Nissan Leaf Cells Test Data

[SamTexas]

That's exactly what I expected to see. What a difference in sag!

Icecube test with and without sense wires.jpg (41.92 KiB) Viewed 4845 times

That said, I'm still disappointed. I expected this chemistry to hold voltage much better under discharge.

[mvly]

Sense Wire Discharge Data for SamTexas

So looking at the updated test, these cells doesn't perform that badly.

This seems like typical discharge curve dropping fast in the beginning and then dipping fast at 3.65V at 90% depleted.

Good update test. I didn't think the charge leads would have such voltage drop, but now that Sam mentioned it, it makes sense.

I look forward to building and attaching these to my ebike for the long haul.

[Arlo1]

Its exciting to see people testing this stuff. Keep it coming guys.

[Hillhater]

That's exactly what I expected to see. What a difference in sag!.

What data are you comparing ?
From the original 20A test to the "sense wire" 20A test i can see only 0.015 volts difference. ? ( typical at 30 mins in)
and infact towards the end (85mins) the "sense wire" test is actually sagging more than the original test by 0.014 volts ?
Edit ..ignore this post. dummy reading data table wrongly. !

And also how are you measuring the internal resistance during discharge ?

[SamTexas]

The two red voltage curves. With sense wire the voltage is always about 0.10V higher from begin to end of discharge.

[Hillhater]

Ahh. OK..i was using the spreadsheets but looking at the wrong column on the "sense wire" sheet !

[mvly]

I, for one, am satisfied. Though the sag is more than my lipo, this is the price you pay for safety and higher cycle count before 80% capacity. Moreover, I dont have to deal with shotty chinese cells... at least I hope. These are Japanese cells.

I am busy with other thing at the moment but once I get the chance, I will revive this thread and update you all on how it preforms. I wont be cell testing because icecube already did that. I will update on how I mount them on my bike, how to build the series and parallel package you need and most importantly, how well they work on an ebike. I am looking at 24s1p. It will be crazy heavy, but I am determined to get it on my bike.

[icecube57]

http://www.ebay.com/itm/310MM-200MM-PVC ... 3369fcd06a

This is the heatshrink you need if you plan to do 6s packs.

If you want the measurements for any other configuration let me know.

[icecube57]

OK here is a status update on where Im at. I have two 6s packs with bus bars soldered and balance taps added.

The pack dimensions for each 6s section is 11.25x8.5x1.75 Inches

For a 48v pack I bought this camera case to house my batteries.
http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 0606377957
Its 13x10.3x5.1 which I think is perfect.

For a 72v battery you want to get a pelican 1450 case.
http://www.pelican.com/cases_detail.php?Case=1450
14.62" x 10.18" x 6.00" which I think fits it perfect.

My bike currently has a MTX rack system. I plan to transplant the rack system mount from my old MTX bag to the camera case to where it slide and locks on to a rear rack. I will do the same for the pelican case when I get it.. when I want more speed and range.

These are my best off the shelf suggestions for housing and keeping these cells safe Im sure you guys have better ideas.

[icecube57]

http://www.ebay.com/itm/NEW-APE-CASE-AC ... 46118077bd

This is a 72v Pelican Alternative Case. Its more expensive though.

[icecube57]

This is purely my observations. I made 3 6s packs. I assembled two and heat shrinked the packs. I tested the packs again and something intresting popped up. When I tested the cells initially I was getting 28.6-28.8 and this was under mild compression. Two cook books and 4 power supplies which is roughly 20lbs of weight. The packs in the 6s assembled but uncompressed state state netted me about 29.3. Maybe the weight of the cells are affecting the performance some how.. I dont know but the two packs that I managed to complete and heat shrink netted me 31.6 AH. But the bare cells gave me 28.6-28.9. These results were gathered across two chargers. Me checking this last assemble but uncompressed pack came back with the same results as on the previous charger so that rules out the charging being a faulty. Im thinking compression does play a role in capacity. This isnt scientific this is just my observation

[circuit]

Interesting data. It is definitely worth looking into.

[mvly]

Here is some preview update.

I'll let the pictures speak for themselves.

Total w/h

IMG_20131015_072029.JPG (389.94 KiB) Viewed 4515 times

Total distance

IMG_20131015_072154.JPG (336.21 KiB) Viewed 4515 times

Forward ah total

IMG_20131015_072538.JPG (128.89 KiB) Viewed 4515 times

End voltage and temperature

IMG_20131015_072830.JPG (121.25 KiB) Viewed 4515 times

The only comment is I charged to 4.15V and end voltage it was around 3.61V to 3.68V.

Set one of end voltage of the trip

IMG_20131015_073620.JPG (103.02 KiB) Viewed 2322 times

Set 2 of voltage at end

IMG_20131015_073639.JPG (85.59 KiB) Viewed 2322 times

Overall I am satisfied. The configuration is 24s1p and I charge as 12s2p.

What I don't have in pictures is the starting voltage. It was 99.4V when I left for my long trip.

Weight of batteries was around 45lbs. So it is crazy heavy. I think these batteries would be perfect for trikes or placed on a trailer. It was crazy heavy in the center of my bike frame and it does affect handling a bit. However if I am drag racing in a straight line, it holds up find... Assuming the motor can hold up to the task without burning out.

Voltage sag is non-existent. I was using between 1500W and 2000W for most of my trip. With burst up to 3400W. Even with the 3400W, the voltage dropped around 1.5-2V during middle of the ride. i.e. this is not surface charge. If I maxed at 3400W early on, it would sag more. So Voltage sag is definitly in check for my purpose.

Internal resistance at full charge

IMG_20131015_073545.JPG (403.4 KiB) Viewed 4515 times

Keep in mind this is for 60Ah because I charge as 12s2p using my Hyperion 1420i. So IR should theoretically be 14 mOhms.

I didn't go too fast because I was not sure if my bike frame can handle the new weight. However, given more and more of riding, I think I will get more comfortable with the ride.

For all intensive purposes, this battery preformed up to specs. It is not the best... not by a long shot, but it does it nicely, conservatively, and with safety in mind. I guess you can expect a realistic 28Ah if I use the full voltage range from 2.8V to 4.2V. The reason why I restrict my voltage range is because this will be the voltage range I will be using it at.

Keep in mind I have not applied any pressure to the cells. From IceCube's test, I can probably get more out of it if I compress it.

I will have to make some more mods, but overall it will be what it is for the for seeable future for now. I just don't have time to mess with it further.

In the next few post I will show you how I mount it and if I have time, show you how I built it and charge/discharge it.

[icecube57]

With these cells and their chemistry cycling isnt what you should worry about. I was suprised that shrink wrap did gain capacity and was giving like 31.7 from 4.2 down to 3.0. maybe worth it... maybe not.

[mvly]

With these cells and their chemistry cycling isnt what you should worry about. I was suprised that shrink wrap did gain capacity and was giving like 31.7 from 4.2 down to 3.0. maybe worth it... maybe not.

I think it is universal with all lithium technology to keep it in storage voltage as much as possible. According to batteryuniversity. Maybe, it only applies to Lico, but I rather not take the risk and 25Ah is plenty for my purpose. Lets put it this way, I am much more comfortable going lower than 3.6V on this battery than my Nanotech Lipo.

Even the Nissan Leaf forum:
http://www.mynissanleaf.com/viewtopic.php?f=31&t=6116
people are recommending a storage voltage range.

Maybe I will use the full range when it gets near its end-of-life.

But yeah $660 battery + $100 build material = $760 total for 88V25Ah LiMn battery is unheard of... though it's used. hahah. Just for reference, All-Cell 48V20Ah LiMn goes for ~ $1200 new. But it does have protection circuit and PCM material. But for my purpose, it's not really needed.

2200Wh vs 962Wh!

[blisspacket]

On Sep 7 Icecube you talked about pressures on the cells. When the modules are installed in the Leaf bellypan, they are confined and compressed together on the perimeter, with a smaller central area provided to expand. Especially under the back seat, where 24 modules are stacked on their side, all 24 are held together tightly by four long bolts. The end plates for that sidestack are massive with as much as 1/4" of steel to keep the modules within a confined space. Between each module there are two spacers on either end of the module so that there's another bit of breathing room between each module. I'll try to post some fotos tomorrow.

[Giovanni LiCalsi]

Nissan Leaf batteries are made in the USA. Nissan bought AES from NEC in Japan.
I'm planning to use 20 modules in my Stanley Rocket.

http://youtu.be/e8s0sxYoJ-s

[Giovanni LiCalsi]

Funny Dutch video!
A Toyota Tundra pickup towed a Nissan Leaf for 4km and charged it to 3 bars.

[Arlo1]

Funny Dutch video!
A Toyota Tundra pickup towed a Nissan Leaf for 4km and fully charged the battery.

I found 1 video and I could not understand the language but It only showed 3 bars on the battery gauge. I don't think it fully charged it.

[Giovanni LiCalsi]

Correct. I looked at the video again and saw that. Thanks.

[miro13car]

..

[MN Driver]

The Ah rating was determined that rate.

[Giovanni LiCalsi]

Nissan Leaf Battery Specs

Type Laminated lithium-ion battery
Voltage 403.2V [1]
Nominal voltage 360V [2]
Total capacity 24 kWh [2] (16 kWh available, 67% DoD [3], 21 kWh declared [4])
Power output Over 90 kW
Energy density 140 Wh/kg [5]
Power density 2.5 kW/kg [5]
Dimensions 61.8 x 46.8 x 10.4 in. (1570.5 x 1188 x 264.9 mm) [1]
Weight 648 lbs [6]
Number of modules 48, each with four cells (total 192 cells) [7][2]
Battery pack contents:
Positive electrodes: lithium manganate
Negative electrodes: carbon
Cells
Modules
Assembly parts
Charging times:
Quick charger DC50kW (0 to 80%): approx. 30 min (Level 3 charging)
Home-use AC240V charging dock (0-100%): 8 hrs (Level 2 charging) [8]
Regular 110/120V 15-amp outlet: 22 hours (Level 1 charging) [9]
Battery layout Under seat & floor

Battery module specs[2]

Number of cells 4
Construction 2 in-series pairs in parallel
Length 11.9291" (303 mm)
Width 8.7795" (223 mm)
Thickness 1.3779" (35 mm)
Weight 8.3775 lbs (3.8 kgs)
Output terminal M6 nut
Voltage sensing terminal M4 nut
Module fixing hole diameter 0.3582" (9.1 mm)

Cell specs[2]

Cell type Laminate type
Cathode material LiMn2O4 with LiNiO2
Anode material Graphite
Rated capacity (0.3C) 33.1 Ah
Average voltage 3.8 V
Length 11.417" (290 mm)
Width 8.504" (216 mm)
Thickness 0.2795" (7.1mm)
Weight 1.7624 lbs (799 g)

[Giovanni LiCalsi]

http://www.eco-aesc-lb.com/en/product/liion_ev/

[blisspacket]

The nice fotos posted by Giovanni of modules arranged in an EV bellypan don't show the serious bolting and strapping and containment of the "breathing" of the modules.
I took a few fotos, but am not wizard enough to post them here. Suffice to say that boltholes on the four corners of each module provide for long bolts that contain the expansion; 2 steel spacers (two holes each) 1/8" thick go between every module; the inner "diaphragm" of each module has about 1/16" of airspace between the top surface of one module and the bottom surface of the next.