Spare a thought for the poor equipment designer
Spare a thought for the poor old equipment designer. He wants to ensure you get best performance from your (his?) battery charger.
He needs to protect it against long term overloads as well as momentary events when somebody either overloads or shorts the output - or worse you connect your batteries or the charger's leads the wrong way round!
He knows that 10 amp fuses will carry 20 amps continuously (just), they need 50 amps to make them blow in 1 second and need 150 amps to blow in a tenth of a second. Add 50% to all above for 15 amp fuses. His electronic components need to withstand this.
What is he to do to save you from yourself?
He simply states the fuse rating which he has tested his charger to be capable of withstanding. If he had designed for, and so thought, a higher rating was correct he would have tested for this and suggested it.
On the other hand, you, as the customer, have perfect freedom to use any fuse you like and any gauge of wiring you like; but please don't grumble if it all turns to dust - or do I mean ashes?
Insurers take a hard view on such matters too, particularly when there are ashes.
Fuses are for when things go wrong. Your present fuses are fine until something does go wrong and then you will not have the necessary protection.
Fuses are cheap. No need for you to be cheap too.
Guess what I did for part of my working life?
Sorry for the little homily.
