I’m looking to purchase an inverter for use on my boat. I have 3 12v batteries in parallel, with a switch. So, I save one for ignition, but the other 2 (260AH together) I use for appliances. Most applications are run through 12v, but I’m looking to run an AC mini fridge (propane and 12v fridges are too expensive and I already have this one), one laptop charger (85watts) and 1 usb phone charger. I’ve tried a 400w inverter but apparently the compressor turn on of the fridge is over the 800w surge that the inverter is capable of. So my question is 2. 1, can an 800w (1600w surge) inverter handle this 3 item load? 2, how much power loss will I be incurring from the inefficiency of the power inverter? I was told that a 400w inverter run on standby with no load for 24hrs would use about 9AH from my 12v bank. Not sure if that’s right or wrong or if I can assume an 800w would be 16AH or not?Thanks so much for the help
Realisticly, a power inverter is the most inefficient way to power those needs. That cheap inverter can damage both of those chargers. The reason is that it only creates a Modified Sine Wave at 60hz for 110-120 volts. Sensitive equipment cannot handle the modified wave long term. The fridge should be OK, but is still subject to damage. While you'll save money upfront, it'll cost you money long term, and kill those batteries in about 2 hours, then how are you going to charge them? I own a boat with 10 size 8D batteries for my house bank of batteries, but I still run my generator away from the dock. I have an AC Inverter, but rarely use it. My inverter produces a full Sine Wave due to all of the sensitive equipment on board. Downside is that the inverter when in use can draw 350 Ah and not meet the needs of my boat, but even with all of those HUGE batteries, I only have 5 hours max, of standby power with the inverter. A small Honda generator would be the best solution. Those have a full wave 60hz at 120 vac, and you can run it when you need it and never worry. Those generators were made for sensitive equipment that cannot handle modified wave power. I have one for when we use the smaller Sport boat and for camping.
You can buy an Inverter that will do what you want but your 12 volt batteries will not last long before they have lost there charge.Running your fridge will kill them in no time.If you want to run this type of electrical equipment you should think of buying a small generator.
I live on my boat and cruise full-time. So I am very familiar with the cost of being off the grid when it comes to electric. Your problem is not the inverter. . . Your problem is not enough batteries. . . So, in the long run, that propane or 12v refrigerator may not seem so expensive. I run 3 banks of 2 batteries each connected to two high output solar panels on my sailboat, and I can tell you as fact, my system will not run a 110v mini refrigerator on an inverter for more then an 8 hour day. . . it just won't happen. I run a 12v refrigerator, and also have a laptop running 24/7 and a cellphone charger - and all the comforts of home appliances - but I don't have enough battery power to run any of my 110v appliances for any more then just a few minutes at a time (ie: coffee pot, microwave, etc) and that's it. Your 110v mini refrigerator, together with the inverter - will suck your 2 batteries dry as a bone in just a few hours (2 maybe 3hrs if your lucky). So, you need to rethink your cooling needs, or invest in about 4 more batteries or even a small generator. . . If I were you, I would think hard on a 12v cold plate for an ice box - or simply just a ice box. My 'cold box' has a 12v cold plate (draws only 3 amps) and I put pack all my food in it, and sprinkle in a little rock salt - and it keeps stuff cold as ice for an entire week. (colder then my 12v refrigerator for the first 3 or 4 days).
