Battery Configuration-gctid356581

[Guest]

My 3218 has 2 accessory, 2 starting and 1 genset battery. I have three master battery switches. My Port engine starts from the accessory batteries and the starboard engine starts from the engine batteries. With the accessory switch off neither engine will start. However with the accessory switch on and the engine switch off, the port engine starts and the starboard does not. Why aren't both engines controlled by the same switch? When on 110, will the batteries charge with the switches off? Thanks for your help. JJ

[mmichellich]

.
..........

[Uncle_Bob]

The factory had the port engine charge the group 27 starting battery that started both engines. The stbd engine charged the house battery which was also a group 27 from the factory. The stbd voltmeter on the two helms were always active if the house battery switch was on even with the key off. If yours is different it is an after market change someone made.

[2850Bounty]

Sounds to me that you have more batteries dedicated to cranking than need be. You should be able to crank each main engine on a shared cranking bank.

This would leave space to increase your HLBB capacity. IOW, freeing up battery space that would better serve you if this space was dedicated to your HLBB.

(your generator can maintain it's dedicated cranking battery of which are usually much smaller in size)

I can only speak for a few of us, but several of us crank our Stbd engine on our large HLBB, and with no issues.

You can use one of the Blueseas ACR units if you have other concerns, such as auto-combining during cranking, and this can be used to take advantage of twin alternators.

Perhaps draw up your existing configuration in schematic form, and post it here.

Uncle Bob wrote:
The factory had the port engine charge the group 27 starting battery that started both engines. 1... The stbd engine charged the house battery which was also a group 27 from the factory.

2.... The stbd voltmeter on the two helms were always active if the house battery switch was on even with the key off. If yours is different it is an after market change someone made.

1... a single 12 volt battery! Sheesh!

2... This came up recently in another thread.

A helm located volt meter is not the best means of monitoring a HLBB via voltage alone.

The Xantrex LINK-lite is now under $200, and sometimes even less.

I realize that no one asked.... just a suggestion!

[SomeSailor]

I have an 8D start battery for the mains, 8 T105's in the house bank + 2 T105's on the inverter and a single Group 27 to start the genset. I don't understand the logic of the two 105's on the inverter, but I think since I have an AC fridge it keeps that cold while cruising, while not affecting the house or starts. Lots of batts... and they all need to be replaced.

[boatworkfl]

It does not matter which bank you have for the volt meter, if somewhere the 2 circuits connect further down the line. I should not need to elaborate on this, think about it? Unless the disconnected bank is totally isolated, including by the charging system.

Someone will chime in on this.

[Uncle_Bob]

The stbd volt meter is wired to the stbd battery switch and fused near the switch. That circuit, the house circuit, is isolated from the port starting battery. The factory house system is too light so most 32's were retrofitted with more house batteries. SomeSailor's configuration of house and separate inverter batteries is a strange one as he mentioned. Usually the inverter is the house and properly wired the inverter charges the house batteries but only energizes 110V on selected circuits...not the hot water tank for example.

[2850Bounty]

Destiny wrote:
My 3218 has 2 accessory, 2 starting and 1 genset battery. I have three master battery switches. My Port engine starts from the accessory batteries and the starboard engine starts from the engine batteries. With the accessory switch off neither engine will start. However with the accessory switch on and the engine switch off, the port engine starts and the starboard does not.

1.... Why arenÔÇÖt both engines controlled by the same switch?

2.... When on 110, will the batteries charge with the switches off?

JJ, I just re-read your questions. I can't explain why B/L or a dealer cables these as they do. Perhaps they're not looking past their nose, or perhaps it's become a factory standard.... who knows?

There are many ways to skin the cat, however, some furrier dealers will prefer one skinning method over another!

1... IMO, they could be if the two engines shared a Cranking Bank.

However, there's nothing wrong with each having their own MBSS or BS and cranking battery.

Either or allows for complete shut down of 12 vdc.

But when/if configured correctly, two MBSS's or BS's can also allow for combining.... whether manual or automatic.

With all of the combining aparatus these days (ACR's or VSR's), I don't see the need to have a separate MBSS/BS for a HLBB unless there is reason to keep it separated from an engine..... normally the Stdb Engine. Larger boats.... perhaps Yes!

Choose your poison, and go for it!

2.... If the O/B Charger is connected to the correct terminals of the MBSS or BS, yes..... it won't know the difference. (this avoids direct battery connections and associated corrosion issues)

While the charger is ON, the position of the MBSS or BS should not make any difference.

This allows the boat to be unattended w/ the MBSS or BS turned OFF, and yet when the Charger is left ON, it does it's thing!

If this were mine, I'd do a shared Cranking battery, two MBSS's, a stand-a-lone small cranking battery for the Generator (perhaps with a combining means), and as large a HLBB as I could fit.

No separate bow thruster bank.... no separate windlass bank.... no separate Inverter bank........ nothing but a large HLBB that can be managed easily.

If this means Cranking from the HLBB, I see no issues. Do the math in Amp Hours for cranking a quick firing engine, and you'll see that the load is peanuts compared to other loads.

If this means Cranking from a shared Cranking Bank...... I see no issues.

Alternators can be configured in an array of methods using an ACR or VSR.

Jim McNeely would be the one to talk to about this.

As for the helm volt meters being used for a HLBB these days......... voltage readings, let alone via a helm volt meter, are rather meaningless compared to Amp Hour data tracking.

I'd take these out of the continuously powered loop, and bring them back in as to show Engine Alternator charging ONLY.

Key OFF.... NO Reading!

Then I'd look at some of the "Amp Hour" battery monitoring instruments that we can now purchase for under $200 today.

Here's the Victron BMV 602. This uses a similar 500a shunt resitor as does the Xantrex LINK.





Here's the LINK-lite by Xantrex.



Either gives us data pertaining to Amp Hours used and Amp Hours replaced.

This is much more meaningful data over that of a voltage reading.

.