Hey Wes,

Good catch on the Stancor's coil rating.
--
Mike "Rocket J Squirrel" Elliott
84 Westfalia: Mellow Yellow ("The Electrical Banana")
74 Utility Trailer. Ladybug Trailer, Inc., San Juan Capistrano
Bend, OR
KG6RCR

On 3/17/2009 4:10 PM pickle vanagon wrote:

> I know the stancor 120-901 relay is popular among listmembers for
> dual-battery setups, so I ordered one when I was preparing to do my big
> electrical project.
>
> I finally got around to looking at the detailed spec sheet, and see that the
> relay is rated for 12v of coil voltage, and is suited to take up to 10% more
> than that.  (The spec sheet is here:
> http://www.stancor.com/wrdstc/pdfs/Catalog_2006/Pg_052_53.pdf).   Of course,
> 10% more than that is just 13.2 volts, which is below what you'll see in
> your van when driving around.  In fact, at the bottom of the spec sheet,
> Stancor has printed the warning:
> "Note: Caution must be used in coil selection for use in 12 volt systems
> where battery charging may expose coil to continuous, higher-than-rated
> voltage. Stancor will not be responsible for consequences of misapplied
> solenoids."
>
> So, is this relay not such a good choice after all?
>
> On the other hand, it seems they have another relay (120-914) intended for
> automotive use and rated up to 15volts (its on the same spec sheet).  If I
> read the spec sheet, this will come online at 11.25 volts (75% of 15), which
> should be fine.  Maybe this is an acceptable choice?
>
> Thoughts?
> -Wes
>