by droopsnoot » Wed Apr 11, 2018 6:31 pm
As I read it - the current draw is basically the wattage of the bulb(s) divided by the voltage, so add up all the bulbs in the circuit and divide through. That assumes no (or little) resistance in the circuit, and this resistance (either by poor contacts, or even breaking down wires in the loom) is what is increasing the draw.
The downside of putting anything too high in place is that it might not give the same protection. If your original 25a breaker was only just enough for the job, moving to the 35a one hasn't fixed it, you've just masked the issue as I'm sure you know.
I well remember fitting some spotlamps in my main beam circuit on an old 1800SL I used to run. All was lovely until I got into this dark country lane and flicked the main beams on, which also brought my lovely spotlamps on. Shortly before the first sharp bend, total darkness for a second or so while I scrambled for the dip switch. That was "interesting".