Question: 3 batt banks, 3 Isolators, twin outboards, 3switches Question - The Hull Truth

TG_190 · 04-02-2005, 12:12 PM

A repost cause I forgot to add a meaningful Subject.

Does anybody have a schematic or know where I can see one, of a twin engine, 3 battery bank wiring employing isolators and a 4 position (1,2,All, Off)*switch per bank?

The Typical setting: If the 3 switches are all in the "1" position, then the port bank feeds the port engine's starter, the starboard bank feeds the starboard engine's starter, and the house bank feeds the Ship's service/house.

I am making the schematic for my wiring and I have twin 200 HPDIs w/ 1 bank and 4 position Perko switch (1,2,both,off) per engine (2 switches and 2 batteries), and*the 3rd*bank for House w/ its own 4 position switch. The House bank charges off of a separate leg of the port engine's* alternator, and all three banks have isolators.

I wanted to see some typical installations before I broke out the DMM and traced stuff to make a truth table of all the combinations of battery positions vs. alternator connectivity, and what gets fed by what bank.

Thanks,

TG_190

SIM · 04-02-2005, 02:31 PM

TG,

Are you planning on using your Yamaha HPDI engines auxilary isolated charge leads? If not......I think you should consider this route and eliminate some of your parts....just a suggestion

Maybe a dedicated engine battery for each engine, and a house battery for all of the boats 12v loads. Then the main Yamaha battery cable goes to its own battery and the aux charge leads on both engines goes to the house battery. No matter which engine is charging, its battery and the house battery are being charged.

Here is a rough drawing of a GB we just upgraded...

Andy

Somethin-Fishey · 04-02-2005, 02:53 PM

Because you have HPDI's, you have a better option. You have built in regulators that Yamaha included free.

Wire the first 2 switches like you have said. port batt, port motr, wired to #1, stbd batt stbd motor wired to #1 and Xconn the #2 sides of the switch. Now your house battery can run to a ON/OFF switch and you attach both the aux charge leads from each engine to the house battery. Wire all (-) connections together. Now place all aux loads on the ON/OFF switch and you're done. Been runing like that for over a year with NO problems and I always have good charged batteries.

Birdman · 04-02-2005, 02:58 PM

You only need one battery isolator, do you mean each bank is connected to the isolator?

Anywho, I'd lose the 4 postiion switch which does nothing but cause confusion.* Install on/off switches and it will be much easier to use:

SIM · 04-02-2005, 05:40 PM

Birdman,

Your schematic may work for a regular inboard powered engine, but why would you want to install an isolator on a HPDI engine that already has 2 isolated charge outputs built into it? One via the main battery cable and the other via the aux*charge*lead? Not trying to be a smart a$$...........

BTW.....my*killer 4hp Yammi 4-stroke that I have listed.....did I forget to mention the other day that it has a 50 amp alternator on it?

Safe for your AGMS as well!!

Andy*

Birdman · 04-02-2005, 06:08 PM

Wow, does that 4hp really have a 50amper on it?

As for the isolators, the built in Yami isolators are useless.* If you connect the secondary charging circuits (as mine is), the charge is not*sent down the main starter cables (as most people think).* So what happens is ALL the charging current always goes down the secondaries into the real battery isolator, which is connected to all battery banks.* So the worst battery bank gets the most charge and everything is always kept trickled...

TG_190 · 04-02-2005, 06:20 PM

Sim, Birdman, Somethin Fishy,Thanks for the help. I am going to take a picture of my power distribution and charging* panel.It has three 3-terminal devices that are labeled as "isolators". The port and starboard batts are cross connected, but I am a little unsure of how the house batt switch leaves me when in the 2 or Both position. I think that only the port engine's Aux altenator output is connected to the house batt as well. So 3 swithes w/ 4 positions each, yields 64 possible combinations (most of which are not*useful and *Off is*one*of the switch positions).Thanks again,TG_190

Somethin-Fishey · 04-02-2005, 10:37 PM

Quote:

Birdman - 4/2/2005 6:08 PM

Wow, does that 4hp really have a 50amper on it?

As for the isolators, the built in Yami isolators are useless.* If you connect the secondary charging circuits (as mine is), the charge is not*sent down the main starter cables (as most people think).* So what happens is ALL the charging current always goes down the secondaries into the real battery isolator, which is connected to all battery banks.* So the worst battery bank gets the most charge and everything is always kept trickled...

HUH? I really don't understand what you are saying.

If I start my motors, the house battery gets very little charging done to it until the starting batteries are recharged. Then the full aux power goes to my house battery. I have run my house down pretty far and my icom will flash low battery. When I started the motors it was a few minutes before the full charge kicked in and turned the message off.