Richard, I'm confused. If your new boat has a generator that can power AC coffee maker and toaster, than it has an AC circuit system probably built to ABYC standards. Also, can't that 400 Ah battery bank be charged either by the generator or the engine alternator? So your existing batteries can make a fair bit of coffee and toast with just an inverter added to the system, and then you've expanded the existing system instead adding a new one that wasn't meant for this use in the first place. Also 2000 Wh at 12.5v equals 160 Ah.

I can see that the Bluetti or one of the many similar power cubes could be valuable for camping or something, but I don't picture it as sensible on a boat (or on a kitchen counter or the front seat of my car):

https://www.bluetti.com/products/bluetti-ac200p-2000wh-2000w-portable-power-station

Richard, I’m based in the Uk and I’ve had exactly the same idea as you for my 40ft sailing boat!  I don’t have a generator other than the main engine/80amp alternator which is a real pain to run when I’m “off grid”.   I think by hooking the 240v (in my case) of the Bluetti back to the shore power socket I can power my A/C system giving me microwave, toaster and electric kettle etc.  Also my 12v system charges via a 40amp A/C charger which could also be used to “transfer” charge from the AC200p into the house batteries.  I would also purchase the solar panels to charge it but only use them when at anchor/mooring (this is when I have the biggest problem with power).  I don’t want to permanently install solar panels as my options for this are limited and would compromise space and sailing pleasure etc.  Also I think that my engine alternator is often “wasting” charge because the house batteries are at 100% so I also think I could wire from the 12v system into the 12v charge port of the Bluetti to harvest this excess. I’m certainly not an expert on this so if you’ve gone ahead and purchased an AC200p for your purpose I’d love to hear about it!

I have a similar situation to Mike (I think).

I have a power cruiser that was built in 1929.  The entire electric system is DC, with 2 marine batteries powered by an alternator.  The only electronics are the chart plotter and VHF radio.  The only other electricity draws are for running lights, bilge pump etc.  There is nothing electrical in in the Cabin, no inverter, generator or shore power.

My problem is that I am trying to power a CPAP machine so that I can sleep on the boat.  The information for the machine says it uses "53 W (57 VA)" I assume that is Watt hours.  I have a "cigarette lighter" plug for the machine that will let me connect to the electrical system on the boat to use power from the boat's batteries, or I can connect it to a portable battery or power station.  53 watt hours X 8 hours sleep = 424 watt hours, so that would be the approximate amount of Watt hours I would need.

Option 1 is to buy a (small medical equipment) LiPo4 battery with 48000 mAh/153.6 Wh. It costs $380.

Option 2 would be to upgrade my battery system and spend $300-400 on a better house battery.  

I would prefer to upgrade the boat's house battery.

The problem is that I "know" the portable medical battery will work.  I have to rely on my math skills to confirm that a house batteries is rated higher than 424 watt hours.  Option 1 is foolproof.  If I upgrade the house battery and use it for my CPAP (Option 2), I might scram my boat's battery.

ideas?

Thanks,

Gary

I still think Bluetti and Zendure brand protable power stations are more suitable for camping and disaster prevention.

Bluetti is amazing, been using it for years!

@parsog 

A bit late to the party - i just found this. I'm guessing you've figured something out by now. But just in case you're still figuring out what to do . . .

The medical device battery of 154 Wh capacity (3.2 V x 48 Ah) would only be able to run your CPAP machine for about 3 hours (154 Wh / 53 W). So you would need 3 of them if you really needed a full 8 hours of use before recharging, at a cost of $380 x 3 = $1140 (if that $380 price you mentioned was for a single battery).

If you were to power the device via a 12 V (nominal) cigarette lighter plug, you would be drawing about 4.4 A (53 W / 12 V). So for a 12 V system, that would require 35 Ah capacity to give you that 424 Wh of energy needed for a full 8 hour use. You didn't mention the existing Ah (or Wh) capacity of your current battery system.

Something else you have to consider is contingency planning. What if the boat, or the separate battery for that matter, fails, or if the charging system on the boat fails. Are you OK going without CPAP for n number of nights?

One advantage of a separate battery system (power-station) is the ability to add some solar charging, as many come with integrated solar charge controller. Plus, you could use it for camping trips as well. An advantage of adding to your boat's 12 V house battery would be increased capacity to run bilge pump, radios, lights etc.

BTW - the medical device battery sized at 150'ish Wh is probably to stay under some airline maximum for carrying batteries in carry-on luggage (TSA in the US has an upper limit of 160 Wh per battery, max 2 batteries).

I think to use a portable power station like the Bluetti AC200P on your boat is a fantastic idea! It's a clever solution that offers plenty of power and functionality without the hefty price tag and complexity of installing a traditional marine inverter system. The ability to easily power appliances like a refrigerator, coffee maker, and small microwave while avoiding the noise and hassle of a generator is a huge plus, especially when you're out on the water. 

Bluetti is amazing. Run 3