acc relay drain

Printed From: the12volt.com
Forum Name: Relays
Forum Discription: Relay Diagrams, SPDT Relays, SPST Relays, DPDT Relays, Latching Relays, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=112538
Printed Date: July 21, 2025 at 7:04 PM

Topic: acc relay drain

Posted By: Matrix7333
Subject: acc relay drain
Date Posted: March 21, 2009 at 11:53 AM

Hello all,

I had some serious battery drain (dead) after using this configuration to power additional adittional accesories wires that my RS/AL system did not provide.

3 relays, terminal 87 of first relay to acc 1, 87 of second to acc 2, 87 of third relay to acc 3. The rest of this info pertains to all 3 of the relays. Ground terminal 85 of all 3 relays. Acc output from your alarm to 86 of each relay. Constant 12 volts to 30 on each relay.

I have double check this several times and if I unplug the 12v constant my battery is ok, when connected, it dies within 8 hours.

can i use diodes instead of the relays to power the accesories? If so, what amp diode?

Thanks

Replies:

Posted By: howie ll
Date Posted: March 21, 2009 at 1:37 PM

You've set this up saying acc from your alarm. This is configured from a pos acc. What alarm has a pos acc? Secondly does this leave the relays latched whenever your alarm is armed? If so expect a flat battery every time, 3 relays = about 2.5 amps draw and that's just the coils, let alone what you are powering. what are you using the relays for?

Posted By: Matrix7333
Date Posted: March 21, 2009 at 2:46 PM

i have an autopage rs1000. it has only one accesory wire. I need to power three acessories during RS. This setup was given to me in another post.

I have change the setup since I posted.

I now have an ignition wire that was not used from the rs powering the third acc, I have the one acc wire powering my acc 1. I have an extra ignition output (-200ma) setup on a relay to power acc 2. it works but i have not checked the drain on my battery.

The Acc2 relay is wired like this

85 and 87 to fused constant (25ampfuse)

30 to acc2

86 to -200ma from AL

This setup eliminated two relays.

I was not aware that a relay at rest used that much power.

Posted By: howie ll
Date Posted: March 21, 2009 at 3:05 PM

You've set it up correctly as a note the neg side of the coil should be 85 but that doesn't matter, that relay is only drawing when ignition is on; at rest it won't draw anything so unless the relay is faulty that's not your problem. Its more a case of using a DMM set to 10 amps DC, keys out of car, remove neg battery terminal and connect red lead to loose terminal then black to battery post. Check drain, it shouldn't be more than 40-70 milliamps. If more start removing all your permanent fuses one by one till you find the cause (including alarm and added acc fuses.)

Posted By: Matrix7333
Date Posted: March 21, 2009 at 3:19 PM

Thanks