A minimalistic kit proposal

[Arbol]

Would that work?

1. 6s1p of Sony VTC4 (a bit more than 2Ah, 15A of max continuous amperage) as suggested in http://endless-sphere.com/forums/viewtopic.php?f=31&t=50015&p=858500#p858500 i.e., inside the seat tube (that works only if the seat tube is big enough)
2. The 100SWXDC24 http://www.keyde.com/?do=product&lang=en&event=view&ids=12 with controller inside

I understand power would be limited (24V) and range would be low (how much???). But if range is low (maybe below 10km / 6 miles, if there is support from the cyclist), that combination could be feasible. What do you think?

 

[Deleted member 4366]

We normally use 7S for 24v. I think 2aH is not enough. There will be a bit of sag at 15 amps, which could mean that you hit LVC sooner than you expect. Two strings of seven would be more like it.

I think that if you want an ultra-light folder to carry into the office and/or up to your flat or on the train, there could be a case for it, otherwise it doesn't really make sense.

 

[Geebee]

The idea is definitely feasable, my trike ran a Tongxin at 24v and a single 5 ah battery and would easily do 25 km with a big reserve but it is not the kind of bike assist that most seem to want, it gives you a fast light bike with assist off the line and on hills for very little weight.
I used Zippy LiPo batteries though and they would not fit in the tube.

D8veh it makes sense from the point of view of having assistance when needed with very few of the drawbacks for normal riding, and if the batteries were hidden it would be very hard to tell it was assisted at all, it was the kind of thing I liked when fitter.

Oh and have you seen this thread http://www.pedelecs.co.uk/forum/threads/very-lightweight-e-bikes.16923/#post-208437

 

[Arbol]

Could 7s2p 18650s and a controller be put in the free space of the chain guard as per

http://bikesales4u.com/wp-content/uploads/2010/08/corvo_05.jpg ? what I mean is a solid chain guard, with no empty space in the middle

 

[Arbol]

We normally use 7S for 24v. I think 2aH is not enough. There will be a bit of sag at 15 amps, which could mean that you hit LVC sooner than you expect. Two strings of seven would be more like it.

I think that if you want an ultra-light folder to carry into the office and/or up to your flat or on the train, there could be a case for it, otherwise it doesn't really make sense.

d8veh, more than a foldable, now I am thinking about a city bike like the one in my previous post, a beautiful singlespeed. My main concern is security. I believe that with pinheads and good Us there is enough for the bike. The problem is the electric side. If I could hide it, burglars would not be attracted. I am trying to find locations within the bike where the combo battery & controller could be hidden:

One possibility is a keyde with batteries inside the seat post. Another, possibly more flexible, is to use any rear motor, and put the battery and controller inside a chain guard, but this would require finding somebody able to work with plastic. A final possibility would be to hide the battery & controller under a rack, but I think this solution would not be 100% stealthy.

 

[103Alex1]

and put the battery and controller inside a chain guard, but this would require finding somebody able to work with plastic.

I wouldn't personally try that .... plastic chain guards fixed to frames are prone to breaking at their fixing points and additional weight will only add to that risk. Especially when coupled with a few bumps or the odd small pothole.

 

[Geebee]

There was a link here recently for an inwheel battery pack

I wouldn't personally try that .... plastic chain guards fixed to frames are prone to breaking at their fixing points and additional weight will only add to that risk. Especially when coupled with a few bumps or the odd small pothole.

A lot of the dutch bikes gaurds are steel, if plastic it would be fairly easy to reinforce the mounting area.

 

[Arbol]

Yesterday I want to a shop, and I believe a better solution than the chain guard, which has limited space, is the skirt guard: The distance between the guard and the spokes is more than 18mm and there is ample space for many cells. The question is how to make the structure robust.

A second question is if it is possible to make two 10s2p batteries, one on the left and another one on the right, to have a full battery of 10s4p. And to make everything more complicated (in order to fit the 10s2p well in the space of the skirt guard) to have 10 cells in the base, and on top of those cells, to have two sets of 5 cells one above the other, to make a "tower" of three (10 cells first floor, 5 cells second floor, 5 cells third floor).

The same could be asked about a total 10s2p battery, resulting from a combination of two 10s1p packages. Can I connect two 10s1p packages to build a 10s2p battery?

Is this possible?

 

[Geebee]

I can't believe that I was thinking about exactly that last night looking at Dutch bikes, but I did not suggest it as I was unsure of the clearance distance of the skirt gaurd although it occurred to me that you could bulge them out if needed.
I still like the chain gaurd with bulged covers, if I come a cross the right bike someday I just might have to try it.

Battery wise they can be layed out however you like it is only a matter of wiring them to give the required (S) Voltage and (P) amp hours.