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newsCable and soldering guidelines
Continuing the lithium powerbox project, this is the previous post:
https://bkhome.org/news/202004/holders-for-blade-fuses-in-powerbox.html
Today's post has some bits and pieces of information about electrical circuit construction techniques. Those who are skilled with soldering, etc., will be OK to construct a powerbox like mine. Others, however, might need some hints.
Cable sizes
I have used various sizes of cable in the powerbox, as you can see in photos posted in earlier blog posts:
https://bkhome.org/news/202004/holders-for-blade-fuses-in-powerbox.html
...the thinner cable is "6mm auto cable", purchased from Big Als via
eBay. This has copper area of 4.59mm2. The thicker cable is two types,
purchased from Altronics. I do have some 8AWG from Big Als, however that
is twin core, besides, I want to use that for extension leads. So I
popped into Altronics and bought one metre of each of their "61A" and
"90A" power cables, red and black. Here are links to the red cable:
https://www.altronics.com.au/p/w4100-630-0.12-red-61a-power-cable/
https://www.altronics.com.au/p/w4216a-119-0.30-90a-red-power-cable/
The differences between these is very interesting. The 61A cable has
thinner strands, which makes the cable more flexible. Here they are
compared with 6mm-auto and AWG sizes:
| Cable type |
Copper area (mm2) |
| 6mm auto |
4.59 |
| 10 AWG |
5.26 |
| 9 AWG |
6.63 |
| W4100 61A |
7.1 |
| 8 AWG |
8.36 |
| W4216A 90A |
8.4 |
Much more expensive buying locally, but ordering over the Internet is
currently very slow, as vendors such as Big Als are based in the
Eastern States. I have used both of those cables from Altronics, using
up what has been purchased.
Soldering
Soldering technique varies, according to individual style. I prefer
the old-school copper tips on soldering irons -- modern irons do have
copper tips, but they are coated with something -- that I file off to
expose the copper -- as I find that solder sticks better to the copper
surface. The copper corrodes, which is why it has the coating,
but I use a file to keep the copper tip clean and flat. I also prefer a
chisel-tip.
This is the iron that I am using for this project:
https://www.bunnings.com.au/tradeflame-60w-240v-soldering-iron-kit_p5910275
...60 watts is more than enough for soldering 8 AWG cable. I use a
wet cloth to wipe the tip of the iron, but it would be nice to have this
one, with stand and sponge:
https://www.bunnings.com.au/tradeflame-30-60w-soldering-iron_p6270385
I do not own a crimping tool, so all joins are soldered. Eyelet lugs
and Anderson plug lugs are connected to cables by the flood-fill method.
See demo here:
https://www.youtube.com/watch?v=6IjG6-PxNBs
...difference for me though, is I apply solder to the expose cable
ends, before inserting. This ensures that solder has flowed through all
the fine wires in the cable, avoiding what is called a "dry join".
The video shows a flame being used to heat the Anderson lug. As I use
a soldering iron, just a dab of solder on the flat surface of the
chisel-tip, held against the side, will heat the wall and the solder can
be inserted -- as the video says, take care not to overfill, otherwise
it will overflow and run down the outside of the lug, perhaps rendering
the lug unusable.
I also solder the ends of the cable that is inserted into screw
terminals. This strengthens the cable, as the twisting action of the
screw can break the fine wires, plus some wires thrust to the side of
the screw are not tightly bonded electrically to the terminal.
Regarding solder, for this fairly heavy work, I prefer 1.6mm thick solder, available from Altronics:
https://www.altronics.com.au/p/t1122-1.6mm-200gm-roll-60-40-leaded-solder/
...Jaycar, only has 1mm solder. Bunnings, on the other hand, only stock much thicker solder, used for plumbing.
Cable splicing
The iTECHBCDC25 DC-DC charger came with Anderson plugs, that I cut
off. It also came with three more Anderson plugs with short lengths of
cable. I need to extend the length of the cables coming out of the DC-DC
charger, so I used the short lengths that were attached to the other
three Anderson plugs. The cable is 10 AWG.
The most common way that two cables are joined together, what we call
"spliced", is a special metal sleeve, which is then crimped. I have
neither the sleeves nor a crimper. Instead, I used this simple method --
just push the two ends into each other.
Doing this, the strands become intertwined, and it will grip
together. Note, I haven't tried this with the ultra-fine copper strands
in the Altronics "61A" cable -- perhaps it might not work. This slightly
out-of-focus photo shows the two cable ends pushed together:
It is then easy to solder, and forms a very strong bond. Heatshrink
tubing needs to be slid over the join. many years ago, I bought a pack
of mixed sizes, and the largest, 6.4mm, fits over 8 AWG cable. Ah yes,
it is still available:
https://www.autobarn.com.au/narva-heatshrink-selection-3-2-6-4-56600
So, there are six Anderson plugs that I have removed the lugs from. I
have plenty other Anderson plugs, but if I wanted to re-use these, it is
possible to buy the lugs, in packs of 20, from eBay.
Tags: nomad
Camping now allowed in WA
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:
Quoting:
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
I posted yesterday about the start of wiring the powerbox, and a problem with using blade fuses at 20-30 amperes:
https://bkhome.org/news/202004/wiring-of-powerbox-underway.html
Originally, I had purchased this blade fuse holder 4-way box:
https://www.autobarn.com.au/narva-fuse-box-blade-54420bl
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":
https://www.jaycar.com.au/automotive-fuse-box-6-blades/p/SZ2002
Jaycar have these female spade terminals, rated at 10A maximum:
https://www.jaycar.com.au/6-3mm-non-insulated-spade-connectors-pk-10/p/PT4630
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:
https://www.jaycar.com.au/standard-duty-30a-blade-fuse-holder/p/SZ2040
...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:
https://www.jaycar.com.au/screw-terminal-30a-blade-fuse-holder/p/SZ2044
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
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:
https://bkhome.org/news/202004/powerbox-external-assembled.html
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:
https://www.jaycar.com.au/machined-brass-busbar-8-way/p/SZ2003
The terminal blocks at top-right are for wiring to the DC-DC charger. I purchased porcelain blocks:
https://www.jaycar.com.au/3-wire-porcelain-terminal-block-30-amp/p/HM3185
...however, afterward I noticed these, which would probably do the job:
https://www.jaycar.com.au/60-amp-12-way-screw-terminal-strip/p/HM3204
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:
https://www.youtube.com/watch?v=kZ76NsvvBE0
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
This is continuation of the new lithium powerbox project. Previous post:
https://bkhome.org/news/202004/powerbox-side-panels-and-battery-clamp.html
I have cut out the front and back panels, here it is assembled, front view:
...no 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...
- 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.
- 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.
- 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:
https://www.jaycar.com.au/dash-panel-mount-cigarette-lighter-socket-with-cap-15a/p/PS2004
Binding posts came from Altronics:
https://www.altronics.com.au/p/p9225a-heavy-duty-red-50a-binding-post/
...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:
https://andersonconnect.com.au/store/index.php?main_page=product_info&cPath=36_72&products_id=352
Tags: nomad
Powerbox side panels and battery clamp
Here is the previous post in the new lithium powerbox project:
https://bkhome.org/news/202004/top-plate-of-lithium-powerbox.html
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:
https://www.bunnings.com.au/metal-mate-12-x-12-x-3mm-1m-aluminium-equal-angle_p1067857
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):
Or:
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
My new project is a "lithium powerbox", see most recent post here:
https://bkhome.org/news/202004/top-plate-of-lithium-powerbox.html
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":
http://rvlithiumsystems.com.au/Portable-Power/portable-power.html
...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:
https://perthpro.com.au/product/customised-national-luna-redarc-portable-battery-box-dual-battery-system-with-25a-dc-dc-charger/
...with Amptron 100AH lithium battery, price is AU$1,990. Weight is 18kg.
Here is another, the "JTS Power Easy" box:
https://jts12volt.com.au/product/lithium-dual-battery-power-easy-pack/
...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
The plywood floor is 235x225x9mm, with 12x20x1.5mm angle assembled around it, see previous blog post:
https://bkhome.org/news/202004/base-of-lithium-powerbox.html
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.
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:
https://bkhome.org/news/202004/dc-dc-charger-issues-and-powerbox-improvements.html
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