I've just noticed that you are connecting the input point of the coil to the negative of the batteries and the back-EMF spike goes to the positive of the battery. This means the battery is charged with postive and more positive, i.e. with a voltage difference just like having a negative and positive. This is like having a DC offset and charging a battery this way. It's insteresting why not using the negative of the battery where the potential difference is greater.
I remember that Joseph Newman said in his book that in order to make a battery last longer we should prevent the positive getting to the negative as much as we can (meaning little current, more voltage). Not sure if this has any relation to that, but it's the first time I've noticed the two positives going into the battery.
I guess the same happens with charging the capacitors and capacitor banks when used instead of a battery.
I remember that Joseph Newman said in his book that in order to make a battery last longer we should prevent the positive getting to the negative as much as we can (meaning little current, more voltage). Not sure if this has any relation to that, but it's the first time I've noticed the two positives going into the battery.
I guess the same happens with charging the capacitors and capacitor banks when used instead of a battery.