240V inverters

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Mike_B

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Does anybody have a 240V inverter fitted to their Land Rover?

I want one for my 110, but am unsure on which type and what specs to go for.

I want it to sit in the battery box under passenger seat, with a mains socket on the outside of the battery box, next to my anderson connector. what spec do I need to be able to run, say a power drill, or angle grinder?

Will a 2000w inverter actually power a 2000w appliance, or is this just a "peak" figure, which will destroy the inverter if used for prolonged periods?

Cheers
 
Add about 15-20% safety factor. Power drill is about 600W, so that would suggest a 720W inverter. They're really good at draining batteries quick, especially car batteries! I had a motorhome and a SMALL inverter in it which didn't even see that much use, and I had battery issues, eventually solved by having a large vehicle battery and 2x leisure battieries, ie 3 in total, all connected by split charger. Beware they get hot too, so siting it where it doesn't get adequate ventilation is a bad idea. Can you fit a couple of fans to cool it during running?
 
The sums make worrying reading - 600 watts at 12v is 50 amps from the battery assuming the invertor is 100% efficient (nothing like it) and you have a stonking great 100ah battery. (yours might be 60ah for a petrol, if it's brand new).
That means you'll flatten the battery in two hours. In practice it might take 30 mins. And then you'll have a flat battery so you can't start your landy,
So, OK for short term use, better with split charge systems, don't forget they need cooling, take about an amp even when not delivering power and most need regular "cooling off" periods to stop them burning out. Oh, and some produce an output which isn't close enough to a sine wave to run motors.
Have you considered a genny?
 
or your other option is buy a cheap geny , or if you just want to power up small items then a baby 200-400 watt inverter will come in handy .
 
Most inverters will shut off when the on load voltage drops below a set threshold to leave enough juice to get the engine started but this does depend on your motor being a good starter:rolleyes:
If you are looking to run something fairly heavy then I would look at a dual battery system where you can isolate the inverter system from the starter battery if required (quite common on boats). I would also look at a leasure battery as the second unit as they can cope with deep discharge far more often than a normal automotive battery. It depends on how often you are going to use this system and how much work it has to do.
 
Thanks guys, think the best bet is a smaller inverter for lower draw appliances, and maybe a genny for bigger stuff...

Cheers
 
My twopence:
Most modern inverters have a 90-95% efficiency. This will be from 0.1 to 1.5 rated current (new devices, running on MosFETs).
If you have a 600W (rated) inverter, it will have either 900W or 1200W peak power outpout for no more than 10 seconds (starting drill, starting fridge compressor)(peak output depends on type). If you have a 600W drill though, there is a cheap motor in it, so the starting current will be 2-3 times higher than rated current (I=P/U; 600W/220V=3A vs 1800W/220V=8.2A)! That is why you have slow fuses on leccy tools. So if you start your drill, it can blow the fuse of the inverter. But the rated power of the drill (example) can be exceeded when you start drilling (bit confusing, but an example follows: Startup 8Amps, rotating freely 0.5Amps, drilling anywhere between 2-30Amps, depending on drill, speed, rotating mass, sine type)
So depending on the type of tool or appliance the limit will be reached on startup (there are softstart inverters) or heavy use(limit your finger on the drill, or drill for short periods only).
If you want to run small devices (<~400W) you SHOULD be safe with a 600W inverter.
I'll get a 600W rated/ 1200W peak myself for running a projector, laptop and sound for open air movies...:D For sound you need one with a real sine though, if you do not have a certain type of amplifier.
 
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You also need to take into account is the thing you want to power continous 2000W draw or peak 2000W draw - some things are hidiously over reated and when you actually run and monitor them they draw next to nothing.
That said, somethings have huge start up current draw (like laptop power supplies) so although normally they would run ok, you can't start them running off a little inverter.
(and if you do want to power a laptop get a car adapter for it - a lot simpler!)
 
MikeDowson said:
You also need to take into account is the thing you want to power continous 2000W draw or peak 2000W draw - some things are hidiously over reated and when you actually run and monitor them they draw next to nothing.
That said, somethings have huge start up current draw (like laptop power supplies) so although normally they would run ok, you can't start them running off a little inverter.
(and if you do want to power a laptop get a car adapter for it - a lot simpler!)
Click to expand...

wtf are you on about?
 
Not sure that was a good example, but some equipment take a larger current draw on start up. Motors are a good example where the continious running load (amps) is a lot less than when getting the motor to start (it has to overcome the inertia of the motor). That is why most fuses blow on switch on.
 
Plug a laptop charger into an inverter - and most small inverters won't be able to cope with it - measure the current draw and you will notice the 'start up current' draw from a laptop charger is huge then it drops down to just a slow trical draw.
so bascailly, if you could pursuade the charger to get past the start up stage the inverter would run it, but, you can't so most littler inverters will struggle with laptop power supplies.

And hense forth the suggestion of just using a 12V laptop car adapter, as they just work.

Or buy a much beefier inverter.
 
Inverters do not have a set level of efficiency but changes according to what percentage of rating is being used. It is fairly logical really, with no load they are at their most ineficient because the electronics of the inverter will be using some power to run but its doing no work. Above 70% of rating the electronics, drive transistors etc start getting pretty warm (even mosfets) which is all wasted energy maxing out at 100% load.

So an inverter which is rated at 50% more than your assumed load will not only almost certainly cope with any form of startup demand but will also extend battery life as well.

The issue with small switched mode PSUs (laptop) is not so far fetched. I found the little inverter in a small power pack I had would kick out when I plugged in the 120w laptop PSU although it was rated at 200w (it is cheaply made). A quick reset of the inverter and it would come on and stay on because the capacitiors of the PSU had charged up sufficiently on the 1st attempt to be not such a high demand the second time. Many SMPSUs have however a thermistor to limit the inrush current on startup that the basic design of the circuit.

Switched mode PSUs are ingenious if anybody wants to be bored by it:D

:hijacked:
 
power factor correction also

I have a 300 watt, 600 peak and upto 150 watt it runs on cigar lighter/ over that you need direct to battery.

I also have a 600 watt,1500watt peak and both have run anything sensible I wanted to run.
 
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I once used an 800w inverter off a car battery in a tent to power an Xbox 360 and 15" screen solidly for over four hours, and it still wasn't flat! That was pretty awesome :)
 
It suddenly occured to me, I've got a 2KVa Inverter sitting under my workbench:eek:

Its a APC 2200 UPS, the only trouble is it's a bit heavy 'cos the battery is built into it. If you press the power button twice it will start up without any AC mains supply going in. So now all I have to do is sus out how to charge the batteries direct from the car and they are gel so the charging is different:D

Oh! and where do I fit it in the Freeby:rolleyes:
 
Missing Link said:
It suddenly occured to me, I've got a 2KVa Inverter sitting under my workbench:eek:

Its a APC 2200 UPS, the only trouble is it's a bit heavy 'cos the battery is built into it. If you press the power button twice it will start up without any AC mains supply going in. So now all I have to do is sus out how to charge the batteries direct from the car and they are gel so the charging is different:D

Oh! and where do I fit it in the Freeby:rolleyes:
Click to expand...


Depending on the model/age of APC UPS, the battery packs could be 24v, 36v or 48v

The individual 12v batteries are usually Yuasa or Panasonic sealed Lead Acid.

I've charged them on a vehicle without any problems.

.
 
The individual batteries are 12v but in packs of two tied with a fuse to make 24v. They could be then split to make a 48v set inside the UPS. I would have to disconnect them to recharge on the car:focus:
 
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