Alien bike from eBay - advice sought

[shrubhill]

Hi everyone, my name is Joe and I'm getting into electric bikes. I've not cycled since I was a teenager - really never liked it because of the hills where I live in Devon! I just won an e-bike on eBay, an Alien of some description, and yesterday cycled it 12 miles or so back from Plymouth to Tavistock for a test.

The drive system is very dicky. I've heard a lot of people talking about batteries cutting out etc, but I'm not sure this is actually what's happening. Definitely prepared to replace the battery if I can find one. It does cut out, but it's intermittent. Of those 12 miles I got 4/5 miles with assistance, off and on, and I just have to wait 20 seconds or so, fiddle with the on switch etc. Many times it will just flash the throttle LEDs and die. But eventually it will kick in and offer assistance for anything between a couple or yards and a couple of miles... Very inconsistent.

Since the battery itself seems to be holding charge okay for its age (2011, mostly unused in that time apparently), this almost sounds like a short or a controller issue. Touch the throttle and it will immediately cut. Leave it on assistance and it can fly along just fine. Talked to my friend who runs a UAV/drone shop, and he seems to thing this is the case too.

If anyone can help identify the model that would be very useful!



Overall I'm pretty chuffed. It was only £128 and even if a new battery is £200 or so it's still a bargain. She rides fine and, though it's like cycling a whale up hills unassisted, when the motor does work it's a scream.

Thanks in advance for any advice. I'm really excited to get my geek on with these things!

 

[Deleted member 4366]

The batteries on Alien bikes seem to give a lot of problems. The cells used in them behave a bit differently to others. When they're worn out, they charge up to the normal 42v and appear healthy, but as soon as you put load on them, the voltage collapses, so the management system switches off. When you take the load off, the voltage bounces back so that it appears OK. If this is what's happening, there should be some evidence of the voltage going down on the indicator LEDs before it switches off. If the LEDs are all lit and then simply switch off when the bike stops, the problem is probably elsewhere.

Another common problem is the two solder joints on the back of the key-switch. As a temporary measure, you can bypass the switch by either bridging the solder joints or cutting the two wires from the switch and joining them together.

Another thing you can do is check all the connections to the controller, which sits in the compartment at the front of the battery, in particular, the two battery wires, though I think the problem is elsewhere.

 

[shrubhill]

Hi d8veh, thanks for your response. I'm not sure if there's a key-switch on this (you mean like an ignition key? if so then there's just the switch on the controller) In motion I can just about fiddle the switch back on again - 3 out of 4 times the LEDs just flash on and disappear immediately, then the fourth time it will restart and I get another short burst of power.

What I find bizarre is that I will randomly get a good duration out of it, pulling up hills included, every now and again. I went out with it again this afternoon and it does just simply cut off from 3 LEDs to none. Intermittent electrical faults, always the best. I think you're right about the load thing - the wheel will spin with the bike on the stand, but will cut out after a few seconds in the main. I'm just a bit bemused by being able to get a couple of miles out of it now and then!

I'll get a volt-meter and do some tests next week. I see that there is a replacement battery pack available on BMS Batteries - does this need any modification? Really want to make sure there's not a simple fix before buying a new battery so I'll look at the connections in the controller as you suggest.

Thanks again!

 

[Deleted member 4366]

Hold on. Where is your switch? What are you calling the controller? Can you show a photo please?

The switch I was referring to would be on the side of the battery. Maybe you don't have one.

 

[shrubhill]

Hold on. Where is your switch? What are you calling the controller? Can you show a photo please?

The switch I was referring to would be on the side of the battery. Maybe you don't have one.

Yes that's the one, but it's a rocker switch like on 80s cars.

 

[Deleted member 4366]

Ok, but it could still be faulty. You need to bypass it to eliminate it as being a probable cause of your problem.

 

[shrubhill]

Roger Wilco. Thanks for the advice