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.
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.