I hooked my hobbico 12V panel battery up lastnight for a overnight charge, as I was doing more work to my gear I started to notice that the battery itself was making odd sounds, like trickling water no more than a few min. since I hooked it up. So I discontinued the charging for the night. The battery is a lead-calcium battery and I was using a hanger 9 12V charger. My thought was it was a reaction to the current running through the battery since it was not charged. So if someone could explain to me what was going on and if it will be okay to continue charging.