Building Custom Li-Ion for Currie eZip Trailz

I got a Li-ion pack with bad cells from work today!

It's in a nice case already, and I have a controller too to charge it. Only problem is that it's 48V!
I will have to break it up and rewire it to be 24V. There is a security screw that I can't take off. Ordering the new bit off amazon.

I know with LiPo, if you discharge it too fast, they will explode. Do I have to worry about that with Li-Ion?





Here is the spec sheet: Spec Sheet for m70x48v024n

fatbbq said:

I got a Li-ion pack with bad cells from work today!

It's in a nice case already, and I have a controller too to charge it. Only problem is that it's 48V!
I will have to break it up and rewire it to be 24V.

I know with LiPo, if you discharge it too fast, they will explode. Do I have to worry about that with Li-Ion.

Click to expand...

<<<It's in a nice case already, and I have a controller too to charge it. Only problem is that it's 48V!
I will have to break it up and rewire it to be 24V.>>>

Huh???
That doesn't really make much sense. A controller regulates the current to the motor. Are you refering to the controller or the charger?

<<<<I know with LiPo, if you discharge it too fast, they will explode. Do I have to worry about that with Li-Ion?>>>

You don't have to worry about either because that statement is factually incorrect.

Huh???
That doesn't really make much sense. A controller regulates the current to the motor. Are you refering to the controller or the charger?

Click to expand...

I've been reading the forums, and the post-2009 Currie eZips controllers don't work with batteries over 24v. If you want to go higher, you have to replace the controller and throttle. Maybe I'm understanding it wrong. I'm not too knowledgeable with circuits and electricity.

Here is a post that talks about it:
http://endless-sphere.com/forums/viewtopic.php?f=10&t=40356

You don't have to worry about either because that statement is factually incorrect.

Click to expand...

On this RC forum, they say if you discharge LiPos too fast, they catch on fire and burst.
http://www.rcshortcourse.com/forum/electronics/5287-guide-lipo-battery-handling-care.html

I don"t know much about Currie systems, somebody will respond, but it may take a while.
Ebikes don't discharge at the high rates that RC models do.
Never heard of a Lipo Batt exploding. Catching on fire yes, exploding, no.

So I cracked up my batter and found it to be a 13P12S pack using 18650C4 cells.

Measured the voltage of across the + and - terminals and it measured 2V!!!!! Each bank of cells measured about 0.17V

I want to balance charge it with my iMax B6 charger. Can I charge each bank of cells individually with my charger? or should I charge the whole thing at once unbalanced with my iMax B6 with a 60W brick PS?

[youtube]AFNLYYw5qF4[/youtube]

A lot of cell testing to do, but I am sure you'll have enough good ones to make a 24v pack.

I want to keep the whole thing in tact as a 48V pack. It's already spot welded and packed up pretty neat.

If I have to pull them all out and break the welds, I can just pick up one of these:
http://www.aliexpress.com/store/536657

fatbbq said:

So I cracked up my batter and found it to be a 13P12S pack using 18650C4 cells.

Click to expand...

You better double check that and I think you'll find it to be 13S12P instead of 13P12S. 13s is typical for these type 48V (nominal) battery packs using 18650 cells.

wesnewell said:

fatbbq said:

So I cracked up my batter and found it to be a 13P12S pack using 18650C4 cells.

Click to expand...

You better double check that and I think you'll find it to be 13S12P instead of 13P12S. 13s is typical for these type 48V (nominal) battery packs using 18650 cells.

Click to expand...

Thanks you're right. It is a 12S13P pack.

Keep trying. It's 13s12p. That's 13 cells in series by 12 cells parallel for 48.1V nominal. 12s13p would be 44.4V nominal.

wesnewell said:

Keep trying. It's 13s12p. That's 13 cells in series by 12 cells parallel for 48.1V nominal. 12s13p would be 44.4V nominal.

Click to expand...

Hahaha sorry I'm a bit dyslexic

So I was able to pull the BMS off. Looks like a Diode blew. Maybe that's why each bank was allowed to discharge 0.11-0.20V. I hope I can still recover them when I charge it with my iMax B6

fatbbq said:

So I cracked up my batter and found it to be a 13P12S pack using 18650C4 cells.

Measured the voltage of across the + and - terminals and it measured 2V!!!!! Each bank of cells measured about 0.17V

I want to balance charge it with my iMax B6 charger. Can I charge each bank of cells individually with my charger? or should I charge the whole thing at once unbalanced with my iMax B6 with a 60W brick PS?

Click to expand...

That all banks show some voltage and nearly equal is encouraging!

Recommend you charge each bank individually, at low amperage.
You will need to begin charging with nicd setting low (1A?) "manual" charge.
Monitor voltage rise carefully!
Keep checking for any cell getting warm

Charge each bank to 3V+.
Lion or Lipo charge setting should work after cells hold 3V or higher.
Check for self discharge after charge removed.

If lucky ... the pack sat at low charge for a brief period and might recover?

Post up charging results ... for further recommendations ... etc.

13s12p is a reasonably impressive pack, shame to break it apart.
But, you could split it into a 7s12p (25.9V 24Ah) that fits nicely into the eZip battery case, 25.9V works nicely.

And a second 6s12p (22.2V 24Ah) pack that also works but seems anemic after voltage drops a bit.
I believe the LVC on the eZip controller limits amperage as Low Voltage Cutoff is neared.
Progressively limits current, rather than an abrupt cutoff?
2nd emergency low performance pack?

24Ah pack 15A limit?
12s 24Ah
That would mean the cells are 2000mAh.
Much better output capability than standard 2600mAh laptop cells!
I believe the Amp limitation is for the BMS, cells alone should be ~40A capable. ... ?

eZip - iZip Specific Threads

EZip Trailz LS - 2013
Re-volting the eZips ... Simple Mods!
The New EZip "StepThrough"
Currie-EZip ebike Kit $289.88 - Amazon.com
eZip-iZip-Currie parts-n-such
13T Drive Sprocket - Currie, eZip, iZip
Re-gearing the eZips - Simple Mods!
EZip Trailz - On Sale!
Multi-Voltage Testbed - eZip
eZip-iZip Usable Controller Voltages
Should I lube my izip motor?
EZip - IZip 20mph Upgrade $20!
eZips - 15T drive sprocket
Currie-eZip-iZip Mods & Such - 5 Year Journey
Currie - IZip eBike Kit - Price Tracking
EZip Trailz - Continuous Price Tracking
Broken Spokes - EZip - Solutions!
14ga to 12ga Spoke Upgrade
EZip Basics ... Electric Bike or Electric Assist Bike
Currie MY1080Z 450w Motor - capabilities (EZip-IZip)
11T Mod - 20mph (25.9V)

Cells are BAK brand.
2200mAh rated
2C max discharge 4.4A x 12 = 52.8A max discharge
1C charge capable = near 1 hour fast charge!

See - BAK 2200mAh

Long over due update.

My Currie eZip Trailz is still going strong. Throttle broke and it took me months to troubleshoot.

I did crack the battery in half took an exacto knife literally cut that battery into a 7s. Used my bmax charger to coax each bank back to life. Really low current, and watched it came back to life. Now it's 29v off the charger.

Soldered one some balance leads, put some blue shrink on it and just used an RC charger to charge it. Haven't done a capacity test, but gone 26km+ without issue.

Next I would like to make a new pack in the old SLA cases like what you did. Maybe put a BMS in there and used the 3pin aviation connectors. My rack is now twisted out of shape, so I might have to try to bend that back some how.

Maybe contact Tom Mator and see if he still sells those modified 36v controllers.

Just bought a spot welder, will be my project for this summer.

7s12p should work great for eZip anf fit nicely in eZip battery case, just cut off center screw post.
Recommend sheets of closed cell foam on each side of cells to hold batteries firmly in case.
I use Masonite ~3/16" as a bottom shelf to support and protect cells from contacts.



6s 12p can be used to build 2nd 7s 10p pack!
Cut 2 cells from each parallel and combine into # 7s. - save 2 spare cells
Solder together with wire to copper tabs and secure with HD tape.