Ladies ebike conversion and battery location

[MikeFB]

A female friend has asked me to build her an ebike. Problem is she wants a ladies bike with the deep step through.

I don't want to mount the battery to a rear rack, as the kit I'm looking at comes with a tube mounted battery. Would putting it on the top tube be OK? I realise that that would take up step through space, but having looked at some ladies bikes would still give a reasonable amount of room if I mount it higher up on the frame (I think?). It may also make it easier for her to remove possibly?

PS: battery has to be locked in and secure as she will be using it for going into town.

Any suggestions or alternatives?

 

[vfr400]

Get a different kit that has the option of a rack battery.

 

[MikeFB]

Problem is she wants to tackle a steep hill to her house after shopping and wants a trailer as well, oh and basket!. It also has to be 250w legal, she's an ex cop...... So I'm looking at one of the 48v Woosh kits with downtube battery.

Pretty limited given the requirements.

 

[vfr400]

A Downtube battery is awkward. You'll have to mount it high up, where it has a pendulum effect, and it's too easy to kick it when mounting the bike, so you need a very secure fixing system. two rivnuts won't cut it.

 

[MikeFB]

mmmm? I wonder? I have a rear rack that has a 10kg max load and attaches to the seat post (it's on my fat bike). The rack is screwed to a long post, so the rack part can be removed leaving the horizontal post only. I could possibly mount the downtube battery to that with numerous rivnuts, although security may be an issue, as the post could be removed?

Going to have to see what she wants I guess. I suppose she could do some leg stretches and ride a bike with a larger triangle frame?

 

[vfr400]

No. You need a steel one if it's a cantilever. Aluminium suffers metal fatigue, so you get sudden failure sometime in the future. You can solve that by adding struts as long as you don't have rear suspension.

 

[MikeFB]

No. You need a steel one if it's a cantilever. Aluminium suffers metal fatigue, so you get sudden failure sometime in the future. You can solve that by adding struts as long as you don't have rear suspension.

Good point. Guess I'm going to have to think about this a bit more and see exactly what she wants to get a better picture of best how to proceed.

Maybe see if she can cope with a slightly higher top tube that is still low like my fat bike or accept a full rear rack that I can modify to accept the downtube battery?

Cheers vfr400

 

[D C]

[/QUOTE]
vfr400 is dead right,
this type can and has damaged frames, if you do a search there's a few posts about it, sadly including mine.
Dave.

 

[MikeFB]

vfr400 is dead right,
this type can and has damaged frames, if you do a search there's a few posts about it, sadly including mine.
Dave.
[/QUOTE]
yeah it wasn't expensive, but mine doesn't have a lot of weight on it. Just carrying some bike tools, tube, repair kit, sun glasses, that sort of thing. Will probably replace it with a proper rear rack soon.

 

[Swizz]

A female friend has asked me to build her an ebike. Problem is she wants a ladies bike with the deep step through.

I don't want to mount the battery to a rear rack, as the kit I'm looking at comes with a tube mounted battery. Would putting it on the top tube be OK? I realise that that would take up step through space, but having looked at some ladies bikes would still give a reasonable amount of room if I mount it higher up on the frame (I think?). It may also make it easier for her to remove possibly?

PS: battery has to be locked in and secure as she will be using it for going into town.

Any suggestions or alternatives?

The top tube.

Yes, she will have to consciously steer her foot through the gap for the first few times but then it becomes second nature.

Most of the weight is still lower down than on a rack mounted battery and I have experienced no ill effect to the handling on my bicycle.

The only advice I will give is actually pretty obvious...leave enough room in front of the battery for it to slide forward & be removed from it's baseplate.

 

[MikeFB]

The top tube.

Yes, she will have to consciously steer her foot through the gap for the first few times but then it becomes second nature.

Most of the weight is still be lower down than on a rack mounted battery and I have experienced no ill effect to the handling on my bicycle.

The only advice I will give is actually pretty obvious...leave enough room in front of the battery for it to slide forward & be removed from it's baseplate.

View attachment 38487

Thanks for that, this was what I originally had in mind, but I couldn't visualize it as google image search didn't seem to show anything appropriate. While it would be nice to have it lower for a lower centre of gravity, I guess it isn't really any higher than having it on a rear rack.

 

[Swizz]

Thanks for that, this was what I originally had in mind, but I couldn't visualize it as google image search didn't seem to show anything appropriate. While it would be nice to have it lower for a lower centre of gravity, I guess it isn't really any higher than having it on a rear rack.

R welcome. You could mount it as low down the tube as she is comfortable with for stepping through. She can work that out better for you when the bike is on its wheels. Am sure Whoosh will give you battery dimensions if you wish to do a mock up before deciding 100% on a HL Battery. Re the space in front, I left approx an inch to allow the battery to be removed.
Isla.

 

[D C]

mine doesn't have a lot of weight on it. Just carrying some bike tools, tube, repair kit, sun glasses, that sort of thing. Will probably replace it with a proper rear rack soon.

I'm sure that will be fine, mine was until I put a battery on it as well!
Dave.

 

[MikeFB]

R welcome. You could mount it as low down the tube as she is comfortable with for stepping through. She can work that out better for you when the bike is on its wheels. Am sure Whoosh will give you battery dimensions if you wish to do a mock up before deciding 100% on a HL Battery. Re the space in front, I left approx an inch to allow the battery to be removed.
Isla.

I currently have Woosh's fat bike kit on one of my bikes with the same battery, so once I find a suitable bike for her, I'll have a play about with placement. Cheers.