Adding a very simple inverter

[Dougcole]

I'd like to add a very basic inverter to our boat, something with only a single outlet. I just want it for the coffee maker in the morning and to occasionally charge a laptop. We have used a "portable" inverter for this in the past, but I hate the wires running all over the cabin.


My rough plan would be to mount it in the compartment behind the AC and DC panels then run the wires behind the bulkhead to where I want the outlet. I would add a breaker to my DC panel for it. Not sure of the best way to rig the ac wiring as the units I've been looking at have the AC outlets on the unit itself. Maybe put a male plug on some triplex? I'd like to spend $150 or less on it.



Any thoughts? Is this a dumb idea?


Thanks,
Doug

 

[kchace]

Its not a dumb idea, but I'm not sure what you mean by "simple"? If you mean an inverter with no charger built in, sure, that makes it a lot simpler. That you want to make coffee with it means it will probably have to be at least a 1000W inverter (check your coffee maker for how much power it draws) which means fairly hefty cables to the battery bank. (1000 watts at 120AC is about 100 amps from your batteries). I don't see any reason why you can't wire to the inverter using the outlets on top as long as that goes to an appropriate breaker. Also, you can probably get away with using a "Modified Sine Wave" inverter which is the cheaper variety.


As far as mounting it goes, in my opinion its best to keep it out of the heat of the engine room and you may want a separate battery switch for it. You certainly need a fuse (or breaker) where the positive cable attaches to the battery. I suggest a MRBF from Blue Seas as the easiest to use and configure for this kind of application.


I just noticed that you mentioned adding a breaker to your DC panel for it. While that's possible, its also quite possible that your DC panel wiring is not heavy enough for something like an inverter when added to other normal loads (or even at all). Also, you WILL need an appropriate AC breaker on the output of the inverter.


Ken

 

[Dougcole]

Its not a dumb idea, but I'm not sure what you mean by "simple"? If you mean an inverter with no charger built in, sure, that makes it a lot simpler. That you want to make coffee with it means it will probably have to be at least a 1000W inverter (check your coffee maker for how much power it draws) which means fairly hefty cables to the battery bank. (1000 watts at 120AC is about 100 amps from your batteries). I don't see any reason why you can't wire to the inverter using the outlets on top as long as that goes to an appropriate breaker. Also, you can probably get away with using a "Modified Sine Wave" inverter which is the cheaper variety.


As far as mounting it goes, in my opinion its best to keep it out of the heat of the engine room and you may want a separate battery switch for it. You certainly need a fuse (or breaker) where the positive cable attaches to the battery. I suggest a MRBF from Blue Seas as the easiest to use and configure for this kind of application.


I just noticed that you mentioned adding a breaker to your DC panel for it. While that's possible, its also quite possible that your DC panel wiring is not heavy enough for something like an inverter when added to other normal loads (or even at all). Also, you WILL need an appropriate AC breaker on the output of the inverter.


Ken

Thanks for the reply Ken and the info. Yes, no charger built in, that's what I mean by simple. I also want to keep the wiring as simple as possible, but make sure it is safe. Our coffee maker is 800 watts, so yeah, we probably need at least 1000 watts for the inverter.



It would be easy enough to wire it directly to the house bank, I'd like to be able to turn it off when it is not being used, that's why I was thinking of putting it on a breaker on the DC panel. I get what you mean on draw though. I could mount a battery switch for it pretty easily just below the DC panel, I just hate drilling holes big enough for the DC wiring through the cabinetry.



I am confused though on the need for an AC breaker. If I was just using it on the dash, plugged in to the cigarette outlet (or directly wired to the batteries) and plugging a coffee pot into it trucker style, it wouldn't need a breaker on the AC side as it has an internal breaker. Why do I need to add one for this application?


Thanks again.


Doug

 

[sbman]

An inverter is a nice idea, but I'm not sure it's possible to do what you are looking for in the budget you stated unless you already have some of the supplies on hand.

A 1000 watt continuous inverter is going to cost at least $100 by itself, and that's for a cheapie walmart modified sine inverter which may or may not be suitable for charging your laptop, it might run the coffee pot though. You'll need some heavy gauge cables made up to hook it to the battery bank along with a 150 amp fuse block and fuse. Don't be fooled by a $50 1000W Inverter that is advertising it's 'peak' power and only able to do 200W or 300W continuous.

Most low end inverters are just going to have a standard AC outlet on them and are not designed to be 'wired in' to an AC system, so an extension cord would be your only option to get the AC power to where you want it, unless you want to cut the end off an extension cord and jury-rig an AC outlet to to it after you run it through behind the panel as you describe. I wouldn't recommend that. I have seen such things done.

You can't plug a 1000W inverter into a cigarette outlet successfully. Those outlets are good for 10-15 amps and that's only 120W-180W. You need heavy gauge cables and proper fusing for that much power.

 

[DavidM]

To stay within your $150 budget you will have to go with one of the no name MSW Chinese brands. Here is one that would work: https://www.amazon.com/BESTEK-Inver...690-f7e1-44eb-ad06-aebbef559a37&tag=cb-osp-20

It has an on/off switch on the front, but if you mount it inside the AC/DC breaker compartment that won't be easy to reach. So leave it on all of the time and put a DC battery switch in the DC circuit where it is easy to reach. You will need a 150-200 amp fuse near the battery and that won't be an easy place to reach either if you are thinking about making it a breaker.

If the batteries are within 10' then #2 wire should keep the voltage drop down to .5 V at 150 amps, 1/0 if 15'.

You won't need a breaker on the AC output as the inverter is limited in its current supply capability. As you note, wire a plug on the end of your cable and plug it into one of the outlets. Use 12 gauge AC wiring.

David

 

[Dougcole]

Thanks Y'all. I can go higher on the cost if needed, I'm just not ready for an expensive inverter/charger on this boat and I haven't been able to find anything in between the cheap Chinese stuff and an inverter charger.


I seem to recall a battery switch where all of the wiring stays on one side of the bulkhead and just the shaft for the switch goes through it, so it only needs one hole through the bulkhead. Am I imagining that?


Understood on not plugging it into a lighter, that was not my plan, I was just comparing it to a "portable" inverter. I know some of them will run small coffee pots.

 

[sbman]

Thanks Y'all. I can go higher on the cost if needed, I'm just not ready for an expensive inverter/charger on this boat and I haven't been able to find anything in between the cheap Chinese stuff and an inverter charger.


I seem to recall a battery switch where all of the wiring stays on one side of the bulkhead and just the shaft for the switch goes through it, so it only needs one hole through the bulkhead. Am I imagining that?


Understood on not plugging it into a lighter, that was not my plan, I was just comparing it to a "portable" inverter. I know some of them will run small coffee pots.

Aims Power sells some inexpensive inverters with warranties that are low to mid-range in price. I've used them in a few places and been happy with them, I've never used a modified sine inverter from them though, I prefer not to have issues with the power quality and have always used pure sine inverters.

https://www.aimscorp.net/1250_Watt_Power_Inverter_12_Volt-value.html

I'm not affiliated with them, only a sometimes customer. For an occasional use, non critical component, I've had good service from some of their units.

A pure sine inverter isn't a lot more money.

https://www.aimscorp.net/1000_Watt_Pure_Sine_Power_Inverter_12_Volt.html

 

[Dougcole]

Aims Power sells some inexpensive inverters with warranties that are low to mid-range in price. I've used them in a few places and been happy with them, I've never used a modified sine inverter from them though, I prefer not to have issues with the power quality and have always used pure sine inverters.

https://www.aimscorp.net/1250_Watt_Power_Inverter_12_Volt-value.html

I'm not affiliated with them, only a sometimes customer. For an occasional use, non critical component, I've had good service from some of their units.

A pure sine inverter isn't a lot more money.

https://www.aimscorp.net/1000_Watt_Pure_Sine_Power_Inverter_12_Volt.html

The sine wave inverter in your second link looks just about perfect.

 

[garmstro55]

Hey Doug, the PO installed an inverter in my 400 so he could watch TV at anchor. It powers the Bose system, the salon TV and the TV and DVD player in the main stateroom. He wired it to the panel so I can turn off the inverter when I leave the boat. I haven't hooked the coffee maker up to it, but that's on my list.

He installed it behind the TV in the salon, on the shelf above the Bose. You can just see the fins peeking out under the TV in the first pic. It's a Centec (Harbor Freight) unit. It has 3 outlets and the Bose and TV occupy two of them. The third outlet is pretty much inaccessible due to the cramped space. He took out the enclosure behind the TV to fit it. He also ran wires to the main stateroom and installed a separate outlet on the counter top next to the other AC outlet.

 

[porman]

Also check out Wagan inverters. I added a 400 watt Wagan for charging laptops, cell phones, etc. That way I can leave our 3000 watt inverter off unless I need lots of AC power. It has two outlets and I plug in a short extension cord that has three outlets. I added a breaker next to the electrical panel and took the 12 volt power from a positive battery post that feeds the flybridge ( not on the battery, but a post behind a panel in the main cabin).

 

[Dougcole]

Hey Doug, the PO installed an inverter in my 400 so he could watch TV at anchor. It powers the Bose system, the salon TV and the TV and DVD player in the main stateroom. He wired it to the panel so I can turn off the inverter when I leave the boat. I haven't hooked the coffee maker up to it, but that's on my list.

He installed it behind the TV in the salon, on the shelf above the Bose. You can just see the fins peeking out under the TV in the first pic. It's a Centec (Harbor Freight) unit. It has 3 outlets and the Bose and TV occupy two of them. The third outlet is pretty much inaccessible due to the cramped space. He took out the enclosure behind the TV to fit it. He also ran wires to the main stateroom and installed a separate outlet on the counter top next to the other AC outlet.

Thanks Gary, that's a lot of help and an interesting idea. Did he wire the DC side directly to an added breaker?

 

[Comodave]

I am adding a 400 watt inverter just to power a small chest freezer. I insta dedicated outlet for the freezer. I got the inverter from Defender but I don’t remember the brand. I am coming off the house bank and to a MRBF fuse holder and then to the inverter. The inverter has an on/off switch on it so I can turn it off when not in use. You want to keep the DC run as short as possible and make the 120 run longer if necessary. Less voltage drop that way.

 

[stubones99]

On any inverter project, I would suggest a low voltage disconnect switch to protect the battery bank, in the event you leave the boat with the inverter running, since that can easily kill a battery bank over a few days...

 

[FoxtrotCharlie]

We have a 3000w (6000 peak) AIMS Pure Sine Wave inverter and have been very pleased with its performance. Have it hardwired to power frig, ice maker and 110 outlets.

 

[garmstro55]

Thanks Gary, that's a lot of help and an interesting idea. Did he wire the DC side directly to an added breaker?

As far as I can tell, he wired it so he could shut off the inverter from the battery. When I turn off one of the accessory breakers, the inverter sounds an alarm for about 3-4 seconds then fades away and the power light goes out.

 

[kchace]

Thanks Y'all. I can go higher on the cost if needed, I'm just not ready for an expensive inverter/charger on this boat and I haven't been able to find anything in between the cheap Chinese stuff and an inverter charger.


I seem to recall a battery switch where all of the wiring stays on one side of the bulkhead and just the shaft for the switch goes through it, so it only needs one hole through the bulkhead. Am I imagining that?


Understood on not plugging it into a lighter, that was not my plan, I was just comparing it to a "portable" inverter. I know some of them will run small coffee pots.

There are plenty of battery switches that can be surface mounted including the cables so that the only holes needed are for the mounting screws.

If the inverter has a fuse or breaker for the output then you certainly don’t need another.

Ken

 

[SoWhat]

Cobra CPI1575 1500W Cont, 3000 Peak, worked with my coffee maker. It has internal short circuit, over temperature, and current overload protection on the AC side. An A20 remote shutoff is available.

An older ProMariner TruePower 1000W cont, 2000 peak, has a GFCI breaker on AC side but tripped frequently at start.

Assuming your battery is already fused, you won't need an additional fuse unless you decide to run it through your DC panel. In that case you will have to determine wire size and breaker size (you will probably be using 4 or 2ga if using strictly for coffee)

 

[larman]

We have a 3000w (6000 peak) AIMS Pure Sine Wave inverter and have been very pleased with its performance. Have it hardwired to power frig, ice maker and 110 outlets.

Just curious how big is your battery bank?

 

[cks]

The smallest Keurig coffee maker is 700 Watts. That’s 60 Amp draw. Locate the inverter as close to you battery bank as possible. Install 100A resettable breaker on the DC side.
If you are going to power one outlet and totally isolated from the rest of your 110VAC system, you’re good to go.

 

[alormaria]

This is exactly how I've run my inverter on my boat since 2000. The inverter ($400.00 in Y2K dollars) is mounted in the vented cabinet under the stove right above the battery bank in the engine room. The cables go directly down to the batteries and a 100amp circuit breaker. Be aware you need large cables for the inverter and one more of the same size to ground the inverter case to the engine. Check the inverter case for this type of large ground connection.



At anchor this powers the refrigerator and coffee maker/toaster/TV/handheld-cell battery chargers from the two plugs on the front of the inverter. No extra wiring.

 

[Ski in NC]

I did it a bit different. I put a 1000w unit under galley sink, which is directly above the batteries in the ER, so short cable run. Put a batt on/off switch next to it. Then ran the AC lead to the AC and DC panels which are right next to the helm. Put another transfer switch in (shore/off/inverter) so on inverter, the entire AC panel is hot. It is up to me to pick which loads to run. Typical is fridge and phone chargers and laptop chargers. All outlets in the boat are hot. I can make coffee or run the toaster oven, but if running any of these, I turn the fridge off. I did not worry about an outlet breaker as the thing trips on its own if overloaded. It does go through the 30A shore power breaker.

To go on inverter, turn on batt switch under galley sink. Go to AC panel and turn off big loads. Switch from shore to inverter on transfer switch. Close shore breaker on panel. Close breakers on loads you want. Done.

System works well for me.

 

[FF]

Boats have a large number of boxes visible , VHF, radar, depth sounder many of the toys mounted on the helm station.

Why the need to hide a simple inverter?

We mounted our truck 1500w unit on the dinette seat base .

Easy to turn on & off, ventilated , easy to plug into, as many devices are used at the table and even has a digital batt voltage gauge for a quick check.

Nobody ever commented on the "look" of the galley.