Need Help With Battery Wiring.

[RWS]

Todd,

I only have three batteries on my 10 meter, port& starboard start and genny.

When I changed out my house charger a decade ago, I made sure it was capable of charging the three batteries independently, as the previously the genny battery was not being supplied by the charger.

now, each of the three factory batteries will be charged/maintained by the charger.

each engine battery is charged by the alternator on it's respective engine

the genny battery can be charged (toggle switch) by the magneto on the generator (very low rate of charge) or simply by the house charger when the genny is running.

I just wanted to make sure your house charger is set up to charge all those batteries.

Can't speak to the whole inverter thing, as we don't use one and simply choose to run the genny for the fridges and A/C, which is most of the time.

The diesel genset is quieter, safer and more economical than the factory MCCK was, and the AC is generally ON when we are out.

RWS

[Big D]

....check out this for a new solenoid
http://www.bluesea.com/products/categor ... -Solenoids

Todd, I was just reviewing a couple of things. Is this the solenoid you plan on using for the emergency start function?

[Big D]

.....
-i plan on using one of my existing alternators to charge the two engine batteries. im leaning towards an acr to isolate them.
-looking into a 130 to 150 amp high output, hot temp rated alternator hooked up to a multi stage voltage regulator to handle the house bank....

This is the way I like to do it. By doing it this way, you are not combining different battery types while charging. What you may want to consider, and is what I always recommend, is a back-up system should the alternator charging the crankers fail while you're out. Use a latching solenoid operated by a lit switch at the helm to keep the start and house banks paralleled until you get home. Under normal circumstaces this is a no no but acceptable in an emergency. In your case my only concern with this is the high output alternator and the amount of charge it would put out during a depleated large house bank that your barely depleated crankers would now be exposed to. This condition would only be temporary but of concern just the same. The other option is to run the generator while heading back and operate the charger to keep the engines running but there would be a conflict with the leg that feeds the house bank given that the high output alternator would also be trying to charge that one bank. In the presence of a charging conflict due to two charge sources, some chargers shut down. If this is the case with yours, and this form of back-up is the way you go, you may need to be able to switch off that alternator's output.

[yorklyn]

Harris, i always had my gen battery hooked up to the charger but from what ive read most people leave it isolated based on the fact that if its only used to start the gen then it should be replenished while the gen is running, however once again my plan is changing. my plan (for now at least for now!) is to have the 3 bank on board charger hooked up to
1-port starting battery
2-starboard starting battery
3- house bank
I spent the entire morning figuring out the size of my new battery box. I made cardboard cutouts for each size battery and played "tetris" to see what i could fit. i reduced the size of the box to allow for the engine bolts and settled on 4 6v t105 batteries and two group 27 (allowed 12-1/2 x 7-1/2 ) starting batteries. the 1st pic shows the layout (lost one of the 6v templates and substituted the one with the blue paint between the two larger starting batteries as a 6v).
I am planning my system without a dedicated gen battery . my thought is that if I have two separate , isolated group 27 starting batteries that are only used to start the engines. I can have a switch off the gen that can utilize either or both of those batteries as a starting battery.
Big D, at this point in my ever dwindling bank account, I am planing on using the original solenoid that trojan had for the emergency crossover. Its my understanding that my new mastervolt 3 bank charger will take in to account the "needs" of each bank and adjust the charge to each bank accordingly. The issue is how things are charged by the engine alternators. my understanding is the "standard" engine alternators are good for topping off the starting batteries after the small drain from the starters. however if a depleted house bank is put into the equation the alternator senses the low voltage from the house as increases voltage . this will over charge the starting battery . I was planning on using one engine to charge both starting batteries based on them both being depleted at about the same rate.
through my research I read that a house bank would accept / respond/ last longer from being charged by a higher amp alternator utilizing an external charge regulator .
im still trying to figure everything out so I'm open to suggestions?
on a positive note I got the inside of the battery box glassed!
(just looked at the preview and believe it or not the cardboard cut outs are actually two different sizes!)

[RWS]

Todd,

I also have a manual battery switch that allows me to tie the gen battery to the port battery.

This way if the gen battery is dead I can tie it to the port battery and get the genny started.

Likewise I can also turn that switch, hit the crossover and all three batteries are tied together to start one engine.

This came in handy ONCE.

If you leave the gen battery without a charging alternative, at least add a switch.

RWS

[Big D]

Consider what I said about adding a back up should the engine bank alternator fail while you're out.

[yorklyn]

Still working out the details. I feel comfortable with everything but the alternator charging. Like BigD said, if I have an engine charging the house bank and the starting battery, the starting battery will most likely get overcharged. I was thinking of switching one engine to a high amp alternator to charge only the house bank, unfortunately this creates other issues.

Another question, if my starting batteries are only used to start the engines and nothing else, will quality group 24 batteries be good enough to start the big blocks rather than larger group 27 batteries? I've seen a few with 1000 cca at 32 degrees? If group 24s will work I can fit 3 in addition to my house bank. If I do that I can use blue sea "add a battery" kit (bought one tonight) the kit contains an ACR and a 3 position battery switch (1, 2 or both) . With one for each engine I could have the house bank and 1 starting battery on one engine and the gen and 2nd starting on the other. If both starting batteries wired to position one on the switches and left on 1, only the starting batteries would be charged by the engines. I typically used the battery charge to charge the house bank and could run the gen to do that. In a pinch I could combine the batteries with the switch and charge both with the engines.
The on board charger would go to both individual starting and house battery. Wouldn't be an issue to leave that battery switch on "combined" and charge the gen and starting battery since neither should be deeply discharged.

????????????????????

[Big D]

24 series for crankers are fine in gas apps. 1000 cca is what you want to go with for gasers. I don't install anything less anymore.

On the subject of charging the generator battery with the house charger, always good to be able to do so if needed so I would build that feature in with a switch. The generator charges it's own and if you use it all the time, then you don't need external charging, however I find that a lot of people rarely use their generator enough, resulting in a slow death for the battery and generator.

[RWS]

in my setup the charger handles all three factory batteries independently.

the ONLY purpose of the switch is to tie the genny battery to a house battery IF NECESSARY.

In 14 years, that only happened once, but it was nice to be able to start the boat when otherwise I would have been calling BoatUS !

RWS

[ready123]

Still working out the details. I feel comfortable with everything but the alternator charging. Like BigD said, if I have an engine charging the house bank and the starting battery, the starting battery will most likely get overcharged. I was thinking of switching one engine to a high amp alternator to charge only the house bank, unfortunately this creates other issues.

Rather than an ACR why not go the way of a smart remote regulator with two legs that will charge the battery needing charging only? I think there is no need for a high amp alternator, a good 70Amp one should work just fine!
My concern here is are you designing the system to suit your actual usage? Have you considered your usage to suit the type of discharge vs recharge methods... i.e. if one in fact travels short trips with long stops (multiple days/nights) then the generator does most of the work of battery upkeep and $$ are best spent on the charging system rather than the Alternator.... if one tends to be underway more than stationary then....???

You know my stance is not to waste money, increasing potential failure points or system complexity by thinking about a backup charging option for the generator battery.... any generator used reasonably frequently should not need a backup system unless the battery needs replacing!
Of my two boats the only time I have had to remotely recharge my generator battery is after off season storage and once when the generator needed service and I ran it down trying to start the faulty generator.

This is how my boats are setup: Both generators have standalone batteries that are only charged by the generator. All batteries are sealed cell design so I do not have to worry about fluid upkeep.

Diesel President
One engine charges engine starting bank which starts both engines.
Second engine charges house bank.

Gas Trojan
One engine charges it's starting battery
Second engine charges it's starting battery and is switchable to house bank when underway.
Solenoid allows to pair both starting batteries in an emergency.

[yorklyn]

Thanks Michael. I really want to keep it as simple as I can.
Just got off the phone with the blue sea systems tech dept. Huge help. All batteries willl have mrbf terminal fuse blocks so there is no wire left unfused. Port engine will go to to a (1- 2- both) combiner type battery switch . Both of leads off the switch will go to a ACR, from there one will go to a starting battery and the other to the house bank, the acr will keep the house and starting isolated .. The other engine will go to another combiner type switch. From the switch one will go directly to the starting battery. The other lead will go to the other battery switch and attach to the terminal for that starting battery.
Basiclly the port engine will charge either the port starting battery only or both the starting and house when set to combine. The reason for this is so on short runs when there is insufficient time to charge the house bank. Charging can be postponed until shore power is available or the gen is run. The other engines switch will be left in the "1" position unless their is a emergeny start situation or one of my alternators dies. If that happens the switch can be turned to combine which would combine all three banks for emergency starting. It would also allow all 3 banks to be charged by on alt.