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Camping now allowed in WA

April 26, 2020 — BarryK

In Western Australia we had zero new cases of Covid-19 for three days, then yesterday there was one, a lady who arrived back from one of the cruise ships. As long as she hasn't started a new outbreak, things are looking very good, attributed to the very sensible restrictions imposed by the WA State government.

Consequently, the Premier today announced some easing of restrictions ...including allowing camping!!!

The eased restrictions are announced here:


non-contact recreational activities such as private picnics in the park, fishing, boating, hiking and camping − all in compliance with travel restrictions and the 10-person rule

WA is broken into regions, and we are still only allowed to drive within the region in which we live. There are DPAW campsites within the Perth/Peel Region -- but perhaps lots of people will be taking the opportunity to go to those campsites.

The main point is though, in theory I can now go camping. Just need to find a nice bushland or coastal spot within my region, that will not have many others also camping there.

Got to finish the powerbox first! 

Tags: nomad

Holders for blade fuses in powerbox

April 26, 2020 — BarryK

I posted yesterday about the start of wiring the powerbox, and a problem with using blade fuses at 20-30 amperes:

Originally, I had purchased this blade fuse holder 4-way box:

However, after watching the Redarc video (see above link), I became concerned. The Narva packaging has "Maximum 30A per circuit", and if you believe that, then you could put a total of 120A through it, 30A per fuse.

I did a bit more reading on the topic, and it looks like the 6.3mm spade terminals, as used in the above Narva fuse box, are only designed to handle 10-15A. A 6-way blade fuse box sold by Jaycar, which, apart from having 6 slots looks identical in its internal construction to the Narva box, states "15A/circuit max" and "45A/block max":

Jaycar have these female spade terminals, rated at 10A maximum:

Comparing different blade fuse holders and spade terminals, some are thicker metal, and appear to be designed to handle higher current.

Looking at what blade fuse holders are on offer, some indeed are thicker metal and grip the fuse more firmly. I bought two of these inline blade fuse holders:

...these have superb grip on the fuse, and actually require some force to fully insert the fuse. Good, but I want to mount these on my "wiring-board". That board is 150mm horizontal by 170mm vertical, 6mm thick marine ply, and I posted a photo of the start of wiring it in the previous blog post. Here is a photo with two of the inline blade fuse holders mounted on the board:


...overkill using that heavy-duty fuse holder for the 1A fuse. To mount these fuses on the board, I used Selleys "All Plastic Fix" glue and a small piece of plastic cut off a chopping board.

I have used that Selleys glue on previous projects. It consists of a primer-stick and an adhesive tube, and will glue all types of plastic, giving a very strong bond. The primer-stick lasts a lot longer than the adhesive, and I was reading somewhere, someone just used superglue and it worked the same as the All Plastic Fix adhesive tube.

The 1A fuse goes to the coulometer, via the shunt. The 15A fuse will go to the cigarette-lighter sockets. I still have to put in fuse holders for the DC-output black Anderson plug, and for the solar input grey Anderson plug -- these will be 30A and 25A fuses. 

EDIT 2020-04-26:
Fuse holders for the 30A and 25A blade fuses have been added to the board:


I wanted screw terminals, so chose these:

These blade fuses need even more force to insert than the other ones, so it is a very good connection between fuse and holder, so I am confident these will handle 30 amperes. The screw terminal holes look like they will take up to 9 AWG -- I have just noticed that the table here has the wrong area for 9 AWG cable -- it should be 6.6mm2.

Same construction, the two fuse holders have been glued together for mounting on the board. Given the force to insert and remove fuses, I put an extra piece of chopping-board plastic to more securely bond the two holders together.

The two red cables going out to the left, have Anderson plug lugs on the ends, for insertion into the black and grey Anderson plugs.  

Tags: nomad

Wiring of powerbox underway

April 25, 2020 — BarryK

I have started the internal wiring of the lithium powerbox, and this post is a progress report. Here is the previous post for this project:

It is progressing slowly, but surely. I had to pause for awhile to think about some construction details. Anyway, here is a photo showing the wiring so far:


...notice that the box is now painted black! I used a cheap "flat black" enamel paint spray can.

A change from the previous photo (see above link) is that I removed the Anderson plugs from the DC-DC charger and cut a round hole for the cables to go into the box. Next to the round hole is "half" of an Anderson plug -- this is for the wiring to the vehicle ignition key.

The wiring-board is propped alongside the box, for the photo. Top-left of the wiring-board is the shunt for the coulometer, the two black and red cables sticking out the top will go to the battery.

The "+bus" and "-bus" busbars were purchased from Jaycar:

The terminal blocks at top-right are for wiring to the DC-DC charger. I purchased porcelain blocks:

...however, afterward I noticed these, which would probably do the job:

The blank space on the wiring-board is where the fuse holders will mount. This is where I had some problems, as the blade fuse holders in local shops, of the surface-mount terminal-block type, seemed too "light" to handle 20-30 amperes. The engine-bay is a more extreme environment, but this Redarc video does show the potential for catastrophic failure when using blade fuses:

Snapshot from the video, of a melted inline blade fuse holder and fuse:


I intend to post soon about what fuse holders I chose, and what got rejected. 

Tags: nomad

Powerbox external assembled

April 20, 2020 — BarryK

This is continuation of the new lithium powerbox project. Previous post:

I have cut out the front and back panels, here it is assembled, front view:

img1 internal wiring yet! Here is the back view:


So, in retrospect, am I happy with the design of the box? If it was done again, would I change anything? Yes...

  1. I used 6mm ply front and back, which is too thin. The Anderson plugs require considerable force to plug-in and unplug. I strengthened with some strips of pine screwed on internally, however, use of 9mm ply would have been better.
  2. Dimensions are a tight squeeze. OK, but if someone wanted to use a slightly different battery, it probably wouldn't fit. For my Amptron 50AH battery, I would have preferred an extra 5mm internal height, to make sliding in and out via the side easier -- though probably once it is in, it will stay in -- I expect the battery to outlive me.
  3. It might have been simpler and easier to go for a wood frame rather than aluminium. Bunnings sell 12x12mm section medium-hardwood, which would have done the job.

I used SolveSpace to figure out where to place the cut-outs on front and back panels. Here is the front panel layout:


...the 165x170mm rectangle is the internal battery, so there is nothing cutout on the front panel in that area. Here is the back panel layout:


...again, the battery is shown. The two 48x74mm rectangles are not cut-outs -- that is where the 30A circuit breakers will mount externally.

I painted it aluminium-silver, however, reckon that matt-black would be more appropriate. Black would match the DC-DC charger, and some of the power sockets.

There are a couple of details to finish off, before starting on the internal wiring.

EDIT 2020-04-21:
For the record, this is where I purchased some of the items screwed onto the front and back panels:

I ordered one of each colour of the Anderson panel-mounts. The vendor agreed on one payment of AU$9.90 to ship all three by Aust. Post Express (you have to ask for that):

This is the cigarette lighter socket:

Binding posts came from Altronics:

...they have holes for banana plugs, but Altronics also have binding posts without the banana plug holes. Note, the tops screw right off, so that eye-type lugs can be attached.

The externally-mounted 30A circuit breakers are available from many places. They are very expensive from some local vendors. I purchased via eBay:   

EDIT 2020-04-22:
Here is another vendor of the flush-mount Anderson housings, at almost half the price. They stock grey, red, black and blue:  

Tags: nomad

Powerbox side panels and battery clamp

April 16, 2020 — BarryK

Here is the previous post in the new lithium powerbox project:

Today I cut out the side panels, and implemented a solution for holding the battery down.

Firstly, the side panels. These are 228 horizontal by 212 vertical, 6mm thick plywood. These will screw onto the sides, and be removable -- the left is where the battery will slide in, and the right is to access the electrical wiring.

Pretty simple, cut them out using a tenon saw, drilled holes in an offset-pattern, and a coat of acrylic paint:


Out of curiosity, I contacted a local business that specializes in custom perforated aluminium. Their quote for the same thing in aluminium, 1.5mm thick, 40%-open pattern, was AU$80 + GST. That would mostly be labour cost of course.

The battery needs to be held in place, both horizontal movement and jumping vertically. I will put some angle to make sure it doesn't creep horizontally. To stop jumping, I created two vertical posts:


...two pieces of 10x10x1.5mm aluminium channel, with 12x12x3mm angle riveted to them. I used stainless steel rivets, for the extra strength, which I think will be OK -- but if someone is following these plans, you might consider using 12x20x3mm angle, with two rivets.

Um, Bunnings only have 12x12 and 20x20 in the 3mm thick angle. Here is the 12x12x3mm:

After riveting it into the box:


...10x10x1.5mm channel is used as the cross-piece. The clamping bolts are M4 10mm hex-head, which is a very convenient size, as the hex-head fits snuggly into the channel.

I have 10mm length, however might pop down to Bunnings and buy 16mm length, so as to be able to use two nuts (to lock them in place):


The cross-piece is shown in the photo for illustration, but it would only be inserted after the battery is placed inside the box.

So, what is next? Front and back panels I think. 

Tags: nomad

Ready-made lithium powerboxes

April 15, 2020 — BarryK

My new project is a "lithium powerbox", see most recent post here:

It is interesting to see what is out there, ready-made. There are many powerboxes, of varying capacities and features. Most of them are designed to be portable and readily removed from the vehicle. One of the biggest of these highly-portable types, that I know of, is a 60AH unit made by iTechWorld:

...which is a very nice all-in-one solution, at an excellent price. It has compromises, such as only charging via the cigarette light socket, so probably limited to 10A charging. The documentation states that it cannot be used when charging.

The more "hard core" solution is a powerbox that is intended as an alternative to a permanently wired-in system. Many 4wd owners go the latter route, with a custom permanently wired-in installation -- which often looks very messy and may be space-inefficient.

The semi-permanent "hard-core" powerbox may be left permanently in the vehicle, or taken out, perhaps if you are not going camping for awhile and need the space for something else, or change to another vehicle. These powerboxes are designed to charge directly from the car battery, at 20A or more.

I did a quick survey of what is available in Australia, in this "hard-core" category. One that I knew of from before is "The Lithium Box":


...the smallest has a 100AH battery and weighs 21kg -- too heavy for me! I can't see prices anywhere.

A Perth company has put together the "National Luna" box:

...with Amptron 100AH lithium battery, price is AU$1,990. Weight is 18kg.

Here is another, the "JTS Power Easy" box:


...price is AU$2,795, with 100AH battery. Weight is given as 55kg ...gulp!

But wait, there's more! If you would like a battery box with DC-DC charger but without the battery, so that you can add your battery-of-choice later (AGM or lithium), there is the "Kickass Premium Battery Box", at AU$689:


...though, not yet available. ETA is August 2020. It is their DC-DC charger that is holding things up -- it has been on pre-sale for a few months. No doubt it is coming from China, and will do once the factories start up again, and shipping improves. 

Tags: nomad

Top-plate of lithium powerbox

April 14, 2020 — BarryK

The plywood floor is 235x225x9mm, with 12x20x1.5mm angle assembled around it, see previous blog post:

The top of the powerbox will be a flat surface. This is plywood measuring 238x228mm (3mm longer on both sides than the base plate). In this case I have used 6mm ply, which will also be used for the sides. It is just that I have 6mm marine ply in my garage, and want to make use of it.

I also have some 12x12x1.5mm angle in the garage, so have used that around the edges:


...that is upside-down. Here it is the right-way-up:


The screws are 6G 9mm dome-head, for metal and wood, which meant the tips stick out the other side of the plywood. However, it was easy to file the metal tips flat to the surface.

This gives me a completely flat surface on top, on which the DC-DC charger will be mounted, plus two grab-handles.

A practical detail for anyone in the future who might follow these plans to build their own powerbox: if you cut the pieces of aluminium angle too short, no problem as they will be hidden by external plywood cladding.
On the other hand, if a tad too long, a simple way to grind the end is like this:


I used coarse sandpaper, 40-grit. The sandpaper is intended for sanding wood, but worked OK grinding aluminium -- the grains did not come off. The trick to doing it is press firmly with the finger closest to the end, and drag towards you -- pushing away from you does not work so well.

The top and bottom plates require corner posts. These are angle pieces riveted on the inside corners. I used 12x12x1.5mm angle, 30mm long. The rivets are aluminium 3.2x3.2mm (requiring a 3.2mm, or 1/8 inch, drill bit). Here they are installed in all corners:


Another practical detail: I used two "clamping pliers" to hold the corner posts while drilling. Otherwise, you could use a small block of wood and g-clamps.

What will happen next, is there will be 175mm lengths of 12x20x1.5mm angle vertically on each corner. The reason for having the inside posts is that the final result will be a flush surface onto which the plywood cladding can be screwed -- except for the little bumps where the rivets are, but that can be fixed by appropriate indenting on the back sides of the cladding.

EDIT 2020-05-01: Important design change
After building the powerbox, I found a very big problem, it was very difficult to access the battery terminals. The fix is to make the top-plate removable.

Which it isn't as shown in the above photos, as the screws are underneath, inside the box. So, instead, screw from the top, through the plywood into the aluminium.

Please see this post, that shows the final box with battery inside:

The box will then have removable panels on all four sides and the top. The screws used are 8G 15mm button-head timber screws:

The drill bit used is 2mm. The wood screws are able to self-tap into the aluminium.

Placement of the screws needs to be thought about. I placed them 8mm in from the edges of the plywood, and they need to be placed so as not to be underneath where the DC-DC charger is proposed to be located. Also, there are two handles on the top, which will also have screws that tap into the aluminium. 


Tags: nomad

Confusing online voltage drop calculators

April 13, 2020 — BarryK

I received an email from Gerard, claiming that my voltage-drop formula is wrong, by a factor of 2. That is, where I calculated 1.11V drop, Gerard said it should be 2.22V. See this post from a couple of days ago:

The factor of 2 difference should have been the big hint. I was confused for awhile, as some online calculators seemed to support what Gerard claimed. But then we both realised the reason for the difference...

Most of the online calculators are for AC cable, with ISO sizes, and use of twin-core. The online calculators require the length of the actual cable to be entered, not the total "round trip" through each core. So for my 15m cable from the solar panel, "15" has to be entered into the online calculator, not "30".

In other words, where it asks for "cable length" it means the length of the twin-core cable, not adding the return path.

Regarding ISO sizes, these are used for electrical building wiring in Australia and just about everywhere internationally. There is a nice table here that shows AWG versus ISO sizes:

In fact, that page is an excellent read to understand about all of the different cable sizes -- and in particular how confusing "auto cable" is: 

...that page has an online calculator, that requires entry of the length of one core, so in the case of 15m twin-core, enter "30". 

Tags: nomad