Well it's been some time what with one thing and another and then to top off all that my boat has decided to have another electrical problem. This is a serious one, enough to make me give up hope of ever floating her again

......
With charged batteries my system works fine for a minute or two and then either the reciever light turns red and nothing responds or it all goes dead except the ESC. Switching the main power off and back on (on the boat but not the radio) usually re sets it to normal for another minute or so. Switching the radio off just causes the receiver light to turn red and then back to green once its switched back on.
The chimney is raised and lowered through a servo slow and takes 3 to 4 seconds (looks great) except when the problem arises and it shoots up or down. I have 3 sail winch servos and when the problem starts they just turn slowly until they stop.
I have changed the ESC and tried a different reciever, same result
I assume it's not the transmitter as that can't cut the power
That leaves three winch servos, a rudder servo, a smoke machine, (on a separate 12v system but connected to the receiver via a brushed ESC with a wire cut) a sound machine on the same 12v system which the motor ESC runs through and the 12v gel battery (for the 12v system which powers the things just mentioned)
QUESTION? If the 12v battery was damaged in any way (not visibly) but still charged to 15 volts before the charger switches itself off could it be the problem?
I'm going to unplug everything and re plug one at a time and see if I can narrow it down but failing that it's going to be a very expensive dust collector............. U2