Aluminium Triangle Case build, minimal tools?

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Skirmish   100 mW

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Aluminium Triangle Case build, minimal tools?

Post by Skirmish » Apr 25 2021 6:55pm

I'm looking into seeing if a triangle battery case is something I can put together, and I'm probably going to be limited to using hand tools.

Features I'm looking for are:
  • Accommodate ~ 15kg
  • Secured to frame as much as possible for public parking
  • Hinged access panel with lock
  • Weather resistant
  • Accommodate 26650 or 32700 cells
  • Power for tsdz2 motor

The plan so far is:
  • Prototype the shape out of cardboard
  • Cut a frame from 1.5(?)mm square aluminium tube with a hacksaw
  • Join the square tubing with strips of aluminium sheet by using a rivet gun
  • Cut some 1.6(?)mm aluminium sheet to the shape of the frame
  • Rivet the aluminium sheet on to the square tubing frame with a rivet gun
  • Seal the inside with silicone

Things I'm not sure how to go about at all:
  • Constructing a hinged panel, and making sure it doesn't rattle from vibration
  • Adding a lock to the hinged panel, and making sure it doesn't rattle / come loose from vibration
  • Water sealing the hinged panel
  • Attaching the case to the frame so that it's at least difficult for potential thieves to remove

Are there any problems you can see with the plan so far? Any tips on how to go about the features that haven't got a plan at all?

Thanks in advance!

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Chalo   100 GW

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Re: Aluminium Triangle Case build, minimal tools?

Post by Chalo » Apr 25 2021 8:33pm

Making a sheet metal battery case is not really a "minimal tools" kind of project. I'd want access to a step shear, finger brake, large format printer, TIG welder, grinder with wire wheel, drills, files, and pop riveter. You could get away with less tooling, but you'd be paying the difference in hand labor and quality issues.

If I wanted to build a good battery box with minimal tooling, I'd use thin plywood jointed with wooden moldings, skinned outside and inside with fiberglass cloth and resin.

Note that you'll never short-circuit your battery pack with a glassed wooden battery box, like you can with an aluminum box.

What are you doing, that you want 33 pounds of cells to run a rinky dink motor like TSDZ2?
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Re: Aluminium Triangle Case build, minimal tools?

Post by goatman » Apr 25 2021 8:59pm

i used a steel stud, an old construction site aluminum sign and waterproof the battery with plasti dip

viewtopic.php?f=6&t=103833#p1522913

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Re: Aluminium Triangle Case build, minimal tools?

Post by nicobie » Apr 25 2021 9:15pm

Do you want a battery box or a way to put a battery on a bicycle?

Check out the cheesey pics in my build thread link below. It's not too sophisticated but can be done with minimal tooling.

If you want a battery box, Chalo has the right idea. If you are comfortable with using fiberglass, try making a mold the right size then covering it with fiberglass

Like Goatman said, use what you're got. Get creative. 🏁🏁🏁
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Re: Aluminium Triangle Case build, minimal tools?

Post by markz » Apr 25 2021 10:23pm

Are you still riding it today?
goatman wrote: ↑
Apr 25 2021 8:59pm
i used a steel stud, an old construction site aluminum sign and waterproof the battery with plasti dip

viewtopic.php?f=6&t=103833#p1522913

Skirmish   100 mW

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Re: Aluminium Triangle Case build, minimal tools?

Post by Skirmish » Apr 25 2021 10:36pm

Chalo wrote: ↑
Apr 25 2021 8:33pm
Making a sheet metal battery case is not really a "minimal tools" kind of project. I'd want access to a step shear, finger brake, large format printer, TIG welder, grinder with wire wheel, drills, files, and pop riveter. You could get away with less tooling, but you'd be paying the difference in hand labor and quality issues.

If I wanted to build a good battery box with minimal tooling, I'd use thin plywood jointed with wooden moldings, skinned outside and inside with fiberglass cloth and resin.

Note that you'll never short-circuit your battery pack with a glassed wooden battery box, like you can with an aluminum box.

What are you doing, that you want 33 pounds of cells to run a rinky dink motor like TSDZ2?
Thanks & yeah, I figure it's going to be more work with hand tools but I don't have access to anything else.
I'm hoping to avoid the need for a brake by riveting everything onto square tube.

How would the plywood be joined, nails? Epoxy?
The reason for the weight is I'd like to get good range & use LiFePo4 cells, they seem pretty heavy per Wh.
Last edited by Skirmish on Apr 25 2021 10:59pm, edited 1 time in total.

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Re: Aluminium Triangle Case build, minimal tools?

Post by Skirmish » Apr 25 2021 10:48pm

nicobie wrote: ↑
Apr 25 2021 9:15pm
Do you want a battery box or a way to put a battery on a bicycle?

Check out the cheesey pics in my build thread link below. It's not too sophisticated but can be done with minimal tooling.

If you want a battery box, Chalo has the right idea. If you are comfortable with using fiberglass, try making a mold the right size then covering it with fiberglass

Like Goatman said, use what you're got. Get creative. 🏁🏁🏁
Thank you, I really like your build. How did you construct the enclosure?

I want to build a space to put batteries inside the main triangle of a bike, similar to your build.

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Re: Aluminium Triangle Case build, minimal tools?

Post by goatman » Apr 25 2021 11:23pm

markz wrote: ↑
Apr 25 2021 10:23pm
Are you still riding it today?
goatman wrote: ↑
Apr 25 2021 8:59pm
i used a steel stud, an old construction site aluminum sign and waterproof the battery with plasti dip

viewtopic.php?f=6&t=103833#p1522913
soon, its almost summer :D

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Re: Aluminium Triangle Case build, minimal tools?

Post by Skaiwerd » Apr 26 2021 5:59am

If you still want to go with metal my recommendation would be to eliminate or minimize the inner structure. Use a hand brake to put a bend alone the edge of each piece. You will be limited to 12” bend. Use the bent flange for the rivets.
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Re: Aluminium Triangle Case build, minimal tools?

Post by neptronix » Apr 26 2021 9:42am

I'd consider using ABS, which can be molded with a heat gun, and also have aluminum or steel bolt thread inserts put into it for a very strong attachment to the bike.

As a bonus, it's not conductive. You'll be thankful for that in the event of a crash.
The battery support on my car ( Mazda 2 ) is built with thick ABS and successfully holds a 35lb battery in a vibration prone environment.
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Re: Aluminium Triangle Case build, minimal tools?

Post by Dauntless » Apr 26 2021 11:45am

neptronix wrote: ↑
Apr 26 2021 9:42am
I'd consider using ABS, which can be molded with a heat gun, and also have aluminum or steel bolt thread inserts put into it for a very strong attachment to the bike.
There are better ways to bend plastic.

https://www.instructables.com/Get-Bent- ... ip-bender/
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Re: Aluminium Triangle Case build, minimal tools?

Post by markz » Apr 26 2021 2:48pm

Is that your only ebike or do you have a year round ebike you ride?
Your other thread talking about Phase Runner so you gotta have minimum 3 ebikes :wink:
It seems like an awkward riding position to be in.
I'll have to read up on that build to get wheel/tire sizes. Seems like a wide tire, 2.60'ish, bigass battery can get you from Stanley Park to Surrey in no time if your riding it 70-80kph with no outside hassles,
I dig the bike and the custom battery box :thumb:
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goatman wrote: ↑
Apr 25 2021 11:23pm
markz wrote: ↑
Apr 25 2021 10:23pm
Are you still riding it today?
soon, its almost summer :D

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Re: Aluminium Triangle Case build, minimal tools?

Post by goatman » Apr 26 2021 5:39pm

its actually a very comfortable ride, very similar to a recumbent
thinking of flipping 1 crank so i have foot pegs instead of pedals :wink:
3 bikes for me and 2 for my boys

rear tire 24x3.0

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Re: Aluminium Triangle Case build, minimal tools?

Post by dogman dan » May 12 2021 5:35am

The simplest method would be a box made of both wood and metal. I used to do this a lot, since I had some old aluminum signs in my garage when I bought the house.

Frame the box with wood, preferably a hardwood. I liked using strips of 1/2 inch thick poplar wood. Then screw the panels to the side. Not as convenient as a hatch, but not hard to unscrew 8 screws with a drill, to access the battery.

this is truly a minimal tool deal, cut the panels with a skill saw or saber saw. Later on, I simplified it even more, and used coroplast sheet for box sides.

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Re: Aluminium Triangle Case build, minimal tools?

Post by spinningmagnets » May 12 2021 7:54am

Many oysters in this link, but a few pearls if you look...

"Show us your homemade battery box"
viewtopic.php?f=3&t=12847

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Re: Aluminium Triangle Case build, minimal tools?

Post by qwerkus » May 18 2021 1:56pm

If you ask me, a clean battery box fitting one specific frame is by far the hardest part of any diy ebike - aside perhaps from programming you own controller.
That's why I nearly only use ready made boxes and just add a sturdy way to clamp them onto the frame. Plenty of good choices around. By fav. is a cheap chinese 52V aluminium box, that can accomodate up to 120cells. Not your size though.

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Re: Aluminium Triangle Case build, minimal tools?

Post by sleepy_tired » May 27 2021 8:56pm

A plastic welding kit is pretty affordable and doesn't require any exotic gasses or anything weird like that . It's nothing more fancy then a heat gun with a tip to focus the heat. People use them for fixing holes in kayaks and such things. If that doesn't sound appealing then you can probably do solvent-based welding.. that is "glue" the pieces together.

It's not too expensive to purchase and ship HDPE sheets either. Easy to shape, bend. More impact resistant then sheet metal, doesn't rust, doesn't need to be painted (as long as it's UV protected) and doesn't conduct electricity.

I made my last battery box out of folding, sewing, and taping corrugated plastic. This worked well but it looks too much like a bomb. Think of a taped up box with big wires hanging from it.

Next time I am going to try to build a box out of plastic sheets. Weld it together with fixtures for the wires, mounting brackets, and maybe some internal ribs for reinforcement if need be.

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Re: Aluminium Triangle Case build, minimal tools?

Post by E-HP » May 28 2021 1:38am

sleepy_tired wrote: ↑
May 27 2021 8:56pm
It's not too expensive to purchase and ship HDPE sheets either. Easy to shape, bend. More impact resistant then sheet metal, doesn't rust, doesn't need to be painted (as long as it's UV protected) and doesn't conduct electricity.
Is that rigid HDPE? I've tried ABS and a couple of different acrylics. ABS was OK, maybe too pliable when using a heat gun, but also flexes more than I want when cool, using 1/8". The acrylics shaped easy with a heat gun, but were brittle and cracked in use. Will the HDPE flex a little without cracking?
I have a Tap Plastics a short ebike ride away, and they have a pretty big selection of scrap pieces for next to nothing (actually nothing during the pandemic, since they were so busy, they'd just said to take it). Just haven't studied up on which work with which application.

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Re: Aluminium Triangle Case build, minimal tools?

Post by sleepy_tired » May 28 2021 3:25pm

Is that rigid HDPE?
Yeah. It's the same stuff they make plastic cutting boards out of. If you have a cheap white plastic cutting board in your kitchen it's probably HDPE. They use it to make 1 gallon milk jugs in the USA (not sure elsewhere).

It's very tough stuff.
I've tried ABS and a couple of different acrylics.
ABS is used a lot in consumer products because it's just about the cheapest possible plastic you can use and still get something reasonable. It's easy and gentle on molds. But you won't see it used in serious tools, for example. For that they use fiber reinforced nylon, which is brutally stronger. Good quality tools like Makita and Milwaukee use reinforced nylon. They use that nylon fiber stuff in firearms like Glocks to give you a idea. The plastic string they use for weed eaters is plain nylon. Pound for pound the composite versions exceeds steel.

ABS isn't something I would build anything with.

Acrylic is "OK". The best things about it is that it's clear and cheap. I wouldn't build anything using Acrylic unless it's only job was to look pretty.

If you want something clear then polycarbonate would be awesome, but I don't know much about welding it. Polycarbonate is what they make things like bullet proof glass out of. They also use it for soda bottles, which believe it or not are extremely tough. Those paper thin walls need to hold back around 50-100 PSI.

Will the HDPE flex a little without cracking?
I would have a hard time making it crack with a sledge hammer, I think. Unless it was extremely cold. It's very impact resistant and can bend and be shaped by heat easily.

HDPE is "High density Polyethylene". They will sometimes use this type of plastic for "Living Hinges", which are thin sections of plastic that act like a hinge.

Think of the caps for plastic ketchup bottles or caps for shampoo bottles and things of that sort. How they have a lid that pops off and pops back on. The lid and the cap are usually one piece that is connected by a thin piece of plastic.

It takes a lot of twisting and folding and hinging to get those tiny bits of plastic to break. The use polyethylene and polypropylene for those types of applications.

Here is a guy building a 125 gallon RV water tank with HDPE:
https://www.youtube.com/watch?v=ddLlSRtYqFU

That's worlds different from acrylic.
I have a Tap Plastics a short ebike ride away, and they have a pretty big selection of scrap pieces for next to nothing (actually nothing during the pandemic, since they were so busy, they'd just said to take it).


Sounds like a good plan. You'll want to check out HDPE, polycarbonate, polypropylene, and polyethylene especially. Probably can ask them for advice on what to use and they will know a hell of a lot more about it then I do. I just got what I know off the internet.

edit:

found this: https://www.mcmaster.com/plastics/

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Re: Aluminium Triangle Case build, minimal tools?

Post by LewTwo » May 28 2021 5:20pm

sleepy_tired wrote: ↑
May 28 2021 3:25pm
If you want something clear then polycarbonate would be awesome, but I don't know much about welding it. Polycarbonate is what they make things like bullet proof glass out of. They also use it for soda bottles, which believe it or not are extremely tough. Those paper thin walls need to hold back around 50-100 PSI.
polycarbonate is also what most optical quality lense are made of these days.
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Re: Aluminium Triangle Case build, minimal tools?

Post by Chalo » May 28 2021 8:47pm

sleepy_tired wrote: ↑
May 28 2021 3:25pm
If you want something clear then polycarbonate would be awesome, but I don't know much about welding it. Polycarbonate is what they make things like bullet proof glass out of. They also use it for soda bottles, which believe it or not are extremely tough. Those paper thin walls need to hold back around 50-100 PSI.
Polycarbonate is unbelievably stinky and toxic when you get it hot. Just don't; you'll regret it.

Soda bottles use not polycarbonate, but polyethylene terephthalate (PETE), which is superficially similar but not the same thing at all. Welding PETE would be a much less grievous idea than welding PC.
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Re: Aluminium Triangle Case build, minimal tools?

Post by Chalo » May 28 2021 8:49pm

LewTwo wrote: ↑
May 28 2021 5:20pm
polycarbonate is also what most optical quality lense are made of these days.
They are highly impact resistant, but "optical quality" only in the broadest sense of the term. Any acrylic or glass lens material is loads better optically.
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