More great tasks to do at home

This straightforward project keeps your extinguisher just where you need it, says Tony Brown

When you’re purchasing a fire extinguisher for your van, the Caravan and Motorhome Club recommends a 1kg AFFF device complying with BS EN 3 and rated at least 5A.

This is bulky and while it does have to be instantly accessible, you don’t want to keep bumping into it. My solution is to recess the device into a cupboard, in an open-front plywood box.

I used some offcuts of 8mm ply to provide rigidity without adding excessive weight.

Measure and cut

First, measure the extinguisher and cut out the plywood sides, back and base. You can then clamp these pieces together temporarily to check the size.

Remember to allow for the angle trims that fit around the opening. These could be made from hardwood or aluminium (which is much thinner).

Bond the pieces together using PVA wood glue and clamp them overnight. Make sure you leave the roof of the box off at this stage, and leave some extra length, as it’s best to cut the top section off at 45 degrees for easier access.

Trim and sand the box, then position it against the wall to mark where your oblong access hole needs to be cut. This hole has to be a short distance from obstructions, to allow clearance for the jigsaw’s baseplate. Any shelves might also need to be temporarily removed.

To protect the surface from the jigsaw, apply a double layer of wide masking tape to the outside of the cupboard. Then measure inside and out, and mark the hole on the outside for cutting. Double-check your markings and drill a hole in each corner to allow access for the jigsaw blade. Be sure to hold the base plate firmly against the surface, and don’t lift it until the motor is at rest.

Once you’ve cut your oblong out of the cupboard side, use a file to true up the corners and remove any bumps. Small imperfections won’t matter, because the edges are going to be covered by the trims.

Your box is now ready to be varnished both inside and out, but remember to leave the mating edge bare – that will help the glue to hold better. Placing temporary plastic fingers along the edge of the hole will help you to position your box in the right place.

Don’t rely just on adhesive to attach the box. Use long, thin screws from the front into the edge, so the heads are covered by the trims. PVA won’t stick well to non-porous surfaces, so for PVC wood-effect finishes, use a cartridge adhesive – and test it first on a ply offcut.

A mitre power saw is ideal for cutting timber or aluminium angles, which can also be fixed using the adhesive.

If you have the Alde heating system in your caravan, you’ll know that from time to time, you have to reset the clock on the display unit. This usually occurs when the caravan’s 12V battery has been disconnected.

But now you can stop this happening. Alde’s Battery Backup unit comprises a

2 x AA battery holder and the means to plug it into the rear of the control panel.

This is what I fitted in our van, but it’s simple (and a bit cheaper) if you fancy making a unit from scratch, or if the cable on the Alde version isn’t long enough. To make your own unit, you’ll need: n 2 x AA battery holder

n T-shaped PP3 clip

n Twin-core 6A figure 8 cable

n Two-way PCB latch housing (Molex block)

n 2 x 0.1 inch series socket terminals

n Heat-shrink

n Selection of screwdrivers

n Snipe-nose pliers

n Soldering iron with fine tip

n Wire strippers/cutters

n Heat gun

First, we’ll fit the Alde unit as bought, then we’ll go through making up the DIY unit.

The Alde unit

Before you start, disconnect any mains supply and the caravan’s 12V battery. The next step is finding a suitable location for the battery back-up unit.

Obviously, it’s best to place it as close to the control panel as possible, but you will need access to it from time to time, to replace the AA batteries when needed.

We have an Alde Smart Control unit in our van, so I decided to put the battery back-up next to that in an overhead locker. But if you don’t mind dismantling the locker to replace the batteries, it could go between two panels.

I removed the shelf inside the locker, then the internal panel behind the Alde control panel – you will need access to the rear of the panel.

In some caravans, it might be easier to remove the control panel from the front, giving access to the rear that way.

Our control panel is the later 3020 touchscreen type, but the following also applies to the 3010 touchscreen and 3010 button panels.

With access to the back of the panel, remove the cover and you’ll see a diagram inside. This will indicate where you need to plug in the battery back-up unit. Each control panel has the connection in a different place, so it’s important to check this.

As I’d previously cut a hole for the Smart Control wiring, I passed the Molex block on the battery back-up unit through the same hole. If there isn’t a suitable hole, you’ll need to drill one 8mm in diameter.

The block was attached to the correct pins on the back of the control panel, then the internal locker panel was refitted. Using double-sided tape, the battery holder was attached to the internal panel next to the Smart Control unit, then the cable was tidied and secured using a self-adhesive cable tie. Finally, the AA batteries teries were inserted.

After having reconnected the van’s 12V battery, I set the time on the Alde control panel. All was well, , so the unit was switched off and the he 12V battery disconnected once again.

Next morning, the battery was reconnected and the Alde system switched on. It was great to see the back-up had worked and the correct day and time were being displayed!

The DIY unit

Starting with the PP3 clip (which was pre-wired, red for positive and black for negative), cut one of the wires so it’s a couple of centimetres shorter than the other, and strip the insulation off each of the ends by about a centimetre.

Next, put a short section of heat-shrink on each of the wires (that way, you won’t solder the wires together, then realise you can’t get the heat-shrink on – not speaking from experience here, I hasten to add!).

Trim one end of the twincore figure 8 cable in a similar way, so the ends are different lengths, then twist the bare wires of the red cable together, then the same for the black ones. Having these joins in different places reduces the risk of the wires ‘shorting’ should the insulation become damaged for any reason.

Where the wires are twisted together and devoid of any insulationinsulation, carefully solder thethe joint. As the wires arare so thin, don’t allow ththe soldering iron to hheat them too much, or you’ll melt the plastic insulation.

When you’re happy thethe wires are joined securesecurely, cover them with the heat-shrink, and using a heat gun, do as the name suggests. I’m a belt-and-braces type, so I covered the two sections of heat-shrink with another single piece. This adds double insulation and keeps the two wires neatly together.

Now, working at the other end of the twin-core cable, separate the wires for about a centimetre and strip about 5mm of insulation from both. Using the soldering iron, ‘tin’ each of the bare wires.

The 0.1-inch socket terminals came in a strip of 10, of which you’ll only need a couple. Using the snipe-nose pliers, attach a socket terminal to each of the wires, then carefully solder the wires into the socket terminals.

The socket terminals push into the latch housing (Molex block), but before doing this, check the polarity by looking at the diagram on the inside of your Alde control panel back cover. Then you can continue as per fitting of the Alde unit. n Many thanks to Alde UK for supplying the Battery Backup unit. All other parts were sourced from Maplin Electronics