" As far as the dual battery i
" As far as the dual battery installation. There's a few ways to go, that would make sense for this type of installation. One thing to note with switches, the engine allways needs to be on a circuit when running, else you will toast things in the engines charging circuit. Playing with 4 position switches while the engine is running is bad news - some switches are made for it, some aren't - best not to at all. Also, there's a phenonmenon called "competing", where if two batteries are wired together, they will trickle power back and forth, charging and discharing into another; this can kill batteries even if they are not being used.
1. 4 position switch (off bat1 bat2 bothe): The cheapest and most flexible way to go; to wire it up, get yourself some power posts, run a lead from the negative of each battery to the post, and then run that directly to your engine/electrical system etc.. Run a positive lead from each battery to the switch and then take the output from the switch and slap that on another power post - that's your positive lead to the engine/electrical system etc. . Very clean and simple way to do it. The downside to this system is that it gives you the ability to accidentally kill bothe batteries at once, for two reasons. For one, if you charge on bothe batteries and then forget to take it off bothe, you could kill bothe; secondly, if the switch is on "bothe" and one battery goes sour or is charged less than the other, the batteries will charge and discharge into each other - this can kill bothe batteries when you aren't even using them.
2. two 2 position switches (off on): A little more complicated, but a little more dummy proof, as flexible as a 4 position switch deal. Bothe negatives go to a power post; each batteries postive to one input on one switch; each output of switches into another power post. Pretty simple and clean - the benifit is that it prevents you from accidentally putting a switch on "bothe" and that you can turn an extra battery on while running the engine. It still allows you to let the batteries compete.
3. battery isolator: The batteries can be wired together with the isolater to act as one; the isolater prevents batteries from charging and discharging into one another. The downside is it will let you kill bothe batteries; solution to that is two 2 position switches could be added to the system so that when bothe batteries are on, they bothe charge/discharge and when one is off, you can only kill one etc..
On my boat, I have enough electronics (inverter is the big pig) to draw an excess of 100 amps. My engine only charges with 20, so even with the engine running, I could kill bothe batteries quick. I have two 4 postion switches and two batteries. There are two totally isolated (common ground, but individual positive) circuits, one for accesory and one for engine. I only use one battery at a time and leave one either charging or if it has good charge, totally unused; this way I allways have at least one good battery. That's pretty much the benifit of having two batteries, in my opinion, that you can save one incase you accidentally kill the other.
As far as charging, it's not going to damage the outboard and there really isn't anything, aside from possibly upgrading the charging system(if possible) that will make it charge any better. That engine probably charges with between 10-20 amps.. I think some "commercial" OMC's charge at 35 amps - but that's top. In addition, I highly recommend using Anchor Marine Grade (or equivlant) 2 guage tinned copper wire and terminators; the heavy wire gets the power there more efficiently and the tinned copper will give you a solid connection for years.
Jon "
