[alanfranz]

I suppose you’re a casual cyclist and you don’t commute on a daily basis.

If you commute on a daily basis, a hub dynamo and light system is a bliss. Just hop on the bike and go. I have used bikes with Shimano, SP and Son for thousands of kms in all kind of weather and never really experienced a fault. It’s as simple as car lights - you just take them for granted.

With battery powered lights you need to take them off and put them back; recharge them; remember to bring them with you and not lose them. A spare battery pack is not enough (front and rear) and may not work during cycling (not all lights can be charged while turned on). And, low quality battery powered lights tend to quickly break (2-3 years) while I now realize one of my b+m systems is 10y old already. Good battery powered lights will probably last more, but they’re as expensive as dynamo powered ones.

So yeah, battery is ok and cheap for casual cycling, but very suboptimal if you want reliable lights every day throughout the year.

[tomn]

You're comparing a hub dynamo with cheap low-capacity rechargeable lights.

Rechargeable lights from the usual suspects are generally not good, they are expensive for what they are, have low capacity, and don't have swappable standard-size batteries.

They make dynamo systems look like a good deal, but if typical battery-powered lights were even close to their theoretical optimum I think people would be much less enthusiastic about dynamos.

[alanfranz]

Good lights last more (I have a Blackburn lamp and it’s working) but it’s still less convenient than dynamo. You need to remove and remount it every time, with the risk of dropping or forgetting.

Ofc if you mount fixed battery-powered lights and you could just swap a usb c battery, maybe it would compete with dynamo. But an easy swappable battery would still ve easy to steal (unless it’s inside the frame with a lock or sth like that)