aux battery light flashing

[Richard palmer]

I have a weird problem, everything is fine while driving down the road, but when i stop with the engine running my aux battery light and breakers start flashing and clicking. When i turn my headlights on it stops. its seem like when my batteries are calling for a charge my volts are up and everything is good, when the volt meter hits 0 thats when the light and breakers go crazy! Also if i high idle it stops, has anyone ever ran into this problem?