4×4 Accessories Pt Two

4×4 Accessories Pt Two

Vehicle electrics


This is a highly specialized field and not ever mastered by those that ‘dabble’, as some 4×4 equipment retailers and off-road trailer manufacturers do. Boy, have I heard some rubbish advice being shared by some 4×4 equipment retailers on this one! There are two types of battery applications that concern us: ‘Float’ and ‘Cyclic’. Typical of a float application is an ordinary car battery, where once the vehicle has started the current is replaced quickly as the vehicle drives. Cyclic on the other hand is when a battery is charged and then used with no or little charge being replaced. Such an application is common to the 4×4 scene when a vehicle arrives at a destination with its battery in an almost full state of charge. The fridge and lights run through the night and in the morning the battery has lost a significant amount of its charge, When selecting the type of battery, ask what is the application, float or cyclic? If a calcium battery (float application) is used in a cyclic application and the battery is not able to be recharged immediately, the battery will sulfate, causing irreparable damage to the plates. An apparent loss of capacity is noticed and after a short while total failure results. Should a battery designed for cyclic application be used in a float charge mode the result is stratification of electrolyte, mossing of the plates and a large amount of active material falling off the plates becoming sediment. This sediment eventually causes an internal battery short-circuit which cannot be reversed.

Battery charge and temperature

A battery charge is also affective by temperature. A rule of thumb for this follows: A battery is rated at 25°C; for every degree below 25° the battery will lose one percent of its capacity. Its life however will be increased (before failure). Also for every one degree above 25°C the battery will gain one percent of its capacity but its life will be reduced.

Dual Battery split-charging systems/ Battery isolators

When a freezer or lighting is powered from the vehicle’s primary battery, there is a risk that it will be flattened overnight or during an extended stay. Should this happen in the bush the vehicle may have no way of being started. Duel battery split-charge systems solve this problem by enabling a second battery to run the fridge and lighting while the vehicles primary battery remains unaffected. This second battery must be able to cope with the cyclic nature of the application. Deep-cycle and high-cycle are designed to cope with the larger discharge and recharge cycles than normal vehicle batteries.

Current draw and recharge

If you are choosing between a number of popular makes of freezers and judging them by current draw then I would suggest you buy any one and focus on the real issue: How is the current going to be put back and how long is it going to take? This is the big question as there are always difficulties experienced with recharging deeply discharged batteries, and there seems to be no cure, just bad , good and better solutions.

Charging Deep-cycle batteries

Lead-acid batteries, be they float or deep-cycle types, have recharging characteristics that can frustrate the user. Because deep cycle types are used in many off-road applications, I will deal with these alone. When a deep-cycle battery’s charge drops below about 11.8 volts it resists accepting a charge. No matter how much current is fed into such a battery it can appear to be lifeless. The reason appears to be associated with voltage. Ordinary car alternators produce between 13.8 (e.g. Bosch-English & German vehicle) and 14.6 volts (e.g. Nipon Denso- Many Japanese vehicles.) it is not enough! This is because when the battery voltage is low, when the charge is initialized, unless the charge voltage above 14.6 volts, only a small amount of current is accepted by the battery. After some hours or charging, the battery voltage slowly increases, and in doing so, Once the battery is in a state of about three-quarters full, its voltage is enough to-receive all the current it needs. One such battery recharge system is under development.

Take a look at the following typical scenario: A battery is used cross country all day. It reaches a point when the engine is shut down for the night and the fridge and some lights are turned on. The following day the vehicle remains stationary. By the morning of the second day, by the morning of the second day, two nights and a day have gone by. The daytime temperatures are high and the fridge has been running about 70% of the time. The operator knows that the battery charge must be getting low but he or she is not too worried because there is a duel battery split-charge system fitted. He or She decides to take the vehicle for a short run, mainly to charge the auxiliary battery. The battery voltage although high enough to keep the freezer working has dropped off the high current accepting plateau, ±11,8 volts’. The vehicle is driven for a two hour game drive; plenty of time so the driver thinks, to recover the battery with the 100-amp alternator fitted. But, over this two hour period the deep-cycle battery has accepted half an amp for the first hour, one amp for 30minutes and 20 amps for the last 30 minutes- a total charge of 10 and a bit amps. However, the operator is under the false impression that he has fully or almost fully-charged battery. Night falls and on goes the electric lights while the freezer continues to keep its contents frozen. By twelve that night the freezer low-voltage cut-out activates and in the morning everything has thawed. The operator is baffled and curses the battery supplier because he thinks he has been sold a bad battery.Time required for a flat battery to accept a measurable charge

On-charge voltage Hours

  • 16 volts : Up to 4 hours -check every half hour
  • 14-15,9 volts : Up to 8 hours -check every half hour
  • 13,9 volts: Up to 16 hours -check every half hour
  • The table above indicates the time required for deep-cycle Delco battery to receive a measurable current and the usable power of two models of the Delco voyager. For standard use, discharge is from 100% down to 50% charge. In emergency use, the table indicates usable power from 100% to 0%. A second battery wired in parallel will double the value. (excluding reductions due to battery mismatch.)
  • Battery split-charge/ recharge solutions:
  • Auto-relay. E.g. Gemini. More expensive, automatic, efficient.
  • A great big heavy duty switch. E.g. Marine type switches. Simple, inexpensive, reliable, subject to user error or forgetfulness.
  • Diode-based battery isolators. Simple and inexpensive but so inefficient that they are not worth considering.
  • Auto-relay split-charging systems

These systems, by far the most complicated, charge all batteries in the circuit and with a monitor unit fitted, tell the user the state of each battery. those that read just the voltage are pointless and need to read in increments of one-tenth of a volt. these systems do not change the voltage so do not solve the recharge problems discussed. they are fully automated, which is a plus. their efficiency varies and some are very inefficient. for example one of the better unit work like this: Input voltage in this case is 14,1-volts from a Toyota Nipon Denso alternator, one of the most efficient. Voltage through transistors and other components drop 0,3 volts. loss through wiring and connectors, another 0,5 volts. Voltage to the battery is 13,3 volts. Not even close! Result: the battery is never fully charged and this is a best case scenario! even the most highly inefficient systems only deliver about 13,2 volts to the battery. The battery doesn’t stand a chance of delivering at rated current or being able to accept current at the rate a vehicle alternator can deliver it.

High-current manual switches

Marine switches are switches able to carry the heavy charging currents produced by alternators running at full revs, sometimes over 100 amps. They connect the batteries in parallel so when the alternator charges the one, the auxiliary battery gets the same charge. There is little voltage drop, as long as the cables are thick enough and the connectors good. On the down side, if one of the two batteries is bad, it will discharge the other and if the operator forgets to switch the main battery off at night when the freezer is running, there is the risk of flattening both batteries.

Constant voltage chargers

The idea behind a 12-volt to 12-volt charger is that no matter what the engine speed, the charge voltage remains constant. A constant range of charge is very good for the battery and the battery’s life is extended. Their downfall is that when the alternator is running at full charge and the battery is in a position to accept such a charge, it will only accept the pre-set current.

Diode-based battery isolators

A diode is a component in a circuit that permits current to flow in one direction only. between two batteries it permits one battery to charge but not discharged. This sounds ideal but for inefficiencies of diodes. The voltage drop across a high-< current diode is often over a volt. They also tend to permit other current loss, although I am not sure how and why. All I know is not to trust them.

Tips to better battery charging:

  • Use heavy cable, solid-crimped connectors (Not soldered).
  • Make the cables as short as possible. For every one meter of cable length, the core diameter must be one millimeter. For example: Three meters of cable should have a core diameter of 3mm.
  • Set the freezer of switch off at now lower than 11.8 volts if you can.
  • Never put a battery in a trailer without the biggest connector you can find. Don’t even consider the tow-hitch connector as the voltage drop is too high. I once measured a trailer battery charge voltage that topped out at 12,2 volts: that is the voltage of an almost flat battery.

Keep it simple

Because this is a complex subject, and few understand it completely, when selecting a system, my advice is to keep it simple.

Deep-Cycle and High-Cycle Batteries

Because Delco is the most popular auxiliary battery found in 4x4s, here is some advice for their use.


Delco Voyager is of flooded cell construction, fully sealed and requires no topping up. The only maintenance required is cleaning and greasing of the connectors. The built-in hydrometer allows an easy check of the state of charge. The battery is often not suitable for use as a regular vehicle battery as its cold-cranking current is often not high enough to start big diesel engines. They are unsuitable for installations in solenoid switch systems when paired to high-cycle vehicle batteries, as they never achieve a state of full charge.

Hydrometer indicator

Green: Above 70% charge: Ready for use.

Black/invisible: Between 50%-70% Recharge if possible. Red: Below 50%: Recharge immediately.

Yellow/clear: Electrolyte level low. Do not charge.

Built-in battery hydrometers are a guide only and regularly malfunction or get stuck.

Normal charging requirements

Optimum battery life will be obtained if a green hydrometer condition can be maintained and batteries should never be left in a deeply discharged state. If the state of charge has reacted 100% charging should only be continued for long periods at a reduced rate to prevent long-term electrolyte loss. On-charge voltage should be 13,5-13,8 volts.

Care of batteries

Deep-cycle batteries are sometimes suitable for normal vehicle use as well as discharging up to 70% of their capacity.

Keeping a battery cool, keeping it charged and not over draining it are the three most important principles in extending the life of a normal lead-acid or deep-cycle battery.

Overcharging causes grid erosion and can seriously diminish the ability to accept a charge. A current taper with timer or a suitably controlled regulated voltage is the best protection against overcharging.

Do not fast-charge a battery, unless in an emergency, especially if it is a deep-cycle type.

Storing batteries

Batteries do not store well. When operating a low mileage vehicle or a vehicle that stands for long periods, make sure that the battery is kept in a good state of charge, otherwise it will deteriorate rapidly. Check and top up the electrolyte and recharge every three months- leaving it longer will damage the cells. If necessary store batteries indoors to prevent the electrolyte from freezing as in most cases this destroys the battery. Batteries must be fully charged beforehand and must be disconnected from all loads, however small.

220-volt inverters

Inverting current from 12-volt DC to 220-volt AC is done with an inverter. new technology has made these devices very compact and virtually indestructible. Overload them and they simply shut down or wire them up incorrectly and they simply refuse to work. for one year I used a solar panel to charge a battery which by means of a 200-watt inverter ran an Apple Mac and printer in ambient temperatures over 40°C. Much of the work on the first edition of this book was done at this time. The inverter became so hot that it could not be touched, yet it operated faultlessly. Current draw reached 10-amps at 12-volts(120-watts). Quasi-sin-wave inverters are suitable for computers, printers, televisions and hi-fis etc. Sin-wave inverters are required for scientific equipment but are unnecessary for most applications.

Portable generators

Despised by all those who work hard to get into the bush, away from noise and stress, portable generators are an unforgivable annoyance. Because they can be easily replaced by alternative power sources that are silent, more ecologically friendly and cost no more, I see no reason why these are used, except in cases where life support systems require high electric current. Running a TV is no excuse: why not then stay at home? As a result, I see no place for portable generators in this site.


Monitoring engine performance while traveling far from home is a good idea. Twice I learned the hard way. the first occasion was when my oil pump failed in central Botswana on the return leg after two weeks in the bush; and the second was a blocked air filter when a gauge monitoring the exhaust gas temperatures would have prevented a damaged turbo.

Exhaust Gas Thermometer (EGT)

Monitoring the temperature of the exhaust gases (EGT) is highly recommended for all turbo-diesel vehicles, especially pre 2005 models. When the exhaust gas temperature exceeds 700°C turbo damage results within a short time. causes of high EGT are: high fuel-air mixture, blocked air filter and pushing the turbo-diesel too hard. In this way the gauge indicates that damage is being done to the engine. It also indicates if the engine is being driven too hard, for example towing up a long hill on a hot day. without such a gauge the driver towing up a long hill on a hot day. Without such a gauge the driver would press on regardless, with the gauge warning, a lighter right foot could prevent engine damage. I highly recommend this gauge, especially if you use your turbo-diesel to low. I bet, in five out of ten cases, an EGT gauge will prevent a huge repair bill.

Oil pressure gauge

The signal is transmitted to the gauge via either an electrical sender unit or thin copper tubing that carries the oil to the gauge. in general, the latter type is more accurate and reacts faster to pressure changes. The electrical gauge is more common in newer vehicles.

Oil temperature Gauge

The signal is transmitted to the gauge via an electrical sender unit. This gauge is an essential item when traversing heavy sand or towing, Know the safe maximum oil temperature for your vehicle and never exceed it. 120°C is the maximum for most vehicles.

Voltage meter

This gauge monitors the condition of the battery. Voltage measurements must be taken with the engine turned off and some electrical equipment switches on e.g. park lights. Only when the battery is working can voltmeter indicate how much more work the battery is capable of doing. This is because it is the voltage drop that determines the condition of a battery. For example, a battery with nothing switches on may indicate 13 volts. If, when lights are turned on, the voltage drops to 10 volts, this indicates a battery in a poor state or one that is old or damaged. If the voltage stays above 12-volts, this can be regarded as normal and the battery in good condition. The higher the load on the battery, the higher the voltage drop will be.


The ammeter measures the flow of current in and out of the battery. Vehicle ammeters have a central indicator that swings to either negative or positive. It is wired to enable a vehicle operator to determine if the load on the battery by electrical equipment is higher or lower than the amount of current the alternator in returning to the battery. For example: If the lights are turned on with no engine running, the indicator will swing to the left or negative. When the engine is started and the alternator engages, the indicator will swing to the right, or positive. If you find that you ammeter tends to run towards the negative when running electrical equipment, then you need a heavy-duty alternator.

Raised Air Intakes

If you intend to drive on long stretches of dusty roads or through deep water, an extension to the air intake is highly recommended. The most well known make is the Australian Safari Snorkel. They are available for almost all 4x4s and can either be fitted at home or by off-road outlets. The benefits are more than just protection from water and dust. The air is cleaner up high and therefore air filters last much longer. The air is also cooler than inside the engine compartment. This clean, cool air will improve engine performance. Fitting a snorkel does mean drilling holes into the body and this is a deterrent to some who want to ensure the resale value of their vehicle. However, engine damage caused by water ingestion is never cheap.

There is some contention as to the effectiveness of a snorkel in dusty conditions. In 2003, during a trip into the Richtersveld shooting one of my 4×4 DVD’s I did a simple test. Two vehicles, one a Colt and the other a Land Cruiser were used. The Cruiser was fitted with a Safari Snorkel, the Colt had its standard air intake behind a headlight, A common location on many vehicles. Both vehicles were new, with about 7000 Kms on both odometers. The drive through the river beds was particularly dusty. The idea was to compare the air cleaners on the final day of the trip. The results were startling. Each filter was knocked against the front wheel to release dust trapped in them above a white towel lying on the ground. The top three photos show the snorkel-equipped Land Cruiser. The filter was dusty but still good for thousands of kilometres. There were no stones or sand in the filter bowl. I would estimate the unprotected filter had fifty times more dust embedded in it than the filter protected by the snorkel.

Suspension Modifications

Most modern 4×4’s are equipped with suspensions better suited to road conditions than off-road work. Modifications are often necessary to increase ground clearance and improve payload. Also, vehicles that excel off-road may need softening up for road use. trouble is not all spring and shock manufacturers make well-researched products and many a disappointed traveler has cursed a salesman. bilstein, koni, Old Man Emu and TJM all make high-quality systems but above all, make sure you purchase them from a competent professional who is able to select an appropriate spring/shock combination. Backyard mechanics with limited knowledge are a liability.

Heavy-Duty Springs

When coil springs are exchanged for higher rated units make your selection carefully. Light-duty units will feel similar to those that the manufacturer has fitted but will ensure longer life of the shock absorbers, especially if they are gas type. Medium rate springs will improve road holding, reduce body roll and improve payload by a small amount. Hard springs will improve road handling, on-road adhesion, reduce body roll and are recommended for vehicles with loaded roof-racks. They they improve heavy payload handling, stability and safety but may feel harsh on road. poorly selected springs often cause instability at speed.

With leaf spring vehicles such as the old Hilux or Land Cruiser pickup, the change is even more impressive. The new springs smooth the on-road ride and at the same time increase the axle articulation due to spring lubrication between the leaves. this improves off-road traction especially over rocks and dune driving.

Spring assisters/Air Springs

Coil spring assisters come in the form of helper coil springs that fit inside the existing coils or rubber blocks squeezed between the coils of a spring to resist its collapse. Firestone make a highly effective inflated to suit load and conditions are another option. Once prone to failures the new models are earning a good reputation.

Problems caused by suspension mods

The most common problem caused when the vehicle’s ride height is increased is over-sensitive steering and most likely to occur with a suspension lift of 50mm or more on a solid front axle. this is caused by a change to the camber angle and must be corrected with replacement bushes. The angle at which the prop-shaft universal joints operate is also increased by a suspension lift, often resulting in accelerated wear or vibrations. Other items to check are the brake hoses. There must be ample length to cope with additional axle travel made possible by the new shock-absorbers. However, mismatching components: taking shocks from one manufacturer and springs from another, is a common cause of premature failure of after-market suspension components. The stretch of the shocks and the height of the springs must be matched properly and not by guesswork.

Gas shock absorbers

Few vehicles have gas shock absorbers fitted as standard equipment and for vehicles expected to work long hours off-road they are essential. In the past, few four-wheel drive manufacturers have paid enough attention to shocks absorbers.

Working 4×4’s need gas shocks. For example, my own Land Rover 110 went through two sets of standard shock absorbers within 30 000 kilometers. Once the second set had worn out, the first being replaced under guarantee, I replaced them with Bilstein shocks. When selling the vehicle after clocking up 130 000 kilometers the shocks were as firm as when I fitted them. Gas shocks often make the ride a little firmer but the real advantage comes when cornering or carrying a load. The difference in my case was a significant improvement in ride even when compared with brand new, standard shock absorbers.

Torsion bar suspension problem

When fitting gas shocks it is essential that the suspension setup is checked and adjusted if necessary. Not centralizing the suspension before fitting gas shocks can cause rapid destruction of the shock absorbers. the reason for this is when a suspension system, particularly independent wishbone types, are set in the ‘central’ position when the vehicle is at rest, the shock absorbers act as bump stops instead of the rubber bumps designed for the job. The internal components are literally hammered to pieces. Secondly, torsion bars set in increase clearance can cause problems when the shock absorbers central or neutral position is altered. in this position the shock absorbers cant work as they should. The resultant poor ride is then blamed on the shocks, when the real culprit is the backyard mechanic who thought he knew better than the vehicle manufacturer about how the torsion bar should be set. Thirdly, do not assume that if your vehicle is brand new that the suspension is correctly set up. Many imported vehicles stay lashed down to the pump-stops in crates for months and when they are delivered the suspension has ‘sagged’ and must be reset. torsion bar suspension is particularly prone to this.

Why gas?

A shock absorber, simply described, is a metal tube filled with oil through which a piston moves. on the piston is a valve which permits oil to pass through a limited rate. The tube is connected to the chassis and through at a limited rate. The tube is connected to the chassis and the piston is connected to the axle. The oil’s limited travel damps the movement of the piston and therefore the axle to which it is attached. This prevents oscillation that the springs would create if left undamped. as the piston moves in the cylinder heat is generated. Heat thins the oil and makes the shock less effective. What is worse, the oil in a hard working shock mixes with the air and bubbles are formed. The mixture of hot air and hot oil is able to pass through the valve easier than pure oil, which means that the shock will lose its effectiveness, to the point where the ride becomes uncomfortable and unpredictable. Gas shocks are different in that they are pumped with a small quantity of inert gas. This gas cannot mix with the oil and so the main reason why shock-absorbers become soft as they get hot is eliminated. Shock-absorbers on a heavy loaded 4×4 on a rough sand track work almost as hard as shocks on a competition rally car. I know of one Range Rover which after being called to rescue the survivors of an accident in Northern Botswana (that was me in 1987), ‘cooked’ a gas shock by racing to get to the accident scene. the shock was blackened by heat and destroyed. I have used three brands of shocks in eight 4x4s that I have owned I can highly recommend Bilstein. They are undoubtedly very robust and are my first choice.

Polyester Bushes

Bushes made from hard rubber are fitted in various locations in suspension systems to soften the vibrations generated by the wheels, engine and transmission. in Off-road vehicles these bushes are stressed more than in a normal road vehicle and as a result wear out and need periodic replacement. Bushes are located in various places, namely leaf spring shackles, steering dampers, control arms locating the axle, radius arms and steering control arms. The effects of worn bushes can be vague steering, a vehicle that steers itself when driving straight, instability, an uncomfortable ride on corrugations, clunks and bangs on rough terrain and clunks when reversing or braking. A worthwhile option when replacing bushes is to fit polyester units. polyester is replacing the rubber in bushes in industry from shipping to heavy machinery and vehicles are reaping the benefits of the research into new age plastics and graphite’s. The advantages of polyester are long life and stiffer suspension which aid stability and safety. A little more vibration is sometimes transmitted to the driver but this is rarely noticeable and they frequently cost less than genuine parts.



How many times have you heard, I would never take that big, beautiful vehicle into the bush to get scratched.” The reason not to take them into the bush has just vanished – Literally. An elastic, plastic sheeting called VPS (vehicle protection shield) is the answer. I tried it on my Land Cruiser and after numerous trips through the Kalahari, the bodywork is as pristine as it was when I bought the vehicle ,this remarkable product can be applied to any bodywork area: For a 4×4 used in conditions where stones may chip and thorn bushes are likely to scratch, I suggest paying particular attention to the front roof supports, front fender, doors and the leading edge of the bonnet. Once applied, it vanishes. It is clear, is guaranteed not to fade and dust falls off it faster than it does on nude paintwork, so the vehicle appears to stay cleaner for longer. It also protects against vandalism and careless shoppers in car parks. Not cheap, but will add considerably to a vehicle’s resale value. A really impressive and practical product. (www.vpsprotection.co.za) Beware of some copies: Many product are out there making the same narrow sheets, which looks terrible.

Radiator grille grass nets

When you travel over grassland, fit a protective net over the radiator grille, but know that most grass seeds find their way to the radiator from underneath, not straight ahead. A grille net should prevent grass seeds choking the radiator and the resultant overheating. This includes the inter cooler radiator. Fine plastic mesh used to make swimming pool scoops work well when layered double and shade cloth also works well. one-size-fits-all grille nets sold in 4×4 stores are sometimes not particularly effective because they do not go low enough. THIS IS VERY IMPORTANT: Because grille nets severely restrict the passage of air to the radiators inefficient air-conditioners, extreme under-bonnet temperatures, damage to batteries and engine damage result when a grille net hinders airflow when traveling at high speeds and high power settings. If the vehicle could run as efficiently with the restricted air-flow caused by a grille net, the manufacturers would have fitted smaller radiators and saved on costs. Your vehicle needs every bit of airflow it can get when moving. I recommend taking grille nets off at speeds over 60Kph, especially on hot days. Vehicles towing trailers in thick sand should only fit a grille net if absolutely necessary, even if speeds are low.

Seat covers and interior protection

The way I see it, seat covers are intended to perform two functions: Improve comfort and protect the seats. Comfort is 100% subjective, si I am not going to say another thing. But protection is not. I believe priorities in this regard are as follows: 1. They must be waterproof to be effective. Water-resistant is not enough. 2. they must be washable and must not shrink when machine washed. #. They must be tear-resistant and if they are cut, the tear should not easily spread and repair should be easy. 4. They should look nice and not attract dirt. There are several seat cover manufacturers in South Africa and I have experience with three of them: Takla, Melville and Moon and Escape. Of them the Takla canvas look-alike cover called CanTech fits all these priorities the best and I can highly recommend them.

Mud flaps

Mud flaps both look good and protect the vehicle and trailer. Vehicle manufacturers, all of them , put horrible, feeble flaps that do not do a very good job. Mostly they are too small and when they are a reasonable size, like on a defender, they are made of material so thin < that the rushing air blows them out of the way. Making your own flaps is easy. use conveyor belting or heavy rubber matt about 1-1,5 cms thick. Cut it with a utility-knife and make some simple aluminium strips as mounts. Simple, effective and cheap.


Water tanks and jerrycans should be locked with small padlocks and chained to the roof-rack if a loaded safari equipped vehicle is to be left unattended-day or night. The padlocks should be removed from the Jerrycans when driving to prevent sand and vibration from wearing the paint and damaging the locks. External water taps should also be secured by a padlock or have a shut-off valve inside the vehicle, especially in desert regions.


Many insurance establishments will not cover vehicles that travel into Third World countries. Make sure that your vehicle is covered and don’t get a nasty surprise should something go wrong far from home.



Leave a Reply

Your email address will not be published. Required fields are marked *

Related Posts

Recent Post