Relay question

Author
Discussion

jakesmith

Original Poster:

9,463 posts

178 months

Monday 22nd October 2018
quotequote all
I have spent the day putting in 4 circuits for some very low draw accessories.
They are each individually fused and have their own ground to the chassis smile
I had connected them to a distribution block and was going to attach that to a piggy back blade in the main box BUT they are all live permanently - on other cars I have had some are switched fuses and those can be used for the accessories so the battery doesn't drain

What are my options?

Could I buy a 30A relay from Halfords (total draw is more like 5A but can't see any lower Amp relays) and connect that to a piggy back fuse holder & use the head unit's ACC cable to turn it on & off?

Dr Doofenshmirtz

15,705 posts

207 months

Tuesday 23rd October 2018
quotequote all
Yes

Spare tyre

10,360 posts

137 months

Tuesday 23rd October 2018
quotequote all
Electric window / heated seat fuse?

jakesmith

Original Poster:

9,463 posts

178 months

Tuesday 23rd October 2018
quotequote all
Spare tyre said:
Electric window / heated seat fuse?
On the r8 literally every fuse is live. Everything is live and a control signal on canbus turns them on or off.
So tapping into a fuse like heated seats wouldn’t work as it would stay live and run the battery down
I’ve fixed it today by running a relay off a piggy back, using that to run the 4 fused circuits (which individually return back to the chassis) and then using the radios acc feed as the relays on off switch
The acc feed for the car turns off about 30 seconds after turning the car off and comes on when I unlock the car so it seems to work well
Never used a relay before but seems all good smile