I saw a short program (probably on one of the cable science channels)
about Canadian experiments on working in the cold. It showed a man typing
on typewriter in a 40-50F room with no gloves on. They explained that
the secret was that he had a heater around his chest that was keeping
his core temperature constant and warm. It seems that you body can
sense when you are losing heat from your body core and will actually
cut off blood supply to your extremities to keep your core temperature up.
Another program was shown recently on the Science channel called "Lost
in the Snow" that showed a similar experiment on the effects of exposure
to cold temperatures on the body.
I have used the Hometics heating pad around my chest to keep warm on
cold winter days indoors. However, there are times when I would like
to use it without being plugged into the wall. Hence my idea for a
portable power supply using a tool belt. Be warned that this is only
an idea that I have used for myself. Someone would have to manufacture
this with UL approval to insure safety.
By using something like this, people could lower their thermostats and
save fuel during the winter months. I used a lead acid battery
because they are easy to recharge and reliable for the cost. A lithium
ion battery could also be used, but they are much more expensive.
The battery can easily be swapped out and using several could extend the
time you can be unplugged. I believe the current setup should last
about an hour and quarter before the battery has to be recharged. The
Chicago Electric inverter will beep when the voltage from the battery
is too low. I use the battery adapter to connect to the inverter to provide
a fake "cigarette lighter" connection to the power inverter.
The power inverter can then be used in the car for the heating pad
(or any other purpose). Otherwise I would have
had to cut off the power inverters cigarette lighter connection to make
a connection to the battery. This also provides a quick way to disconnect
the battery in case of problem. This tool belt provides a way to keep all
the electronics in front of you in case of a problem. You could also use
a backpack to hold the battery and inverter if the weight around your
waist bothers you.
In the summer, you can take the tool belt heater apart and use the battery
and inverter for other purposes.
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Step 1: Make the Battery Connector
Make a connector for the sealed rechargeable battery. Cut off the alligator
clips and solder on the quick disconnect connectors that plug into the battery.
The power connector shown is an Optronics A-203. It has alligator clips on one
end and a "cigarette lighter" style connector on the other end. Be sure to keep
track of which of the two connectors are the positive and which is the negative.
On the A-203, the positive wire has a white stripe.
Step 2: Connect Inverter
Connect the battery connector to the inverter. The inverter is a
Chicago Electric eight square cylinder model (150 Watt/ 450 watt peak).
It has a cigarette lighter power connector for input. I purchased this
at Harbor Freight tools ( SKU 93095).
Step 3: Connect the Battery
Connect the battery to the power connector and the inverter.
The battery is a 12 Volt/ 9 Amp hour sealed rechargeable lead acid
battery ( PowerSonics PS-1290 F2 model). This or similar batteries
can be found at a battery only store.
Step 4: Plug in the Heating Pad
Plug the heater into the inverter. The heating pad that I used
is a Homedics HPA1. It has a control that allows you set the
heat level from 1 to 6. It also has a timer that will turn the heating
pad off if unattended. It has a strap that allows you to wrap the
pad around your waist. I wear a shirt between the heating pad and
my skin. The battery has enough juice to power the pad for over
Step 5: Load the Tool Belt
I used a BucketBoss Builders Rig brand tool belt. It has a big front pocket
that can hold the battery. The inverter has a small fan, so I left
if dangling in the air off the other front pocket. I wrapped the heating pad
around my back waist and plug it into the inverter. Make sure the battery
connection has the right polarity. Connections should be well insulated to
prevent accidental shorting. The battery will be able to power the
heating pad for over an hour. I used a small Schumacher 1.5 amp battery
maintainer to recharge the battery (Available at Walmart). You may need
to add suspenders to keep the belt up. Or you could also use a backpack
to hold the battery and inverter.
I found that a shoulder bag works great to hold the
batter and the inverter as well.
Participated in the
Stay Warm Contest