Hooking it up without the lamps got me great support in the first few miles this morning - I saw the battery rise to full and at a constant speed it maintained EV support - a constant rush of electricity keeping the gas use level low (not zero, but definitely low).
At a T junction it threw an IMA code so I switched the lamps back in series. Again, they did hardly glow at all.
At work the lamps were slightly warmer than ambient. I could not see them glow anymore. FE was quite good for a morning commute - especially this cold and foggy. But foggy means no wind - and that helps.
Going home I hooked the batteries up straight again, without the lamp shunt.
On the highway, no problem whatever, but neither did it yield good FE. Nearly home in the residential area it threw another IMA code. Ah well. Reset and do the last mile.
The battery tested at 115.5 Volt. Hm, seems it did not drop much.
I compared the 3 packs and one was 0.4 Volts lower than the others.
I opened the battery box and found one cell that dropped below 3 Volt while the rest was hovering around 3.15 Volt.
One bad cell then, or what?
Time to hook up the chargers.
The bad cell quickly came back in line with the other cells. The pack was soon indistinguishable from the other two, based on overall voltage. On all 3 pack it quickly built up to over 40 volts on charge (3 Ampere).
And it stayed there.
3½ hours into the 3 Ampere charge it's getting late and I quit the charging. Still at 41.0 Volt while the cutoff is 42.6 Volt!
It is clear that I pulled the pack to almost 0% SOC. As I must have put over 10 Ah into this 12 Ah pack and it still does not show signs of nearing a complete fill. I want to monitor that last phase, to see whether the BMS does balance the cells again or not.
While the batteries are charging I could upgrade the cases they are in.
Simple plastic page binder strips cut to length now serve as BMS wire organizers.
Black 3M duct tape, one edge folded over to form a non-stick lip, make sure even the last bits of exposed case metal are insulated - though anything bearing current was isolated on its own anyway.
While and after doing so I hook up the volt meter to the subpack I work on just to make sure all is well.
On the last subpack the voltage suddenly dropped from 40.6 Volt to 30 something.
Argh! Is it a short? And where? I should see smoke or find something getting really hot now... but everything seems just normal.
I unplug the charger and the voltage jumps back up to 39.8 Volt!
What the?
OK, the light on the charger had turned green, indicating the charge is done.
Except I'm pretty sure it wasn't yet. But what then causes this?
I examine the batteries up close and pull up the BMS circuit from the box.
The BMS wire connector is loose!
So the BMS shut off the pack, and the charger shut off itself because the voltage outside the BMS soared to its cutoff limit. Then the charger puts out a feed voltage of just 30 Volt while maintaining its green light indicating a full charge.
The BMS connector goes back in and all its well. Hooked up the charger and it goes again.
I need to finish the charge tomorrow. It is a full charge, that I know now.
The Prius was nice. Just a Comfort - but it has Climate control, HUD and a lot of other stuff. All in all quite a bargain.