Spec sheets said 50grams
1 Like
Blupenguin gave you the answer already 
It’s not too far off from my ebike battery: 20s7p of NCR1650PF cells.
I wish I had gone with 30Qs though, I want moar power.
3 Likes
Less than 10% more weight in battery vs. nearly 15% increase in energy. 
1 Like
Doood we need a build thread on that bike 
In either case it’ll be an upgrade from using lead and weighing 210lbs (which is madness, I weigh 127 
)
I guess it’ll come to price and delivery to canada
1 Like
Unfortunately I didn’t take as many photos as I should have during the build. I can give y’all a look at it as it stands currently though.
14 Likes
One thing I can highly recommend not to do, because I did it and it sucked:
Do not 3d print your battery spacers/holders. It takes forever and it’s easier/cheaper/faster to just use the ones you can buy online from ali or whatever. I wasted so much time doing that, to save maybe 5mm of width.
3 Likes
I like those spacers: #Aliexpress US $1.84 21%OFF | 2pcs 10x Cell Plastic 18650 Battery Spacer Holder Black High Quality Battries Cylindrical Cell Bracket For Battery Mayitr
I still have to try them in battery build, but they are slim!
9 Likes
Do they have them for 21700 cells?
#Aliexpress US $9.84 | 10pcs/lot 21700 Battery Holder Bracket ABS Plastic 20 Cells 10S2P Battery Spacer Expandable Battery Holder
They do exist, but I don’t have them
3 Likes
Here’s my idea for an external pack. This is 10S4P to use as an extension to the internal 10S5P for extra long weekend trips.
The intention is to connect the packs in parallel. This has a few advantages compared to running on internal pack only first and once empty, switch to internal:
- I don’t have to worry about switching.
- Less current load on each pack.
- Less sag.
Now obviously the risk is that the pack votages won’t be close enough, which will cause too much current to flow from one to another, which may lead to many not nice things. So, my plan to connect them safely is this:
- Charge the external pack slightly higher than the internal pack.
- Connect the external pack to the charge port first.
- Check the current flow from the external to internal.
- If OK, connect the external pack to the internal pack’s discharge wires and go riding!
Now, if I mess up the charging and there’s too much voltage difference between the packs, no harm should be done (as long as the connect-to-charge-port-first-procedure is strictly followed).
- If the external pack is higher, the BMS over-current protection and/or the 10A fuse on the charge port should save the day.
- If internal pack is higher, that’s also OK since BMS doesn’t allow current to flow from internal battery to the charge port.
- sounds reasonable
- fireworks incoming in 3, 2, …
0
voters
4 Likes
Build in progress…
https://cad.onshape.com/documents/0a9efd05da18bbe5cbf8413a/w/70b41a20d74b9f242ca72970/e/f702f1b5d9f7b96c21494427
3 Likes
BATTERY NOOB TRIGGER WARNING
What diameter solder do you folks generally like to use for your serial connections? I’m used to this stuff:
Use it for connectors and such but seems like it might sucks for something big like a battery? What do you guys think?
2 Likes
I actually like this idea a whole lot more than a “charge and ride” that would negatively impact braking regen. Where this type of setup seems like all pros! Minus having to verify pack voltage equilibrium.
4 Likes
Here’s my “more awake and alert brain” calculations
Based on m50s (21700)
Open to thoughts and advice
I buy the thin stuff but do multi strand twists for stuff that demands more solder fill.
6 Likes
Thats some good advice. If one can afford a couple of rolls though… I alternate between these two. Life has been better ever since
3 Likes