An alternator is very different to a Dc-Dc converter in this respect. Modern high frequency DC-DC conv. Have very small inductors storing very little energy. An Alternator has a HUGE inductor storing a lot of energy, and this is not on the output but in the control side! So has much more effect! You won't get much overshoot from the DC-Dc converter.
-----Original Message----- From: EV On Behalf Of Lee Hart via EV Sent: Wednesday, 21 April 2021 5:32 pm To: Robert Bruninga via EV <ev@lists.evdl.org> Cc: Lee Hart <leeah...@earthlink.net> Subject: Re: [EVDL] From my nissan leaf .com: Why the Leaf 12v system undercharges the 12v battery. Robert Bruninga via EV wrote: > what is the "load dump" problem? In automotive parlance, the dreaded "load dump" occurs when the alternator (or DC/DC) is charging at a high rate, and something causes a sudden drop in load current. It could be a loose or corroded battery cable, or a cracked or intermittent connection inside the battery, or a momentary short somewhere in the wiring (like hooking up jumper cables backwards) that pushes the alternator (or DC/DC) to its maximum output... and then suddenly that load goes away. The voltage then skyrockets to 30v, 50v, even 100v or more; until *something* absorbs the current (Bang!), or the alternator or DC/DC detects the loss of load, and backs off. Here's an example that happened to a friend of mine. The car was running, and he reached up under the dash wearing his wrist watch with a metal band. It shorted +12v to GND. The voltage sagged, and the alternator went to full power. The wristwatch band melted off his wrist (YOW!) Now the load was suddenly removed. And then... every light in the car that was on flashed and burned out. It also blew a number of uses, but luckily the electronics were either well enough protected, or off at the time. Lee ARCHIVE: http://www.evdl.org/archive/ LIST INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org _______________________________________________ Address messages to ev@lists.evdl.org No other addresses in TO and CC fields UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub ARCHIVE: http://www.evdl.org/archive/ LIST INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org
