Battery Sequence

[Atalla]

Hey folks - Is it typical for Port and Stbd batteries to be laid out in parallel like this? I'm spending more time at anchor without the genset running than I really ever had before and have started to think about long battery soak times. I would expect that an ideal setup would be to have dedicated starting batteries and dedicated house batteries but, as mine are wired up in parallel, unless I'm in dumb question space right now, I do not have such.

What best practices do you all have to offer? Worth a battery monitor?

Thanks.

 

[Little Ducky]

Yes that looks typical.

Looks like you might have room to add a 3rd on your house pair if you are running a bunch of 12v stuff while at anchor.

 

[Lkbum]

That is normal factory, same as my 06 340DA. I've heard critiques of this but assume factory knows best. My starting batteries and house are split (one of each, two pair) on port and stbd. I think this allows more draw without being on charge. Should a house battery or bank lose charge, the crossover switch should allow cranking onto the weak side. Also gives balance to the battery charger while charging the 4 batteries at different levels of discharge. Wet battery life is typically 3-4 years in humid areas. "They" say when one goes bad , replace them all. I doubted and replaced one. 3 months later replaced them all with AGM. "They" say all batteries should be same size, type and age. Noticed that yours are not. Also learned that my refrigerators default to 12V even when on shore power. Thus drawing on battery while charger keeps up for days. This fried a previous battery. Now I turn off the batteries when departing slip and on shore power.

 

[Atalla]

That is normal factory, same as my 06 340DA. I've heard critiques of this but assume factory knows best. My starting batteries and house are split (one of each, two pair) on port and stbd. I think this allows more draw without being on charge. Should a house battery or bank lose charge, the crossover switch should allow cranking onto the weak side. Also gives balance to the battery charger while charging the 4 batteries at different levels of discharge. Wet battery life is typically 3-4 years in humid areas. "They" say when one goes bad , replace them all. I doubted and replaced one. 3 months later replaced them all with AGM. "They" say all batteries should be same size, type and age. Noticed that yours are not. Also learned that my refrigerators default to 12V even when on shore power. Thus drawing on battery while charger keeps up for days. This fried a previous battery. Now I turn off the batteries when departing slip and on shore power.

Just to make sure I'm not entirely mixed up here. You're saying you have 4 batteries. 2 of them support all your house systems and 2 support starting. The crossovers switch allows for the port or stbd battery for starting or for house to support its weaker twin. But the house and starting batteries aren't connected in parallel, correct? They are distinct? I'll be honest, for all my digging into this boat, I've not spent a bunch of time with the electrical system beyond fuses and overhauling the genset.

Maybe a better way to ask the above question is, if I'm on DC at anchor, I am only drawing the 2 house batteries and the starting batteries should be untouched, correct? If so, isn't the connection layout of my batteries incorrect with starting and house on port and stbd each in parallel?

EDIT: To be clear, I'm looking at the port/stbd labels on the battery trays and making some assumptions.

Separately, I always shut off my batteries while on shore power. Mostly just to ensure, if I lose shore for some reason, I don't drain the batteries entirely lest I have a catastrophic thru hull failure and my bilge pumps don't kick in.

 

[jmauld]

My factory setup is two batteries for the port engine and two batteries for the stbd engine. One side runs the cockpit accessories, the other side runs the cabin accessories.

I’ve considered adding a fifth battery to start the generator but my list of other items needs to get shorter first.

 

[Lkbum]

The photo shows your 4 batteries grouped. The 06 340 also has 4 batteries, 2 on port side and 2 on starboard side gunnels. Mine are wired parallel ON Each Side of the boat. Sea Ray is good about 'getting you home' with 2 engines.
Separate fuel tanks, batteries, ignition switches, keys and rocker switch starters. Anyway, 1 battery is starting port and the other is 'port house'. On stbd, 1 battery is for starting the other is 'stbd house'. Shared load but separated side to side. Port house supports cabin lighting, audio etc. Stbd house supports dash ops like cockpit lighting, engine hatch, bilge lighting etc. So there is a starting battery on each engine in parallel with a 'house' battery on each side, sharing (but separating) the load.

 

[Atalla]

The photo shows your 4 batteries grouped. The 06 340 also has 4 batteries, 2 on port side and 2 on starboard side gunnels. Mine are wired parallel ON Each Side of the boat. Sea Ray is good about 'getting you home' with 2 engines.
Separate fuel tanks, batteries, ignition switches, keys and rocker switch starters. Anyway, 1 battery is starting port and the other is 'port house'. On stbd, 1 battery is for starting the other is 'stbd house'. Shared load but separated side to side. Port house supports cabin lighting, audio etc. Stbd house supports dash ops like cockpit lighting, engine hatch, bilge lighting etc. So there is a starting battery on each engine in parallel with a 'house' battery on each side, sharing (but separating) the load.

Got it. This is what I thought I was looking at. But this means you could drain all four batteries on the hook. I suppose a dedicated genset battery would have to also be dead. I was wondering if the intent was to have at least one starter battery not carrying a house DC load. Sounds like you're saying no.

 

[jmauld]

You should have battery alarms that will go off before you drain them. Also you can jump the batteries together, to start your generator or one of your engines, which can then start charging the batteries.

 

[Carpediem44DB]

This where a good battery condition monitor comes in real handy.

 

[Atalla]

This where a good battery condition monitor comes in real handy.

I had one in hand last fall but returned it thinking I was over engineering. Might have to get back to it.

You should have battery alarms that will go off before you drain them. Also you can jump the batteries together, to start your generator or one of your engines, which can then start charging the batteries.

Tell me more about battery alarms. I'm not aware that I have anything like this. I know I can put in a monitor with alarms but are you suggesting I might have a stock alarm?

 

[jmauld]

I guess it depends on the year and the electronics package you have. My dash goes nuts with lights and warnings when a battery bank gets low.

 

[jmauld]

This where a good battery condition monitor comes in real handy.

Do you have one that you recommend?

 

[Lkbum]

Yes, you are correct. No matter how many batteries you have, you can exhaust them on the hook.
The question was, how they work and why.

 

[MoonRiver]

I was told by previous owner that on my 96 330DA the Port bank (2 6v batts wired in series) was the "house" bank for all 12v items and start of Port main engine. And the Stbd bank was for main engine and genny starters. He had some weird jumper cable setup running between both banks and used them to isolate the banks and provide Port start when the bank goes low off shore power. He to never run with jumper cables attached, but connect them while on shore power. And I never turn my barrel switches off while on shore power.

 

[RollerCoastr]

What best practices do you all have to offer?

Someone has mixed batteries within the groups. That can shorten the life of all of them, as an older/weaker batteries demand a charge that the healthier ones they're paired to don't need, thus over-charging the healthier batteries.

You're missing some terminal covers. That can be a spark risk, and accelerates corrosion.

The photo shows your 4 batteries grouped.

You mean 2 groups of 2?

 

[Atalla]

Someone has mixed batteries within the groups. That can shorten the life of all of them, as an older/weaker batteries demand a charge that the healthier ones they're paired to don't need, thus over-charging the healthier batteries.

You're missing some terminal covers. That can be a spark risk, and accelerates corrosion.

Thanks for the mixed batteries tip. I have heard that from a few folks and hadn't thought through the negatives of the mix. That was the previous owner who had just replaced two of them it would seem, based on dates. They are due for replacement, so I will replace all four and, yes, I know I'm missing covers. Have them in my bag of stuff for the boat, just haven't ticked it off my list yet. Good kick in the pants to replace the batteries and get the covers on.