Hey All. Just to kick on this discussion, I'm new to boating with a electric start motors and what not. My boat currently has a dual battery setup, 1 starter, 1 deep cycle. My understanding is turn on using switch 1 (the starter battery), and leave on switch 1 while boating around. When stopped and engine off, change over to battery 2 for gadgets (fish finder / VHF / lights). That's all good and well. I've learnt about not switching while motor is runnings, even if switch allows, just to form a good habit of not cooking the alternator.
My question is, if you shouldn't be starting the motor on battery 2 as it's a deep cycle, and you shouldn't be switching after engine is on, then how do you charge up battery 2? My understanding of the position 1+2 on the switch was for emergency situations where battery 1 is lacking charge and you need to jump start battery 1 with battery 2 effectively.
Also, somewhat related, I need to replace the deep cycle battery as it's beyond dead (couldn't even power on the battery tester!) ... anyone have any experience with the Kings 115AH battery? On their site says can be used for boats too.
I know some people use the CCA + Semi Cycle batteries as their second, but I have some pretty strong front and rear spots for night fishing, so imagine they can draw a decent amount coupled with the sounder, cabin light, etc. Hence wanting to keep to deep cycle for the second.
(I know there are relays and what not that can be used to automate this, but let's ignore those for this question to help better my understanding).
Thanks
Itai