Tidal Fish Forum banner
1 - 5 of 5 Posts

·
Registered
Joined
·
187 Posts
Discussion Starter · #1 ·
Here is my thoughts, however I need some advice on the best electric design.

I have twin engines, two starting batteries, one battery switch, one dual bank battery charger. Currently I believe the wiring that provides power to by consule/electronics is incorrecly wired, because when I start my engine, a power surge is sent to the electronics that is realized through my audio radio.

I would like to replace the oldest starting battery with a deep cycle battery that will also serve as my house battery.

What is the best way to achieve the above so that in a pinch I can use the deep cycle to start both engines if needed as well as properly protect my electronics and ensure one battery does not drain the other???

Thanks.
 

·
Registered
Joined
·
919 Posts
I sort of disagree. I think the simplest, best way to wire two batteries (in a single-engine boat) is to have a dedicated ENGINE battery and a dedicated HOUSE battery with a charge relay (ACR, like the Blue Sea type), and a separate on-off switch for each battery. ALSO, use AGM-type batteries only (like Odyssey, Deka, Optima, etc). It is well worth the money.

The dedicated ENGINE battery is just for starting the engine, AS WELL AS the throttle/control system (if digital) and the power steering pump.

The dedicated HOUSE battery powers EVERYTHING** else. (**It's a toss-up on which battery it is best to wire you bilge pump to).

If your engine battery ever dies at sea, you could jump it with the other battery or, if desperate, you could physically switch the batteries around (you'd obviously lose your non-vital, house electronics.)

I would never use a "combine" switch where you have two batteries being drawn from by everything at the same time. You could actually be riding around with one dead battery and one good battery for a long time but you (and your charging system) will never know it.....until the good battery dies too.

This has been posted on extensively on another website I belong to (it's a forum for Verados), and there are schematics, photos, and explanations. I learned the hard way - 50 miles offshore - why this is important. It turned out one battery was already dead and the other one died because it wasn't charging (it got a little wet and fried a diode on the alternator). I just barely made it home with minimal electronics. I changed my setup to the Engine/House setup using an ACR (with $$$ AGM Odyssey batteries) and I haven't had an issue in two years of going offshore since then. I did the whole re-wiring thing myself and THEN I went and had an electrician check over it.

Go to your local West Marine and just look at, for example, the Blue Sea battery switch - ACR combo pack. The packaging actually has a simple schematic on the front (superimposed on the switch and ACR) showing how they're wired together. It really does make sense NOT to have everything drawing from both batteries at the same time.
 

·
Registered
Joined
·
2,236 Posts
i have mine rigged up simply through a perko battery switch. when i run offshore, i run the switch in "both" position for the long run. that gives both batteries a charge on the hour-2hour ride out. i shut off off the boat (YOU MUST DO THIS, NEVER SWITCH IT WHILE THE MOTOR IS RUNNING!) then go to battery 1. i run off it, an i have another ready to go if needed. i do not have an extensive electronic draw on my boat. FF and GPS, and occationally a washdown pump when we bloody the boat thats it.

make sure you buy big cables for running the wires, and buy large capacity, quality battery. sometimes i bring a 3rd battery just in case..... oh yeah, replace them every 3-4 years. im due now.
 
1 - 5 of 5 Posts
Top