Time is the coin of your life. It is the only coin you have, and only you can determine how it will be spent. Be careful lest you let other people spend it for you. -- Carl Sandburg
There's only one rule that I know of, babies -- goddammit, you've got to be kind. -- Kurt Vonnegut

September 16, 2011

Pondering Van Electricity

In pondering what to get for a new refrigerator, I used my battery monitor to see how much juice each thing in my van takes.  It is an interesting exercise.  Here are the results:

Item qty/state
Amps for item Watts
un plug DC sockets, ant off 0.8 9.9
G4 LED light 1 LED 0.1 1.2
PS int. light 1 1 incandescent bulb 0.2 2.5
DS ext light 1 LED 0.3 3.7
Ext Porch light 1 LED 0.3 3.7
Roof light 1 Florescent – 2 T8 bulbs 2.1 26.0
Bath light 1 1 incandescent bulb 1.5 18.6
Roof Fan hi
2.2 27.3

1.5 18.6

1.0 12.4
Bath Fan 1
1.4 17.4
Water pump Turn on
2.7 33.5

run water
5.0 62.0

run water
5.5 68.2

0.0 0.0
LP Water heater Turn on
0.1 1.2

0.7 8.7
Heater fan
3.0 37.2

3.4 42.2
Inverter On
no load 0.9 11.2
TV+converter on
4.0 49.6

ch scan
3.9 48.4

tv on
3.9 48.4

+ speakers
4.2 52.1
Monitor panel lp
0.1 1.2

0.1 1.2

0.1 1.2

0.1 1.2

0.1 1.2
DC Off
battery monitor itself 0.1 1.2

The baseline is the battery monitor itself and the sensors (CO,LP,smoke), I believe.  The watts are calculated based on the 12.4 V reading on the battery (watts=amps*volts).  It looks like the battery monitor itself only takes 0.1 amp to run wired directly to the battery.  The LED lights are clearly a big savings even over florescent.  The LP appliances need a little juice to run.  I guess that's the regulator or solenoid or something.

I've been looking at marine 12V DC refrigerators.  It is looking like it will take a max of 35-50 amps per day to run one with a freezer compartment.  Now, I have to get serious about what size to get.  I found some Isotherm and NovaKool that will fit into the existing cavity with little or no modification.  They also provide a little more interior volume because they are deeper than the Dometic that I took out.

BUT - if I took out the microwave and some or all of the tiny cupboard above it, I could get a bigger refrigerator and a sizable separate freezer compartment.  That option runs on the higher side of the amp usage.  So far, I've used the microwave only twice.  I would really like having freezer space for my pet food and some for me too.  I suppose I could stow the microwave somewhere for the occasional use I make of it.  What to do?

1 comment:

  1. Subscribed...

    Thanks for the great info. Just what I was looking for. Real numbers of actual usage.

    Do you know of any other sites with this information? Need real figure not published numbers for solar sizing.

    BTW, how many BTU is your roof a/c and do you by any chance know how many amps it draws on low and high with and without the compressor running?

    Thanks and Happy Holidays...



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