kirbe 48v 1000w kit - is it for my mtb?

[Barefoot_Wanderer]

Hi All,
I recently purchased THIS from KirbEbike - my intention is to convert my Saracen Raw3, using it off road up steep tracks and looking for 2 hours range, that sort of thing.

I wonder, in the listing it says the smart controller is rated at 48v25amp 9mosfets; is this ampage too low (I've been reading of 30-40amp for 1000w motor).

Any further thoughts about this kit would be welcome; if you think this is an inappropriate kit for my bike let me know your thoughts.

BFW

 

[matthewslack]

It is a direct drive motor, unsuited to off road and steep hills. It is intended for relatively high speed cruising on relatively flat tarmac roads.

Not really any overlap with your intended use.

 

[saneagle]

First thing: If your bike has rim brakes, forget it and get a bike with disc brakes that can be upgraded to hydraulic.

Those motors are only efficient at constant high speed. Your 16 AH is going to to give you 16 amps for an hour, so if you're running with 30 or 40 amps, it's half an hour maximum, which would be about 15 miles, not 2 hours.

From the description, it's a 25A max controller, so rated at 13 amps. It's a little weak for that motor. At an average of say 20A, it might stay cool enough. It'll drain the 16Ah battery in 48 minutes, which would give you about 18 miles.

Which version of the Raw 3 do you have? AFAICS, none of them are suitable for the battery, as there is nowhere to put it.

For off-road steep tracks, you really need a crank motor or a very strong low-speed geared hub-motor.

It's a shame you didn't ask before purchase. I think you've bought the wrong kit and have the wrong bike to convert. Sorry for the bad news. I'm just saying it as it is.

 

[Barefoot_Wanderer]

First thing: If your bike has rim brakes, forget it and get a bike with disc brakes that can be upgraded to hydraulic.

Those motors are only efficient at constant high speed. Your 16 AH is going to to give you 16 amps for an hour, so if you're running with 30 or 40 amps, it's half an hour maximum, which would be about 15 miles, not 2 hours.

From the description, it's a 25A max controller, so rated at 13 amps. It's a little weak for that motor. At an average of say 20A, it might stay cool enough. It'll drain the 16Ah battery in 48 minutes, which would give you about 18 miles.

Which version of the Raw 3 do you have? AFAICS, none of them are suitable for the battery, as there is nowhere to put it.

For off-road steep tracks, you really need a crank motor or a very strong low-speed geared hub-motor.

It's a shame you didn't ask before purchase. I think you've bought the wrong kit and have the wrong bike to convert. Sorry for the bad news. I'm just saying it as it is.

Appreciate your candor, saneagle. I was going to install the battery on a pannier rack (attached to seat post) but before I start the conversion wanted an honest opinion. I originally bought this for my tandem then got worried about the legality in retrospect and thought instead of sending it back maybe convert my Saracen Raw 3 and put a 250w on the tandem (discussed in my other post if you recall). At least I found out before converting the bike, the kit is still in original packaging and I will be able to get a refund albeit after paying postage back to China (which ain't cheap) maybe I'll put it on eBay...

 

[saneagle]

Appreciate your candor, saneagle. I was going to install the battery on a pannier rack (attached to seat post) but before I start the conversion wanted an honest opinion. I originally bought this for my tandem then got worried about the legality in retrospect and thought instead of sending it back maybe convert my Saracen Raw 3 and put a 250w on the tandem (discussed in my other post if you recall). At least I found out before converting the bike, the kit is still in original packaging and I will be able to get a refund albeit after paying postage back to China (which ain't cheap) maybe I'll put it on eBay...View attachment 60197

You won't be able to send it back to China. I'd either sell it on Ebay or look for a cheap bike to fit it to that has disc brakes and a triangle frame.

A big rear motor and a battery over the back wheel will make the bike quite unstable. It'll tend to wheelie whenever you go up a steep hill.

Also, those cantilever seat post racks break with the weight of the battery on - not immediately, but any time thereafter to catch you by surprise when the aluminium breaks due to metal fatigue. You can get steel ones that are a lot better, but the sellers never describe them properly, so you can't be sure what it is until it arrives.

I've been through all this myself, which is how I know about it. Here's one that I did which wasn't too bad. The rack is steel and I had to modify the flat bit with a plywood board because it wasn't flat, then I added a couple of struts to give it a bit of extra support. It's very limited where you can attach them. We didn't have nice downtube batteries in those days. A bike is a million times better with a downtube battery compared with a heavy one on a rack.

Are Cheap Bikes OK.

Here's something that might help you decide. Since I built this bike, it's done exactly 1000 hilly miles at an average speed of 13.5 mph with absolutely no maintenance. That means no cable adjustments, no chain lubrication, no other lubrication, no cleaning, no replacement parts - absolutely...

www.pedelecs.co.uk

A better picture of the rack in post #4 here. Note the big steel lever on the quick release clamp that shows it's a steel one rather than aluminium.

XiongDa Two-Speed Motor

I started a new thread with a new title so that it'll e easier to find in a search. The motor weighs 3.283kg. It's the same size as a Bafang QSWXK5, The spoke holes are on the same PCD too of 120mm. Here's a photo of it next to a Q100 that has its spoke holes on a PCD of 108mm: The thread...

www.pedelecs.co.uk

 

[Az.]

1000W rear hub is not suitable for MTB.
Direct drive motor is not suitable for MTB.
Battery on rear rack is a bad idea as well.
Your Saracen is not suitable for conversion - there is no space on downtube. Out of desperation you can print battery case, build it and install under downtube, but it is not an easiest thing to do. For example: