Why must the battery even be on the bike at all?

General Discussion about electric bicycles.
The Mighty Volt   10 MW

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Re: Why must the battery even be on the bike at all?

Post by The Mighty Volt » Mar 16 2012 7:27am

MikeFairbanks wrote:I'm sure I'm not the originator of this thought. If you have a geared hub motor plus controller on the bike, but have the battery in one of your backpack pockets with a telephone-style cord (spiral) to the controller, you could have a very light ebike.

Think it would work?

I do.
Sure why not. I used to carry a 24s 2p A123 pack around on my back. It was fun feeling those cells get warm and die as I pumped her at 100A a go. :D :D

The Mighty Volt   10 MW

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Re: Why must the battery even be on the bike at all?

Post by The Mighty Volt » Mar 16 2012 7:28am

John in CR wrote:The backpack weight is no big deal even for me, one of the least in shape guys on the forum. My issue is connecting with a wire long enough to conveniently get on and off the bike, but short enough to avoid getting entangled in anything. Imagine the fireworks potential of battery mains entangled in your wheel. :shock:
Oh, we've been there, trust me. Its part of the reason why I insisted on building the pack back onto the bike. Every kid who "wanted a go" ran the risk of becoming the new Plasma Boy.

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Re: Why must the battery even be on the bike at all?

Post by jerrysimon » Mar 16 2012 8:16am

Kind of a half way house, on the bike attached in a bag but removable. For me this is essential as I ride small wheeled portable bikes.

Brompton. Splits bike weight 13kg (using the narrow width 2kg Tongxin motor) and 2kg battery/controller in the bag.

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Bag with a small 1kg A123 12s1p battery pack in one back pocket. The controller is also in the other back pocket.

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Bag and bike connect via an umbilical cable/connector.

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Regards

Jerry
Last edited by jerrysimon on Mar 16 2012 9:21am, edited 5 times in total.

jerrysimon   10 W

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Re: Why must the battery even be on the bike at all?

Post by jerrysimon » Mar 16 2012 8:19am

My other bike a Moulton TSR2 with a simlar setup. Rucksack uses Klickfix fitting and attached again with umbilical to the bike.

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Regards

Jerry

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Re: Why must the battery even be on the bike at all?

Post by Scottyf » Mar 16 2012 9:44am

Hello Jerry,
I used exactly the same setup with that Maplins connector. Worked for about 3 months in the rain etc and 2.2kw though it untill it eventually died.
Still it was worth it for testing methods. That and as a connector it wasn't really meant to have that wattage chucked at it.

I use a backpack battery as My bike is left outside at work. I also prefer that if I park my bike somewhere its one less thing I have to secure and I can take it with me. This also works for charging too.

It does make the backpack heavy with 660w of Lipo in it but not much so that the bike and controller weight in at just under 5 kilo.

As others have said there are pro's and con's to different setups.
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Sacman   10 kW

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Re: Why must the battery even be on the bike at all?

Post by Sacman » Mar 16 2012 11:45am

jerrysimon wrote:Kind of a half way house, on the bike attached in a bag but removable. For me this is essential as I ride small wheeled portable bikes.

Brompton. Splits bike weight 13kg (using the narrow width 2kg Tongxin motor) and 2kg battery/controller in the bag.

Image

Regards

Jerry
Isn't your steering response a bit sluggish with all that battery weight attached to the front like that?

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Re: Why must the battery even be on the bike at all?

Post by jerrysimon » Mar 17 2012 3:59am

Not with a 1kg, A123 12s1p battery no 8)

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As I said its all in the two back small pockets leaving the rest of the bag to carry other stuff. I think the limit on the front carrier is around 8kgs.

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Also note the bag sits on a front carrier block which is attached to the static frame not the upper steering tube.

Regards

Jerry

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Re: Why must the battery even be on the bike at all?

Post by dogman dan » Mar 17 2012 7:28am

However it's done, a removable battery is a good thing if you must leave a bike parked someplace less than perfectly secure.

Nothing particularly wrong with carrying in a backpack for street riding. I just don't like it on the trails. But like I did for years on skis, you can adjust to it if you have a good pack. You just can't trail ride or ski or mountain climb with a pack that has weight slopping around inside it, shifting all over this way and that. You need a good fitting pack you can strap on tight, and get the weight low on your hips.

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Re: Why must the battery even be on the bike at all?

Post by Sacman » Mar 17 2012 3:48pm

Ahhh... that IS a small battery pack. The huge empty bag it's in just looked decievingly heavy. And it's hard to see that carrier block attached to the frame even tho you pointed it out.
jerrysimon wrote:Not with a 1kg, A123 12s1p battery no 8)

Image

As I said its all in the two back small pockets leaving the rest of the bag to carry other stuff. I think the limit on the front carrier is around 8kgs.

Also note the bag sits on a front carrier block which is attached to the static frame not the upper steering tube.

Regards

Jerry

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Re: Why must the battery even be on the bike at all?

Post by Beachcruzer » Mar 18 2012 3:09am

I've got my whole drivetrain and power supply in front of the head-tube. (Aotema front hub and up to six bricks of lipo in the basket). Tried it just to see if it was possible, and to my surprise the handling is actually really good. World's better than mounting the batteries on a rear rack. Oatnet, Gensem and others have shown that this can be done on high-performance bikes as well (fork-mount battery with rear hub). I think Jerry's setup is an elegant solution for the kind of riding he's doing.

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Re: Why must the battery even be on the bike at all?

Post by ddk » Mar 18 2012 7:08am

I'm building a dashboard that's to be placed between the ape-hanger 17" deep handlebars for my trike project.
Besides the other stuff mounted on the dashboard itself (voltmeters, chargers, video monitor etc,) I also intend to mount the controller underneath and 6 sticks of 5S@5000ma LiPo batteries within it. (10s3p for 36v@15AH) about 9 kilos altogether.
So no, the batteries won't be easily removable (will take a few minutes, removing security-head bolts), but they also won't be visible nor do they need to be with voltage monitoring for each cell
I believe this will work out ok, as the sitting position is somewhat akin to a recumbent bike -meaning I don't use the handlebars for any leverage-assist.
Time will tell

Curiously enough I'm also building a battery bank container holding 6 each 12v@10AH AGM sled acid batteries hooked up for 36V@20AH that mounts along the bottom tubes of the trike's frame (3 batteries per side) because:
a- I have them
b- I actually think I need the additional ballast weight. (because of my fat a**, which I'm balancing against using the battery locations)
If not I'll eventually replace the SLA batteries with only 2 sticks of 5s@5000ma LiPo hooked up in series for 36V@5AH (guesstimated actual power requirement)

Can't think of a way to levitate (the batteries) without adding more weight to the bike. Levitating with magnets only adds lots more weight (the magnets + the batteries) :lol:
:idea: Light-weight anti-gravity device next up on my agenda!
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Re: Why must the battery even be on the bike at all?

Post by cwah » Mar 31 2012 6:58am

jerrysimon wrote:My other bike a Moulton TSR2 with a simlar setup. Rucksack uses Klickfix fitting and attached again with umbilical to the bike.

Image

Image

Regards

Jerry
Jerry, I think the Klickfix fitting is a wonderful idea for carrying a bag:
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http://www.amazon.co.uk/Rixen-KaulKlick ... 823&sr=8-2

I'd like to have one on the rear rack :lol:

Do you know if there is any way to have a "quick release" you have for any bag? and especially for bigger bags on the rear rack?

I'm for now thinking about getting some clips glued to the bag. Then do the same for the bike rear rack. I would then have my own custom quick release. But not sure if that would work. :lol:
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