The Problem of Battery Placement

[kudos]

Of all the issues the diy ebike convertor faces, where to place and mount the batteries I think is the hardest.

If you only need a small battery then it's no problem, they can be popped in a bag behind your saddle or plenty of other places.

If you require a larger battery though suddenly you're faced with having an ugly heavy rear pannier wrecking your handling.

Or you could use a frame bag which are handy but arguably ruin the look of your bike.

Some people with triple-crown forks have fabbed mounts to attach to the front of the bike but again ruin the bike lines.

I'm surprised with all the talent on these forums no one has come up with a ready to go battery case/mount that doesn't look like a elephant strapped to cat.

I'd like to have a unit that attaches under the down tube near the bottom bracket.

There's enough width there between the pedal cranks, the centre of gravity would be low and in the middle for good handling and it could be shaped with a curve so as not to ruin the lines of the bike.

One end could hook over/around the bottom bracket and the other attach to the downtube.

Does anything like this already exist?

Kudos

 

[docnjoj]

Kiwi has one!
otherDoc

 

[cal3thousand]

Of all the issues the diy ebike convertor faces, where to place and mount the batteries I think is the hardest.

If you only need a small battery then it's no problem, they can be popped in a bag behind your saddle or plenty of other places.

If you require a larger battery though suddenly you're faced with having an ugly heavy rear pannier wrecking your handling.

Or you could use a frame bag which are handy but arguably ruin the look of your bike.

Some people with triple-crown forks have fabbed mounts to attach to the front of the bike but again ruin the bike lines.

I'm surprised with all the talent on these forums no one has come up with a ready to go battery case/mount that doesn't look like a elephant strapped to cat.

I'd like to have a unit that attaches under the down tube near the bottom bracket.

There's enough width there between the pedal cranks, the centre of gravity would be low and in the middle for good handling and it could be shaped with a curve so as not to ruin the lines of the bike.

One end could hook over/around the bottom bracket and the other attach to the downtube.

Does anything like this already exist?

Kudos

I'm pretty surprised too.

It's one of the areas of compromise on an ebike though. Until they put their first ebike together and ride it for extended periods, people will compromise on the battery location as it is the easiest thing to compromise on. Duct tape, ABS, cloth triangle, pannier, backpack, etc...

It is also one of the most expensive areas to properly construct and can take much effort due to the different bike and battery geometries available.

Having said that, I still feel that someone needs to make some ebike battery boxes for general use. Kiwi already did that with the EVLab boxes, so that's a start.


I'm currently making an ABS/Aluminum/Carbon box for my Norco DH ride that mounts underneath the bike for 24S 2P of LiPo. It could easily be used for other types of cells as well. The problem comes with the cost of materials to make a box like this. The ABS and aluminum are relatively cheap and are only about $25-30. But the carbon, depending on how much it takes to cover the piece with an acceptable thickness (This is the part I'm on now).

The design of the box is somewhat versatile. i.e. I believe I could make it work on other frames as well.

Question remains though, if I were to make more of the boxes, would someone buy it and how much do people want to spend on a box for their batteries when duct tape is now $4 a roll at Home Depot?

 

[amberwolf]

The problem with downtube mounts (or any other "universal" mounting place) is that bikes are all different enough that it's only going to fit a percentage of bikes.

Then there's the problem of what kind of batteries it's meant to hold--if it fits one kind it may not fit another, and it could be tough to make it universal enough to fit all of them.

If you have a number of versions, or a modular system to allow for differnet pack sizes (primarily depth and length for differnet numbers or types of packs or cells), it could be possible to make a mostly-universal packholder that mounts on the downtubes of many bikes.


It has to accomodate the fully compressed state of the front suspension, though, and in the states of full right or left turn as well as straight ahead and all in between.



Just some points to consider.

 

[cal3thousand]

The problem with downtube mounts (or any other "universal" mounting place) is that bikes are all different enough that it's only going to fit a percentage of bikes.

Then there's the problem of what kind of batteries it's meant to hold--if it fits one kind it may not fit another, and it could be tough to make it universal enough to fit all of them.

If you have a number of versions, or a modular system to allow for differnet pack sizes (primarily depth and length for differnet numbers or types of packs or cells), it could be possible to make a mostly-universal packholder that mounts on the downtubes of many bikes.


It has to accomodate the fully compressed state of the front suspension, though, and in the states of full right or left turn as well as straight ahead and all in between.



Just some points to consider.

Those are all good points. All things that I did have to consider when designing the box. I made my box with dimensions larger than my 8 packs required, but not too large as to hinder the suspension or crank. It will have plenty of room for the packs, wiring, switchery and Method's Detector boards.

If I offer this box for sale, it will be only useful to a handful of folks. First, this forum is about sharing ideas and using them. So I expect many to make one for themselves.

Second, the cost of making one will make point #1 more attractive. :wink:

 

[friendly1uk]

My typical looking no suspension bike has 55mm from tyre to down tube. This will accommodate a 2x2 section. A 2x2 16swg section has an ID of 48.6mm X 48.6mm. A HK 4S 5Ah LiPo Hardcase is 43x45x139mm. Three such packs in a row form a 12s 44.4v 5Ah 2x2 stick measuring 417mm in length.

Alternately a 2x4 could house 10Ah. Without being a great deal longer it could also house a bms. A small controller. DC-DC. The 5Ah stick struggles to get a bms in there, but bestek sell a 50x60mm board that might sit in diagonally.

Using common sizes means you can get all sorts of fittings and end caps.


Edit: I picked up some rectangular shaped kitchen extractor hard pipe. It measured ?? bugger... measuring... Different to the product description, but I have cut it up now. It's ID is 106x50mm shrinking to 49mm in places. 50mm is the width of a few bms boards. This material is a bit bendy though and I have not seen end caps. It needs a lot more than a few finishing touch's. I'm just using it for segregation within a frame bag

 

[999zip999]

Always start wit a better than a good cell. Make a cardboard box the size you need and go from there. Here is a 12s A123 20ah in the triangle. If could easly be a 16s.

 

[parajared]

There are some pretty neat triangle bags out there like the falconev bag and Iberra bag. I have had issues with triangle nylon bags because the batteries bounce around and rub against each other, but I am willing to bet this can be worked out easily enough.

I have had a fair amount of frustration with battery mounting myself
Rear rack is no good: broken spokes, rough ride
Front rack is no good: wonky steering, hammer into potholes hard
Middle is perfect.

So far my favorite middle of the bike solution has been to drape the batteries over the bike like you put a saddle on a horse. This allows you to quickly and easily take your batteries with you, or swap your batteries/controller over to a non-triangle bike, however I have not seen any factory made “saddle style” setups worth their snuff yet.

 

[amberwolf]

There are some pretty neat triangle bags out there like the falconev bag and Iberra bag. I have had issues with triangle nylon bags because the batteries bounce around and rub against each other, but I am willing to bet this can be worked out easily enough.

Sure: build a tight-fitting battery box to secure them, and put that inside the bag.

 

[majornelson]

Can you post a pic of the box you're building?

 

[cal3thousand]

Can you post a pic of the box you're building?

Me?

 

[majornelson]

Cal3thousand,

Yes. I wasn't clear...

I like the idea of what you're doing... If its not too much trouble.

 

[Blackssr]

Of all the issues the diy ebike convertor faces, where to place and mount the batteries I think is the hardest.

If you only need a small battery then it's no problem, they can be popped in a bag behind your saddle or plenty of other places.

If you require a larger battery though suddenly you're faced with having an ugly heavy rear pannier wrecking your handling.

Or you could use a frame bag which are handy but arguably ruin the look of your bike.

Some people with triple-crown forks have fabbed mounts to attach to the front of the bike but again ruin the bike lines.

I'm surprised with all the talent on these forums no one has come up with a ready to go battery case/mount that doesn't look like a elephant strapped to cat.

I'd like to have a unit that attaches under the down tube near the bottom bracket.

There's enough width there between the pedal cranks, the centre of gravity would be low and in the middle for good handling and it could be shaped with a curve so as not to ruin the lines of the bike.

One end could hook over/around the bottom bracket and the other attach to the downtube.

Does anything like this already exist?

Kudos

When I first decided to build a 55mph ebike this was a major concern of mine. I had no prior knowledge of ebikes until I stumbled upon this forum. IMHO the EV Global frame/placement is ideal.

 

[cal3thousand]

Cal3thousand,

Yes. I wasn't clear...

I like the idea of what you're doing... If its not too much trouble.

Sure. Here's what I've got so far. What you see is the plate that will be the "top" of the box as it mates with the frame. Basically, upside down.

It's made of 1/4" ABS and 1/8" angled aluminum bar riveted together. The carbon/ABS cover will be somewhat aeroshaped and cover all the metal bits as well. Mounts underneath the frame with the skinnier part between the cranks

 

[Supertux1]

I struggled with this for awhile and I think frame bags are the best. Plenty of room for padding if done right:

It does limit your options for rear suspension though. The next best thing is then a Thudbuster or other suspension seat post, or maybe a Surly Fat bike.

 

[John Bozi]

So far my favorite middle of the bike solution has been to drape the batteries over the bike like you put a saddle on a horse. This allows you to quickly and easily take your batteries with you, or swap your batteries/controller over to a non-triangle bike, however I have not seen any factory made “saddle style” setups worth their snuff yet.

Unfortunately the additive "the bike bag" won't ship outside of germany austria switzerland.

 

[made_in_the_alps_legacy]

Always start wit a better than a good cell. Make a cardboard box the size you need and go from there. Here is a 12s A123 20ah in the triangle. If could easly be a 16s.

then, choose the bike which might fit around the battery :lol: (actually, that's what I did: the battery chose the bike, not me :wink: )

 

[Arbol]

So far my favorite middle of the bike solution has been to drape the batteries over the bike like you put a saddle on a horse. This allows you to quickly and easily take your batteries with you, or swap your batteries/controller over to a non-triangle bike, however I have not seen any factory made “saddle style” setups worth their snuff yet.

Unfortunately the additive "the bike bag" won't ship outside of germany austria switzerland.

Is there a link for this product? Thanks.

 

[wesnewell]

Some scrape wood made this in a 17" frame. 12s4p or 24s2p with room left over. Solid as a rock with the top block. Can get in or out in seconds.

Same 12 4s packs as above. Made this from an old aluminum for sale sign. Not quiet as solid as above but I flipped the bike when I hit a large dog and none of the batteries got damaged. Handles almost as good as the one in the triangle.

I couldn't care less what it looks like as long as it's functional.

 

[spinningmagnets]

These guys aren't in business any more, but I thought their large square battery that's mounted low was interesting...

 

[cal3thousand]

These guys aren't in business any more, but I thought their large square battery that's mounted low was interesting...

That's a very nice design keeping the weight down low between the wheels. Looks removable too. Not really a bike with just pegs though.

 

[John Bozi]

Some scrape wood made this in a 17" frame. 12s4p or 24s2p with room left over. Solid as a rock with the top block. Can get in or out in seconds.
View attachment 1
Same 12 4s packs as above. Made this from an old aluminum for sale sign. Not quiet as solid as above but I flipped the bike when I hit a large dog and none of the batteries got damaged. Handles almost as good as the one in the triangle.

I couldn't care less what it looks like as long as it's functional.

wish they made 6s hardcases, would save me so much hassle. they look tough enough to just gaffa tape to the frame.

 

[friendly1uk]

Group buy
http://endless-sphere.com/forums/viewtopic.php?f=31&t=57623&p=859305&hilit=additive#p859305

I'm about to do a 12s 5Ah top tube pannier. Attempt number three. I'm hopeful the parts on order come the right size this time. If so, the 3 4s bricks and a controller will be in something like this

That bag is sold by many, with dimensions ranging from 150mm to 170mm long, but still the 139mm Bricks won't fit. I have one on it's way with express postage claiming to be 180mm long. Maybe 139mm will fit in this one.

I have also looked at these, thinking I could buy two and just pair up the larger bags at 22x15x7cm each. If that is to be believed, 10Ah at 48V would fit.

Both are cheap on ebay.

The problem with cheap bags is there strength. I wouldn't hold batteries within them. I would rather sling everything in place, then use the bag as a cover. Something like that. Eyelets stamped in can be used for cable entry, and looping cable ties through. You can quite easily fill a bag then strap up it's contents. I'm still exploring options, but think I could offer bikes to friends with such an arrangement. 4s Bricks in bags cable tied up through eyelets. The problem is the exaggerated size's of the bags. They just keep coming wrong.

 

[spinningmagnets]

It's possible to mount a triangle pack in the low area just behind the front tire (the "Prow"?). A pack that is there might not be large enough, you might need a second pack in parallel, but...I think this is a very useful start:

 

[Toorbough ULL-Zeveigh]

It's possible to mount a triangle pack in the low area just behind the front tire (the "Prow"?).

yeah, that would be the m.b.position