CHARGING.
The first charge is the time when you get to know your cells and how they behave, unless you use a BMS (battery management system) I don't.
After bottom balancing all 73 cells to 2.7 volts per cell, I charged as a whole pack in series using my Zivan 3kw charger, monitoring all the cells with a digital volt meter. All the cells aventually got to around 3. 4 volts each pretty evenly, but then I started to notice around 6 cells climbing in voltage ahead of the rest. So I now watched these closely untill the first cell hit 3.5 volts, at this point I made a note of the pack voltage 249.5 volts, This will be my charge cut off point also the amp hours put into the pack read 126.4, I was told that these 100ah cells were new spec with extra capacity and the numbers prove it.
Now with the cells bottom ballanced and a known pack voltage when the weakest cell hits 3.5 volts when charging I have my first lines of defence to stop me killing the battery pack prematurely.
I will have the charger reprogramed to end charge at 249.5 volts, also my JLD404 meter is wired to the charger enable control and can terminate charge at a given amp hour or voltage of my choice, on top of that I've put a secondary programmable volt meter inline with the charger which can also turn the charger off at a pre-set voltage.
Hopefully with the charger shutting off automatically at the correct end voltage, with 2 secondary back up meters turning the charger off in the event of the charger malfunctioning I should be safe from over charging the battery pack.
On discharging the pack when driving, the Soliton controller can be programmed for minimum pack voltage with no load and also minimum pack voltage under load so this gives me warning of the pack getting low. Also and probably the best way of monitoring the state of charge or range in miles left is the ability to count amp hours in and out of the pack, pretty much like a fuel gauge. theJLD404 meter does this job nicely.
So, my safe usable capacity is 80% of the 126.4 AH that went into the cells that's 99AH.
DRIVING WITH LITHIUM.
wow!
The Sinopoly cells have transformed the car, I've gone from 5 miles range with the lead batteries to anywhere between 60 and 80 miles depending on type of driving.
the performance is better than I hoped for, still being careful gaining confidence in the batteries but when you put your foot down it's well? NUTS!
The cells are behaving perfectly, I've charged about 5 times now and the same cells I'm still running around with the volt meter checking individual cells, also I've monitored individual cells under load and when the pack is close to my safe empty state the sag under load is only 3volts per cell
