M1225 Ignition turn-on, relay vs. sense pin

ltec123 · Post by **ltec123** » Mon Jul 01, 2002 7:58 pm

Hi guys,

On a M1225, or any mobile, is it OK to use a relay to switch power on ignition or use the ignition sense. Does it make a difference?

Thanks,

LT

jim · Post by **jim** » Mon Jul 01, 2002 8:09 pm

I've done it many times with a relay to main junction block and the relay triggered with ignition. It works just fine.

Don't do it with a CDM series, however!

Post by **HumHead** » Mon Jul 01, 2002 8:37 pm

When powering up the M1225 with a relay rather than ignition sense, the radio (in my experience) will occassionally "forget" its last setting and power up on the first mode with scan off, etc.

Not a problem, just a nuisence. I finally switched to ignition sense.

Will · Post by **Will** » Mon Jul 01, 2002 9:27 pm

The Maxtrac/Radius/GM and M1225 loose the settings of the channel it was last on if the main battery is disconected from the radio for a lenth of time, there is a very small tickle current that keeps the last chann, ect; in a small memory.
So if you must use a relay, that is the only drawback. Using the Ign sense line allows the radio to retain settings. Always try to obtain the IGN sense from a stable source or use a filter on the line as noise can sneek into the radio.

jim · Post by **jim** » Tue Jul 02, 2002 1:36 pm

On the MAX and GMs, you can change a capacitor to a small 3V lithium battery to avoid this. This also works on a vehicle with a master battery shutoff switch that remains off for several days.

Will · Post by **Will** » Wed Jul 03, 2002 12:54 am

Yes that is a good idea. What I do not like is the radio allways sets the Monitor to disabled weather you had it on or off at turnoff. The Maratrac always comes back on the same as it was when shutoff.