We have come to enjoy so-called “free camping” in National Parks and similar locations. Whilst often not free of fees, they are are certainly free of mains electricity and mains water to the van. Some have one tap with drinking water but many do not. Our van’s water tanks are good for 5 days or so if we don’t shower. Beyond that, we have three (3) 20 litre jerry cans with which we drive to the nearest town or location with a publicly accessible drinking water tap where we fill them, then drive back and empty them into the van’s tanks.
We use a hose to fill the jerry cans without removing them from the back of the tug, but emptying them into the van’s tanks is another matter. Whilst 20kg is an acceptable weight for one person to lift, holding it on the angle that gets the water into the tanks without spilling it or dropping the jerry can or pulling off the spout is tricky. Being mindful of this and our ageing backs, a “no lift” solutions is needed.
They key objective was to transfer the water from the jerry cans into the van tanks without removing the jerry cans from the tug. A 12 volt, self-priming pump that tolerated running dry and was not of the submersible variety for less than say $50 was first sought. We tried numerous camping stores, aquarium suppliers and hardware stores but without success. Pumps on offer were not certified for use with drinking water, or were submersible, or both. (A submersible pump is not suitable because you can’t get it down the jerry can’s neck!)
We ended up buying a pressure pump like those used in caravans, but with the lowest rating available: 4 litres per minute. This size of pressure pump is used in camper trailers that have a small tank and one tap, and sells for approximately $100. Whilst this application does not need a pressure-switched pump, that turned out to be the most suitable, albeit expensive, type available.
The pump’s inlet and outlet are barb fittings to suit 10mm hose. We purchased a 6 metre length of clear, beverage-grade plastic hose from the pump supplier for a couple of dollars per metre. You can buy this type of hose at camping or hardware stores but be sure that it is beverage-grade. Cut into one 2 metre length and one of 4 metres, we have one short hose from the jerry can to the pump inlet and the other from the pump outlet to the tank fillers. In the interests of hygiene, we first sterilised the hose with Milton and, when not in use, store it in a zipped plastic carry bag.
The pump’s electrical connectors out-of-the-box are two insulated wires with stripped, bare ends. I crimped four (4) pairs of bullet connectors like so:
- one pair to the bare leads on the pump,
- one pair to the bare cable ends of a 12V “cigarette lighter” plug (e.g. Jaycar PP1995); and
- one pair to each end of a length of insulated twin-core cable.
Our current tug (Ford Territory SZ, 7 seater) has a 12V outlet in the boot compartment so the overall cable did not need to be very long. This arrangement is more complex than necessary and was based on what I had on hand at the time. Simpler solutions include:
- a cigarette lighter plug with a long tail (e.g. Jaycar PP1998) joined with crimped barrel connectors or screw terminals to the pump wires; and
- a cigarette lighter plug with a short tail (e.g. Jaycar PP1995) joined to the pump wires together with an off-the-shelf 12 volt extension lead (e.g. Jaycar PP1992).
As expected from the 4 litre/minute specification, one 20 litre jerry can is emptied in about 5 minutes. To get out the last couple of litres, we found it necessary to tilt the jerry can on a 45 degree angle and manipulate the hose to the bottom corner. There is no manual lifting, and the manual tilting occurs when the jerry can is near empty.
The pump and cables are stored in a sealed plastic box. The hoses are stored in a soft plastic carry bag with zip closures (which originally contained an awning shade).
Hints and Tips
- flushing the pump and hose by running some water through them before inserting the outlet hose into the tank filler seems like a good idea;
- the outside of the hoses will come in contact with the water in both the jerry cans and the van tanks and so giving them a clean before each use also makes sense.
- residual water will be left in the hose and pumps regardless of how hard you shake them, so if the most recent use was not recent, consider sterilising them before use.
A pump for this purpose should:
- be self-priming (since it will not be gravity fed from the jerry can);
- be able to run dry for a short time without damaging itself;
- have a maximum current demand that is less the 12 volt accessory sockets in your vehicle can supply;
- be certified for use with drinking water.
Note that these pumps:
- are not able to run dry indefinitely, so don’t leave it running unattended whilst it tries to pump out of an empty jerry can;
- are not designed to run continuously, so give the pump a rest every so often (check the specifications for “duty cycle”).
Naturally, your hoses should be sized and adapted to suit your pump’s inlet and outlet. Our pump has 10mm barbed connectors over which we push 10mm tubing. Hose clamps could be used but we have not found them necessary (the pump is only ever run with someone present).
Some larger pumps have a male threaded inlet and/or outlet, which would support a more robust, though complex, fitting. If your pump has a threaded inlet or outlet, it will most likely be of the BSP thread standard for which a variety of adapters are readily available in hardware and plumbing supply stores.
I suggest taking your pump to a self-serve hardware store and playing with their hoses and fittings to invent the simplest, cheapest and most effective arrangement. Use only BSP fittings for a BSP thread or you will suffer leaks and/or use a lot of teflon tape. BSP connections should not need teflon tape (one or both sides of a join has a tapering diameter, which gives a water-tight joint). Alternatively, take the pump to a plumbing supply store, tell them your application and they should easily do the same. If you are buying the pump from a plumbing supplier and describe your application, they should be able to supply all the “wet” parts required for an optimal end-to-end solution.
If using crimped spade or bullet connectors, remember that a connector supplying +12V should be female to avoid shorts and blown fuses (or worse) when it accidentally touches a metal part of the vehicle. (Hence the connector receiving +12 volts is male.) I use opposite genders for the earth (a.k.a. ground or 0 volts) connectors. This prevents accidentally connecting one cable to the other with polarities reversed and hence reverse polarity being applied to the pump motor, though it does allow the 0V supply male to be inserted into the +12V supply female, which is also not good.
If using connectors (e.g. screw terminals) that leave any live +12V points exposed, wrap them with electrical tape.
If using insulated crimp connectors for the first time, it helps to know that the colour of the insulation on this type of connector corresponds to the diameter of the copper in the wire to be crimped (red is smaller than blue is smaller than yellow) rather than to the size of the spade, bullet, etc. The spades and bullets themselves are the same size, for example, a red male bullet fits a blue female bullet.
Soldering of these electrical connections is not recommended unless care is also given to the “mechanical connection”. When the ends of two flexible wires are soldered together, the two points at which the flexible copper meets the less flexible solder are subject to extra stress when the wires flex and will eventually break.
Some cigarette lighter plugs have an internal fuse; this can cause confusion if it blows and you don’t know it is there.
If you are not confident in choosing appropriate connectors and cables to suit the current draw of your pump, and/or in making reliable connections, you should use off-the-shelf components or engage an auto-electrician.
Given that the jerry cans no longer leave the tug’s boot, at least not when full, they do not need to be limited to a gross weight that can be manually lifted. You might consider using fewer but larger and more efficiently sized and shaped containers. Your choice!
For accessible drinking water taps in country towns we have found the following locations fruitful:
- around the back of community halls;
- at fish cleaning stations next to boat ramps;
- RV Friendly Towns – the conditions of “RV Friendly Town” certification by CMCA mandate access to of potable water and encourage the existence of an Information Centre (e.g. to tell you where that water is).
We always remove any existing hose from the tap, run some water to flush the tap, and connect our own hose to fill the jerry cans (being sure, of course, to replace the pre-existing hose before leaving!).
Estimating the length of the two hoses can be fraught. Consider where the pump will be located when operating to help decide the length of the inlet hose; don’t forget the metre or so needed to get to the bottom of the jerry can. The outlet hose length depends on how close to the tank fillers you expect to be able to get the vehicle; think about how to route and secure it so that it doesn’t fall out of the tank filler and doesn’t trail in the dirt.
A couple of weeks after buying and setting up the small pump described above, we had to replace the larger (11 litres/minute) pump installed in the van. Whilst the old pump worked OK in the forward direction, it developed a slight flow in the reverse direction. Because the van is plumbed in a way that relies solely on the pump to prevent mains water entering the tanks, this resulted in the tanks overflowing when mains water was used.
As a result, we now have a spare 11 litres/minute pump that would be quite suitable, and indeed quite fast, for transferring water from the jerry cans into the tanks!