Modify HIACE VAN for comfortable trip

How to predict the temperature of a car cabin parking in the very cold weather?

The result of previous tests

Result 1

Temperature of inside of the car will be higher than outside by 3 degrees Celsius until midnight with following items.

  1. Electric blankets or 1 person ( 120W heat generator)
  2. Fiberglass insulator (Installed inside of inner linings.)

Result 2

If you add the items below, temperature of inside of the car will be higher than outside by 4 degrees Celsius until midnight.

  1. Styrofoam window panels
  2. Curtains between the passenger cabin and cargo room

Hereinafter, I shall omit “Celsius”.

Heat insulating items I brought to Hokkaido

Taking them into consideration, I went to Hokkaido with following items.

  1. Electric blankets
  2. Fiberglass insulator (Installed inside of inner linings.)
  3. Styrofoam window panels
  4. Curtains between the passenger cabin and cargo room
  5. Heat insulation mats

Temperature graphs in Hokkaido

Typical 3 types of difference variations are found.

Feb/27 Very warm => Very cold

I arrived at Tomakomai, Hokkaido by ferry at 21:00 on Feb/27/2018. Then, drove to Shimukappu village, and reached there around 23:00. At that time, outside temperature was -10 degrees, and inside temperature was more than 15 degrees. So the difference was almost 30 degrees at first.

I stopped the engine, and started again around 5:10 next morning. While the car was parking, outside temperature fell rapidly and was below -20 degrees, and difference also fell rapidly as well, but still it was about 8 degrees 6 hours after engine stopped.

At 5:00 next morning, inside of the car temperature was -15 degrees, and it was very cold, but still difference was relatively high compared with previous tests.

Predict the temperature of car cabin

The effect of IMPROVED thermal insulation on HIACE VAN

Still not enough

As explained in my previous article The effect of thermal insulation on HIACE,

  • Car inside temperature will be higher by 3 degrees Celsius with 120 W heat.
  • It would be 4 degree Celsius if you add heat insulation panelS on cargo room windows, and a curtain between cargo room and passenger cabin.

This 3 or 4 degrees are better than nothing, but it is not enough in Hokkaido winter, where temperature sometimes goes below -10 degrees Celsius.

So I tried some of additional items to improve the heat insulation.

Added items for better heat insulation

The added items are below.

Heat insulation mat

This is 7 mm thick tile shape mats. I laid them out on the bed floor.

test the improved heat insulation on HIACE VAN
Heat insulation mats

Heat insulation sheet

This is a large size 4 mm thick sheet. I stand it to cover the cargo room to keep cold air out.

test the improved heat insulation on HIACE VAN
Heat insulation sheet

The effect of thermal insulation on HIACE

Add thermal insulation to my new HIACE VAN

My newly ordered HIACE VAN was delivered on Aug./5/2017.

One of the popular modifications among HIACE buffs is add heat insulation material between the panel and inner linings.

I was planning to go to Hokkaido, northern part of Japan in winter, so adding thermal insulation was my first priority.

I started the work in August, and it was very hot inside the HIACE VAN in the middle of summer.

Source of information

Beforehand, I got useful information from the following blogs. (They are all written in Japanese.)

Quest for enjoyment with HIACE

It was really hard work

Remove the carpet on the floor.


Improve the fixture of HIACE VAN solar panel

Very difficult to detach the panel

The solar panel was mounted on the roof with roof carrier.

The panel is fixed onto the carrier by C-shaped metal parts and hexagon head bolts and nuts.

I hope my poor drawing below may help you.

Fixture of solar panel

The solar panel is fixed on the cross member of roof carrier with C shaped metal parts and M6 hexagon bolts and nuts.

improve the fixture of solar panel
C shaped metal parts

You’ll see the below image if you see the direction of arrow B shown in above drawing.

(The bolts and nuts are already replaced by butterfly nuts and bolts.)

improve the fixture of solar panel
Outside view of fixture

Add batteries to HIACE VAN solar photovoltaic system

Prepare for winter trip to Hokkaido

Stored electric power in the solar system

As mentioned in previous article, 2 batteries were installed in the solar system in HIACE VAN. Battery is ACDelco’s M27MF, its nominal capacity is 105 Ah.

HIACE solar system modification

105 Ah means 105 Ah × 12 V = 1260 Wh.

Assume that 70 % of stored energy can be utilized, 1260 Wh × 0.7 =882 Wh.

Multiplied by the quantity, 882 Wh × 2 = about 1700 Wh.

Required electric power in Hokkaido winter

On the other hand, expected daily electric power consumption in winter Hokkaido is

Electric blanket 30 W × 10 h = 300 Wh

Electric water boiler 440 W × 0.5 h = 220 Wh

USB charger 15,000 mAh × 3.6 V × 2 unit = 108 Wh

Therefore, roughly estimated daily electric power consumption is 628 Wh


Install curtains on HIACE VAN to maintain privacy while door are open

Open the doors to circulate the air inside

In summer, it’s necessary to open both of slide doors keep open when relaxing in HIACE. Though, if you keep the doors open, you want to curtain off the opening to maintain privacy. So I decided to install curtains.

First I tried to find ready to attach curtains, that is specially designed for HIACE, and I could only find curtains that covers windows, but none that is long enough to cover whole slide door.

Then, I was considering to install curtains by myself.

I started DIY curtain project

It’s easier to suspend a curtain with hooks attacked onto the ceiling, but I wanted to draw curtains to keep them half open or full open quickly. So I tried to find how I can install a curtain rail for a house to achieve better usability.

How to install curtain rails ?

How about making a hole on each pillar, then attach a curtain rail directly?

It may work, but as far as I checked, curtain rails for houses are attached with φ2.7 mm or φ3.5 mm wood screws. If you attach a curtain rail directly to pillars, you can only use  2 of M2 or M3 screws, and  apparently, it’s not strong enough.

I guess it’s not good looking, but better to attach a curtain rail to a square timber, then attach the timber to the pillars.

Select suitable parts and buy

A) Curtain Rails

I chose the one that was light and flexible in case it falls. It’s length is adjustable between 1 m and 2 m.

Square Telescopic Curtain Rail 2m single type (white)

B) Plates to fasten the timber to the hole on the pillars

I purchased stainless plates with a hole of φ6.5 mm to fix it with M6 bolts and nuts.

They can be iron plates, but ones I found was painted black, and I wanted silver ones, so I bought stainless ones.


How to install a solar photovoltaic system to HIACE VAN

Why I wanted to install a solar panel

When  I travel by a car, sometimes I stay in one place for several days, and in such case, solar system is very convenient. 

Additionally, in Japan, major earthquakes are expected,and if you use a car as a shelter, solar system is indispensable.

So I decided to install a solar photovoltaic system to my HIACE VAN.

In this article, I’m going to explain how to select each equipment, and how to install the system.

Decide the specification of solar system

What appliances do you want to use in the car?

I want to use the followings.

Electric water boiler 440W

Electric blanket 60W

Portable refrigerator 30W

USB charger 30W

=>Total capacity should be not less than 600W