House electrical

[Maravilla1]

We currently live on a monohull sailboat full time, but we are getting ready to transition over to a trawler. I do not understand how the house electrical load is managed on a trawler. On the sailboat we have a big house bank (625 AHr) of deep discharge-capable batteries. Everything runs on DC power and I maintain the house bank with solar and the engine alternator when the sun isn’t shining. If you have a few small AC powered items you install an inverter. The trawlers I am looking at all have generators, relatively small house banks, and many have no inverters. Do people run the generator all day at anchor to keep the AC-powered refrigerator running? Do you have to turn on the generator to cook a meal? How does a typical day on an at anchor trawler go electrically? Thank you!

 

[O C Diver]

It varies all over the place depending on the boat. Some people start the generator before unplugging shore power and turn the generator off after plugging shore power back in. Others do similarly to what you do.

While I have a generator and occasionally use it to charge batteries and when I absolutely need air conditioning, most of my battery charging occurs from a large second alternator on the engine. I have a 3KW inverter that runs the refrigerator, microwave, and can be used while underway to do laundry. Also, the inverter gives you the ability to use lots of home appliances such as a crock pot, rice cooker, toaster oven, blender, expresso machine, etc.

Obviously you could use solar to recharge the batteries instead of the generator or the main engine. Depending on the size of your new boat, there can be lots of options as far as power for everything. One last bit of information I will offer you is that some devices such as apartment refrigerators are much less expensive and more energy efficient than the RV / marine versions.

Ted

 

[rslifkin]

Electrical configurations vary a lot between different boats. Other than more time spent motoring with alternator power available, there's nothing inherently different about a trawler vs a sailboat for power systems.

Some boats are configured to be relatively generator dependent, especially if it's an older boat with lots of power hungry equipment on board (built before big battery banks, inverters, solar, etc. were practical). Others are a lot more like the sailboat power systems you're used to, although they may also have a generator on board (especially if the boat has air conditioning).

Using my boat as an example, our current house bank is 415ah at 12 volts and we have a 2kva inverter. We also have 820 watts of solar. That means in decent weather we can cover the majority of our needs on solar and battery power. When we're away from shore power, we run the generator for 40 - 60 minutes per day to cook dinner (electric stove) and that also takes care of letting the water heater warm up for showers. We only end up needing the generator for battery charging on dark, rainy days if we're not moving the boat.

Our future plans involve adding more battery capacity and a larger inverter setup as well as more solar. Once we do that we'll be able to handle the stove and water heater from solar/battery power. At that point the generator will only be needed if we want to run the air conditioning away from shore power (which we rarely do) or for battery charging when the weather is giving poor solar production for too long.

 

[Maravilla1]

O C Diver, thank you for the response. If you don’t mind, how big is your house bank and inverter? I would definitely LOVE to have a full sized refrigerator/freezer and those tend to be AC systems.

 

[rslifkin]

To add to OC Diver's fridge/freezer point, once you reach the point where you're leaving an inverter running 24/7, it no longer matters if a given appliance is AC or DC. It only matters how much power it uses in a typical day.

 

[Maravilla1]

Rslifkin, thank you for the response and the details of your set up.

 

[jgwinks]

With no inverter these boats typically run the generator a lot. Maybe not all day but a lot. If the stove is electric they have to run the gen for that, and for hot water if the heater isn't engine heated. These boats usually avoid anchoring, they run from marina to marina. My current boat was set up this way but coming from sailboats myself I made some changes. I added an inverter, solar, and a bigger house bank. I also dumped the electric stove and installed propane. I run it like my sailboats, I avoid marinas and anchor whenever possible. I can run the fridge and other house loads for about two days before I have to run the generator, and in a six hour trip the engine alternators will bring the bank up to around 90 or 95%. The boat is not really a trawler, it's more of a motor yacht or cabin cruiser type and was pretty typical of the type. There are less generator dependent boats out there but I think most were owner converted to that state. I spent around $5000 doing it.

 

[STB]

You can also use a point of use inverter for a household refrigerator. Basically size an inverter for the appliance, install it with the appliance, and the appliance becomes DC.

As compared to an AC appliance, it'll obviously require fatter wires from the panel to the inverter because the voltage is lower.

This let's you downsize your main inverter and maybe avoid having one.

Of course, you need the battery bank and way of charging it to meet your DC demand and converting an appliance from AC via a generator to DC via battery ultimately means either a lot of solar, wind, etc -- or the generator.

So, in many cases it gives you more choices w.r.t. appliances. But it doesn't save you the generator capacity.

There are threads on this, but in my humble view an inverter-charger needs to be marine rated as shore power can be in the box, but a point if use inverter is just a type of load, just like the appliance, and no more needs to be marine rated than any other pure load.

Having said all of this -- my own refridge and freezer are iaother marine AC/DC units.

 

[sunchaser]

M
You’ve gotten some spot on advice. Might I suggest that you focus on a vessel that is already set up with the electric systems described above. This could or should include:

- house bank
- inverter
- panels
- genset
- engine charging system with external regulation
- separate starting bank
- flawless shore power setup
- good rotary switches for shore power
- well organized breaker panels
- no shoddy wiring hanging around

And, no trips when plugged into newer GFCI pedestals

Good luck

 

[Lou_tribal]

I guess that the answer to your question highly depends on what you have aboard and your cruising style.
On my boat we have a fridge 12v/110v, a water heater 110v/engine heated, all typical electric stuff like lights, bilge pump, and anything in the kitchen is propane (galley stove, upper deck stove, bbq).
I also have 12v tv that I almost never turn on.
What burn most of the energy is the fridge. Water heater is enough for 2 days for shower and dishes, after a cruise water is burning hot.
We had 2x 110ah batteries and this was enough for a weekend at anchor.
Now we want to change this for 600 to 800ah so to have few days capacity.
Again depends on your style, if you like to keep all your lights on all night, run air conditioner, oven, dancing mirror ball and so on things are differents.

Note: we have no inverter, we went opposite direction and switched pretty much everything to 12v.

L

 

[O C Diver]

O C Diver, thank you for the response. If you don’t mind, how big is your house bank and inverter? I would definitely LOVE to have a full sized refrigerator/freezer and those tend to be AC systems.

Bank size can be deceptive depending on chemistry. Probably a better way to describe size would be my normal usable amount. I'm somewhat conservative in how far I'm willing to draw down, so my normal usable is 400 AH.

The inverter is 2,800 watts, but I rarely exceed 50% capacity. The second alternator on the engine is capable of 220 amps continuous at 14 volts which means it could match the inverter's consumption.

Here's a thread about my apartment refrigerator installation. Lots of good information on power consumption and inverter standby consumption:

https://www.trawlerforum.com/forums/s31/my-new-apartment-refrigerator-41392.html

Ted

 

[Iggy]

As mentioned, it depends on how the boat was setup. In my case, I highly recommend a charger inverter. It is a simple setup that takes care of both items. Charges my batteries and and gives me 3000 watts of power. Just a suggestion...........

I like having the genset too, but it came with the boat. I find that I don't need solar panels. In the morning and evening I run the genset for to 30 to 40 minutes to make hot water, coffee or anything else. At the same time, recharge the batteries.

If I need A.C. during the day for a short time I use the inverter. I was going to install solar but the genset needs to be used. I have it, so why let it seat and do nothing?

But it all comes down to the math. What are you powering and for how long? Once you come up with your daily "amp hours". Than you can decide on how to handle the problem. Bigger house bank, solar, genset, inverter and how to use them for your needs.

Good luck

 

[mvweebles]

Hi Maravilla - thanks for your first post!!! Good one --

There are two reasons powerboats in the middle size range (40-ish footers) often have generators - either they want/need air conditioning; or/and they have electric stoves which remains very common. The older resistance coil cookers are energy hogs - there is no practical way to run them on an inverter so the generator is run frequently. An induction cooktop is feasible (barely) on a large LiFePO4 battery bank. If the boat has propane cooking, the battery bank can be smaller. Converting to LiFePO4 batteries plus high-output alternator is preferred. For DIY, cost is around $5k-$8k including a 3000W/125AH inverter/charger. Adding solar isn't very expensive, though the physical mounting of the panels can be challenging depending on the boat.

As OC Diver mentioned, many larger powerboats (say, starting in the upper 40's foot range) run generators 100% of the time they are away from dock. Sometimes its for convenience to keep refrigerators and A/C running, sometimes its needed because the boat's electrical system requires AC current and inverters won't fully support.

Peter

 

[ranger58sb]

We currently live on a monohull sailboat full time, but we are getting ready to transition over to a trawler. I do not understand how the house electrical load is managed on a trawler. On the sailboat we have a big house bank (625 AHr) of deep discharge-capable batteries. Everything runs on DC power and I maintain the house bank with solar and the engine alternator when the sun isn’t shining. If you have a few small AC powered items you install an inverter. The trawlers I am looking at all have generators, relatively small house banks, and many have no inverters. Do people run the generator all day at anchor to keep the AC-powered refrigerator running? Do you have to turn on the generator to cook a meal? How does a typical day on an at anchor trawler go electrically? Thank you!

Our non-trawler was built with AC-only fridge and freezer, and doesn't have great natural ventilation.... originally marketed toward a marina-hopping market... expecting genset always on while underway... to service the fridge/freezer loads but also the aircon systems.

The DC electrical system is reasonably robust. Two banks of (now) 255-ah capacity at 24VDC, each starting one engine and each also servicing about half of the DC house/nav loads.

Our third large bank (255@24VDC) was originally for thruster only, and had its own charger. We changed that to an inverter/charger so the bank now services all the light AC loads (including fridge and freezer, coffee maker, microwave/oven combo, etc.) while we're underway or at anchor with generator off. (On a previous similar boat, we did mostly the same thing but also had to add battery capacity to get to the same place.)

But then we have an electric cooktop, electric water heater, both heavier loads... and there's still that poor ventilation thing. So a day in the life at anchor, assuming benign temps with aircon not required... we start the genset in mid morning to heat water, charge batteries... and then again at dinnertime.

We have a hardtop and space to add solar; too much bother, for me, have other priorities. But it would be a good thing if I had nothing else to fix in the meantime. Adding battery capacity is not uncommon, either with original chemistry or these days, perhaps with LFP.

-Chris

 

[Bmarler]

My electrical system more closely resembles what I had on my sailboat, but much larger. My house bank is 1125 ah agm. All of my critical systems are 12 volt, no need for 120 volt to fully enjoy the boat. Fridge is quite large built in, with remote Adler-Barbour compressor, propane cooking. Big alternator and solar for charging. Genset hardly ever gets used. No need for air conditioning here thankfully, heating is by hydronic which also heats the domestic hot water.
3000 watt inverter is on 24/7 for luxury items like internet, chest freezer, and other 120 volt doo-dads like microwave or hair dryers, etc…
While my setup may not be what a typical trawler might have, there are many others similarly equipped. We’ve been living aboard for thirty years or so,(only the last few years on this one) and this boat fits our needs perfectly. It was a perfect transition from sailboats.

 

[Bacchus]

Clark
Welcome aboard TF.
As you can see from the above replies there are many ways to satisfy electrical needs aboard. A lor depends on the boat you choose and how it is already configured, assuming you are looking at used trawlers. The other factor to consider is your style of cruising... relatively short stays at anchor vs extended, long enough cruising between stops to recharge via eng alt and whether you want to utilize gen or avoid it completely and frequency of shore power to completely recharge. That doesn't even include the house bank chemistry question that adds another layer of complexity with today's LiFePO battys available.

I would not eliminate a potential good fit boat for your must &:wants solely based on its current electrical set up as you can always modify / add components to optimize fir your use... just consider the cost to modify as part of the decision process.

Good luck with your new venture / adventures

 

[sunchaser]

M
On the one hand Don is correct, don't reject a vessel just because the electrics are not "perfect." On the other hand, if you're not electrical handy modifying a vessel to suit your needs can be very expensive. Then comes the hiring of capable trades people, not quick, cheap or easy. Thus you could be left with a vessel that could take far longer to use as you desire.

 

[av8r]

40’ boat, 705 ah house bank, propane cooking, diesel heating, natural cooling. 8kw genset for water heater and microwave and 2 chargers 70a and 40a. Max 20a solar and 165a engine alternators. 1200w inverter for charging devices, crockpot, and coffee-maker. Frig is dc only. Water heater also heated by engine heat.
Our daily consumption varies between 120 and 180 ah including coffee. June-july-august the solar almost keeps up, especially if we heat coffee water with propane. We normally run the generator for heating and charging for about an hour a day when we are not moving.

 

[Solstice1981]

Not all Trawlers are alike. It depends on how it is et up and intended purposes. Our 60 foot Grand Alaskan has two genesets, 800 amp/hr battery bank, solar, 24 volt 150 amp alternator on one engine and 12 volt 75 amp on the other engine. While on anchor we use the inverter to run everything except AC and water maker, We don't need the genet unless at anchor greater than 3 days or while the engines are running. As in everything the more stuff you have the more that breaks, thus one genset is for back up purposes in case one goes down and we don't have spares on hand.

 

[fgarriso]

You can also get 12VDC RV refrigerators.

 

[LargeMarge]

.
...my battery charging occurs from a large second alternator on the engine. I have a 3KW inverter that runs the...blender...
...apartment refrigerators are much less expensive and more energy efficient than the RV / marine versions.
.

.
We heat and cook with propane.
We changed the stock 160-amp small-house 'intermittent-duty' alternator to a 220-amp 'continuous-duty' big-house alternator.
.
Around sunset, we hit the sack.
Not much use for interior lights.
.
A couple-three years ago, we acquired a SnoMaster 61qt/liter/litre dual-zone fridge.
Extremely sturdy, these are engineered for extended expeditions in remote regions.
Extremely frugal, it happily operates on the wafting fumes from the general vicinity of the bank.
.
An aside:
In our tiny space, we have:
* two smoke detectors from different manufacturers
* two CO detectors from different manufacturers
* two propane detectors from different manufacturers.

 

[dutch-barge]

20 KWH battery bank ( 24V) Lithium
1800 W solar
90 amp house alternator ( 24V)
Mitsubishi split air
kabola hot water and heating ( diesel)
hotwater heater ( engine heating) feeding the Kabola
normal household 220V fridge
Lighting 1/2 on 24V other 1/2 on 220V
Microwave
Induction cooking
2 * 3KW Victron multiplus (one for all 220V systems and one for the induction cooking and Mitsubishi)

Use 10 - 20 KWH shore power a year.