Conversion kit recommendations..

Ben

New Member
Hi everyone, I'm new to the world of ebikes and I'm looking for a little advice. I've been scouring the interwebs for a suitable ebike conversion kit and so far I'm looking towards the BBS02 750 W kit from Bafang (purchased through em3ev.com). I was hoping you could weigh in on my decision based on what I want to use the bike for, and tell me what you think.

My project is outlined below:

  • Bike: Giant Trace 3 dual suspension (see photo)
  • Planned Kit: bbs02 750 W
  • Battery: unknown
  • Commute: 30 km one-way (60km round-trip), relatively flat with an overall elevation gain of 100 m
  • Other factors: want to be able to maximize top speed (my trip is 100% on nicely paved bikepath with little-to-no traffic. I also would like to take this on the trails on the weekend for some shredding!
  • MAIN PROBLEM: as you can see from my pic below, the Trance 3 frame is a little too small for the battery packs sold through em3ev so I'm looking at some of the other "bottle-type" batteries out there (mostly on ebay and alibaba). Anyone know of any other battery resellers in North America that might have a suitable small battery in stock? Also, I'm open to the idea of building my own battery pack and can just have a nice case machined out of aluminum or 3D printed. Would rather buy something off the shelf though :)
Giant Trance 3 A-Frame dims.jpg


Thanks for looking over my post and I'm open to any other suggestions at this point; I'm not 100% sold on the bafang bbs02 but I do want a mid drive kit as I do a fair amount of trial riding. I think a hub-drive unit would push my C. of G. a little outside where I want it to be.

Thanks!
 

stevenast

Well-Known Member
Nice bike. I was on the same path as you a couple months ago, same kit. I have a full suspension Trek. I ended up buying a purpose-built ebike (hardtail) for reasons of quality and way less hassle lol.

If you do go forward with the conversion, I think you would be very smart to be cautious about the battery. There can be some fire danger if its not done right.
 
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Ben

New Member
Thanks for the warnings! Yeah, I recognize that I don't want to make a battery if I don't have to. I'm a mechanical engineering technologist (last exam on Wed!) so, with the best of intentions, electricity is still more-or-less magical wizardry to me. I'm hoping someone has been able to source a small enough bottle-battery to fit in a smaller A-frame like mine. This would make things a lot easier.

I don't want to give up the dual suspension just because I want to build the bike with top speed in mind, and I'd like to have as much traction as possible :)
 

flymeaway

Well-Known Member
Thanks for looking over my post and I'm open to any other suggestions at this point; I'm not 100% sold on the bafang bbs02 but I do want a mid drive kit as I do a fair amount of trial riding. I think a hub-drive unit would push my C. of G. a little outside where I want it to be.

Thanks!
You're going to have a hard time finding a 48V pack that will fit in the frame. You should be concerned with CG and unfortunately the only place that will easily accommodate the battery is above the rear wheel. JMO I wouldn't count out a hub motor but the issue you will have to overcome is torque versus speed. It's difficult to get both. Consider a 36V 500W conversion...it's a compromise but it will be easier to find a battery that would fit in the frame.

Good luck in your search.

Court J.
 

Ben

New Member
You're going to have a hard time finding a 48V pack that will fit in the frame. You should be concerned with CG and unfortunately the only place that will easily accommodate the battery is above the rear wheel. JMO I wouldn't count out a hub motor but the issue you will have to overcome is torque versus speed. It's difficult to get both. Consider a 36V 500W conversion...it's a compromise but it will be easier to find a battery that would fit in the frame.

Good luck in your search.

Court J.
Yes, this is what I'm looking for! Please, I'm not sold on the 750 W model, I'm just using that as my starting point. If you know of any combination that might work I'd be pleased to hear about it.

Cheers
 

Rustynut

New Member
I'm looking towards the BBS02 750 W kit from Bafang (purchased through em3ev.com).
  • Bike: Giant Trace 3 dual suspension (see photo)
  • Planned Kit: bbs02 750 W
  • Battery: unknown
  • Commute: 30 km one-way (60km round-trip), relatively flat with an overall elevation gain of 100 m
  • Other factors: want to be able to maximize top speed.. I also would like to take this on the trails on the weekend for some shredding!
  • MAIN PROBLEM: as you can see from my pic below, the Trance 3 frame is a little too small for the battery packs sold through em3ev so I'm looking at some of the other "bottle-type" batteries out there (mostly on ebay and alibaba). Anyone know of any other battery resellers in North America that might have a suitable small battery in stock? Also, I'm open to the idea of building my own battery pack and can just have a nice case machined out of aluminum or 3D printed. Would rather buy something off the shelf though.. Thanks!
Em3ev has a 48v dolphin battery that might fit your frame, here is a pic from his site with dimensions.
frame pack (with dims)-500x500.jpg
If the pic doesn't load you can see it here and click on the pic, scroll through to the last one or so http://em3ev.com/store/index.php?route=product/product&path=35&product_id=161
The tail at the low end of a dolphin pack is removable if you replace the output plug with 2 wires. I did that to the bike in my avatar with the same size battery just from bmsb like the post above. It might help with your frame size.

Here is a guy building up a Giant Trance with a big battery pack http://endless-sphere.com/forums/viewtopic.php?f=3&t=67951 he made a battery box and welded it in place of the top tube i think.

The problem with many US vendor batteries is 1) they are expensive and 2) they are mostly big rectangle packs meant for a rear rack.

With all your requirements you are going to have to compromise somewhere. Basically with a battery it's like: speed, range, smallness, pick 2.

Basically with li-ion you can get around 1.2 miles per Ah, slightly more if you pedal a lot. With a small pack you'd probably need a 2nd charger to keep at work as chargers don't travel well. Em3ev will include a 2nd charger for like 25 bucks i think.

18 miles 1-way will be straining a 12Ah or less pack unless you can pedal a lot. Paul's 750w bbs02 kit uses a 25a controller that will drain a lot of current wide open. His 500w kit has a 18a controller that might be more efficient wide open.

If your riding is mostly flat you might get by with 36 volts but you will lose around 5mph off the top speed. An advantage to a small 36v pack is you can get more amperage than the same size 48v, so more range. Paul has a 36v dolphin pack with like 16.5ah i believe.

Another option might be a "thermos" type bottle battery like this
http://www.greenbikekit.com
The issue with that style is they are 36v with around 10-12ah b/c of the small size, good luck-
 

Ben

New Member
Unfortunately, that battery does not fit in my A-frame. I'm also considering making a backpack battery setup with an Ultem (an aerospace super high-temp, smokeless plastic somewhat similar to nylon) 3D printed firewall along the back (between my back and the battery). Anyone have any experience or know of anyone who's made something like this? I like the idea of increased-stealth, and having the bike lighter, and its CofG really low.
 

Ben

New Member
You're going to have a hard time finding a 48V pack that will fit in the frame. You should be concerned with CG and unfortunately the only place that will easily accommodate the battery is above the rear wheel. JMO I wouldn't count out a hub motor but the issue you will have to overcome is torque versus speed. It's difficult to get both. Consider a 36V 500W conversion...it's a compromise but it will be easier to find a battery that would fit in the frame.

Good luck in your search.

Court J.
Do you have any experience with backpack battery setups? I'm considering building a custom backpack mount located in a backpack.. would have a firewall, padding for the battery, and spiral chord wiring going to the integrated controller of the bbs02 (in case of fall, would have a couple meters of cabling wound up in the spiral cord).