BrendanS
Well-Known Member
Nits?
True power consumption of laptops vs chartplotters?
- Thread starter Duffer
- Start date
Ships_Cat
Well-Known Member
Yer talking of head lice or cd/m2 /forums/images/graemlins/smile.gif.
Anyways, cats have fleas, humans have nits.
John
Anyways, cats have fleas, humans have nits.
John
BrendanS
Well-Known Member
just nits, which most people talking about outdoor screens will understand
Ships_Cat
Well-Known Member
Ok, candela nits you mean - as long as not calling me a nit (but maybe that too
).
John
).John
BrendanS
Well-Known Member
750 of them do fine on a laptop, as least as far as I understand it. 1000 will make a very good outdoor screen
Ships_Cat
Well-Known Member
Can't see in any documentation as to how many nits I have for the 6120 (as Tome photo'ed), nor for other HP's - maybe Tome knows?
John
John
tome
Well-Known Member
There's a good technical paper here which you might find interesting. This would suggest around 2,400 nits equivalent is required for outdoor sunlight use.
We manufacture a transflective screen which has an equivalence of around 1,000 nits and is designed for outdoor use. In fairness, the Raymarine E series beats it easily so I'm guessing that the E series is close to 2,400
Most laptops struggle to beat 300 in full-power mode
We manufacture a transflective screen which has an equivalence of around 1,000 nits and is designed for outdoor use. In fairness, the Raymarine E series beats it easily so I'm guessing that the E series is close to 2,400
Most laptops struggle to beat 300 in full-power mode
Duffer
Well-Known Member
Thank you all for your very helpful replies on this subject. Perhaps I can attempt to draw a few conclusions (a risky business I know!)
(1) It is a myth that a modern laptop with a mobile processor uses the 60-100w quoted on the charger - once charged a more typical figure is under 30w, perhaps under 20 watts if you have a fairly specialised set up. Clearly you can extend battery life using power management options and putting it into standby (though this can require rebooting some set ups).
(2) A Raymarine C70 screen uses more like 10-20w than 40w though larger screens and the brighter E series will use 20w or 30w.
(3) A dedicated plotter is likely to use less power than all but the most specialised PC setups (which was my point on the other thread) but both use a lot less than I understood to be the case. The reason a laptop uses only 50% more power than a plotter with half the screen diagonal/quarter the screen area is because the screen on a daylight viewable plotter is much brighter than your average laptop (even a C screen is hard to see in direct sun light - I gather the E screen is better but it costs a lot more). Also mobile chips (centrino, core duo, turion etc) use a lot less power than desk top equivalents especially if you use power management options.
Two more questions:
(a) roughly how much power is lost by running a device e.g. a laptop off a cheap 100 or 150w inverter via a mains transformer compared with running it direct from 12v?
(b) how much power does a 2kw radome use? (One post said about 20w just in standby so turn it off to save this but remember it takes 1 minute to warm up again)
(1) It is a myth that a modern laptop with a mobile processor uses the 60-100w quoted on the charger - once charged a more typical figure is under 30w, perhaps under 20 watts if you have a fairly specialised set up. Clearly you can extend battery life using power management options and putting it into standby (though this can require rebooting some set ups).
(2) A Raymarine C70 screen uses more like 10-20w than 40w though larger screens and the brighter E series will use 20w or 30w.
(3) A dedicated plotter is likely to use less power than all but the most specialised PC setups (which was my point on the other thread) but both use a lot less than I understood to be the case. The reason a laptop uses only 50% more power than a plotter with half the screen diagonal/quarter the screen area is because the screen on a daylight viewable plotter is much brighter than your average laptop (even a C screen is hard to see in direct sun light - I gather the E screen is better but it costs a lot more). Also mobile chips (centrino, core duo, turion etc) use a lot less power than desk top equivalents especially if you use power management options.
Two more questions:
(a) roughly how much power is lost by running a device e.g. a laptop off a cheap 100 or 150w inverter via a mains transformer compared with running it direct from 12v?
(b) how much power does a 2kw radome use? (One post said about 20w just in standby so turn it off to save this but remember it takes 1 minute to warm up again)
pvb
Well-Known Member
Radome power consumption...
Raymarine quote 28W (typical) and 9W (standby) for their 2kW radome.
Raymarine quote 28W (typical) and 9W (standby) for their 2kW radome.
mikejames
Well-Known Member
Old B/W 4 inch Garmin GPSMAP130 : 0.13 to 0.3A or about 1.5W to 3W for backlight on. Inherently daylight viewable. s*d all charts cartridges available.
Use waypoints all over the place with the builtin basemap.
Use waypoints all over the place with the builtin basemap.
Ships_Cat
Well-Known Member
roughly how much power is lost by running a device e.g. a laptop off a cheap 100 or 150w inverter via a mains transformer compared with running it direct from 12v?
If off an inverter at very worst lets say 20% loss, so if notebook draws, say, 25 watts then around 5 watts loss. However, I would expect 20% loss to be a pretty lossy situation for an inverter and so I would assume that the inverter loss PLUS the loss from your notebook's charger plugged into the inverter's 230 v is somewhere around 7 - 10 watts total worst case over plugging 12 v straight into the notebook (ie no DC step up converter is used).
As a guide to inverter efficiency Xantrex quote 85% efficiency and >90% efficiency for their 1KVA upwards Freedom inverters. I don't know how efficient the cheap small ones really are but would be surprised if less at what are when powering a notebook low efficiency low current outputs for the large Freedom.
Which leads to another claim often made that it is important to use a DC voltage step up buck converter rather than an inverter as they are more efficient. Even assuming a large 20% loss for an inverter (which would be surprising) and a minimal 5% loss for a buck converter (and they are likely more lossy than that) the difference between the two (including the likely loss from the notebook charger when using the inverter) is only about 5 - 6 watts or so.
Now I know on some boats that a few watts saving may be important but some seem to have it that it is important to ALL so a step up converter MUST be used (the difference is a little more than 2 minutes extra charging per day with a 100 A alternator for us and many others if extra loss was expended for 10 hours/day).
Again, it gets back to the boat and the circumstances and that may be just simple convenience - in our own case where an extra few watts is little difference to us, I still use a step up DC buck converter off 12 volts rather than the inverter as I find it convenient and means I have both the converter and the inverter for the case of failure of one or the other.
John
If off an inverter at very worst lets say 20% loss, so if notebook draws, say, 25 watts then around 5 watts loss. However, I would expect 20% loss to be a pretty lossy situation for an inverter and so I would assume that the inverter loss PLUS the loss from your notebook's charger plugged into the inverter's 230 v is somewhere around 7 - 10 watts total worst case over plugging 12 v straight into the notebook (ie no DC step up converter is used).
As a guide to inverter efficiency Xantrex quote 85% efficiency and >90% efficiency for their 1KVA upwards Freedom inverters. I don't know how efficient the cheap small ones really are but would be surprised if less at what are when powering a notebook low efficiency low current outputs for the large Freedom.
Which leads to another claim often made that it is important to use a DC voltage step up buck converter rather than an inverter as they are more efficient. Even assuming a large 20% loss for an inverter (which would be surprising) and a minimal 5% loss for a buck converter (and they are likely more lossy than that) the difference between the two (including the likely loss from the notebook charger when using the inverter) is only about 5 - 6 watts or so.
Now I know on some boats that a few watts saving may be important but some seem to have it that it is important to ALL so a step up converter MUST be used (the difference is a little more than 2 minutes extra charging per day with a 100 A alternator for us and many others if extra loss was expended for 10 hours/day).
Again, it gets back to the boat and the circumstances and that may be just simple convenience - in our own case where an extra few watts is little difference to us, I still use a step up DC buck converter off 12 volts rather than the inverter as I find it convenient and means I have both the converter and the inverter for the case of failure of one or the other.
John
Birdseye
Well-Known Member
I really dont see the point of this discussion. Most people already have a laptop, often provided by the employer and therefore both waterporrf and shock resistant. For the extra cost of buying a chartplotter, they can easily invest in extra batteries, still have loads of beer vouchers left over and still be able to do email etc from the boat.
But you cant in practise use a laptop on deck so if you need nav guidance where it should be (in front of the wheel ) you have no choice.
Boils down to money not amps - or is that just a Yorkshireman speaking.
But you cant in practise use a laptop on deck so if you need nav guidance where it should be (in front of the wheel ) you have no choice.
Boils down to money not amps - or is that just a Yorkshireman speaking.
Ships_Cat
Well-Known Member
provided by the employer and therefore both waterporrf and shock resistant.
Like company cars /forums/images/graemlins/smile.gif.
Tend to agree with you tho', seem to be alot of hang ups by some over power consumption - one can buy a big capacity set of the best deep cycle batteries and probably a big alternator too for the price of a teeny screened plotter and have plenty of power for other things as well.
John
Like company cars /forums/images/graemlins/smile.gif.
Tend to agree with you tho', seem to be alot of hang ups by some over power consumption - one can buy a big capacity set of the best deep cycle batteries and probably a big alternator too for the price of a teeny screened plotter and have plenty of power for other things as well.
John
bluedragon
Well-Known Member
Actually I can't bothered to read through the zillions of posts here, so maybe you've been answered. If it's of any help I did a detailed comaprison last year. Laptop took over 4A (50W)with screen on, standard power-saving setup and the battery in place. Best I could get down to with maximum Windows XP power saving and the battery out was about 2A (25W). Bit of a nuisance having the screen go off every few mins though and the harddisk shutting down. Lowrance 3500C plotter I have now uses 0.8A (10W) and is fully functional all the time.
tome
Well-Known Member
[ QUOTE ]
Actually I can't bothered to read through the zillions of posts here...
Lowrance 3500C plotter I have now uses 0.8A (10W) and is fully functional all the time
[/ QUOTE ]
Silent chuckle
Actually I can't bothered to read through the zillions of posts here...
Lowrance 3500C plotter I have now uses 0.8A (10W) and is fully functional all the time
[/ QUOTE ]
Silent chuckle
Ships_Cat
Well-Known Member
For those others like yourself, not prepared to read zillions of posts you could have bin more concise, along the lines of -
"My laptop draws over 4 A and my plotter draws 0.8 A so plotter always best, and I have not allowed myself to be confused by reading the facts".
John
"My laptop draws over 4 A and my plotter draws 0.8 A so plotter always best, and I have not allowed myself to be confused by reading the facts".
John
