Member Since: 16 Jan 2005
Location: On the sofa
Posts: 2185
What is the maximum power invertor that can be used?
having now got a Garmin GPS and laptop based memory map in the car, as well as TomTom, Phone, Ipod etc I want a more powerful invertor to keep things charged. My 75w invertor struggles to keep thelaptop going.
As there's not a heck of a lot of difference in price between a 300w i(£24) nvertor and a 600w (£38) and even 1000w (£83) I'm tempted just to get a nice powerful one and leave it at that.
Does anyone know the maximum wattage that would be safe to use on the rear passanger socket (next to the AUX in socket).
Are all the power outlets rated the same?
best regards
RobAll opinions expressed in this posting are my own and are not necessarily those of someone who knows what they are talking about.
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27th Aug 2007 11:10 am
heine
Member Since: 07 Feb 2007
Location: Midrand
Posts: 4054
15 A IIRC - not sure what that is in W
27th Aug 2007 11:12 am
christyler
Member Since: 31 Dec 2005
Location: Cork, Ireland
Posts: 1168
you are mixing up you watts and amps.
the watts is refering to the 220v output of the inverter.
the amps is refering to the max allowed draw from the 12v socket, although they are related there relationship can varey depending on how efficent the inverter is.
Typically inverters draw more DC amps as you demand more AC amps from them.
the best plan is to assume that you can safely draw 10 amps from the socket, then pick the highest wattage inverter you can get that draws 10amps or less. Other than that you are into running thicker cables from the battery.CLUB "Ah Shor it'll be grand"
First D3 in the World with a Hydraulic Winch.
2006 Disco 3 TDV6 S Auto,
Diff Locks, Turbochipped, Raised Air Intake, 220volts Onboard, Onboard Compressor, Large Bore Exahust, Underbody Protection, One or two Other Mods as well.
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27th Aug 2007 11:24 am
gilmore
Member Since: 16 Jan 2005
Location: On the sofa
Posts: 2185
Um,
OK
So if we go
Power=VoltsXAmpsx0.6 (estimate that I multiply by 0.6 to compensate for the sine wave in AC)
So for 10 amps
Power = 230 X 10 X 0.6
= 1380watts
Estimate 90% efficiency on invertor
Max power = 1242 W
So a 1000 Watts invertor should not drain more than 10amps continuously.
Does this make sense?All opinions expressed in this posting are my own and are not necessarily those of someone who knows what they are talking about.
Land Rover Defender V8, 50th Anniversary Edition
Mercedes ML350CDI
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1974 Honda CB750K4
1975 Honda CB750K5
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27th Aug 2007 11:45 am
bkehoe
Member Since: 25 Feb 2006
Location: Wexford
Posts: 1481
Rob, that's more like 100Amps .
If the engine is running and the voltage is slightly higher, around 14V, then the current consumption will drop to 88Amps, which is still slightly more than the accessory sockets can supply. IE - 05 D3 TDV6 HSE - Zambezi Silver
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27th Aug 2007 11:52 am
xtc
Member Since: 27 Mar 2007
Location: Hampshire
Posts: 1072
Hi, No, the 10amps is at 12v from the vehicle, not mains. So very roughly 10x12 =120 x.8 ish for efficiency = 100w at mains from a 10amp, 12v socket.
A easy rule of thumb is you need 10 amps at 12v for every 100 watts of 240v power. ie. a 1000w inverter will draw a min of 100 amps at 12v. Remember though this is only drawn when the power is being drawn from the inverter. These are rough figures for illustration only!!
Hope that helps, even though it's not what you wanted to hear!!
27th Aug 2007 11:58 am
christyler
Member Since: 31 Dec 2005
Location: Cork, Ireland
Posts: 1168
Correct, you are looking at over 100amps for 1000watts,
My 1500watt inverter draws over 140amps when i use it in anger.CLUB "Ah Shor it'll be grand"
First D3 in the World with a Hydraulic Winch.
2006 Disco 3 TDV6 S Auto,
Diff Locks, Turbochipped, Raised Air Intake, 220volts Onboard, Onboard Compressor, Large Bore Exahust, Underbody Protection, One or two Other Mods as well.
Other toys include, Argo Avenger 8x8, Tatra 6x6 Motorhome (Being Built)
27th Aug 2007 12:13 pm
gilmore
Member Since: 16 Jan 2005
Location: On the sofa
Posts: 2185
Thanks everybody!
regs
robAll opinions expressed in this posting are my own and are not necessarily those of someone who knows what they are talking about.
Land Rover Defender V8, 50th Anniversary Edition
Mercedes ML350CDI
HM Moto CRE300X
Honda CRF250X
1974 Honda CB750K4
1975 Honda CB750K5
Ford Transit Custom (for the bikes)
27th Aug 2007 12:14 pm
DiscoDunc
Member Since: 08 May 2006
Location: Bristol
Posts: 16390
Yes it is, but I would buy a bigger one now. I got that about 3 years ago when it was a bit more expensive !!Duncan
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27th Aug 2007 1:44 pm
drivesafe
Member Since: 23 Feb 2006
Location: Gold Coast, Australia
Posts: 867
Hi gilmorr, what you need to do before buying your inverter is to work out how many of the devices you mentioned that you will need to have on at the same time.
Then total up the wattage of these devices and this will give you an idea of the minimum size inverter you will need.
A little advice, try to get an inverter about 50% bigger then what your maximum requirements will be. Inverters do not like running continuously at or near the maximum rating, they tend to die prematurely plus some inverters start to change their AC characteristics when operated at near their limit.
This not only eventually damages the inverter, it can harm the AC devices be powered from it.
Cheers.2008 TDV8 RR Lux + 2009 D4 2.7
27th Aug 2007 2:13 pm
gilmore
Member Since: 16 Jan 2005
Location: On the sofa
Posts: 2185
xtc wrote:
Hi, No, the 10amps is at 12v from the vehicle, not mains. So very roughly 10x12 =120 x.8 ish for efficiency = 100w at mains from a 10amp, 12v socket.
A easy rule of thumb is you need 10 amps at 12v for every 100 watts of 240v power. ie. a 1000w inverter will draw a min of 100 amps at 12v. Remember though this is only drawn when the power is being drawn from the inverter. These are rough figures for illustration only!!
Hope that helps, even though it's not what you wanted to hear!!
According to this, even DiscoDunc's 300w invertor should be too much for the socket circuit as it would result in 30 amps.
regs
robAll opinions expressed in this posting are my own and are not necessarily those of someone who knows what they are talking about.
Land Rover Defender V8, 50th Anniversary Edition
Mercedes ML350CDI
HM Moto CRE300X
Honda CRF250X
1974 Honda CB750K4
1975 Honda CB750K5
Ford Transit Custom (for the bikes)
27th Aug 2007 3:28 pm
christyler
Member Since: 31 Dec 2005
Location: Cork, Ireland
Posts: 1168
30a yes but only if its running a full capacityCLUB "Ah Shor it'll be grand"
First D3 in the World with a Hydraulic Winch.
2006 Disco 3 TDV6 S Auto,
Diff Locks, Turbochipped, Raised Air Intake, 220volts Onboard, Onboard Compressor, Large Bore Exahust, Underbody Protection, One or two Other Mods as well.
Other toys include, Argo Avenger 8x8, Tatra 6x6 Motorhome (Being Built)
I have a 2000 w in the 130 Home of RLD Hidden winch mounts Spare wheel Locks Trailer Body Fabrication ray@rld-tech.co.uk D3/4 sump plates MY 14 sump plates and the Discovery Sport wheel protectors Discovery 5 wheel locks
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27th Aug 2007 3:57 pm
xtc
Member Since: 27 Mar 2007
Location: Hampshire
Posts: 1072
Hi Rob,
As another thought, if you are intending to run electronics from the inverter, not power tools, lighting etc then it's worth thinking about getting a professional one with a sine wave output. Most of the cheepies (£100 & less). have a modified sine wave which some electronics do not like. Especially equipment with switched mode power supplies or LCD screens etc.
A decent 300w sinewave inveter though is £150+ and a 1500w £500 so maybe over the top, but anything less will be a modified sine...
I have used the S600 for a few work jobs and they have been superb, £200 for a 600w, but run at 200w is drawing 20amps and idling so will last for ever.
Know the last 2 won't interest you Rob, just mentioned them for anyone reading that may need a larger unit. We have fitted the PM1500SL's to a couple of D3's now and they have been running for a couple of years without fault. Would highly recommend them.
27th Aug 2007 6:22 pm
AndrewS Tarquin of the Desert
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I have an 1800w in the 110In the Beginning there was nothing, which exploded.
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