Building a protective battery pack enclosure for lipo

[swbluto]

Trying to get ideas for building a good battery pack enclosure. Saw the battery pack enclosure on the ultrafast recumbent in this video and how it was mounted under the frame and immediately thought that was a great idea for center of gravity reasons. (I noticed my bike starts dangerously weaving at high speed when there's too much weight on the back.)

[youtube]lTqkdGgRbPU[/youtube]

But, I'm thinking it need to be durable enough to survive a crash if it's carrying lipo. Anyone know of any threads that go over this? Have ideas? I thought I saw a humongous "Post your own battery pack enclosure" thread once, but I can't seem to find it.

 

[swbluto]

http://endless-sphere.com/forums/viewtopic.php?f=3&t=12847

Found it!

Google is a powerful thing. My query: How to build a battery pack enclosure site:endless-sphere.com

It was second on the list. Clearly google uses some kind of semantic technology to 'interpret' the query, which is a lot better than the verbatim search engines that most forums use.

 

[dogman dan]

My favorite method for building sturdy custom boxes is to use two materials. Start with wood, using high quality half inch thick hardwood like aspen or poplar. Frame a box, typically 4 1/4" for lipo bricks. The extra quarter inch is for additional padding material like coroplast. Then the larger sides of the box are 1/8" aluminum sheet. Lucky me, when I moved in the garage had 6 road signs in it. But you can buy aluminum diamond plate.

Using two materials allows building the entire thing with simple tools, skill saw, drill, screws. Build it just right to fit very tight. I use coroplast to shim that last bit super tight, compressing the coroplast inner box. Zero movement of the pack in the box, just from the compression is the goal. As you know, compressing pouches is good.

If a pack should puff like hell, you can simply unscrew the aluminum plate and get it back out. A carbon fiber box, you'd have to cut that sucker apart to get a really puffed pack back out.

 

[TheBeastie]

I can give you advice on building the most dodgey battery bag.
I fit 6 x 6S 5Ah Turnigy lipos in this polka dot 2 layer toiletry bag.
http://www.ebay.com.au/itm/390580450199?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

I then wrap/secure it to the top tube of my frame so it hands down via 10cm wide velcro straps. http://www.ebay.com.au/itm/120953225649?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

This has been by far the most bounce/rattle free setup I have had since the batteries are suspended via velcro.

 

[dogman dan]

For a triangle bag on a normal bike It's hard to beat this.

 

[swbluto]

Thanks all! I'm looking at putting a battery box at the bottom of this recumbent (Mine has a 9c 20" rear motor instead of a midmount one):

I saw hyena's build and how he used a rectangular plastic PVC pipe. Here's another aussie with the tubing:

http://www.endless-sphere.com/forums/viewtopic.php?f=6&t=34039

I couldn't find a rectangular tube at the local home improvement stores, and looking online, it looks like it's mostly available to Australian/UK markets.

The tubing looks really nice because it's relatively narrow and compact and minimizes the exposed frontal area on the bike, which is important for aerodynamics (I.e., speed and range).

 

[swbluto]

My favorite method for building sturdy custom boxes is to use two materials. Start with wood, using high quality half inch thick hardwood like aspen or poplar. Frame a box, typically 4 1/4" for lipo bricks. The extra quarter inch is for additional padding material like coroplast. Then the larger sides of the box are 1/8" aluminum sheet. Lucky me, when I moved in the garage had 6 road signs in it. But you can buy aluminum diamond plate.

Using two materials allows building the entire thing with simple tools, skill saw, drill, screws. Build it just right to fit very tight. I use coroplast to shim that last bit super tight, compressing the coroplast inner box. Zero movement of the pack in the box, just from the compression is the goal. As you know, compressing pouches is good.

If a pack should puff like hell, you can simply unscrew the aluminum plate and get it back out. A carbon fiber box, you'd have to cut that sucker apart to get a really puffed pack back out.

Do you mean like this? (Definitely not aiming for realism in microsoft paint, lol)

 

[dogman dan]

That's it. Easy to make custom size, and no fancy tools needed. Like that square tube though, if you can get some.

I don't see any under on that bike to mount a box, but the top of the beam between your legs looks logical.

Have you looked at pvc rain gutter for making a small square tubes? There is more or less square downspout, but the gutter itself might be easily made into a pair of L shapes to create square tube from.

 

[cassschr1]

Heyena even had some alum extruded exactly for this .

 

[nechaus]

Hey, I think taping lipos with POLYMIDE prior to packing is not a bad idea..


Why not get a 3d printer swbluto?

 

[kfong]

Carbon Fiber is what I use.

 

[cwah]

Where did you buy your carbon fiber?

 

[kfong]

Best source for information is RC groups composite forum.

 

[swbluto]

My favorite method for building sturdy custom boxes is to use two materials. Start with wood, using high quality half inch thick hardwood like aspen or poplar. Frame a box, typically 4 1/4" for lipo bricks. The extra quarter inch is for additional padding material like coroplast. Then the larger sides of the box are 1/8" aluminum sheet. Lucky me, when I moved in the garage had 6 road signs in it. But you can buy aluminum diamond plate.

How do you cut the aluminum? I've cut my aluminum in the past by hack sawing to get the general shape and then refining it with an angle grinder, but I'm thinking there might be better ways. (You have to get the cut angle near perfect with the hacksaw as it doesn't want to go any other direction after getting started, which is a problem sometimes, especially when cutting at an angle.)

 

[biohazardman]

You can get blades for circular or skillsaws for cutting soft metals including aluminum. Me my favorite stuff for building packs is abs you can bend it with a heat gun into whatever shape and heavy leather or an insulated nylon bag for the outside. A bit of thin foam inside for to cusion nonflat stuff on the batteries and it's done. I use the 3/16ths abs and have crashed pretty hard with no damage to the batts. Aluminum and wood are just as good though maybe a bit more weight.