decide to use an isolated DC/DC converter as a charger. This means,
we can take the power from the whole pack and put power into the
weakest cell. Our Siemens inverters give us 360 volt to 12 volt
and we choose a Vicor VI-200-EX to take the 12 volts to 4.2 volts.
Vicor set up is limited to 30 amps which is the current carrying
capacity limit of our relays as well.
Based on these friendly charts in the application
manual, figure 1, we expect that even at current limit, as
long as the cell is above 2 volts, the Vicor will give us our
This does not turn out to be true.
The Vicor dc/dc converter only gives us a few amps. Vicor tech
support says we need to design a current limiting circuit. They
send us an example, but it will require extensive modification
and testing which we do not have time for.
Luckily we have a plan B.