When you’re travelling by boat, RV or caravan it’s inevitable that eventually you will ask yourself ‘Do I need an inverter on my boat’. The same question also applies to RV’s and caravans etc. Read on. It should help…

 

An inverter is a device that converts D.C. current to usable A.C. current. Standard inverters are available that can be connected to either 12 or 24 volt systems and have a large range of output wattage depending on your needs and your battery bank capacity. Years ago I asked the question ‘Do I need an inverter on my boat’ the answer was a resounding YES! I chose Victron because they are amongst the top three manufacturers and have a great warranty.

The benefits

There are real benefits in having an inverter on your boat or recreational vehicle. Although things like battery driven TV’s and fridges are available, they do tend to be much more expensive than standard domestic items that use mains electricity. Small battery powered items are okay if they are for only occasional use, but for more serious use you’ll need to consider a more practical approach.

As we live aboard our boat full time, our setup may be more than you need to meet your own requirements, but you will still be able to ‘cherry pick’ parts of this article to suit your own situation.

Seperation of starter and leisure banks

It’s generally accepted that your engine’s needs and your ‘domestic’ electrical needs should be kept separate. If you try to make your engine starter battery power other equipment, without your engine running, you will soon find that you have a flat battery. Do this regularly and your starter battery will expire prematurely. A starter battery is simply not capable of regular deep cycle use. You need a separate deep cycle battery bank for domestic use. It’s very useful to be able to use your engine to charge your domestic and starter batteries.

Going the Lithium route?

If you have space, you can also use solar panels to help charge the domestic bank too. If you have deep pockets, you may want to consider Lithium Iron Phosphate batteries, also known as LiFePO4. This technology is the only Lithium form recommended for mobile use. It is the only Lithium technology accepted for marine use. They weigh less, charge very quickly and can be very deeply discharged without damage. The only real downside to Lithium technology is their price. More about lithium batteries here

The inverter

Once you have a workable domestic battery bank you can consider the purchase of an inverter. The inverter is a piece of equipment that converts battery current to mains A.C. voltage and current. They are available as either ‘pure sine wave’ or ‘modified sine wave’. Although the modified sine wave is cheaper to buy it is not suitable for use with modern electrical circuits that use delicate components including microprocessors. Televisions are a very prone to damage from this kind of unit. The inverter on my boat, a Victron, has a pure sine wave that is safe to use with the most sensitive equipment.

For AC current use a pure sine wave inverter. These are safe to use with all types of equipment. They are a little more money initially but worth every penny. I couldn’t be without an inverter on my boat.

The unit shown below is the 12 volt 3000 watt inverter / charger. Click your link below to see just how much it can do. You really will be surprised. I’m using eBay because on the landing page you’ll find all the information, but also, a big choice of other Victron models. All guaranteed by eBay’s rock solid quarantee.

This is an inverter / charger that is rated at 3000 watts. It produces clean AC voltage that is safe to use on the most delicate equipment. It’s clever too. In the event of inadequate mains input from shore power or generator this unit will @borrow’ battery power to make up the shortfall. It has so many features that I’d you to click your eBay link above to view what you can actually have in an inverter / charger unit. Even if you don’t actually buy the unit, there are more on the the landing page for more choice. All of my important electrical units are Victron, and have been for years. Take a look!

Please be aware that your inverter must not overload the battery capacity you have available. Unless you have a decent sized Lithium setup, you generally will not have the capacity to turn on a normal domestic kettle.

On the subject of battery capacity. There is no point whatsoever in buying a large capacity inverter if your battery system is not up to the job. A couple of lead acid 110Ah batteries will overload very quickly! A couple of lithium iron phosphate ones would cope much better but even then you’d have to be careful and understand the constraints of battery capacities.

Deep cycle batteries and solar

Our boat’s systems all run on a 24-volt setup. Since 12 volts is more common on most boats and recreational vehicles, I’ll describe our system converted to 12-volts. Our domestic bank is made up of deep cycle Trojan T105 batteries and at 12-volts they provide us with a 450 amp-hour bank. This may sound like a great deal, but it really is not. We also have 300 watts of solar connected directly to the battery bank and a backup mains charger.

Conclusion

When we are on our home mooring, we are connected to mains electricity, so kettles and other power hungry equipment runs directly from the mains shore power. To save cost, all our smaller electrical items run directly from the inverter. These items include TV, CCTV (for security), phone charging and backup central heating pump. On good summer days we can also connect either the freezer or one of the two fridges we have on board because of the extended solar hours. The inverter on my boat is one of the best pieces of equipment we have.

In case of a power cut, we can use the inverter for bigger equipment using our 150 amp (equivalent) engine driven alternator to pick up the slack. The nett result is that we are using an average of 9.6KWh mains from shore power per day. On our current electrical contract that equates to just under £2 per day. I’ll take that!

If you’d like to know more about my site, there are lots more articles here, Look for categories on the Homepage.

If you want straight, unbiased information, take a look at this Wikipedia description of  Power Inverters Everything you need to know.