Advise needed please from auto electrician

[Bigkev75]

Evening peeps so today I started fitting my heated seat pads to my st150 seats. I’ve taken my power from fuse box with a fuse splice I’ve used the electric window one which is 30amp rated fuse I need two feeds for the each heated seat is it ok to split that one power connection to feed both seats or will it draw too much current 
Current Draw: 3 Amps on Low Heat Setting and 5 Amps on High Setting per Seat

 

[Geoff1946]

Personally I would only use an ignition controlled circuit for the feed to ensure the heaters can't be left on without the engine running.

The window circuit MAY meet that criteria but I wouldn't be sure. You also don't know what load the window motors draw should they be operated simultaneously.

It's common to use the cigar lighter / auxiliary circuit for extras. I think that is commonly fused 20 amp which is fine for 2 X 5amp loads.

 

[Sidewinder]

Personally I would only use an ignition controlled circuit for the feed to ensure the heaters can't be left on without the engine running.

The window circuit MAY meet that criteria but I wouldn't be sure. You also don't know what load the window motors draw should they be operated simultaneously.

It's common to use the cigar lighter / auxiliary circuit for extras. I think that is commonly fused 20 amp which is fine for 2 X 5amp loads.

The “cigar lighter” is often live with the ignition off.

The issue with new vehicles is that they are engineered within inches of their lives!

It is often better to take a fused feed directly from the battery for the load, and switch via a relay using an ignition controlled feed, again fused.

With the fuses as close to the source as possible.

 

[Bruspark]

None of my last 3 cars had always on lighter plugs.   Something to do with people leaving chargers and things plugged in and draining the battery  etc 

and yes for anything heavy duty like that a direct connection is best -although some of todays smarter cars use a fuse-link there at the terminal to monitor battery amps in/out and if you connect right to the terminals this load won’t be seen