12V Distribution Box for Camping

I’ve been meaning to write this for a while, but a year ago I had a some gear failure on the 12V side while camping. We use 12V for all our refrigeration, lights, water pump and phone charging. Fortunately we had power near by so all was not lost at the time.

But it led me to create something hopefully a bit more reliable and useful. The root cause of my issue was the following:

  • Cigarette connections corrode easily and are “loose”. Apparently rated for 10A, I would personally not use them for anything more than 1A. If I have to use them I’d get good quality ones.
  • I had a DC-DC converter for my laptop (http://www.sidewinder.com.au/page210.html). Both the cigarette lighter connections and the DC-DC converter got really hot. Here’s what it looks like. It is rated at 90W, but I think it’s more like 30W. So this is rubbish even though it comes with a great number of connectors:

12VDistributeOldDCtoDCSo after some thought and research I then built the following (photo taken after a couple of camping trips):


This box has the following features:

  • 4x20A Anderson plugs for 12V output
  • 2x10A Hella (Merit) sockets for 12V output
  • 2x10A Cigarette sockets for 12V output
  • 2×2 USB charger sockets (5V, 2.1A rated).
  • 2xAnderson plugs.with 10A/19.5V output (around 200W total power) and has a switch. 2 laptops can be connected concurrently.
  • 1x50A Anderson plug output.
  • 50A rated current and voltage readout. A switch enables the meter.
  • 12V Anderson plug input to power the whole thing.

These are all protected with 10 regular blade fuses and 2 thermal fuses at various ratings.

The 12V feed comes via an MPPT regulator which takes power from a solar panel, but could come from any 12V source.

The internals are shown below. The 50A shunt resister, the blade fuses and the DC-DC converter take up most of the space and made the wiring a little complicated:


The DC-DC converter needed to be pulled apart and attached to the chassis. The heat-sink is on the bottom. A side view is below:


Why power laptops with a DC-DC converter? I personally hate 240V inverters as I don’t have it safely mounted, so 12DC->19.5VDC is the way to go for powering a laptop and much safer 🙂 It has the bonus of not wasting energy through a 2nd inverter (which is your laptop power supply).

I did try powering my laptop(s) through 12VDC directly, but it appears they need the extra voltage. You can see what a laptop requires by looking at the label on the laptop power supply and they all appear to be around 19.5V. So looking for a good converter was challenging but I eventually found one.

I cut the DC side of the laptop power cable and put Anderson plugs on both sides. This enables me to directly connect my laptop to this box or to use the regular mains supply.

Here’s a pickie of the box in action. I’ve got a laptop powered via the box with a wi-fi connection to a 4G dongle that is in one of the USB ports. 2 LED light strips, 1 fridge, 1 water pump and a smartphone complete the connections. My laptop is playing music from my NAS at home while 120km away 🙂



For reference I’ve got as many parts listed below:

The chassis is the earth on the load side of the shunt resistor. This made the wiring much simpler but if the chassis is connected to say the car or the trailer, then the current readings will be incorrect.

The Anderson plugs holes were drilled out with a regular drill and attached directly to the side of the case which had the right amount of height to attach the plugs.

This box has been on two camping trips now without any issues. I did modify it to add an extra USB dual-charger. With 3 smart phones, two tablets and a USB powered bluetooth sound system we didn’t have enough ports.

And no we don’t camp. We glamp 🙂


Samsung S5 Drops WiFi

The Samsung S5 has a nice feature to automatically switch between Wi-Fi and 4G to make sure there is always an internet connection. You go to Wi-Fi and then select the option at the top:


And for the most part this probably works pretty well. Except for me and some others.

The problem began when I was trying to communicate with my new amplifier via WiFi and it lost connection every 10 seconds. At first I blamed the amp and then the router. It was still losing connection when the phone was 2cm away from the router. I was contemplating buying a new router (lots of cursing and swearing at this stage) when I did checked if anyone was having the same problem.

Then a little pointer from this site (and some others) http://forums.androidcentral.com/samsung-galaxy-s5/387300-samsung-galaxy-s5-constantly-dropping-wifi-2.html pointed me to this setting.

I turned the setting off and happy dayz 🙂


A Doubling of Server Performance

I’m always in the market for something that makes my server faster. At the end of last year I bought a ASRock Z97 Extreme 6 motherboard with a i7-4790K Intel CPU.

I don’t have the performance improvement but considering I was running an Intel i7-880 (Lynfield series – around 4 generations ago) processor before the improvement was dramatic.

This time I’ve bought some kit, and decided to share the improvements. So I had 12GB of existing Corsair 1600MHz CL9 RAM and a Samsung Evo 750GB SSD. I’ve now put in 32GB of Corsair 2400MHz Dominator Platinum RAM and a 512GB M.2 Samsung SSD (the fastest available SSD at present). This SSD takes 4xPCI channels and claims over 30GB/s in transfer speeds. So some pickies. The first thing you notice is just how small this SSD is:


It took just a few minutes to install it on the motherboard:


You can hardly see it against the rest of the mobo, but this shot shows the memory sticks without the fan (which I’ve temporarily taken off to show the memory sticks):


So the stats – the key PassMark figures I have are:

Before: Memory - 2048
After: Memory - 2472 (a 20% improvement)
Before: Disk - 4471
After: Disk - 8858 (a 100% improvement).

Just to show you the actual figures:


And all of this was inside a Windows VM. Wow 🙂

Fixing the Wi-Fi Reception on a Dell Inspiron 1501 Laptop

I’d just updated an old Dell laptop with the latest version of Linux Mint. But the Wi-Fi reception was poor and didn’t connect if I moved it more than a few meters from the router.

Time to pull it apart.

DellKeyBoardThe plate at the top of the keyboard comes off (there is a small recess on the right to lift it with a screwdriver). A couple of screws later and the keyboard comes out revealing the Wi-Fi daughter board. There were two connections that go into the screen hinge as the antenna.


One of these connections wasn’t quite right so I put it back in. Then a quick reboot and a connection was possible from the other side of the room:


Happy dayz. As to the root cause of all of this? It was probably one of my previous efforts of pulling the laptop apart and bumping the cable 😦

Fighting the Broadcom STA Wireless Driver in Linux Mint 17.1

A small saga began when I took an old laptop and installed Mint 17.1 Cinnamon. The first problem was no Wi-Fi. I’ve installed Mint on a few machines without issue, so this was a first.

The first thing to do was to do an update of Mint and after several minutes this all worked nicely. I also installed the proprietary Broadcom STA wireless driver via the driver manager:

Screenshot from 2015-01-28 10:53:53

After the reboot I had then had two problems – no Ethernet and no Wi-Fi. Not good at all 😦

A bit of research starting from here showed that I had to start with the following:

> inxi -N
Network: Card-1: Broadcom BCM4401-B0 100Base-TX driver: b44
         Card-2: Broadcom BCM4311 802.11b/g WLAN driver: b43-pci-bridge

The hardware was detected so it had to be a driver issue. The first problem was to get Ethernet going. So I tried removing the black listed module as was suggested in the above post:

> sudo rm /etc/modprobe.d/blacklist-bcm43.conf

And the a reboot. And voilà! I had Ethernet back. OK, the next problem was do get Wi-Fi back. The first thing I did was to play around with the proprietary driver. It appears that activating the Broadcom driver via the driver manager causes the blacklisting to occur.

After much poking around I looked a dmesg and found the following:

b43-phy0: Broadcom 4311 WLAN found (core revision 10)
b43-phy0: Found PHY: Analog 4, Type 2 (G), Revision 8
b43 ssb0:0: Direct firmware load failed with error -2
b43 ssb0:0: Falling back to user helper
b43-phy0 ERROR: You must go to http://wireless.kernel.org/en/users/Drivers/b43#devicefirmware and download the correct firmware for this driver version. Please carefully read all instructions on this website.

And that was the clue and found myself here. So I installed the b43 driver and removed the bad driver(s):

> sudo apt-get remove bcmwl-kernel-source
> sudo apt-get install firmware-b43-installer

Another reboot and then I had Wi-Fi (and Ethernet) 🙂

Other Useful References:

  1. http://linuxwireless.sipsolutions.net/en/users/Drivers/b43/
  2. https://help.ubuntu.com/community/WifiDocs/Driver/bcm43xx#b43%20-%20Internet%20access
  3. http://community.linuxmint.com/tutorial/view/379
  4. http://forums.linuxmint.com/viewtopic.php?f=150&t=138826

And one little comment to Mint/Ubuntu – please fix the Broadcom driver in your distributions 🙂

Upgrading a HDD with a smaller SSD

So I’ve done this a few times, but always with a 1:1 disk size. I always used Clonezilla to write the image onto the new laptop.

But this time I was going cheap selecting a more appropriate SSD for my wife’s laptop. So here are some quick notes on what I had to do to get it to work.

So the challenge: take out a 512GB HDD and replace it with a 256GB SSD on a UEFI boot system (Windows 8.1) on an ASUS S500C. And there is no CD/DVD drive, so bootable USB drives were required. Just to make it more interesting, there were other partitions present at the end of the HDD (some Clonezilla posts about using advanced mode to ignore disk sizes etc didn’t work for me).

Step 1: What you’ll need:


Firstly, a portable USB drive (preferably USB 3.0) that can hold the image. One USB stick which holds a bootable image of Clonezilla (http://clonezilla.org/downloads/download.php?branch=alternative, iso) and the other with GParted (http://gparted.org/download.php, iso). Burn as bootable USB images with Rufus (https://rufus.akeo.ie/).

Step 2: Back it up with Clonezilla. If you stuff it up, you’ve got an exit strategy (there was no way I was going to tell my missus her laptop was stuffed). So the laptop was using Windows 8.1 with a UEFI boot which means you can’t boot without going through the following process.

Go to the update and recovery screen (you can find it by doing a search on “UEFI”):


Select “Advanced startup”, then “Troubleshoot”, “UEFI Firmware Settings”, then “Restart” when you see the option.

Then you’ll reboot and the you’ll see the bios appear. You’ll need to change the boot order to show the Clonezilla USB first.


Then you’ll see Clonezilla and back-up your entire HDD onto the USB drive (beginner mode was fine for me).

Step 2: Run GParted. So you need to make all of this fit into the smaller drive.

Change the USB stick and repeat the UEFI boot sequence from above and boot into GParted.


This process will be different for each environment. What I had was a large useless partition /dev/sda6 (“D” drive). This has nothing in it, so I deleted this partition.

This left an “Restore” partition way on the right which then had to be moved to the left to fit it against /dev/sda5. But you may have to move/resize your own partitions as appropriate.

Ensure the new size all fits into the new SSD size. Things won’t work unless you do 🙂

Step 3: Clone this image on to the USB drive with Clonezilla.

If all goes well, you’ll be able to reboot back into Windows and then repeat the back-up process and create a new Clonezilla image.

Step 3: Modify Clonezilla’s parted file

In the new image, go to the parted file which was called sda-pt.parted for me. It showed the following in my system:

Model: ATA Hitachi HTS54505 (scsi)
 Disk /dev/sda: 976773168s
 Sector size (logical/physical): 512B/4096B
 Partition Table: gptNumber Start End Size File system Name Flags
 1 2048s 616447s 614400s fat32 EFI system partition boot
 2 616448s 2459647s 1843200s ntfs Basic data partition hidden, diag
 3 2459648s 2721791s 262144s Microsoft reserved partition msftres
 4 2721792s 392714239s 389992448s ntfs Basic data partition msftdata
 5 392714240s 393431039s 716800s ntfs hidden, diag
 7 393431040s 435394559s 41963520s ntfs Basic data partition hidden, diag

Back this file up and change the disk size. In my case I just took 976773168 and divided by 2 (multiply by 512 to get the number of bytes on the disk)

Do another sanity check and make sure the last sector is smaller than the sector size you’ve selected.

Step 4: The exciting bit. Pull your laptop apart and replace the HDD with the SDD.

So time to get out the jeweler’s screwdriver and pull the laptop apart by removing the 10 or so screws. There were two different sizes, so be careful to note where they go.

OLYMPUS DIGITAL CAMERAPull the HDD out and its little bracket. Put the new SDD in and replace the cover. If you’re feeling confident, put all of the screws back in 🙂

Step 5: Burn the new Clonezilla image onto this new drive.

So put the Clonezilla USB stick back in and this should be picked up automatically when you boot. Put the USB drive in and burn the new image that you’ve been playing around with (I used Clonezilla beginner mode). Hopefully there’ll be no complaints from Clonezilla.

Step 6: Reboot and enjoy the faster performance 🙂

All this took a few hours – the backup/restore and the GParted partition writes take some time. And of course mucking around with the partitions in GParted is “fiddly”.