Conversion kit - Alien 24v

[hellnick]

Hello all. I'm on the verge of converting my very average mountain bike to an e-bike - partly to help me out on hills but also an interesting little techie project. The Alien 24v seems to fit my price range and I like the size and styling of the battery unit, but I have a couple of general questions about conversions that I hope someone can help with.

The kit comes with brake levers that cut power to the motor when applied - unfortunately my brake levers and gear change levers are a single unit. Aside from the legal requirement, how important is the cut of power to the motor and how would the motor behave if brakes are applied without power being cut? I managed to get hold of the December 2008 copy of Velovision with reviews of various kits and the reviewer said that he didn't bother with this feature. If it is genuinely useful, does anyone think it would be possible to simply hack the sensor on to the existing brake setup?

The next question is to do with the throttle - the supplied throttle is a thumb version but I'm not really sure how this will work with my gear selectors as they are the trigger type. Is this throttle sprung so that you have to maintain pressure?

Sorry if these are daft questions - I did search several times before posting but my search terms are rather vague. I have emailed the vendor a couple of times but he appears to be out of reach at the moment.

Anyway, thanks for reading and thanks in advance for any advice.

 

[torrent99]

Hello all. I'm on the verge of converting my very average mountain bike to an e-bike - partly to help me out on hills but also an interesting little techie project. The Alien 24v seems to fit my price range and I like the size and styling of the battery unit, but I have a couple of general questions about conversions that I hope someone can help with.

The kit comes with brake levers that cut power to the motor when applied - unfortunately my brake levers and gear change levers are a single unit. Aside from the legal requirement, how important is the cut of power to the motor and how would the motor behave if brakes are applied without power being cut? I managed to get hold of the December 2008 copy of Velovision with reviews of various kits and the reviewer said that he didn't bother with this feature. If it is genuinely useful, does anyone think it would be possible to simply hack the sensor on to the existing brake setup?

The next question is to do with the throttle - the supplied throttle is a thumb version but I'm not really sure how this will work with my gear selectors as they are the trigger type. Is this throttle sprung so that you have to maintain pressure?

Sorry if these are daft questions - I did search several times before posting but my search terms are rather vague. I have emailed the vendor a couple of times but he appears to be out of reach at the moment.

Anyway, thanks for reading and thanks in advance for any advice.

Firstly you might find the 24V a bit anaemic power wise, 36V is generally better in that regard, however it should still provide some useful assistance.

2ndly re: brake cut outs. Are they needed yes and no. If you can guarantee to release the throttle when you brake, no. Otherwise what will happen is that the motor will fight the brakes until the effort is so great that the overcurrent detector in the controller trips and cuts out the motor. This is unlikely to be good for the motor or battery YMMV.

Brake cutout switches are simply microswitches that close (i.e.switch on) when the brakes are pulled. Some people have grafted an arrangement onto normal brake levers, however you need to pay attention to waterproofing as if there's a short, then your motor won't work.

3rdly Thottle. You can get thumb or twist type throttles. With care they are usually interchangeable. Some people have removed the springs from their throttles (see brake cut outs...)


hope this helps!

 

[hellnick]

Thanks very much for your informative and incredibly fast reply. I realise that the 24v won't be fast but I'm fairly light (about 10.5 stone) and it's probably better that I get something that requires me to pedal too.

That said, I imagine that upgrading just the battery might be difficult if I change my mind, and I do live around one of London's high points (Crystal Palace). Do you think that a 24v could carry 10.5 stone up a 1 in 7 hill? Or at least enough for me to stop peddling every now and then for a rest?

Cheers

n

 

[torrent99]

Thanks very much for your informative and incredibly fast reply. I realise that the 24v won't be fast but I'm fairly light (about 10.5 stone) and it's probably better that I get something that requires me to pedal too.

That said, I imagine that upgrading just the battery might be difficult if I change my mind, and I do live around one of London's high points (Crystal Palace). Do you think that a 24v could carry 10.5 stone up a 1 in 7 hill? Or at least enough for me to stop peddling every now and then for a rest?

Cheers

n

In a word....no probably not. (That's 3 words darn!), it would help considerably though so you might not need to stop pedaling. I have no direct personal experience of 24V though, maybe someone else who has will provide a more hopeful answer. It would also be a very good idea to try out some electric bikes so you can see what the effect feels like. The Electric Transport Shop in Camden have a wide range of bikes to try.

 

[flecc]

I only know one e-bike that will just about carry a 10.5 stone person up 1 in 7 without pedalling, and that's the eZee Quando. The trouble is that it has no gears, just single speed, so on anything much steeper it can be hard work since the rider's pedalling speed is so slow.

If the motor is geared for 15 mph assist, with any 24 volt kit on the market you'll have to provide around half the hill climb effort on 1 in 7 with continuous pedalling, and still a fair proportion with 36 volt ones.

In general they're all electric assist rather than electric powered, as I know from living up a 1 in 7 hill.
.

 

[hellnick]

I don't mind doing a share of the work - I did get the bike to avoid going to a gym. Suppose I'll just have to do my usual trick of stopping every now and then and pretend to fiddle with the gears, or check my phone for really urgent and very important messages.

 

[Caph]

Hellnick, I've got a 24V 24 speed MTB with no brake cutouts. My motor is optimised for 4-10mph.

I'll deal with each point in turn.

The lack of brake cutouts are no problem. It is rare that you brake as you are pedalling, normally I stop pedalling then break a second or two later. The motor cuts out very quickly after you stop pedalling but even in that second you can easily out brake the motor and I've never had a problem doing so nor have I detected the motor complaining about it.

Climbing hills on 24V on a normal 7 speed electric bike when pedalling may be a problem but with 24 gears then my lowest three gears will get me up ridiculously steep hills with minor pedal assistance. The lowest gear gets me up off-road slopes that make me feel like I am defying the laws of physics.

Regarding the throttle, mine is pedelec only so I can't say.

Hope that's of some use.

 

[drgcb]

Hi,

I have some experience of both the 24V and 36V Alien kits.

My father has the 24V kit on his MTB (see this thread for some photos).

A couple of things with the 24V kit. Firstly, as you can see from the photos, it mounts on the seatpost and you need a LOT of clearance. Secondly, the battery tends to bounce up and down quite a bit, which has led to cracking in the plastic casing and some signs of the metal bracket cracking as well. So if it's for off road (or your roads are as poorly surfaced as Sheffield's) you may run into similar issues.

The thumb throttle works fine with most trigger shifters; I'd suggest mounting it on the left bar (assuming that's where your front chainring shifter is). It is sprung, and as such can be uncomfortable when held open for long periods. I've got mine angled so that it can be wedged in the web space between my thumb and index finger, where it's more comfortable. My bike started life as an Alien Cruiser, but I took the electrics off it and mounted it onto a Revolution Trailfinder (from Edinburgh Bicycle Cooperative). In so doing I changed it from twist to thumb throttle (they're interchangeable, but the wiring colours are different and require some experimentation!) I also did not transfer the brake levers with the cutouts. The levers themselves were not great (my LBS said they were for cantilever not V-brakes), and I found them very unreliable in the wet (randomly cutting the motor).

Here's a random picture just to show it off.



I don't think there's a massive amount of hill-climbing difference with the 24V versus 36V Alien kits experientially. I reckon it depends more on which kit suits your bike better.

Kind regards,

Greg

 

[john]

Many of us don't bother with brake cut-outs. Just another thing to go wrong. You will habitually let go of the throttle before breaking so will likely do this in an emergency. Even if you didn't, other than a few high torque motors, there would be little affect on braking with decent brakes. The motor would create heat, but not enough to overheat in the few seconds required to stop the bike.

 

[hellnick]

Thanks very much for the very useful information and links. The 24v seems to need an awful lot of clearance so I think I may have to look at the 36v a little closer.

I'll try to post some pictures if I go ahead with it.