I have a Honda Accord 2003 which has a 7.5A fuse going to the accessory power sockets.

I want to run something which would need an 8A fuse, but I recognize I can't simply swap it out. Could I otherwise limit the power my device would use? It's a manual slow cooker, so there are no sensitive electronics.


So, just run a fused supply from a suitable point for that device.

  • Do I need to worry that my alternator won't be able to charge the battery fast enough? – wizlog Jun 20 '18 at 0:42
  • As long as the alternator is charging properly it will be fine, but don’t discharge the battery too much when the engine is not running. – Solar Mike Jun 20 '18 at 4:05

You can't really easily limit current draw from the car, but the cooker may draw less current when the environment is relatively warm.(room temperature) The rated current may be true for a lower temperature, and actual current draw may differ in reality, ie. it can be lower. You can try to run it with the 7.5A fuse and see if it doesn't blow. Simple to try and the worst thing you can do is blow a fuse, which is easily replaceable.

You found a 7.5A fuse in the fusebox, but maybe it's put there by a previous owner when that was the only fuse he had lying around. In other words, chances are the original fuse could be rater higher. Lots of cars use 15A fuses in that place. If you car also originally does so, it's an easy fix to put in a bigger fuse.

Otherwise, you need to connect a separate wire from the outlet to the fusebox and connect it to a main 12V wire. You can either use one that always gets power from the battery, or only when the key is in 1st or 2nd position.

  • Do I need to worry that my alternator won't be able to charge the battery fast enough? – wizlog Jun 20 '18 at 0:42
  • @wizlog Nope it can easily put out 100W while idling, or the idling of the engine will be highered a bit to cope. – Bart Jun 21 '18 at 11:03
  • thank you! what if I wanted to do this same idea but for 240W? – wizlog Jun 21 '18 at 15:08
  • @wizlog Then it'd be smart to just lay a sufficiently thick and fused wire from the fuse box to the connector. Then you can be sure everything is safe. The alternator will probably deal with it just fine, but maybe a small car will have a bit trouble delivering enough power. There's one way to get to know that. – Bart Jun 22 '18 at 15:33
  • That's what I plan on doing :). Do you know how I could tell if my alternator is working too hard? – wizlog Jun 22 '18 at 15:49

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