusted.

I also wonder what it means for staying legal, when one's controller is 350w or 450w and of course we're in a country where this "max 250w" business has legal significance (but is confusing because in engineering terms a 250w motor just means the minimum continuous rating without overheating if I'm not mistaken, and a "max 250w" motor will sometimes draw 700w or so - D8veh knows whether this is true much better than I, so maybe will correct me).

 

[Deleted member 4366]

There's no legal implications. You can use whatever controller current you want. The motor has to be rated as 250w by the manufacturer, so as long as it's marked 250w or appears in a catalogue/listing as 250w, you're OK.

Different motors can handle different amounts of current. Which one do you have?

You can turn down the current of most controllers by filing or crimping the shunt, and you can adjust it up by adding solder to it. Some controllers can handle more current than others, and it also depends on which motor you have and how you use it. If I want more torque I adjust it up a bit and then keep checking that the controller doesn't get too hot, then adjust a bit more.

The markings on the controller normally indicate the maximum current it'll allow.

 

[jonathan75]

There's no legal implications. You can use whatever controller current you want. The motor has to be rated as 250w by the manufacturer, so as long as it's marked 250w or appears in a catalogue/listing as 250w, you're OK. .

Excellent.

Different motors can handle different amounts of current. Which one do you have?
.

Thanks, I've got Bafang SWXK 250w 36v and a Bafang CST 180mm 250w 36v, both marked 205rpm.

Do the motors automatically draw the same wattage at the same load, regardless of the controller wattage? So in a sense the wattage on the controller might be relatively immaterial, compared with say the number of amps it's made to allow?

 

[awol]

Thanks for the links, the elifbike lcd controller only does a 250/350w which I suspect I have on.
I have the bafang 250w cst by the way and would be using either 20a battery or 12s lipo's.
So my choice would be either conhismotor 500w with some jiggery, I have emailed for delivery costs to UK, or
I could wait till my little 10ah battery gives up then solder my current shunt a bit more at a time and see how far I can take it and how hot it gets maybe. Knowing me by then I will be wanting to try the lcd3 display from BMSB or some other new one.