| |
| Everything
runs hotter in Florida. So we spend a lot of time thinking of ways
to make our racecars run cooler. |
| |
| On
the Electric Imp, our priority is keeping the batteries cool. Heat
over 60 degrees Celsius will damage them. |
| |
|
Our
next priority is keeping the inverters cool and motors cool. The
inverters need to stay below 75 degrees Celsius. The motors need
to stay below 175 degrees Celsius.
The
motors and inverters are liquid cooled. Cooled water comes from
the radiator, flows through the two inverters, then the two motors.
The hot water then flows back to the radiator.
|
| |
| The
radiator is at the front of the car. Outside air flows through the
radiator picking up the heat from the motors and radiators. That warmed
air is then used to cool the batteries. |
| |
|
This
is a working system. At our race in Savannah in April, the batteries
stayed within their limits. They got hottest, up around 55 C during
the long 30+ mile race. 5 C is not a lot of margin. The inverters
ran at about 50 C, well below their 75 C limit. The motors hovered
at 170 C, very close to their limit.
It
would make more sense to use the coldest air to cool the batteries
and the slightly warmed air to cool the radiator.
|
| |
|
We
remove the stock Subaru radiator from the front of the car.
|
|
| |
|
We
fit a sturdy air filter (designed for a home air conditioning unit)
to keep rocks and dust from the car.
|
|
| |
|
We
order a custom aluminum racing radiator from Howe
Racing Enterprises. We spend some time on the phone with them
discussing our needs. The radiators cooling fin area is 10"
by 26" by 2". That is 520 cubic inches. The original radiator
was 28" by 13" By 1/2" or 182 cubic inches so we
should have over double the cooling surface area.
The
radiator arrives when promised and looks well made.
|
|
| |
|
We
fabricate brackets to attach to the radiator tabs.
|
|
| |
|
We
mount the water pump down low to get keep it full of water.
|
|
| |
|
The
pipes run from the radiator forward with the return to the top opposite
corner of the radiator.
|
|
| |
|
The
water goes into the first inverter.
|
|
|
|
|
Out
from the second inverter, into the rear motor, out to the front
motor, back to the radiator. It is simple.
|
|
| |
|
We
make the radiator cap the highest point and accessible for quick
checking and filling.
|
|
| |
|
For
proper air flow, there must be high pressure in front and low pressure
in the rear and no other places for the air to go. We get out the
Coroplast and Velcro to make this happen.
Some
sections become smooth works of art.
|
|
| |
|
Seen
from the outside.
|
|
| |
|
Some
less so...
|
|
| |
|
And
some are just the best we can do under the circumstance.
|
|
| |
|
We
stick the cover on and we are ready to test.
|
|
| |
| |
