Charger is out for reprogramming. Then we will fine adust with pots afterwards. The BMS bars/hookups are bridged because we are paralleling.
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The Nissan Leaf battery pack is made of 192 Lithium-Ion (LiMnO2) cells, in a 96s2p configuration.
Each cell is 32.5Ah @ 3.75V nominal, (3.2V - 4.2V). Four cells per module in a 2s2p configuration.
And with 48 modules in the pack, this results in a 65Ah @ 360V.
SO HOW DOES ONE CALC AMP HOURS?
nominal vs min cell voltage? anyone?
Depending on the design and chemistry of your lithium cell, you may see them sold under different nominal āvoltagesā. For example, almost all lithium polymer batteries are 3.7V or 4.2V batteries. What this means is that the maximum voltage of the cell is 4.2v and that the ānominalā (average) voltage is 3.7V. As the battery is used, the voltage will drop lower and lower until the minimum which is around 3.0V. You should see the number 3.7V written on the battery itself somewhere.
INFO FOR DEALING WITH ELCON, I AM POSTING IN TWO PLACES
BECAUSE SOMEONE ELSE MIGHT NEED THIS INFO; MAKES IT EASIER TO FIND
To
Electric Conversions
Message body
I did not know how to figure amp hours. A friend finally emailed me the info. I attached his
commentary at the bottom. CRITICAL INFO I PUT IN BOLDFACE SO YOU DONāT
HAVE TO GO THROUGH IT ALL.
And I shipped by USPS. Supposed to arrive to you tomorrow Saturday.
Please let me know how and when to pay for the reprogramming.
Thanks,
Jeffrey Gillette
Tarzana, CA 91356
8189160787
2002 Gem Car with Zivan Charger OEM
BMS 24 Chargery.com
Battery Chemistry Lithium with lithium-manganese-oxide nickel oxide Cathode from 2013 Nissan Leaf
Each Cell is rated at 32.5Ah OR
75V * 65Ah = 4,875 Wh = 4.875kWh. (at Nominal see below)
20 Cells x 500W = 10 kWh
Max. Cell Voltage 4.2V times 20 = 84V
Nominal Cell Voltage 3.75V times 20 = 75V
20 Cells x 500W = 10 kWh
USE ONLY 80% OF CAPACITY TO PRESERVE CYCLE LIFE
SO MAX DESIRED CELL VOLTAGE:
4V times 20 = 80V
CUT THAT TO 78V nah nevermind; LEAVE AT 80V MAX
MAX CELL VOLTAGE 3.9V times 20 = 78V
MIN CELL VOLTAGE 3.0V times 20 = 60V Please see boldface last paragraph below
The Nissan Leaf battery pack is made of 192 Lithium-Ion (LiMnO2) cells, in a 96s2p configuration.
Each cell is 32.5Ah @ 3.75V nominal, (3.2V - 4.2V). Four cells per module in a 2s2p configuration.
And with 48 modules in the pack, this results in a 65Ah @ 360V. I am using 20.
Per a Friend named David:
Amp-hours add in parallel, voltage adds in series. Volts * amps =
watts which also means that Volts * Amp-hours = Watt-hours. To
estimate the kWh of a pack the nominal voltage is typically used
though depending on the load the pack is under the actual amount of
useable energy can be different. I assume you have a string of 20 cell
pairs meaning that you have a 2p20s arrangement. If this is the case
you add the Ah of the 2 parallel cells and get 65Ah. Next you add the
nominal voltage of the cells in series which gave you the 75V figure.
75V * 65Ah = 4,875 Wh = 4.875kWh.
As for using only 80% of the cell capacity, the reserve should be at
BOTH ends of the charge/discharge curve. I donāt recall what Nissan
uses for the top and bottom end but I would start with stopping when
the cells are 95% full on charge and consider empty when there is 15%
left at the bottom end. Also, if you can have a lower cutoff point for
when you donāt need the full capacity then I would only charge to 80%
for daily use. In fact, my Kia Soul EV cuts off at about 78% actual
battery capacity when the dash says 80%. The dash only shows available
capacity to the user not the actual battery capacity so the only way I
know of to charge the battery over 95% actual SOC (state of charge) is
to charge fully at the top of a hill and then regen down the hill.
It looks like your Gem system is calibrated to 78V target voltage.
What I would do is charge to that point and then just before the
charger shuts off adjust the voltage trim pot a little to raise the
voltage a little at a time. If you turn the pot and the charger stops
charging you probably turned the pot the wrong direction. If the
charger shuts off before you are finished just restart it and it
should cut back quickly so you can continue to adjust. If it is quiet
enough and your hearing good enough you can hear a high pitched whine
from the Zivan charger when it is charging. This whine will stop and
start several times at the end of charge. This is when you want to
adjust the voltage trim pot. Adjust a little at a time so you donāt go
too far.
HTH,
David
I think that I might mount the BMS on the top of the front battery pack with velcro or two sided tape. Iāve been monitoring the individual cells after every charge and now Iām checking them as I am discharging them. Iām pretty confident that the BMS wonāt need to be where I can keep an eye on it all the time.
Heading
Looks nice Man!!! Clean.whats BMS are you going to use.
Troy Hoggardās iPhone
I only have the temp sensors going to the pack closest to the dashboard; that is all the length
the Blue BMS24 wires have. I did extend all the BMS current/voltage sensors/leads though.
I used wiring looms, tape, cable ties, and heat shrink tubing to make sure none get frayed
on sharp edgesā¦
JUST WAITING FOR ELCON/ZIVAN SACRAMENTO TO REPROGRAM MY ZIVAN CHARGER!
I hear this is a common bottleneck.
Jeffrey
The biggest problem that I had with them is communication. They absolutely refused to let me talk to the tech. Questions could have been solved in minutes on the phone took a week worth of emails.
I tried to bribe them with a pizza lunch but they said the reprogrammer was out of town.
So, you are using only 11 Leaf modules?
The one from Dave āINWOā. I have it, just wasnāt sure where to put it. I mounted a digital volt meter in the dash to monitor overall voltage, so Iām thinking that the BMS can be under the hood. Itās only one quick release fastener to unclasp if I want to check on the BMS. Iām just loving the increased acceleration that Iām getting from the extra voltage and lost weight. It does ride a bit rougher now, though. I even put 5 flats of shotgun shells under the seat to add some of the weigh back.
Yes, 11 modules. It is currently working great, I am making a lot of short trips daily and charging every 3 or 4 days.
im not sure what my deal is but I think I have a controller issue! My range doesnāt seem to be as far as is should be with 20 modules in my 4 seater. Send a pic when you get the bms all in. Im going to start on mine soon.
troyocfa@gmail.com
Measure your amps and volts when fully charged.
Iām going to try that today with my neighbors meter.
Measuring amps without a load would be 0. Or are you talking about charging amps?
Runningā¦also check for drain
Hell I didnāt know what I was doing. Iāll just have to get the BMS installed and let that tell me the rest. I was just trying to see if I could check the amp draw so I would know what my motor was pulling. Oh well Iāll try when I get back home from work in three days. Thanks fellas!