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There are a couple of electrical questions that keep coming up, this is one of them.
At home, you have constant 240v power supply from the mains, and thus pretty much everything you have connects to 240v. Most modern “portable” appliances however use a transformer to step down the voltage to 5v, 12v, 19v or similar to power small electrical devices. Looking around my house, the only truely 240v appliances are large LCD TV, kettle, dishwasher, washing machine, hair dryer, and my PC.
The vast majority don’t actually use 240v. And to be fair, the vast majority you’d take with you in a campervan would use lower voltages.
The only exceptions which you’d may take away with you are kettle and hair dryer, but really you’d not want to run these on an inverter!!!!
Some basic maths for you.
- Electric kettle at home takes 240v and is rated at, say, 2kw or 2000W. 2000W/240v is 8 Amps
- Your campervan is 12v, so 2000W inverter sufficient for your kettle would pull 2000W/12v = 166 Amps!
Now thats huge! The cable to the inverter would need to be massive and the energy required from the battery would not help its life expectancy! Now say your leisure battery is 85AH, this means it can provide 85 Amps for an hour (or any ratio thereof) though its recommended not to flatten your battery more than 50% on a regular basis, so you really have around 42AH to use. A kettle on an inverter using 166A means it would flatten your battery within (166/42) = 15 minutes!!!!!
So what I’m saying, is huge energy appliances like a kettle amd hair dryer and not really sutiable to run in a van from battery even if you had an inverter.
Most portable appliances, such as digital cameras, iPods, GPS, laptops, TVs, DVDs etc can all run from a 12v supply but with a small transformer in the way. Maplin sell for instance a generic power supply that fits both laptops. It takes the 12v supply and “ups it” to 19v which the laptops require. Their range includes smaller units, 40W, for netbooks, up to 120W that will work bigger laptops. I suggest the 120W version as even though you may not need one so big, it means it is more efficient and doesn’t get as hot.
eBay is also a great place to buy 12v chargers for mobiles, cameras and the like and these are only a few £ each.
TVs / DVDs
A lot of people take TVs and DVD players away, and some of these are motorhome specific (MEOS, Avtex) and thus designed for 12v. Some use 240v ones via an inverter. Some buy cheaper 240v ones which actually have an external transformer 240v AC–>12v DC and they simply buy a converter to plug directly into the van.
Some tips and comments on TVs:-
- Do not use inverter. These are very inefficient loosing maybe 20% of power to “heat” and other losses. Always run from 12v if you can.
- MEOS 12v TV works fine for me and does pretty much everything you want.
- Rememebr, 12v in a motorhome is actually variable 11v to 13.6v when on hookup to 14.6v when driving. Motorhome specific TVs are designed to cope with this range, whereas home TVs converted to a van use are expecting a clean and stable 12v supply. Thus some may be sensitive and fail when on a van. That said, they are a lot cheaper and to be honest I’d reckon most would be fine, so I would give it a go if you fancy it! You could of course use a voltage regulator to maintain 12v.
- Motorhome specifiv TVs should be lower power and more resistant to vibration than home units.
- If you buy a home TV to use in the van, then make sure it has an EXTERNAL transformer that converts 240v AC to 12v (or so) DC. I’d recommend you get a good voltage converter with multiple adapters such as from Maplin
Extending Battery Life
Only use things when you need!
Change Halogen lights to LED – this made the biggest difference to us and is very easy (though not cheap) to do
Get a smaller TV. We’ve got a MEOS 13.3″ because it fits perfectly. It takes 2A. 15″ TVs can take 4-5A which takes 2x the power. Do you really need a big screen?
Get a decent laptop! My old laptop used to draw around 65W to charge, around 6 Amps! And even then then when fully charged the battery lasted 1.5-2hrs. My new laptop is an ultra-low voltage Asus UL30A and is superb. It uses only 3A to charge and the battery lasts 8+ hours. And its got a better screen, lighter etc….
Blown air heating uses a lot of battery, so make sure you use this only when necessary and perhaps insulate the van better and block draughts.
Finally, add more batteries We have 2x 100AH and these last us very well indeed!
So, Do you need an inverter?