I have been experimenting with a two step charging system that would allow a full charge on an empty pack in 5-7 hours while still allowing a 350ma finishing charge.
Instead of using three 48V RS-25-48 supplies. I went with three RS -50-48 supplies. They have 1.1A output current VS the RS-25 .57A supplies.
I use two CC supplies in parallel,to supply a 1A charge the LPC-20-350 which supplies 350ma, and a second CC supply, the
LPC-35-700.
The second 700MA CC supply is powered via a latching relay on the AC input, that is latched on at the start of the charge.
Once the pack reaches an adjustable threshold voltage, the 700ma supply will be disconnected, allowing the 350ma supply to safely finish the charge.
It is looking like the threshold voltage should be in the 163V - 168V range.
The voltage while charging with a CC with the fan running, has a pretty reliable and linear relationship to the SOC, unlike the voltage while charging with the IMA, which has a widely variable voltage as we pump charge and pull assist from the pack.
I will build up a prototype when I get the supplies next week.
The same system will work on a Prius pack, with an additional fixed supply added to the series to bump up the base voltage.
The relay/threshold circuit and larger and additional power supplies should only add about $40 to the system.
Last edited by Mike Dabrowski 2000; 12-12-2009 at 08:44 PM.
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