Field Day - Laptop Power Consumption

[Bill W4ZV]

        Do any of you folks have experience running
a laptop from battery power via an inverter?  I will be
operating Field Day from a remote location and cannot
use a generator.  I'll be using my K2 QRP with a fully-
charged 75AH deep-cycle marine battery topped off by
a 3W solar cell.  I'm planning to dedicate my RV's 84AH
battery to the laptop via an inverter.  I'll put the laptop into
maximum power-conservation mode but I cannot seem
to find any specs on what its power consumption may be.
The label on the laptop simply says "100-240V and 0.68-
0.37A" which I assume is at maximum power-consumption.
This implies about 70 Watts and I'm wondering if I can make
it through 24 hours even in max power-conservation mode.
Has anyone been down this road before?

        If the 84AH battery dies, backup plans are:

1.  Run the laptop for 3 hours from its internal battery.
2.  Switch to a second laptop for another 3 hours.
3.  Switch to the 75AH battery if there is enough power
left for both the K2 and laptop.
4.  Switch to my truck battery...last resort since I also
need to get home!  ;-)
5.  Pencil and paper (ugh!)

                                Help please!

                                Bill  W4ZV

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[n6wg]

Bill
I'll be running my IBM Thinkpad from a 12v battery.  The TP wants to
see at least 13v, though, so I'm using the "All-Purpose Voltage Booster"
from N4UAU.  I set mine to deliver 13v with an input from 12v down to 10v.
Current drain is a steady 1.5A.  I plan to move the converter from battery
to
battery when it drops to 11v so I can take advantage of the recovery time in
the battery.  Also have some solar panels to help perk up the offline
batteries
for max battery life.
73, Bob N6WG

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[John, KI6WX]

Bill;
Most laptops will draw less 2A from 12V;  many are down around 1A.  You
should have plenty of power to spare from a 84AH battery even with the
inverter inefficiency.

However, many laptops generate significant amounts of HF interference when
running from AC power.  You may want to check out the interference level
with your laptop running off of the AC inverter.
-John
 KI6WX

----- Original Message -----
From: "Bill Tippett" <[hidden email]>

> Do any of you folks have experience running
> a laptop from battery power via an inverter?  I will be
> operating Field Day from a remote location and cannot
> use a generator.  I'll be using my K2 QRP with a fully-
> charged 75AH deep-cycle marine battery topped off by
> a 3W solar cell.  I'm planning to dedicate my RV's 84AH
> battery to the laptop via an inverter.  I'll put the laptop into
> maximum power-conservation mode but I cannot seem
> to find any specs on what its power consumption may be.
> The label on the laptop simply says "100-240V and 0.68-
> 0.37A" which I assume is at maximum power-consumption.
> This implies about 70 Watts and I'm wondering if I can make
> it through 24 hours even in max power-conservation mode.
> Has anyone been down this road before?
>

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[John [N5BSD]]

I ran my ThinkPad from an inverter last year off a 1050 amp CCA car battery
Along with my FT-100D at 100 watts all day Saturday, no problems what so
ever,
I have seen some noisy inverters, but I have been lucky so far in that
Even my inexpensive ones (read 50 bucks or less) have been pretty quiet
In the HF RFI aspect.


Good luck, Hope to work you this year from the club station here
K5SLD,

------------------------

73
John
N5BSD / NNN0OYH
Soon to be KX1 # 730
www.n5bsd.com



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