BT80 electric start

Joined
Jul 21, 2018
Messages
31
This is my other bike, I just picked up The motor on friday, installed it on my 3g,
20181104_111419_HDR.jpg
Wanting to know of any ideas on relocating the component box, and battery; or a smaller battery. Thought about a rear cargo rack or hard shell saddlebags. plan on adding headlights and rear turn signals and brake light anda rear drap stand. Still dialing it in, and breaking in,happy with it so far; Any advice?
 


Old Busted Hotness

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Joined
Jul 2, 2018
Messages
218
Man, that battery box is low. Is there room to turn it sideways for more clearance? I'm sure you can put a smaller battery on it.

Personally, I'd want better brakes, too.
 
S

Sanny

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I'm looking around for a smaller battery with same or more capacity, I'm going to relocate it on a rear cargo rack. As far as. Brakes, I'm thinking of doing disk on front and back.
 

junglepig

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Oct 30, 2018
Messages
218
What kind of battery are you running? A small lithium-ion pack should be able to easily deliver the amps you need.
 
Joined
Jul 21, 2018
Messages
31
The stock came in at 12v 7.5Ah; I looked at some that are the same rating, and came up up with a couple, bit the size were about the same.
 

junglepig

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Oct 30, 2018
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218
I'm assuming that's a sealed-lead-acid (SLA) battery. If you have (or are willing to learn) the skills to work with some lithium-ion cells, I believe you could replace it with a smaller pack, probably 3S (three in series) with a small charging/protection circuit added. I doubt that you need the 7.5Ah capacity, but you'd need to make sure your pack can supply the brief high current you need to run the starter.
You could probably skip the engineering part and try using a lithium jump-starter pack instead. It would have a charging port that may be compatible with your charging supply, and a short jumper cable lead. You'd have to separate the "charging" from the "starting" side.
Note, I have not done this myself, and I'm not familiar with your setup, so take what I say with a grain of salt. I'm a noob to the MB world. I do have some experience with li-ion though. What I'm suggesting would take some work on your part, and you do have to really understand what you're doing with li-ion pack charging and discharging, both for fire safety, and to make the cells last. So this is really just a suggestion of something you might investigate.
Note that if you use one of the little jumper packs, you'll also get USB charging ports as a bonus. Some of the packs I have also have DC output ports at multiple voltages, so you could charge a 19V laptop, or run 6V LED lights from it, which may be a useful feature.
If I were engineering an electric start system for one of these bikes, I'd almost certainly go with lithium over lead-acid just for the weight and bulk savings.
BTW, that's a really sweet looking bike. I love it!
 

JerboaJohn

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Joined
Jul 29, 2018
Messages
663
I wondered about laptop LiPos in electric starting, since they are not good at high amp discharge bursts, but are great for weight savings. I used 4, 5000mAh and regulated it down to 12v for my lights
the RC battery packs, those are made for high drain bursts but I thought kind of expensive compared to making your own
 

junglepig

Active Member
Joined
Oct 30, 2018
Messages
218
You won't hurt anything by trying a pack made from 18650s from laptop packs. I'd try to use good (Samsung, Sanyo, eg) cells usually found in original packs though, not the crappy cells that come in cheap replacement packs.
RC packs can be had fairly cheaply online ($20-25), and can easily supply enough current to start a V8.
the LiFePO4 cells are the easiest to adapt to an existing 12V system, but you can build something that works well with li-ion/lipo too.
Have fun!
 

JerboaJohn

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Joined
Jul 29, 2018
Messages
663
there are some SLA batteries 12v for security systems. they tend to be long and thin. I have a couple I used for lighting before I went to Li Ion packs which are great for LED lighting but maybe not good for a high current draw starter.
the thin one is 3 aH. shorter one is 10aH. these were $18 and $13 off fleabay
 

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