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Discussion Starter #1
Hi,

My Thundersky 100aH cells are almost 8 years old, and are showing their age. They have over 50k miles on them now, but I need to begin my search for a replacement pack. I seek suggestions on what to buy as a replacement.
My first and most convenient option is swap out with Calb CA100 cells. I will entertain other manufacturer LFE cell options, also Leaf, Volt, Tesla etc. are an outside choice.
My car can be seen here with all the details.

Thanks!
 

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Hi,

My Thundersky 100aH cells are almost 8 years old, and are showing their age. They have over 50k miles on them now, but I need to begin my search for a replacement pack. I seek suggestions on what to buy as a replacement.
My first and most convenient option is swap out with Calb CA100 cells. I will entertain other manufacturer LFE cell options, also Leaf, Volt, Tesla etc. are an outside choice.
My car can be seen here with all the details.

Thanks!
If I were you (or anyone else) I'd forget about CALB and all the other manufacturers of hobbyist cells. There's no point any longer. Just find batteries from a wrecked EV and use the pack. Leaf, Volt, Tesla. They're all decent options. You might find it difficult to fit a whole Tesla pack in your car even if you take the modules out and arrange them differently. But, salvaging OEM packs is really the way to go. They're cheaper than new and they tend to come with a lot of useful hardware like contactors and BMS.
 

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Discussion Starter #3
So, basically, I would need 40 Leaf cells. What about using a BMS for the pak...necessary? I currently use an Elithion BMS, and I am fairly certain it would not be able to monitor the Leaf cells. I would at least want some sort of display for monitoring purposes while driving and while charging.
 

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So, basically, I would need 40 Leaf cells. What about using a BMS for the pak...necessary?
While some people have implemented a human BMS I think an electronic system makes sense. I purchased a couple of Leaf BMS for $65 each recently and hope to have Wolf modify them for use with his control system at some point. Third party BMS are available but I can't comment on those.

Here's Wolf's thread;

http://www.diyelectriccar.com/forums/showthread.php?t=181490
 

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salvaging OEM packs is really the way to go. They're cheaper than new and they tend to come with a lot of useful hardware like contactors and BMS.
I completely agree with Collin and think OEM is the way to go. It even has the added benefit that you can order new parts from mainstream parts suppliers... I purchased a new Nissan battery BMS wiring harness and insulator kit for $100 (iirc) which was less than I could make it for, and less than eBay vendors wanted for second hand :cool:
 

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So, basically, I would need 40 Leaf cells.
You would want about 40 cells in series to hit the right voltage. I haven't seen anyone break the Leaf battery down to individual cells, and that makes sense to me; the obvious thing to do is to keep the Leaf modules together. These modules contain 4 cells, with two in series, so you would be using:
  • 20 of the Leaf's 48 modules,
  • containing 80 of the Leaf's 192 cells,
  • weighing 164 pounds (before interconnects, BMS, etc)
and giving you
  • the same 65 Ah as the Leaf, and
  • 10 kWh of a 24 kWh Leaf pack.
You would essentially be using one of the 150 volt pacs as described by WolfTronix in his Leaf module based 150V 65Ah battery pack... thread (linked by Kevin above).
 

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Discussion Starter #7
I would then go with 2 of the 65aH modules like WolfTronics assembled, giving me 130aH? As for a BMS or monitoring, is there a display available? I saw where WolfTronics was attaching his own chip on the board, but I have not seen is this is able to show cell information on any type of in dash display.
 

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Haha, you would know! If I went with 38 modules, would I be able to use your device for monitoring/balancing/status etc.?
Depends...

If you are using (38 modules in series), then yes.

If you are using (19 modules in series) in parallel with (19 modules in series), then no.

The modules have to be in even numbers, since the BMS chips are powered by the cells in the modules, they need to have all 4 cells* connected, which is two modules.

*each module has 4 cells in it, but they are 2S2P, so the BMS sees them as only 2 cells per module.

So, (18 modules in series) in parallel with (18 modules in series), would work.

And, (20 modules in series) in parallel with (20 modules in series), would work.

I would recommend (20 modules in series) in parallel with (20 modules in series), because that is what I am using and I already did all the hard work to figure out the module configuration and BMS cell wiring. ;)
 

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Discussion Starter #11
OK, I understand, (20 modules in series) in parallel with (20 modules in series)it is, I will just need to get my Elcon charger reprogrammed for the slightly higher voltage. Also, thank you for the excellent documentation, and all of your incredible work on "sniffing" out the Leaf cells!
What information will be able to be displayed?
 

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What information will be able to be displayed?
What is displayed will be user configurable.

The display will have different pages, these can enabled/disabled through the display config file on the microSD card.

Or it can cycle through different pages (this might be distracting while driving, but useful for diagnostics).

Data available from BMS:

Individual cell voltages.
Individual cell balance state.
Total pack voltage.
Temperature sensors.
Current in/out of each parallel pack (if you have two current sensors).
Amp-hours in/out of each parallel pack (if you have two current sensors).
Watt-hours in/out of each parallel pack (if you have two current sensors).
Total Current.
Total Amp-hours.
Total Watt-hours.
Watt-hours per distance, (If I can read/or get distance data from else where in the vehicle).
Sate of charge.
Sate of health, (If I can figure out Nissan's algorithm).
Etc...

Typically, while driving, I would think you would want a page displaying Total Pack voltage, Total Pack current, Amp-hours, or Watt-hours, Watt-hours per mile/km, State of Charge, etc... Something simple.

Then the display would switch to anything that is out of the ordinary...

For example, if any one cell gets out of range from the others, high/low, it would display which cell it having a problem so you can keep an eye on it.

While plugged in and charging, I would think you would want a different screen showing only battery info...

It is a work in progress, and so open for suggestions. ;)
 

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Discussion Starter #13
That is plenty of info! Would there be a way to show amp hours as a percent, counting down from 100%. My display shows Amp hours(as a percent), Pack Voltage, and Amp draw. I only pay attention to the Amp Hours, since it is like a gas gauge. I can also see a bar graph of individual cell voltages and/or temperatures in real time, that is how I have figured out I need a new pack soon....horrible voltage sag under acceleration.
 

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That is plenty of info! Would there be a way to show amp hours as a percent, counting down from 100%. My display shows Amp hours(as a percent), Pack Voltage, and Amp draw. I only pay attention to the Amp Hours, since it is like a gas gauge. I can also see a bar graph of individual cell voltages and/or temperatures in real time, that is how I have figured out I need a new pack soon....horrible voltage sag under acceleration.
Yeah, I could do on top row something like:
XXX% XXX.XV XXXA

Bottom row could be a bar graph showing all the cells.
16 chars * 5 = 80 lines.

Each line would be 0-7 pixels tall to show cell voltage at a glance. :)
 

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Yeah, I could do on top row something like:
XXX% XXX.XV XXXA

Bottom row could be a bar graph showing all the cells.
16 chars * 5 = 80 lines.

Each line would be 0-7 pixels tall to show cell voltage at a glance. :)
20 mV per pixel would look like this:

4.0V+
3.8V
3.6V
3.4V
3.2V
3.0V
2.8V

All Pixels off below 2.8V
 
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