Fitting too big battery on downtube

[Cyclomania]

So the battery I have is too big for my downtube.
Putting it on the upper tube I think looks a bit weird.

What would you recommend me do? Could I angle grind out an hole at the green ring circled?

See here in vid and pic:

sinokilovipp33's Video - Jun 4, 2024 - VEED - Online Video Editor - Video Editing Made Simple

www.veed.io

 

[rudivb]

I would not just randomly start grinding.

If you do, open the case first and see how thick the material is, but you are probably going through the material leaving an open gap, not ideal.

Few things I could think of:

1. Do you have a bracket installed? Maybe it fits without the bracket, but you would need to secure it differently.

2. You could redo the whole battery in more of a triangle shape and get a fitting triangle bag.

3.Or just sell and get a smaller battery or different shape(triangle) battery.

 

[Cyclomania]

I would not just randomly start grinding.

If you do, open the case first and see how thick the material is, but you are probably going through the material leaving an open gap, not ideal.

Few things I could think of:

1. Do you have a bracket installed? Maybe it fits without the bracket, but you would need to secure it differently.

2. You could redo the whole battery in more of a triangle shape and get a fitting triangle bag.

3.Or just sell and get a smaller battery or different shape(triangle) battery.

I meant more grind on the upper tube kind of. I mean grind on the top tube of the bike. To make some space. But maybe a stupid idea ?

 

[Mongo]

Hi @Cyclomania - the upper tube on this style of bicycle frame is called the "top tube", and while difficult to determine my guess would be that you'd end up taking pretty much all of the structural strength out of that (aluminum) top tube grinding a notch out of it big enough to 1.) retain the battery mounting tray and 2.) being able to slide the battery off said tray. Dunno about you, but keeping the ability to remove the battery is important to me (storage safety, sharing battery(s) between bikes, charging ease, etc.)

If this bike was used as an analog bike, at analog bike speeds, on smooth pavement, with a light load, maybe, just maybe you could get away without the top tube entirely. But I'm guessing this is the same bike you amped up the BBS02 motor on, so grinding on the top tube is not a path I'd go down personally. Admittedly I'm not a mechanical/structural engineer, but I've looked at a fair amount of step-thru frame designs, on which the down (lower) tubes are usually quite a bit bigger in size, and there's often added gusseting.

I have to ask - UPP provides the battery case dimensions. Did you mock it up before purchasing the battery?

 

[rudivb]

I meant more grind on the upper tube kind of. I mean grind on the top tube of the bike. To make some space. But maybe a stupid idea ?

Yeah I wouldn't do that, you are already putting more stress/forces on the frame by adding a battery and motor, and higher speeds, last thing you want to do is making the frame weaker with the potential for it to fail.

 

[Az.]

Rear rack.

You not only need enough space to fit battery in triangle, but also need extra space to slide it into battery base.

Mounting such a huge battery on rear rack will change handling of your bike. You didn't think it through well.

 

[99t4]

What would you recommend me do? Could I angle grind out an hole at the green ring circled?

Get a different bike, one with a triangle large enough to fit your battery.

 

[Cyclomania]

Hi @Cyclomania - the upper tube on this style of bicycle frame is called the "top tube", and while difficult to determine my guess would be that you'd end up taking pretty much all of the structural strength out of that (aluminum) top tube grinding a notch out of it big enough to 1.) retain the battery mounting tray and 2.) being able to slide the battery off said tray. Dunno about you, but keeping the ability to remove the battery is important to me (storage safety, sharing battery(s) between bikes, charging ease, etc.)

If this bike was used as an analog bike, at analog bike speeds, on smooth pavement, with a light load, maybe, just maybe you could get away without the top tube entirely. But I'm guessing this is the same bike you amped up the BBS02 motor on, so grinding on the top tube is not a path I'd go down personally. Admittedly I'm not a mechanical/structural engineer, but I've looked at a fair amount of step-thru frame designs, on which the down (lower) tubes are usually quite a bit bigger in size, and there's often added gusseting.

I have to ask - UPP provides the battery case dimensions. Did you mock it up before purchasing the battery?

This is actually another bike UPP is the triangle battery right? I think I have gotten to a solution which is more towards this direction now.

Only thing was I liked this fat bastard of a battery, because it has high AH. But the triangle batteries fits in that hole better.

 

[neptronix]

Center of the triangle is the best place to mount a battery. That's where the weight is most neutral.
Upper front towards the steer tube is the second best place for a battery. Some fabrication needed, but possible.
Rear rack is the third and will have some noticeable negative effects on handling because of how it wags while you are steering.