Battery Wiring

[KindOfBlue]

I posted this wiring diagram about 2 weeks ago (sorry for the duplicate post), but didn't receive any feedback. I am planning on setting this up this weekend so wanted to see if I could get some feedback before I start. The house bank is 3 Group 4D AGMs and the starting battery is 1 Group 24 AGM. Both are dual purpose and the engine is a 40-something HP Yanmar diesel. The 3 Group 4D batteries will provide me with enough Ah between charging and I have enough charging resources to top them off.

Why I like this system. I think that it's simple, yet it has flexibility. I can start with the starting battery and switch over to the house bank after the engine is running or just start on the house bank and only use the starting battery when it's needed.

[sailingdog]

I would recommend replacing the battery switch you've got with a Blue Sea Dual Circuit Plus battery switch instead. That would isolate and protect the electronics from starting related voltage drops and surges. The engine would start using the starting bank, and the house side would use the house bank... while still allowing you to combine the banks to start the engine in an emergency.

It has four posts... and is basically a single pole double throw switch that has a combine position added.

[negrini]

I don't like your schema. 1- There is no switch to isolate batt from the charger/alt 2- What dog mention above 3- I'd swap House <> Engine for alt sensing wire 4- you cannot isolate starter from dc loads if neede

[KindOfBlue]

Originally Posted by negrini

I don't like your schema. 1- There is no switch to isolate batt from the charger/alt 2- What dog mention above 3- I'd swap House <> Engine for alt sensing wire 4- you cannot isolate starter from dc loads if neede

I also see Dog's point and am looking for Dual Circuit switch. This will allow me to isolate the starter from the DC Loads and charging loads. This covers your points 2 and 4 (I think).

Why would I want to isolate the house battery from the charging sources (point 1)? Will adding this, make it possible to break the alternator diodes? What benefit does it provide?

Can you restate point 3? I am reading it as "I would swap House does not equal Engine for alternator sensing wire", and I don't think that is what you are saying.

[negrini]

1- You need not only a switch for isolation but a big fuse as well. This is to protect your boat as per ABYC recommendation. In case of shorts, alt draining current during unattended period, etc... The only exception would be a shore charger. You need to have means to isolate your batts, Benes for instance switch not only positive, but ground as well, for total isolation 3- I'm assuming your volt sensing is wired internal to your alt, so there is only one wire leaving the alt. If that's the case, then you're sensing the house batt to decide about current output and that would create some volt gap against your engine batt, wich is the one where Yanmar takes reference for all electronics (solenoid, panel, alarms, etc ...). I'd use a separator for both banks, or attach the alt sense wire to the engine batt. Another option is to swap engine <> house on you drawning.

[bhcva]

Negrini....would you elaborate on your statement "the only exception would be a shore charger".

Thanks, Bruce

[sailingdog]

The shore charger can be taken off-line by unplugging it, shutting off the Shorepower, or flipping the breaker for its circuit, so doesn't really need to have a separate disconnect from the batteries, unlike the alternator or other charging systems.

[Bene505]

Wow, I can't seem to follow this thread. Darn it.

This would be great to talk about over a beer, with a pen and napkins.

[KindOfBlue]

Originally Posted by sailingdog

The shore charger can be taken off-line by unplugging it, shutting off the Shorepower, or flipping the breaker for its circuit, so doesn't really need to have a separate disconnect from the batteries, unlike the alternator or other charging systems.

I have fuses that (if blown) isolate the batteries from the charging sources. Do I need more?

[KindOfBlue]

Updated wiring diagram..