Try searching for "slip ring". A slip ring is a rotary coupling used to transfer electric current from a stationary unit to a rotating unit. Either the brushes or the rings are stationary and the other component rotates.
You can use a 12v charger IF you disconnect one of the batteries when charging and charge each battery separately. I have this setup on my bike and use a 12v charger.
Thanks Dan, it is not a grinding noise. I have heard the term "cogging" used before. You can feel a vibration as well as the noise. I live in the boondocks of Idaho and I there aren't any other electric bikes around for me to compare as far as motor noise is concerned. Maybe most motors make...
A friend just bought a Pedillac pedicab. It has a Yongkang 500w hub motor with 48 volt SLA batteries. I rode it the other day and was shocked at the noise the motor makes. I have a Crystalyte 408 that is very quiet. Is this noise normal for a Yongkang motor or does my friend have a problem.
My bike is a front wheel drive Crystalyte X-408F motor with 3 12V-35AH SLA batteries mounted on the trailer. Not much for speed, but I have hauled some very heavy loads.
I made this trailer entirely from dumpster materials including the tires, tubes and wheels. May not look like much, but it works great. It carries heavy loads plus 70# of SLA batteries.