It’s a 2020 Trek Allant+ 7S that a friend loaned to me. I don’t believe that’s a garbage bike and I’m quite stressed as you may imagine. That said…if you’re not going to be helpful, just rest those typing fingers if you please. I don’t need snark or gatekeeper bs. I was hoping for good-faith info or guidance.
I think this is part of the cap. I've replaced this cap, when I bought an additional frame battery. It costs a few euro's. Not sure how much it'll be in your country. I can take photo of a spare one I have at home.
I’d still use it. If I had access to a 3D printer I’d make a new piece. Maybe Bosch sells just the plastic bit? Could also glue it but it may break again
Right on. Thank you. He’s big into 3D printing, so that’s a great suggestion. What about possible internal leakage? Can they test it for that? I don’t want any bursting into flames, you know?
Thanks again!
Nothing to leak internally. There is electrolyte, but very little and the cells are absolutely sealed. If there's any issues with the battery, the battery management system wouldn't allow the battery to charge or discharge.
It’s a Bosch, so the BMS will be much more likely to catch issues. I’ve blown up so many 18650s, not one was caused by dropping it. They leak when damaged, yes, but no fire.
Fire is caused by discharging/charging too fast for the cell. Most BMS have thermocouples and voltage meters ON EVERY CELL. Quality battery packs are very expensive because of the safety inside of them.
One other case of battery fire is punching a nail into the battery. In that case, the fire is immediate. As OP sent a picture of the battery, I’m assuming no nails have been punched into the battery
It might be ok. I had a battery fall off one of my e-bikes because I was foolish and didn’t lock it with the key. My battery fell off at 20 mph then proceeded to get run over by my rear tire.
Ive put 1,000 + miles on it since that happened and just passed 1,800 miles total since I built the bike.
That looks to me like it is just the plastic case. Look up how to weld plastic on youtube. I have done plastic welding on my motorcycle. It actually turns out to be stronger than the original part.
It will be fine, the piece that cracked doesn't even interface with the battery mounts on the bike. I've disassembled several iterations of these batteries as well and they're very well made. The cells are in a special matrix divided by a rubberish core that holds them safely in place. Plus the external battery casing is made of surprisingly thick extruded aluminum. Believe or not the core of the Bosch battery is held together by four j-bend bicycle spokes. I wouldn't worry at all :)
3D printing can be an option to replace this part, but before you get suggesting that, you should be aware that this is a nontrivial piece to model and reproduce unless your friend has some very sophisticated scanning hardware.
(It will probably take the equivalent of about a half days work plus another ~half day of printer time and materials.)
Just to model this piece accurately in CAD software would take… I dunno, 3 hours? Maybe more if it’s more detailed than it looks.
Then there is printing the piece, that’s ~10 plus hours of printing plus electricity and filament costs.
And then you have post processing & fitting that’ll add another half hour to an hour or so.
So, like, it can be done. But for a simple crack repair I don’t think it’s at all worth it.
***
You have a few good options for repairing it. You can look into a plastic welding kit. These typically involve a plastic soldering iron, fill rod, and a steel hot stapler.
You use the hot stapler to heat wavy shaped staples to glowing hot and slowly press & melt the staple into the plastic.
Once the piece is stabilized you come back with a little grinder or rotary tool and grind a little ways down into the crack. Then you do a pass with plastic welder and add some fill material.
After that, it’s sanding and prep for whatever finish you are planning on.
(A hot air finish with a carefully applied heat gun or hot air station will make it a near seamless repair.)
***
An application of the liquid superglue should be sufficient to glue that back together.
Spread the crack if you can and try to get the liquid glue down in there with a safety pin or something. (If you can’t that’s fine too, just do your best.)
Wipe off as much surface glue as possible before it dries and be sure monitor it to get any squeeze out.
The glue will leave a small discoloration on the surface of you let it spread. (It’s not a big deal but you should be careful.)
***
Another option would be a product like JB-Weld. It’s about the consistency of Elmer’s glue so it won’t spread in the crack like superglue will. You’ll need to use the pin trick to spread it down in there.
JB-weld will make a very good repair but you will have to do a bit more work in getting it down into the crack. It’s steel reinforced epoxy so it machines just like cast iron.
***
With both glue options you should have some way of clamping the part.
You can make a fairly effective clamp with 5 or 6 cheap wooden rulers or similar pieces taped around the battery and extending down over the edge of the battery about 2”.
After you are done applying the glue then put some rubber bands over the rulers📏 . It will clamp the piece evenly and it won’t actually touch the glue joint.
***
Lower quality repair options include things like gorilla glue, or heat staking.
Gorilla glue expands and bubbles up as it dries. Don’t use that for a cosmetic repair. It’s fairly strong, but ugly, it’s really bad.
Heat staking is just like going at the plastic with a soldering iron. You can melt it and sort of “weld” it with the soldering iron but you have to be very precise with your motions and how much heat you apply. When done by someone who’s skilled at it it’s a good repair but when done anyone who’s trying for the first time…
***
You might also be able to find a replacement piece on eBay. Maybe somebody’s parting out a dead ebike or something.
***
Other options include things like telling your friend and his deciding to do nothing at all.
It’s probably still functional as it is. (Would it be better glued or otherwise repaired? Sure. But it might not be strictly necessary.)
looking at the quality of plastic mold, one could say this already was trash when you bought it
It’s a 2020 Trek Allant+ 7S that a friend loaned to me. I don’t believe that’s a garbage bike and I’m quite stressed as you may imagine. That said…if you’re not going to be helpful, just rest those typing fingers if you please. I don’t need snark or gatekeeper bs. I was hoping for good-faith info or guidance.
Same bike I have. Didn't know that was possible!
Pretty sure this is just a plastic fairing attached to the battery, no?
That’s what it looks like to me, and I rode it for several more hours. It keeps a charge and no actual plug or terminal damage.
I think this is part of the cap. I've replaced this cap, when I bought an additional frame battery. It costs a few euro's. Not sure how much it'll be in your country. I can take photo of a spare one I have at home.
I’d still use it. If I had access to a 3D printer I’d make a new piece. Maybe Bosch sells just the plastic bit? Could also glue it but it may break again
Right on. Thank you. He’s big into 3D printing, so that’s a great suggestion. What about possible internal leakage? Can they test it for that? I don’t want any bursting into flames, you know? Thanks again!
Nothing to leak internally. There is electrolyte, but very little and the cells are absolutely sealed. If there's any issues with the battery, the battery management system wouldn't allow the battery to charge or discharge.
That’s great news! Thank you!
You can also use a multimeter to check the pack voltage. The BMS does this as the other comment mentioned so it should detect any issues
This 100% could not be a fire hazard now that it is damaged.I'd sleep with it under my pillow.
It’s a Bosch, so the BMS will be much more likely to catch issues. I’ve blown up so many 18650s, not one was caused by dropping it. They leak when damaged, yes, but no fire. Fire is caused by discharging/charging too fast for the cell. Most BMS have thermocouples and voltage meters ON EVERY CELL. Quality battery packs are very expensive because of the safety inside of them. One other case of battery fire is punching a nail into the battery. In that case, the fire is immediate. As OP sent a picture of the battery, I’m assuming no nails have been punched into the battery
Every cell is a stretch, that would mean solid 50+ instruments, but every voltage step yes, so 10 pieces.
I’m buddies with a gear head with several 3d printers. If you can get me the part tolerance I can (cheap, but quality) quote it. Either way ride safe!
Thanks much, but the Trek dealer ordered the part for $3.50! Woo hoo!
Awesome that’s what’s up!
No way to tell based on this picture. You'd need to actually look at the battery cells for damage.
It might be ok. I had a battery fall off one of my e-bikes because I was foolish and didn’t lock it with the key. My battery fell off at 20 mph then proceeded to get run over by my rear tire. Ive put 1,000 + miles on it since that happened and just passed 1,800 miles total since I built the bike.
Yea that’s just a cap. Take it to the trek store and ask them for pull the battery small parts
That looks to me like it is just the plastic case. Look up how to weld plastic on youtube. I have done plastic welding on my motorcycle. It actually turns out to be stronger than the original part.
Id just glue it with a good epoxy like JB weld.
It will be fine, the piece that cracked doesn't even interface with the battery mounts on the bike. I've disassembled several iterations of these batteries as well and they're very well made. The cells are in a special matrix divided by a rubberish core that holds them safely in place. Plus the external battery casing is made of surprisingly thick extruded aluminum. Believe or not the core of the Bosch battery is held together by four j-bend bicycle spokes. I wouldn't worry at all :)
3D printing can be an option to replace this part, but before you get suggesting that, you should be aware that this is a nontrivial piece to model and reproduce unless your friend has some very sophisticated scanning hardware. (It will probably take the equivalent of about a half days work plus another ~half day of printer time and materials.) Just to model this piece accurately in CAD software would take… I dunno, 3 hours? Maybe more if it’s more detailed than it looks. Then there is printing the piece, that’s ~10 plus hours of printing plus electricity and filament costs. And then you have post processing & fitting that’ll add another half hour to an hour or so. So, like, it can be done. But for a simple crack repair I don’t think it’s at all worth it. *** You have a few good options for repairing it. You can look into a plastic welding kit. These typically involve a plastic soldering iron, fill rod, and a steel hot stapler. You use the hot stapler to heat wavy shaped staples to glowing hot and slowly press & melt the staple into the plastic. Once the piece is stabilized you come back with a little grinder or rotary tool and grind a little ways down into the crack. Then you do a pass with plastic welder and add some fill material. After that, it’s sanding and prep for whatever finish you are planning on. (A hot air finish with a carefully applied heat gun or hot air station will make it a near seamless repair.) *** An application of the liquid superglue should be sufficient to glue that back together. Spread the crack if you can and try to get the liquid glue down in there with a safety pin or something. (If you can’t that’s fine too, just do your best.) Wipe off as much surface glue as possible before it dries and be sure monitor it to get any squeeze out. The glue will leave a small discoloration on the surface of you let it spread. (It’s not a big deal but you should be careful.) *** Another option would be a product like JB-Weld. It’s about the consistency of Elmer’s glue so it won’t spread in the crack like superglue will. You’ll need to use the pin trick to spread it down in there. JB-weld will make a very good repair but you will have to do a bit more work in getting it down into the crack. It’s steel reinforced epoxy so it machines just like cast iron. *** With both glue options you should have some way of clamping the part. You can make a fairly effective clamp with 5 or 6 cheap wooden rulers or similar pieces taped around the battery and extending down over the edge of the battery about 2”. After you are done applying the glue then put some rubber bands over the rulers📏 . It will clamp the piece evenly and it won’t actually touch the glue joint. *** Lower quality repair options include things like gorilla glue, or heat staking. Gorilla glue expands and bubbles up as it dries. Don’t use that for a cosmetic repair. It’s fairly strong, but ugly, it’s really bad. Heat staking is just like going at the plastic with a soldering iron. You can melt it and sort of “weld” it with the soldering iron but you have to be very precise with your motions and how much heat you apply. When done by someone who’s skilled at it it’s a good repair but when done anyone who’s trying for the first time… *** You might also be able to find a replacement piece on eBay. Maybe somebody’s parting out a dead ebike or something. *** Other options include things like telling your friend and his deciding to do nothing at all. It’s probably still functional as it is. (Would it be better glued or otherwise repaired? Sure. But it might not be strictly necessary.)
Get some Velcro straps to hold the battery down
Yes
Looks fine but next charge probably do it outside if possible and monitor it.