Spikes and low voltage with ST60002

[macbeth]

I'm just about to install a Autopilot which has a ST 60002 display/control head.

A friend of mine has just blown his ST 45 through causing a spike as he switched through from one battery to the other. Apparently ST's are susceptible to spikes and low voltages.

Do I have to worry about either of these situations ?

I have a Smart Controller which doesn't allow the alternator to charge for 2 minutes after starting, and a combiner joining the two batteries which doesn't start to charge the 2nd battery until after 2 minutes of the first. i.e. it can be four minutes before the second battery starts receiving a charge.

The house circuit is connected to the starter connection, which in turn is supplied by the cable that comes from the battery switch "common" connection. (which can be switched to either house or starting battery).

I have a deep cycle for the house battery, and a starting/deep cycle combination for starting. My friend just has two starting batteries (he's a bit of a cheapskate :>) !