The pack is floating related to the cars chassis ground, so as long as you only touch one pack lead, you would not get shocked.
If the pack got shorted to chassis ground in an accident, the diodes on both legs would stop current to chassis.
A single diode will prevent current from flowing out of the pack, and since current must flow to the other side of the pack, the diode blocks it.
The charger has more voltage than the pack, so it can run through the diode in the forward conduction direction and charge the pack, but a short or a person between the sides of the pack would be blocked by the diode.
The second diode just adds a second level of protection on the other lead.
The built in pack isolation is protector #1 ( no current from either lead to chassis, no protection if you get across the terminals)
The two diodes are protection # 2 and 3, (no current out of either lead for any reason.)
Last edited by Mike Dabrowski 2000; 06-18-2009 at 07:17 PM.
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