Are my batteries being used while on shore power?

[Dave22q]

The short answer is yes. Your batteries will be powering any 12 v appliance that is in use (refrig, bilge pump, lights, etc. However, of you have a charger running off shore power as most of us do, the charger will be putting juice into your batteries and after a while, the net result will be fully charged batteries.

[ramblinrod]

IMHO if you need to ask these rudimentary electrical questions before starting an electrical refit, you should be studying electrical and electronic theory, ABYC (or appropriate marine electrical
standards for your region) and building some practical skills, or
Hiring a sparky, before attempting a boat electrical refit that will otherwise probably end up in an unsafe electrical system that will not pass a marine survey and will devalue the vessel.

Sorry for
Being so blunt, but I witness unsafe DIY electrical mods every day, including the absolute worst I've ever seen, about a month ago, where the surveyor correctly declared the electrical system a "mess" and the owner was pissed cause I'm all his years of boat ownership he had only had one blown fuse. Just because faulty wiring hasnt caught fire yet, there's always tomorrow.

Be safe, you don't know what you need to know until you do know.

[Stu Jackson]

Rod, be careful here. If you read reply #12, you may get put on the same list as me!

Some people still don't "get it."

[malyea]

Originally Posted by Stu Jackson

Some people still don't "get it."

Seemingly not.

[Stu Jackson]

Originally Posted by malyea

Seemingly not.

I truly appreciate all the good advice you've given over the years about the dangers of certain inlets along the eastern seaboard.

You have the mindset of sharing knowledge for safety purposes.

Good on you.

We feel the same way.

[malyea]

Originally Posted by Stu Jackson

We feel the same way.

Mainly a style difference - I like to encourage beginners to ask basic questions. We always had a saying in aviation training - "no such thing as a dumb student question, just an a#%hole instructor".

I vote for encouraging basic questions not belittleing those who ask them. I suspect at your core you probably agree.

Cheers

[170122]

Vert confusing question Will require a very confusing Answer: Most réfrigéra tors are dual voltage AC/DC, 115v breaker must be on
Battery charger must also be on
Ice makers are only 115v
Inverters / chargers with auto transfer must also be on
QUOTE=TitoSoto;2141109]I honestly haven't had the time to inspect my (new to me) boat's electrical wiring...

But, does power usually go THROUGH the batteries before going to my 110v appliances EVEN while connected to shore power?

Or, is there some sort of "battery bypass" that directly connects my 110v appliances to shore power?

It seems like batteries would get "used faster" by always draining for 110v devices instead of directly taking from the shore...[/QUOTE]

[GulfportBarb]

We asked our electrician to draw us a diagram showing us how our solar panels, wind turbines,generator, shore power and inverter all work together. We thought we had it all figured out until we realized that the refrigerator and freezer are always on (can't turn them off at the panel) and we need to turn them off inside. The PO has them direct wired into the batteries/shore power and not thru the panel. Good luck!

[mitiempo]

Originally Posted by GulfportBarb

We asked our electrician to draw us a diagram showing us how our solar panels, wind turbines,generator, shore power and inverter all work together. We thought we had it all figured out until we realized that the refrigerator and freezer are always on (can't turn them off at the panel) and we need to turn them off inside. The PO has them direct wired into the batteries/shore power and not thru the panel. Good luck!

Every load on the boat should be able to be turned off, whether a normal item on the panel or a bilge pump wired for 24/7 use.

[TitoSoto]

Originally Posted by Dave22q

The short answer is yes. Your batteries will be powering any 12 v appliance that is in use (refrig, bilge pump, lights, etc. However, of you have a charger running off shore power as most of us do, the charger will be putting juice into your batteries and after a while, the net result will be fully charged batteries.

Exactly. So my batteries ARE still being used, if only for a little bit?

I'm wanting to replace my 12v fridge with a 110v if only because I am not looking to spend over $1,000 to get a "marine" stand up fridge - being that I am a liveaboard I just can't handle a 2 foot deep chest refrigerator plus a tiny freezer that doesn't keep anything frozen...

Of course perhaps I could buy a small home fridge, but use the 12v compressor that I currently have (getting the best of both worlds). Problem is, I don't know if I could just disconnect the compressor lines from the 110v compressor and into the 12v compressor. Plus, what about the thermostat?! Ah, much easier to just replace the whole damn thing lol

[mitiempo]

Originally Posted by TitoSoto

Exactly. So my batteries ARE still being used, if only for a little bit?

I'm wanting to replace my 12v fridge with a 110v if only because I am not looking to spend over $1,000 to get a "marine" stand up fridge - being that I am a liveaboard I just can't handle a 2 foot deep chest refrigerator plus a tiny freezer that doesn't keep anything frozen...

Of course perhaps I could buy a small home fridge, but use the 12v compressor that I currently have (getting the best of both worlds). Problem is, I don't know if I could just disconnect the compressor lines from the 110v compressor and into the 12v compressor. Plus, what about the thermostat?! Ah, much easier to just replace the whole damn thing lol

Sounds like you want a marina live-aboard boat rather than a cruising boat.

As far as the batteries if they are fully charged the AC charger will supply your DC needs, ramping output up as items are turned on. The batteries are in the middle but as long as the charger is capable of supplying any amperage needed by the loads they are not cycled.

[TitoSoto]

Originally Posted by mitiempo

Sounds like you want a marina live-aboard boat rather than a cruising boat.

As far as the batteries if they are fully charged the AC charger will supply your DC needs, ramping output up as items are turned on. The batteries are in the middle but as long as the charger is capable of supplying any amperage needed by the loads they are not cycled.

Gooooot it! That's basically what I was wanting to figure out

I just see my battery monitor not going to 100% anymore every time I go out sailing and disconnect from shore and was wondering if this was why (e.g. batteries being used even while at the dock).

Thanks!

[StuM]

Originally Posted by TitoSoto

Exactly. So my batteries ARE still being used, if only for a little bit?

No, your batteries are not being used when you have a charging current going to your DC circuit. The charging voltage from your shorepower powered charger will be slightly higher than your battery voltage and any current flow through the batteries will be into them, not out of them.

[tkeithlu]

Wow! Getting heated, and not by the batteries. Try this. While on shore power disconnect the inverter. See whether anything that uses AC stops working. Those things are being supplied by your batteries and inverter rather than directly by shore power. In all likelihood, you'll find that the inverter only runs when you are disconnected from shore power, but it could be that shore power supplies your battery charger only and everything is downstream. There's no chance short of Darth Vader having done your wiring that any 120 AC device has a way of being supplied by both direct shore power and your inverter - the two would be out of phase and you'd be more concerned about smoke inhalation than wiring. You should be reading, but you can figure out your wiring system by removing bits of it and seeing what stops.

[mitiempo]

Originally Posted by StuM

No, your batteries are not being used when you have a charging current going to your DC circuit. The charging voltage from your shorepower powered charger will be slightly higher than your battery voltage and any current flow through the batteries will be into them, not out of them.

As long as the current being used is less than the charger's max output.