Justin,
Right, I need a high current DC contactor (not necessarily high voltage
but that may be the way they come).
I was planning to hook the relay to a normally-open thermostat (one that
will fail in the open state) rather than have it controlled by the
arduino. If the arduino fails, I want to be sure my contactor will still
shut off if something overheats.
Do you think I'm doing something unnecessary ?
Peri
------ Original Message ------
From: "Justin Kenny" <jkenn...@gmail.com>
To: "Peri Hartman" <pe...@kotatko.com>
Cc: "Electric Vehicle Discussion List" <ev@lists.evdl.org>
Sent: 19-Apr-20 8:08:10 PM
Subject: Re: Re[2]: [EVDL] custom battery
Well I assumed by disconnect you meant a manual one (e.g. big on/off
switch), which would still have to take all the power required through
it. That'd be the service disconnect I linked from EV West. The battery
management system would control the contactor, which also switches all
of the required power for your application, and that would handle over
temp, over voltage, under voltage, etc. fault conditions. None of those
*should* happen in a well designed system, so it shouldn't need to
hard-switch hundreds of amps, but it should be designed to be able to
without welding contacts shut or arcing etc., and that's why you need a
proper high voltage/high current DC contactor, and not just a big relay
that technically can handle hundreds of amps.
- Justin
On Sun, Apr 19, 2020 at 7:55 PM Peri Hartman <pe...@kotatko.com> wrote:
Why shouldn't I use a disconnect. Or am I using the wrong term:
something like a contactor that breaks the power connection if the
temp
rises too much. I'm figuring I'll need two: one for the load and one
for
the charger power. The latter should be easy: 120VAC, 15A.
With 6kW or more, if something goes wrong, there'll be a lot of heat
in
the wrong place.
Peri
------ Original Message ------
From: "jkenny23 via EV" <ev@lists.evdl.org>
To: ev@lists.evdl.org
Cc: "jkenny23" <jkenn...@gmail.com>
Sent: 19-Apr-20 6:16:39 PM
Subject: Re: [EVDL] custom battery
>Well you shouldn't need to use the disconnects; but yes, those
amperage
>levels are used commonly in EVs of course. EV West has pretty good
prices
>for stuff like this (service disconnect, rated for max current your
system
>would see):
>https://www.evwest.com/catalog/product_info.php?cPath=2_42&products_id=267&osCsid=na4hdbkd5u5i6u7ne1lltda641
>
>And here's an example of the contactor you'd need to control with the
BMS
>(quite cheap for this model, good deal actually):
>https://www.ebay.com/itm/293546196201
>
>--
>Sent from:
http://electric-vehicle-discussion-list.413529.n4.nabble.com/
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