Hi Fred and All,              I measured them with a known good meter at 
3.53v/cell so use that to calibrate yours.  I don't charge them up so safer to 
ship.I parallel the 2 48vdc nom sections in a 4 kwh module and charge them with 
a MPJA  sold   hf240w-sf-48.    Once you get it, adjust it to 49.2vdc  and you 
are good.  Don't charge over 49.2vdc.  I too am looking for more powerful and 
reasonably priced solutions that can handle lithium in 48, 96, 120 and 144vdc 
packs.I think your 3vdc/cell is too low and I'm using 3.2vdc/cell for now.Would 
like to hear others on what voltages the 2013 Volt uses or what they are 
using.?And what inverters at a reasonable price one can use to run off the 
48vdc EV pack to give V2H?Thanks,        Jerry Dycus

      From: fred via EV <ev@lists.evdl.org>
 To: via EV <ev@lists.evdl.org> 
Cc: fred <fred_do...@yahoo.com>
 Sent: Tuesday, January 30, 2018 6:15 PM
 Subject: [EVDL] Leaf module charging recommendations
   
Thanks to Jerry Dycus for selling me a great looking clean Volt battery module. 
My still-working Radio Shack (top of the line) digital multimeter tells me all 
the cells are within 0.01 at 3.56 or 3.57 volts.
I've found this useful bit of data:
Number of cells        36
Construction            12 in-series x 3 in parallel
Length                      9.5"
Width                        9.5"
Height                      10.5
Weight                     45 lbs
Output terminal        M6 nut
Amp Hour                47
Total Voltage           48vdc

 

CELL SPECIFICATIONS
Cell type                        Laminate type
Cathode material           LiMn2O4 with LiNiO2
Anode material              Graphite
Rated capacity (0.3C)   17 Ah
Average voltage            3.8 VDC
Maximum Voltage         4.2VDC
Minimum Voltage          3.0VDC
I measured 42.5vdc across each 12 cell block and the math says it should be 
42.72vdc, which is close enough for my meter. It's not 48vdc and from an 
earlier discussion I expected that to be the case.
When it comes to charging this battery, I would like to ensure to get the right 
stuff. My experience with other lithium based batteries is that the nominal 
voltage of the charger is referenced to the battery and in all cases, the 
battery voltage is higher than the nominal voltage "listed." That is to say, a 
36v battery charges to 42vdc and rarely drops to the 36v reference figure in 
regular use. The charger, of course, pushes electrons into the battery at those 
higher levels.
In the case of the Volt battery, I believe I would not want to use an 
off-the-shelf charger rated for a 48v battery. My search results have all been 
ending in devices with excessive top-end termination.

I would like to have an off-the-shelf solution, however, if such a charger 
exists. My current collection of chargers are plug-in and go type, in that they 
have appropriate profiles for charging to a specific level and tapering off as 
appropriate for the pack.
As an additional consideration, this battery does not need to be charged in an 
hour or even two or three. I'm amenable to a configuration that requires a ten 
hour or longer charge period, especially if cost is lower.
I welcome corrections to my train of thought, even to the point of derailment 
as appropriate. I'm hoping for an off-the-shelf solution that works 
out-of-the-box or works with appropriate adjustments on the panel or equivalent.

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