Wouldn’t that also lead to an unbalanced battery when discharging?
Thanks for this link! I will have to read whole thread
I just thought, if I could have pack that lasts x3 for same amount of money, why not?
It would but not by much. The difference is not too concerning, if you built your pack I would just double check that no welds came loose on the last P group. If all cell capacity is the same between all P groups, but one group has a weaker connection, then the voltage will remain balanced under no load, but will spike/sag more during charge/discharge.
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Both Vesc 6 and Unity can support 12s, so go 12s because it means you need less amps for the same amount of power. Also gives you a higher top speed at the same gearing. (Or in your case, you get a larger motor pulley, which is better because more teeth are engaged with the belt.) Losing 2 cells is worth it for those reasons. Use those cells to test your welds.
P.S. Your poll is locked from voting somehow
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Yeah, for cycle life the 30Q is one of the worst options, but is one of the few that can supply the current we need in smaller packs, but once you have bigger battery there are better and depending where you look, cheaper options
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Hey @glyphiks you have bought the bluetooth bms from aliexpress right? I just got mine and it is way huge. I thought it would be smaller. I know I selected the lowest amp one but they sent me a 100amp. Is yours the size of a unity?
Can someone recommend a good e bike cell for high cycle life? Will be a 13s5p pack for a 30A controller.
Looking for a cell with ~3000mah and ~10A discharge.
30q has unnecessary high discharge and has very bad cycle life reportedly (can take abuse for quite some time, but then drops quickly after ~500 cycles).
I am looking at LG M29 currently. Does someone have experience with those?
Nice! Looks good from here!
what cell did you use?
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Lg mj1 has 3500mah and 10a
Panasonic sanyo ga 3450mah 10a
Lj mh1 3200mah 10a
Not sure on cycle life tho.
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Lol nice. Luckily I can easily fit the massive bms in my killshot. Going to put a 12s8p or 9p haven’t decided yet. Vtc6 cells.
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Got my battery hookup order! Wish I had gotten another one of the A123 packs they look sweet.
not really liking how they let the spim08hp cells slide around the boxes, one slid under some power tool packs and got dented slightly. They should be packed in a separate box because they are bare cells!
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They told me they had a 5lb weight limit per each package they sent. Obviously that was a lie.
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1/2inch braid or 8ga? I have to resolder the whole thing anyway. I intentionally left slack on the braid to hopefully combat the vibrations ripping it apart, and 80% of the length is still flexible. What do y’all think?
Also, rate my solder joints?
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Braid but your joints definitely need some work. More flux, more heat. If you want those to be perfect, buy a $10 pack of hemostats/forceps on Amazon, clamp the braid onto the strip, then pour heat (kapton tape/aluminum heatsink the plastic, or bend the tabs up to do this part) and it should be perfect.
Braid if the insulation of the wire gets in the way that is…
Keep in mind you could overshoot the length, clamp both ends of wire/braid to the strip, solder the middle, then chop off excess.
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The 8ga pictured was done with a 40w iron, resulting in what you see there. The lack of sufficient heat transfer also meant that solder wicked all the way through the length, which is why I have to re-solder the whole thing. I have since upgraded irons.
Used needlenose pliers, but otherwise this is exactly what I did. The dull grey spot on the right side of the braid is where the pliers were. Otherwise, i think the joints (on the braid) look ok. Am I wrong?
That is one of my concerns pushing me towards braid. What are your thoughts on flex/vibrations tearing the braid apart?
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I’m assuming the tab can handle the current that they’re soldered to? Is that copper?
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NESE 21700 tab. Tin plated copper. Supposedly the 18650 modules are tasted up to 200A
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