Adding a battery in my boat

[haydenlake 0]

This is how my boat is wired as of now.

2 ga. from the alt (pos) and the neg. (don't know where it is grounded but most likely the engine somehwere). These are connected to the starting battery. Then I have additional 2ga cables running in series to the aftermarket stereo battery (a deka intimidator), off of this is where my 4 ga. amp wires run (pos and neg in the same fashion).

My question has to do with the grounding. I would guess that it would be better to ground my aftermarket battery directly to some big ass piece of metal (but alas only fiberglass around) and the same goes for my amps.

It seems that all the ground is running all the way back to the starting battery and then (somewhere I don't know where, whereever the factory grounds it).

Questions

-Is this wrong, if so help

-I read somewhere you have to have you're second battery grounded (somewhere near, vs wired to the first battery) or else it won't charge, is this true.

-Although it would be a pain in the ass I could try to run a ground from my aftermarket bat to a ground in the motor, (this goes for my amps too. Should I do this, if so will it make much differece.

Notes,

My old set up (1 original battery 5 years old) is being drawn on my an Audiobahn 1800d (supposedly 1800rms) and a very small kenwood amp. When the bass hits the volt meter really shows it, I don't know if it will still do that now bc my subs are at my friends house and I wanted to ask a few q's before I really taxed the electrical q

-The inital wiring (one battery and both amps was done my a reputable shop in town, they didn't ground the amps to anything but the battery; again I'm wondering if this is okay)

-as it is now the boat works perfectly (both batteries and I only hear my small kenwood bc my subs aren't in yet)

Thanks guys, you really help out.

B

[Shyne151 0]

I know in my friend boat that we are redoing(1982 Lund 16' i think) all the grounds are ran back to the battery then the battery is grounded to the motor. I don't think there is a single piece of metal in that thing... just fiberglass and wood.

*edit* you can just ground your battery to a big ass peice of metal, it has to be a complete circuit so if it was grounded to a a big piece of metal make sure you run wire from that piece of metal to the battery or motor... because if not you won't be running a complete circuit... atleast that's how it has always been explained to me.

[haydenlake 0]

I know in my friend boat that we are redoing(1982 Lund 16' i think) all the grounds are ran back to the battery then the battery is grounded to the motor.  I don't think there is a single piece of metal in that thing... just fiberglass and wood.

*edit* you can just ground your battery to a big ass peice of metal, it has to be a complete circuit so if it was grounded to a a big piece of metal make sure you run wire from that piece of metal to the battery or motor... because if not you won't be running a complete circuit...  atleast that's how it has always been explained to me.

<{POST_SNAPBACK}>

Thanks for the input!

Today I ran my boat for 30 min at 3400rpm's so the bats would charge a little, I don't know how long it takes to really charge em since they were fairly charged when I got them. So then I turned off the boat and ran the stereo for an hour and thrity min's and according to the volt meter on my sub amp (as well as my multi meter) the voltage only decreased from 12.7 to 12.6 in that amount of time. I figure this is pretty good since the volume was right below distorting on the subs as well as mains. (I could hear it inside my friends car two house's down! Sweet!

[Supa_c 1]

thats pretty good.