Invertors Or Not

Many people are asking me a simple question, should i fit an invertor to my vehicle, my answer is very simple, NO.

Invertors use 12VDC from the vehicles batteries and convert it to mains 240V AC, and are great for mains powered items using 240V, but very few people understand just how much power they consume from the vehicles batteries to provide even a small amount of 240V power.

In simple terms an invertor uses more than twice the power input to the output it provides, this means even the largest vehicle or leisure batteries we may use will be of very little use with an invertor as they will be flat in a very short time, and a flat battery could be a major issue with a 4X4 or expedition vehicle.
Many ask me why i have two large invertors fitted to my boat, again my answer is simple, it is a 60' boat weighing over 20 tonnes and has very large battery packs designed solely for running two large invertors which power an electric cooker, domestic fridge/freezer, and a multitude of other domestic appliances. My battery packs are 24V 11,000 amp rated, and i have two, and they have the capacity to run these appliances, and in conjunction with two large diesel engines churning out in excess of 1000HP each they have the massive 24V alternators and the 240V alternators; in addition i have a 25KW generator for when the engines are not running. Therefore the batteries are not used that often.

If we put this into context with a camper or expedition vehicle we can make a few comparisons, it may have an average 110 A/H leisure battery, or even two of these batteries giving 220 A/H maximum.

To boil a energy efficient kettle of 2KW rating my boat invertor draws around 335 amps from the batteries, and this is continual power draw from the batteries for the duration of the kettle boiling, immediately we can see the vehicle leisure batteries could not provide this sort of power to begin with, so could not provide any power at all. If we take a cheap, current invertor of around 150 watts which are available cheaply from many retailers we can note a few interesting facts; they do not actually provide 150 watts, this is the maximum they will provide for a short period, most will only provide around 80-100 watts continually. In addition to this we see they are drawing around 40 amps from the battery, so they are hardly power efficient, and with a 110 A/H leisure battery it would not give more than 15 minutes at this power without flattening and destroying the battery through excessive discharging.

One other point is that of 240V, who would want this power running through their metal bodied vehicle, if any fault occurs it could kill you; so why bother when you can get most things in 12V anyway.

How do you, or what is the calculations for figuring out how much an electronic item like your 2KW Kettle draws in amps?

Jas

We actually measured them when we used my boat for testing a number of invertors as its massive battery packs ensure consistent power for doing tests.

The issue is with the two main types of invertors, the cheaper modified sine wave models or quasi-wave models are very inefficient and suck masses of power when they start, with something like a kettle it does drop as the kettle boils, but still sucks a hell of a lot of power due to the way they operate.

Pure sine wave models are much more efficient, and much more expensive, which generally precludes their usage, typically they cost 3 times more than Quasi types as a minimum, and depending on make and capacity can cost many times this.

We have invertor just to charge out laptop and camera batteries. We are using it while we are driving. Is this Ok or we can damage something? We have leisure battery.

delica wrote:

We have invertor just to charge out laptop and camera batteries. We are using it while we are driving. Is this Ok or we can damage something? We have leisure battery.

ditto we have a Discovery 3, and have a 300 inverter only charge mobils and use the computer to upload memery map always have motor running.

Unfortunately the answer is both yes and no, to a large extent it depends on what system you operate, the type of invertor you use, and the power consumption of your vehicle as well as its potential output.

Most people use cheaper invetors, these are usually the problematic ones, but if the alternator output is sufficient and its battery capacity is sufficient there may be no problems, likewise there may be problems if an alternator output and battery capacity is too small.

What i would suggest is as follows:

If you only run the invertor while on the move, and with good and well charged batteries and you are not experiencing problems, then fine, just as long as you are happy with 240V in your vehicle, do not use it with your batteries discharged as it could potentially damage them and your alternator. Ensure your invertor has a minimum voltage input shutdown facility which shuts it off if the battery voltage drops below a certain level as this is a useful safety device in preventing battery damage.

What i do is to use a 12 volt charger for my laptop, and i standardised all my batteries to AA rechargeables and use one of the excellent 1hour multi voltage digital battery chargers which works on mains input voltages of 100-250V AC or 10-28V DC directly from a cigarette lighter socket. My laptop is a Toshiba, Toshiba do an intelligent 12V charging lead which charges the laptop batteries and once charged, maintains a sensed trickle charge to provide only enough power to maintain it to a fully charged condition when operating. Most other laptop manufacturers provide something similar.

Both cost around £30 each.

Thanks for the reply, have it in my D3 just past 3year old, full LR service, all been ok no problemes at the moment, battry is good gets very cold up here in North East Scotland no starting problems,
May have to rethink about getting one for my Discovery 1, eI also have a Toshiba so will look out for that charger, also use rechargable battries, butin the D3 have been using a 240v charger, pluged into inverter, so have to invest in a charger to go in cigar lighter.

There has been several cases if inverters causing fires in vehicles as well as a number of electrocutions, so its worth considering.

Not to mention the fact that many people have things running on their invertor while driving. Should they have an accident, they also put their rescuers at great risk

well i guess i'm in the minority then , i run my Engel through my inverter and have done for the last 15 years.

Likewise, but as the man says, it depends on the quality of the inverter. I know mine was really handy for running a drill on Landy Rally - spanning five years.

Yes, I know I could have charged batteries for a re-chargeable drill on the move, but at the time all I had was a 240v power drill. Did the job just fine.

Hillbilly Raider wrote:

well i guess i'm in the minority then , i run my Engel through my inverter and have done for the last 15 years.

What size inverter please

Where people have concerns and an invertor I have a possible solution which removes 240V from the vehicle which I used for the Son in Law who is a builder and often works on sites without power.

I obtained four semi traction batteries and made two battery packs each containing two traction batteries each, they fit in his van and are permanently locked in for travelling purposes, he now has an intelligent charging system with two channels and I replaced hus alternator with a larger capacity one I had lying around (189 amp unit) and this charges both battery packs. He has a modified invertor which just plugs into the battery packs and powers his lighting by removing one battery pack and putting it where he needs light, this gives him around 12 hours of light at full power and much longer at less power, and is a much safer solution. By doing this his invertor is never used in his vehicle, he charges his battery packs as he drives, and still has the benefit of 240V lighting where site lighting cannot be used as electricity is not available.

This issue of raised voltages is now rearing its head with the electric cars as most operate within the 400-600 volt range, when new they are fine, when properly maintained they are fine, but when they are involved in an accident people are being electrocuted, these being passengers and rescuers such as the fire brigade and ambulance crews. Currently they are suppressing the figures, but both ambulance and fire brigades have begun to act, so theres clearly a problem even though it is being denied; this is to provide insulated clothing to crews to prevent electrocution when attending accident damaged electric vehicles. In addition there have been several incidents (also denied) where electric vehicles involved in accidents have started fires through short circuits which have even been hot enough to ignite diesel fuel which is much harder to ignite than petrol.

Here lies the issue, do you actually want 240V in a metal bodied vehicle with the potential risks involved? many have cited caravans and motorhomes where it is safe; what we have to remember is that most of these vehicles have plastic bodies except for the cabs and chassis, so are fairly well insulated, they are also designed for 240V operation by having the appropriate wiring, equipment and safety protections for 240V.

I think the biggest problem is not wattage but useage.
I run as i said my Engel through my inverter ..NOTHING ELSE.
I dont NEED a laptop , or any other electrical gismos and gadgets, and on the rare times i need to charge my phone it is done via the ciggie lighter WHILST we are driving. And i dont have a split charge system either.
Night time in the mountains does not require the Engel to be switched on ..
Many of our clients make the mistake of believing that split charge systems / inverters mean they have the same amount of electrical power in their vehicles as they do in their homes ... and run fridges 24/7, GPS's , laptops, DVD players camera batteries , you name it they want to use /charge it , whilst stationary, THEN wonder why they have battery failer or worse still , fuses blown or wiring faults.

You are where ever you are to Enjoy that country and its enrioment , NOT to spend time on your laptop or phone .. you can do that at home.

How true, but for many who may be less experienced a mobile has become an essential even if it is just for the security of being able to summon help, and a laptop may only be used for navigation as it can store so much information instead of carrying lots of maps.

Dont get me started on eyes on screens instead of watching where they are going

Whenever 'laning or driving anywhere off-road, I always turn off the radio or CD. As you say, enjoying the countryside is what it's all about - and of course that includes the sounds. Can't hear cowbells, crickets or whatever with Quo blaring out at full tilt! Radios are for boring tarmac!

I agree but i was talking more about following a route on your 40 inch plasma screen or seeing what altitude you are at whilst off road instead of looking at the track you are driving. A gps or whatever device you are using can not spot that rock in the middle of the track.and it wont stop you from going over the edge. We once had a guy with us who gave a running commentry on the way up a mountain for what seemed like every ruddy 2 foot , i very nearly threw his expensive boys toy off the ruddy top of the sodden mountain
Old tecnophobic fart moi? yes and proud of it

"40 inch plasma"