Lady needs a little help with battery build

[Sh4z]

Hi
I have some electrical knowledge from my father who was an electrician
I have built a coup,e of ebikes with rear hubs and found it reasonably easy(voilmart kits)
My sister came to me and asked if I knew how to build a 72v battery for my nephews bike, I said I think so, I can certainly get it to the point where someone fits the bms & finalises the build. Well I’m sure you all know it’s not as easy as people think, including me
We have a limited space inside frame but if i can work 2 layers of 100 batteries 20s 10p so 10 lots of 10 batteries in each I worked out it’s certainly possible. I have 200 Samsung 30q to work with and a soldering machine especially for battery builds bought from allie express.
The battery is to drive a 3k rear hub.

Please see attached build suggestion and if anyone can check it I would be grateful.
If you have any advice at all regarding this build I’m all ears, it might be best to start with ‘is theis even possible or realistic.
Thank you in advance
Shaz(Chantelle)

 

[Sh4z]

Frame space available

 

[spinningmagnets]

This link will give you a good start. At the very least it will provide a common frame of reference for any questions and answers you may have going forward...

https://www.electricbike.com/introduction-battery-design-1/

 

[Sh4z]

Thanks for that, I will have a read later

What I’m stuck on specifically is what goes on on the opposite side of this pack and where to place the strips.
I think , on the top showing in my pic (and correct me if I’m wrong) I need to connect 1 pack off 10 negative to one pack of positive, if I’m I’m right then on the reverse I connect one pack of positive this time to one pack negative.

Also and here is the big question how can 1 pack of 10be connected to a second pack of 10 to complete 20s 10p (around 72v)

 

[999zip999]

Make sure you get a good working spot welder a few in the battery section with support. As she of the Chinese ones blow your house fuse's and are to get right. Make a 14s4p pack and BMS first. For practice in so you can get your head around it.

 

[Sh4z]

This one , it’s rated very highly
I will connect it to the mains plug at the cooker, it’s on a separate fuse

 

[goatman]

your picture is 11s10p

are you making 2 10s10p connected in series?

might be better off with 20s5p

 

[zacksc]

I'm no expert, but I think you want the p first, then the s. as in 10p20s for 200 cells at 72 volts

 

[zacksc]

so you would have a single string of (20) groups of 10 in parallel

 

[goatman]

doesnt have room in the triangle for 20s10p unless its made side by side so a split pack.

id rather have 2- 20s5p connected in parallel than 2-10s10p in series so i could leave 1-12lb pack off the bike for short rides but thats me

 

[Sh4z]

We have a limited space inside frame but if i can work 2 layers of 100 batteries 20s 10p so 10 lots of 10 batteries in each I worked out it’s certainly possible.

From my original post

Pic show 11 rows as I thought maybe people had a preference or idea about the best row to remove for BMS

 

[Sh4z]

I think it should read 10s 20p 20 groups of 10cells

 

[Sh4z]

Goatman ,
thanks for the reply

The frame is strong enough & it’s well out of the way of pedals and legs so 2 layers of 100 we would like to aim for.

Please tell me how I connect both layers, is there a video tutorial somewhere?

Thanks
Shaz

 

[goatman]

my favorite youtuber

https://www.youtube.com/watch?v=dSncYA35Gqc

 

[monster]

Looking at your pictures, the pack seems very close to the frame. I would be a little worried about the battery insulation being worn away by the frame banging into it on the bumps.

You could get have a meltdown if it shorts out!

 

[B1gD]

Bump