Author Topic: What 18650 cells would you recommend for a 36v 10S 12P power pack?  (Read 7730 times)

Offline Papagino

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What 18650 cells would you recommend for a 36v 10S 12P power pack?
« on: September 30, 2016, 11:02:46 PM »
Hey guys, I have built this battery housing with my 3D printer for my Magic Pie Vector 5.
It has 120 cells, 10 in series by 12 in parallel (10S 12P) for 36V.
It also has 2 fans to keep everything cool when necessary.

Last spring, I managed to collect over 180 used cells from computer repair shops in my region, total cost for the cells = 20 bucks...  ;D
I had tested all the cells using my Foxnovo F-4S Digital Charger and salvage the best ones. The average capacity of the cells was 2100mAh.

The battery pack worked great for the first 2 months. I have over 1200km on the bike with this battery, but now, the battery has no more capacity and I can barely do 30km with it. This is understandable due to some of the cells may be over 10 years old.

My battery housing is design in such a way that I can easily replace the cells (120pcs) in about 30 minutes as there are no welds or solder involved in the battery contacts. Instead, it is using springs riveted on 1/8" thick aluminum rails (as shown in the pics). I only have to undo a few screws, insert the new cells and voila!

I mainly use my bike on trails in the woods and drive very little on the road, so range is a good priority.
I always peddle my bike; I simply set the speed on the cruise control (40 - 45km/h) and go for long ride 60Km+ on average.

So, I need your recommendation on what cells to get for my power pack.

I can't decide on what cells I should get:
- Samsung INR18650-30Q 3000mAh (15A Max. continuous discharge) @ $3.45ea (This would be a 36Ah battery pack)
- Samsung INR18650-25R 2500mAh (22A Max. continuous discharge) @ $2.43/ea (This would be a 30Ah battery pack)
- Any other recommendations...

Cheers
Dan
« Last Edit: October 01, 2016, 01:14:16 AM by Papagino »

Offline Pwd

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Re: What 18650 cells would you recommend for a 36v 10S 12P power pack?
« Reply #1 on: October 01, 2016, 12:39:10 AM »
Hi Dan, that is nice battery pack.  8)

The Samsung INR18650-30Q 3000mAh and Samsung INR18650-25R 2500mAh may actually be over-kill if you plan on using a  Magic Pie 5. The pie will pull 25 amps max continuous. With a monster pack size of 12P; you can get away with a cell that delivers lower amps and go for even more range if your budget allows for it. Perhaps something like the Samsung 32E or 35E. Sanyo and Panasonic also have a 3500mah battery I believe too. You could probably even go with a cheaper 2500 mah cell if you wanted to spend less than what the 25R would cost.

I only have a bit of experience with the 30Q in a 14S5P configuration; its really nice.
« Last Edit: October 01, 2016, 12:41:31 AM by pwd »

Offline Papagino

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Re: What 18650 cells would you recommend for a 36v 10S 12P power pack?
« Reply #2 on: October 05, 2016, 01:27:08 AM »
Thanks for the advise pwd, I am currently shopping for the Samsung 35E... 3500mAh 8 Amps continuous.
This will give me a 42Ah pack... and plenty of range...
Cheers
Dan