1500W inverter (1 Viewer)

[stevec]

We are just about to pick up our new MH and I'm thinking about adding an inverter. We would like to use a Remoska and possibly a small 900W heater (not together!). SO thinking a 1500W inverter would be sufficient. We don't have hairdryers or coffee machines or microwaves! Are some brands better than others? Some to be avoided. There looks to be an aweful lot out there so some help in narrowing down the choice would be helpful.

The MH will run with twin GELS for a short while then plan a 280Ah lithium.

 

[funflair]

OK 1500watts would be OK for Remoska and a small kettle but forget the heater as it will take too much power, it's all about the size of the load multiplied by time, the Remoska if it's the small one takes 400 watts I believe and usually cooks for 45 minutes, your battery at 280ah has around 3360 watt hours Wh of power, limit that to 80% gives you about 2700 Wh to play with, the remoska for 45 minutes will take 400x45/60 Wh so around 300 Wh or just over 10% of your capacity.

I only mention kettle as it's an example of relatively high load but for short period so does not take loads of capacity.

I will just add, Pure Sine Wave and not the cheapest available and preferably something with remote start/stop would be my advice.

 

[stevewagner]

I recently fitted a Renogy 2000watt inverter that works very well and includes an internal automatic changeover switch. I believe they have a sale on at the moment too.

 

[autorouter]

To put things in perspective, you need to appreciate just how little energy a leisure battery can store. Two 100Ah 12V leisure batteries, total 200Ah, can store 200 x 12 = 2400 watt-hours (Wh) of energy, and of that it's best to only use 80% to avoid the risk of battery damage. So that's 1920Wh. A 1500W inverter at full power will last just over an hour before it's flat.

The best way to use inverters is in short bursts of high power, like a coffee machine, microwave, hair dryer etc. Sustained high power like a 900W fan heater will quickly flatten the batteries. Remoskas are popular because they are relatively low power, very efficient, and are used for a fairly short time. For serious heating like water heating, keeping the MH warm and much of the cooking, people still mostly use gas.

The other consideration is that an inverter takes a small amount of power even when nothing is plugged into it, and that can add up if you leave it on 24/7. Best to switch it off unless you are actually using it. If you intend to install it in an inaccessible place, it's a good idea to get one with a remote switch that you can put in a convenient place. And as you can guess, the more expensive models usually have the best no-load drain.

Apart from the total energy stored in the batteries, the other consideration is that there is a limit to how fast you can take the power out. For lead-acid-based batteries, including gels, the maximum recommended amps is about a fifth of the battery amp-hour capacity, so for 200Ah that's 200/5 = 40A. In terms of power, since it's 12 volts that makes it 12 x 40 = 480 watts. That's a bit conservative, and short bursts of high power are better than sustained loads, but if you regularly go over this limit the batteries will degrade faster. One advantage of lithiums is that they can take a much faster discharge rate, so are less affected by this problem.