Small triangle, big problems. Trying to find a battery that fits my bike.

I have a Small (15.5") Trek Marlin 6 I want to convert, I'm trying to find a battery that will fit.

My 3 top choices were:
1) Hard Triangle battery from EM3ev
2) EM3ev Supershark
3) Luna Wolf Pack

But I'm not confident any of them will fit into my frame...


- EM3ev Triangle Pack: Might fit, possibly wont
Assuming my crude cutout is correct, this is the only battery that will actually fit. Problem is the bag is too big by several inches. I suspect I could probably mash the bag fabric in to make it fit but with the fabric and padding of the bag, I don't know if I'll be able to fit the battery inside. There's not a lot of clearance. I might be able to make it fit by filing down the bottlecage mounts but I don't really wanna do that for obvious reasons.



- EM3ev Supershark: Might fit
The rectangular dimensions they gave don't fit, I tried cutting the corners a bit to see how much space they would provide but it still doesn't fit. It's not accurate to the shape of the battery though so the battery *might* still fit in there, but I don't know if I'll have enough clearance to actually put in the battery and remove it since the battery needs space to slide forward a bit.



- Luna Wolf Pack: Most likely will not fit at all
They offer a printable cutout but no dimensions to ensure your printed size is correct. It also isn't clear whether that printable shape includes the mount or if the magnets on the mount sit flush with the bottlecage rivets. Regardless, if the size is correct it almost certainly will not fit and if it does it is going to be REALLY tight, maybe a millimeter of clearance.




Main Options I'm considering:

- Forget about the triangle completely, buy an EM3ev rectangle battery and a rear rack and be done with it. Dunno how I'd secure the battery though, and with the motor + battery this adds almost 25lb (11.4kg) to the rear of my bike.

- Get one of the above batteries, try to fit it in my triangle, if I can't then strap it to a rear rack. Same problems as the rectangle battery plus the added challenge of securing a weirdly shaped battery to the rack.

- Get two mighty mini batteries, carry one in a bag and swap them out as needed. I kind of like this option but Luna has none in stock and I am getting impatient. Also they're expensive and I dunno if the connectors would hold up over time...

- Lunas wolf pack is waterproof, could probably mount it upside down on the underside of the downtube. Would require drilling to the frame though which I REALLY don't wanna do.



I'm pretty torn here about what to do here. What would you guys do in my situation?

Sorry for the long post.

Edit: Also want to note, I'm not comfortable building a battery myself. So that is not an option for me.

This company gives dimensions to their batteries
https://www.ebikes.ca/shop/electric-bicycle-parts/batteries.html

They also sell LiGo batteries, if your into 36V or 72V in multiples of 2.7Ah.
https://www.ebikes.ca/shop/electric-bicycle-parts/batteries/b362-7-ligo.html

More dimensions from Unit Pack Power
http://unitpackpower.com/goods/65.html
and
https://unitpackpower.aliexpress.com/store/1178407

I am dealing with the same issue, looking to convert a bike with a really small front triangle. Best option I can think of is the Luna batteries with the new Panasonic GA 3500 cells. I mocked up one of the EM3EV triangle batteries but there will be so little space it'll be tough to do any sort of secure mount that allows for quick removal.

Waiting for the Luna batteries to come back in stock, if I get a good mounting solution figured out I'll post it.

New bike time. One that fits the EM3ev triangle.

Not joking. get another frame. Very often my first advice is to leave your favorite bike alone. Electrify something cheaper, without going to completely shit bike. You need a trek 820.

dogman dan said:

Not joking. get another frame.

Click to expand...

You might not be joking, but that is not going to happen. Either I make this work with the bike I have or I just don't get an ebike, those are my two choices...

If I have to get a rack battery and abandon the rear hub entirely for a BBSHD to keep the weight balanced, that's what I will do, but I won't be getting another bike.

saukit said:

I am dealing with the same issue, looking to convert a bike with a really small front triangle. Best option I can think of is the Luna batteries with the new Panasonic GA 3500 cells.

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Can I ask which battery you're referring to specifically? Luna has a few batteries using those cells, all out of stock.

After cutting my foamcore to better match the Hailong/Supershark shape I think it is my best option for keeping the battery in the frame. I may buy an empty hailong case off of ebay and try mounting it to the bike to see if I can get the battery in and out. It adds some additional cost ($50) but I think it's probably worth it for the peace of mind.

I had the same problem with an e-cruiser built for my daughter, and found a solution with SKS "anywhere water bottle mounts" ($20 @ Amazon) on the top tube adjacent to the seat, then mounted the battery there. Solid mount made stronger with a wrap of Velcro. Not the best weight distribution, but the best solution for her.

There is space in FRONT of the down tube for a bottle-type batt. plus whatever you can fit in the triangle. Your bike may even have the rivets for mounting, but if it doesn't, they are easy enough to install.
I use LiPoly (bricks), so I made the frt. batt. I use on my 2WD (see link below) using a welding rod canister.
Due to my LiPoly packs not using a bms, I did not parallel them, but due to the modular nature of LiPoly, this is just as well (I often change the capacity to match the range I need to a specific ride or swap in a pre--charged pack). I simply swap the leads over to the other pack.

For the em3ev triangle pack; have a look at this thread if you haven't seen it already:
https://endless-sphere.com/forums/viewtopic.php?f=2&t=91500&hilit=em3ev+triangle+battery&start=50

I see your space is a lot tighter that the bikes in there; but you might still be able to do something similar to what I did; although it is not easily removed.

As motomech has pointed out; you may be able to do one of the shark type packs underneath the triangle if you have enough clearance from the front wheel.

Capsloast said:

I'm pretty torn here about what to do here. What would you guys do in my situation?

Click to expand...

I'd make sure the triangle pack fit and get that one. I wouldn't hide it in a bag though; just fabricate a mount and put it on display.

Whats with the ultimatum, gosh I find abondoned bicycles all the time and convert them if I like them.
Also used bicycles are cheap, just convert one of those.

Perhaps your ultimatum has to do with you do not have enough space or whatever the excuse is.

If your ultimatum is a battery in the triangle, then there are other options, like an overhanging bag near the headset, or the battery goes on the rear rack.

markz said:

Perhaps your ultimatum has to do with you do not have enough space

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Exactly right. I share a living space with other people and it was really painful negotiating space for the first bike. A second one just sounds like a really good way to piss everyone off. I gotta weigh the benefits here man... and having electric assist just isn't worth the added stress.

2old said:

I had the same problem with an e-cruiser built for my daughter, and found a solution with SKS "anywhere water bottle mounts" ($20 @ Amazon) on the top tube adjacent to the seat, then mounted the battery there. Solid mount made stronger with a wrap of Velcro. Not the best weight distribution, but the best solution for her.

Click to expand...

motomech said:

There is space in FRONT of the down tube for a bottle-type batt. plus whatever you can fit in the triangle. Your bike may even have the rivets for mounting, but if it doesn't, they are easy enough to install.

Click to expand...

Thanks I think this may actually work well for me. I have clearance in front of the downtube for a supershark but maybe not a luna wolf pack, depends on how much space there is with the fork compressed, I'll have to check later when I have someone to help. But I will probably have to cobble something together myself because the mounts on amazon all seem to be designed specifically for cylindrical tubed frames. My toptube and downtube are both rectangular.

I'll have to see if I can come up with something without drilling into the frame. Really don't wanna do that.

pwd said:

For the em3ev triangle pack; have a look at this thread if you haven't seen it already:
https://endless-sphere.com/forums/viewtopic.php?f=2&t=91500&hilit=em3ev+triangle+battery&start=50

Click to expand...

E-HP said:

I'd make sure the triangle pack fit and get that one. I wouldn't hide it in a bag though; just fabricate a mount and put it on display.

Click to expand...

Hadn't seen this thread. I'll have to see what I can come up with. I know the battery will fit... I'm just not optimistic I can put together a mount for it. Will have to try to think of something.

Being able to remove it is a big deal for me. Summers almost here and I really don't want to have to worry about leaving the battery on the bike, locked up and baking in the Texas sun.

Thanks everyone for the input, this has been really helpful.

em3ev custom builds battery packs!
solid reputable company

markz said:

em3ev custom builds battery packs!
solid reputable company

Click to expand...

Will keep that in mind, thank you. I don't know that I have the budget to afford a custom battery build right now though.

Capsloast said:

markz said:

Perhaps your ultimatum has to do with you do not have enough space

Click to expand...

Exactly right. I share a living space with other people and it was really painful negotiating space for the first bike. A second one just sounds like a really good way to piss everyone off. I gotta weigh the benefits here man... and having electric assist just isn't worth the added stress.

2old said:

I had the same problem with an e-cruiser built for my daughter, and found a solution with SKS "anywhere water bottle mounts" ($20 @ Amazon) on the top tube adjacent to the seat, then mounted the battery there. Solid mount made stronger with a wrap of Velcro. Not the best weight distribution, but the best solution for her.

Click to expand...

motomech said:

There is space in FRONT of the down tube for a bottle-type batt. plus whatever you can fit in the triangle. Your bike may even have the rivets for mounting, but if it doesn't, they are easy enough to install.

Click to expand...

Thanks I think this may actually work well for me. I have clearance in front of the downtube for a supershark but maybe not a luna wolf pack, depends on how much space there is with the fork compressed, I'll have to check later when I have someone to help. But I will probably have to cobble something together myself because the mounts on amazon all seem to be designed specifically for cylindrical tubed frames. My toptube and downtube are both rectangular.

I'll have to see if I can come up with something without drilling into the frame. Really don't wanna do that.

pwd said:

For the em3ev triangle pack; have a look at this thread if you haven't seen it already:
https://endless-sphere.com/forums/viewtopic.php?f=2&t=91500&hilit=em3ev+triangle+battery&start=50

Click to expand...

E-HP said:

I'd make sure the triangle pack fit and get that one. I wouldn't hide it in a bag though; just fabricate a mount and put it on display.

Click to expand...

Hadn't seen this thread. I'll have to see what I can come up with. I know the battery will fit... I'm just not optimistic I can put together a mount for it. Will have to try to think of something.

Being able to remove it is a big deal for me. Summers almost here and I really don't want to have to worry about leaving the battery on the bike, locked up and baking in the Texas sun.

Thanks everyone for the input, this has been really helpful.

Click to expand...

Thanks I think this may actually work well for me. I have clearance in front of the downtube for a supershark but maybe not a luna wolf pack, depends on how much space there is with the fork compressed, I'll have to check later when I have someone to help. But I will probably have to cobble something together myself because the mounts on amazon all seem to be designed specifically for cylindrical tubed frames. My toptube and downtube are both rectangular.

Click to expand...

There's tons of room. The sm. frame model only has 3 1/2 inches of fork travel, most of it up and down, not frt. to back.

I'll have to see if I can come up with something without drilling into the frame. Really don't wanna do that.

Click to expand...

It already has 4 of them. Just take it to any bike shop and have them install the two riv-nuts. It wouldn't cost much.
You are worrying too much and you only just started. In the world of ebike building, you haven't seen anything yet.
Remember, you have us as a resource.
The question now is, how do you connect two packs to a single controller? I suppose you could use an "either/or switch". One that would not allow both packs to be On at the same time.

Capsloast said:

dogman dan said:

Not joking. get another frame.

Click to expand...

You might not be joking, but that is not going to happen. Either I make this work with the bike I have or I just don't get an ebike, those are my two choices...

Click to expand...

Disregard the right answer all you want; that doesn't make it wrong.

The qualities that make a good pedal bike are similar, but not identical to, the qualities that make a good e-bike. The good news is that an optimal donor bike for e-assist can be cheaper to buy and easier to maintain than an optimal pedal bike would be when pressed into the same role. The bad news is that if you can't take good advice from experienced people, you'll have to spend time, effort, and money to demonstrate for yourself why they were right.

FYI, the "anywhere mounts" are secured with Velcro straps; the type of tube, square or round, shouldn't matter.

T-Bolt clamps would work as well, and just find a flat head and drill the clamp, place some washers and a steel plate from Home Depot, great anchoring point for velcro, bungee cord, rope, zip ties (I like the metal ones, but if you go plastic, buy good quality plastic zip ties, no nothing from any Lowes or Home Depot, go to a real hardware store, like FastenAll, Bolt Supply House, Auckland Grainger, Gregg Distrubutors.
T-Bolt Clamp https://www.princessauto.com/en/detail/1-11-1-25-t-bolt-clamp/A-p8828493e
Outdoor Zip Ties/Cable Ties http://store.boltsupply.com/storefrontCommerce/itemDetail.do?item-id=14663&order-quantity=1&item-index=100&customer-item=TECHICE14160C&order-uom=&warehouse-id=1&item-number=TECHICE14160C
https://ebiz.techspan.ca/products/CABLE%20TIES.aspx
Artic Ties are good, they are the blue ones!


My preferred method is zip ties and Gorilla Tape!

2old said:

FYI, the "anywhere mounts" are secured with Velcro straps; the type of tube, square or round, shouldn't matter.

Click to expand...

Look up the previously mentioned riv-nuts. It's No big deal to add an extra set of water bottle mounts. In fact, Many bikes come stock with a set of mounts on the bottom of the downtube. And if you're using a long, tube mounted battery pack, it may well have three spots to mount, so you'll want to install three rivnuts to secure the battery as well as possible.

Electric Earth said:

Look up the previously mentioned riv-nuts. It's No big deal to add an extra set of water bottle mounts. In fact, Many bikes come stock with a set of mounts on the bottom of the downtube. And if you're using a long, tube mounted battery pack, it may well have three spots to mount, so you'll want to install three riv nuts to secure the battery as well as possible.

Click to expand...

Two issues to stay aware of if you do this:
1) leave enough room for the fork to bottom out and flex backwards without hitting the battery, and
2) drill a drain hole in the battery case at it's lowest point.

When mounted right side up, there's not much way for moisture to find its way into say a Shark pack, but what does get in there will tend to sit clear of the cells and BMS until it drains or wicks out. Not so when it's mounted upside down. It's easier for water to get in, and once inside it will pool indefinitely until it kills cells, the BMS, or both. One of my close friends killed two Shark packs in rapid succession this way-- one after she was already aware of the problem. So hedge your bets and poke a drain hole in there.

Maybe a good way to help avoid water issues would be to make a guard that acts kind of like an umbrella on top and wraps over the front to also protect from tire spray if there isn't a good fender on the front wheel.

Capsloast said:

- EM3ev Triangle Pack: Might fit, possibly wont
Assuming my crude cutout is correct, this is the only battery that will actually fit. Problem is the bag is too big by several inches. I suspect I could probably mash the bag fabric in to make it fit but with the fabric and padding of the bag, I don't know if I'll be able to fit the battery inside.

Click to expand...

Would a Blackburn Design Outpost frame bag help ? They make it in 3 sizes and also a derived "Elite" model.

Well, do it with that bike. But it might not work with any of the batteries specifically designed to fit in frames with a more horizontal top tube. That's it. They are not designed for your bike, and that's that.

36v 10 ah square pack will fit.. lipo will fit. But the cased 48v packs might not fit, unless you ditch the case.

So buy the shortest one, and ditch the case if you have to.

FWIW, anything that will fit in that smaller space you have, won't be a burden to carry on a rear rack. It won't be over 10 pounds.