10S1P 36V 8AH LIPO pack using surplus hybrid Bus cells.

[pullin-gs]

FYI here are a few details on how I built my packs (10S1P for a 36V trike project, and a 3S3P for an e-powered kayak). I used a BMS for one pack, the 10S I did not bother (I monitor each cell with a pair of 5S RC voltage monitors/alarms). I charge them with my bench power supply dialed in at 41.0V and 3Amps for the 10S pack.
I paid about $6/cell. Capacity tests out to almost 9AH/cell.

https://www.ebay.com/itm/20-SPIM08HP-3-7V-8AH-LITHIUM-POLYMER-BATTERIES-25C-200A-SUPER-CELLS-24V-36V-48V/173305036284?hash=item2859c8fdfc:g:QXIAAOSw8~5a72gx:sc:FedExHomeDelivery!34442!US!-1:rk:3f:1&frcectupt=true

I've built two packs now. Based on my own observed performance and reliability, I am not concerned w/ their quality. I'm told they were used in a prototype bus and have few cycles on them. Also the seller is well known and respected in the DIY battery community.

View attachment 3

 

[Bublifuk]

Hallo, I would like to ask you. Are you satisfied? I am very interested about these batteries, but I'm a little afraid of the quality. Because the price is unmatched. Thanks

 

[Grantmac]

How do you keep the terminals separated? Do they need much compression?

 

[999zip999]

DrAngle talked about these a year ago as I remember. Those are some big numbers for discharge and charging. Plus I would need 40 cells. For a 20s2p pack. Or 400amps Haha. Wish they had a 20ah or 15ah cell.

 

[pullin-gs]

I'm getting about 7.5Ah capacity real-world capcity.
I discharge them at about 2C. Burst from time to time to 3C.
My cutoff voltage is high. Currently set to 33v (3.3v/cell).
I charge them at .5C and cutoff at 41V (4.1V cell).

I love them so far. Like I said, I built two packs. Both going strong. Cells seem rock-solid for my application.
I bought a lot of 20. All cells tested good. Two cells had loose pouch (not puffed though). I did not feel comfortable using them, so I mentioned to seller and he shipped two good cells no questions asked.

200A discharge is being tossed around online, seems very high though. I wouldnt do it.
For pack assemply, here are a few notes:
I put 4 layers of shrink (shrink measures 4" wide BEFORE I apply heat) over each clamped terminal.
As a secondary precaution I also separate terminals with strip of plastic.

My builds are stacked cells. I used 5 (4 corners, and in the middle) 1-inch square 3M double-side tape.
I dont even try to solder the tabs.....I only use clamps as described above.
Stainless pan head #12-24 x 1/2" screws are more than enough to keep bars clamped tight and conducting.
The bar also serves as a nice mounting point for "+/-" terminals. I drilled/tapped 1/4" holes that mount wires from controller.
I did not go with a BMS on the 10S pack. Instead I bought 2 5S charging connectors (used for homemade RC packs) and plugged in RC pack voltage monitors, which give an alarm if voltage drops below 2.7V on any cell.
The other pack has a BMS....although balance current is so low it really serves no purpose other than to provide over-current, and over/under voltage protection.

PS: 3S3P pack powers a 12V BRUSHED trolling motor mounted on Kayak.....I ditched the motor's stock resistor network (provides 3 speeds forward) and put in a nice PWM brushed motor controller.

PSS: Important.....install fuse on pack that is maximum (no more) amp draw of motor/controller system.

 

[Grantmac]

So no compression on your pack at all? And getting 7.5ah from an 80% SOC running down to perhaps 10%?
Bulk charging?

I'm very tempted by the form factor but I'd like to pull 60a in bursts and about 20a continuously.

 

[pullin-gs]

I'll be shrinkwrapping entire pack as soon as shrink gets here from China.
What benifit will compressing the pack give me?

I bulk charge the 10S pack using a precision power supply.....set at 41.0V @3A....using per-cell voltage monitoring while attended.
I charge the 3S3P pack using via the BMS which is fed at 12.6V.

20Amps continous from a 1P pack is nothing at all for this cell. My pack does not even get above ambient room temperature when I switch my speed controller up to "high" which draws 20amps full throttle.

I can not speak from experience regarding 60amp bursts though.

 

[999zip999]

Looking for 20s 2p for 80amps. I'm going down to make a cardboard model first. It needs o fit a F.S. frame. I tried to look them up and couldn't find any info ? Is the length 190mm with the tabs ?

 

[pullin-gs]

203mm

 

[999zip999]

Great thank you now I need to mock something up.

 

[999zip999]

I can't get 2p to fit and 1p 8ah is small. It's like when I fell in love with a girl at the Bunny Ranch until I found out what her profession was. I'm bummed.

 

[amberwolf]

What benifit will compressing the pack give me?

There are a number of discussions for various types of pouch cell. Some of them are listed here by thread
https://endless-sphere.com/forums/search.php?keywords=cell*+compress*&terms=all&author=&sc=1&sf=firstpost&sr=topics&sk=t&sd=d&st=0&ch=300&t=0&submit=Search

and more are listed here by post
https://endless-sphere.com/forums/search.php?keywords=cell*+compress*&terms=all&author=&sc=1&sf=all&sr=posts&sk=t&sd=d&st=0&ch=300&t=0&submit=Search

Not every result is relevant, but you should be able to see which are pretty quickly.

 

[999zip999]

Cell compression put a piece of rigid material on one end and put a piece a rigid material on the other have third hand push in Center rap with duct tape great compression you don't want to squirt the jelly out of the jelly mold. Slight compression no expansion is really the important part no expansion. If anyone cell has a problem is just going to burst it no matter what. Or pressure ring and or valve.
After that they'll be a certain type up almost sweet smell and liquid please do not touch the liquid or drink it in any way shape or form
Please do not like the smell or get to like the smell of the Electoral Grand open the envelope.

 

[999zip999]

As you are using the batteries you can just wrap it with duct tape in plates and that would be fine.

 

[999zip999]

Ok don't let the bus bars short against the cell don't let series connections connect the worst commute congratulations. Sun people say don't let eat cell touch each other I haven't had a problem but the pouch sells I have used for 5 years game crafted by the gods this is my kind of place but with rubbing vibration and movement Danger
Or no bus bar should be touching a pouch are a pouch on both sides imagine touching negative to positive with the bus bar against the pouch overtime keep keep keep away. Don't short . Separate in the center or something make sure sometime a block of plastic flat plastic as a separator the width I made sell a mmmm could do good as an insulator Etc good luck my friend

 

[pullin-gs]

What benifit will compressing the pack give me?

There are a number of discussions for various types of pouch cell. Some of them are listed here by thread
https://endless-sphere.com/forums/search.php?keywords=cell*+compress*&terms=all&author=&sc=1&sf=firstpost&sr=topics&sk=t&sd=d&st=0&ch=300&t=0&submit=Search

Thank you.

 

[Chalo]

The eBay listing didn't specify the weight of a cell, as far as I could tell. Do you have this information?

 

[pullin-gs]

10 ounces