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Moped Battery Build
#1
Question 
Hey everyone, I am building my first pack and was curious about how to solve this.

I am running a 10s8p build with low-cost Samsung INR18650-13Q cells running a 36v 10.3ah pack. I was following the way this guys tutorial with using this busbar method. Youtube link

When I was designing the packs I assumed I could just run one side to be positive and one to be negative. Now that I am doing this that is not the case. Do I just run 2 more bus bars? I did not solder the bus bars yet, and was hoping one of you could tell me how to fix it or what to do before I move forward. I attached a pic to show what I am doing.

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#2
Your current pack layout would allow for Pos/Neg to be on the same side. With the way you have it laid out in the pic, they would be on the other side.
Had you done 10s16p, then you'd have a bit of different layout/configuration/pack-size.

Before putting the bars on the pack, I would recommend heating the bars up with a heat gun or on a stove or such and then hit each of those solder points again with the iron. By heating the whole bar up, the iron won't have to work as hard to heat up the one spot. You joints look a little to "balled" and not fused enough with the bar.
Headrc likes this post
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#3
Oh, so if I had a heat gun and heated up the bus bar then re-soldered each joint with the fuse wires? Is that what I should have done from the beginning when I first lay the solder down?

I still don't understand how I can fix this so that the negative is on one side and the positive is on the other? (both on the left or right) Is that what you meant? From the video, the guy had the positive and negative bus bars on opposite sides and opposite ends? Is my project salvageable by just moving some batteries around?

Thanks, Korishan!
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#4
His pack is a 7s, that's why his Pos/Neg are on opposite sides. Even number in series will end up with them on the same side, odd number in series is on opposite sides.

The heat gun trick is just so the whole bar is hot so when the iron is being used, it's heat isn't being sucked away faster than what it can apply. Honestly, that trick just came to me when I saw what you had and needed to be done Tongue maybe I saw it somewhere else before
Also with the guy in the video, his iron looks to be about 100W, it's a got large barrel and a pretty good sized tip.

If you want the Pos/Neg terminals on different sides, you either need to change you series to an odd count (9 or 11), or play with different designs to see what gives you that with the 10s. I'm not sure how you would get them on opposite sides. I doubt it's really critical. Having them both on the same side actually would make working with it slightly easier as you don't have a lead on the "bottom" of the pack
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#5
I gotcha, I just didn't know where to put the positive vs. the negative if they are both on either side. Are you saying you can only do it with an odd number of parallel cells?
I would like to have the terminals on both sides.
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#6
As your pack design, you Pos/Neg will be on the same side. In the picture as the pack sits, will be between the back and the table. I drew in the last bar on the pack, and put labels where your connectors would be at.




On the other side of the pack, the bus bars would be off set from the ones shown. So you wouldn't connect a bus bar at the same location, otherwise you'll blow fuses. So, you currently have bus between 1 & 2, 3 & 4, 5 & 6, 7 & 8, 9 & 10. The other side would be 2 & 3, 4 & 5, 6 & 7, 8 & 9
Proceed with caution. Knowledge is Power! Literally! Cool 
Knowledge is Power; Absolute Knowledge is Absolutely Shocking!
Certified 18650 Cell Reclamation Technician

Please come join in general chit-chat and randomness at Discord Chat (channels: general, 3d-printing, linux&coding, 18650, humor, ...)
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#7
Thanks, Man. That makes sense now. You are awesome! What does everyone wrap the batteries in? I was looking at this? Amazon lInk

Soldering today or tomorrow.
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#8
Usually most of us don't wrap the cells since they won't be exposed to weather conditions. However, being a moped pack, you'd be similar to the eBike groups. I've seen them use the larger shrink wrap like that. I've also seen those who just make a small box then wrap that in duct tape or something similar. I guess depends on permanent you want it or ease of accessibility.
Proceed with caution. Knowledge is Power! Literally! Cool 
Knowledge is Power; Absolute Knowledge is Absolutely Shocking!
Certified 18650 Cell Reclamation Technician

Please come join in general chit-chat and randomness at Discord Chat (channels: general, 3d-printing, linux&coding, 18650, humor, ...)
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#9
Oh gotcha, I ordered that shrink wrap. I was wondering what gauge of wire that my batteries would be using if I'm running 2- 36v packs in Series? Is there a standard guide as to which size wires will go from each battery to the controller? I am getting ready to finish one of the batteries and am looking to charge it soon. The controller says it can draw up to 192 Amps. I don't think I'll program it to do that. Any recommendations? I found some guides online, but nothing definitive.
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#10
The wire size totally depends on the amp draw. 192Amps is MASSIVE.... You need HUGE cables.

http://www.solar-wind.co.uk/cable-sizing-DC-cables.html

Thats like 35mm2 wires from the pack to the motor if its max 1 meter and up to 5% loss.
Between cells for no large loss then you need decent thick fuse wire that easy can do 20A to lower the losses as much as possible.

Personally i would only fuse the pack and not individual cells if they are new. Its a Ebike pack Smile
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