On 4/5/2013 12:53 PM, Ds2inc wrote:
Hi lee!
So would this, and pardon my ignorance there are still some tech
aspects of this I haven't been able to fully logic out for all the
variances, not be a good main for my system? Would it be an
acceptable secondary?
Ate you familiar with this product I can't find specs any where!
It is a Toyota part, probably custom built to their specs. Toyota
doesn't publish specs, and you are unlikely to find them anywhere else
unless the manufacturer also sells a similar version on the open market
customers.
I have one of these contactors as a spare part for our Prius. Judging
from its physical size, I doubt if it can carry more than 50 amps
continuous. It might be able to carry 100 amps for a minute or less, and
can probably switch a couple hundred amps *ONCE* on an emergency basis.
That would be adequate for accessory loads (heater, charger,
DC/DC converter, etc.) but not for the main controller.
Your main contactor (the one that cuts power to the motor controller) is
there for two reasons. First, because your controller still draws power
even when it is not running the motor. Without a main contactor, you'd
find your pack would run dead in a month or so just from the
controller's power.
Second, it's there for SAFETY. Motor controllers can fail *ON*. The car
can take off all by itself (unintended acceleration). So, you want a
contactor that can be turned off no matter what, to guarantee that the
car will stop. To do this, the contactor needs to be able to break the
worst-case peak current that the batteries can deliver. This can easily
be 500 to 1000 amps! A properly chosen contactor can do this safely. It
may arc like crazy and destroy its contacts in the process -- but it
WILL open!
--
The most dangerous enemy of a better solution is an existing one that
is just good enough. -- Eric S. Raymond
--
Lee A. Hart, http://www.sunrise-ev.com/LeesEVs.htm
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