Many people install electric winches incorrectly, and many are afraid to install winch electrics; the main reason is lack of knowledge and an incorrectly installed winch electrical system is dangerous, and many commercially installed systems are not as cheap as they can be. This is because many winch installers have agreements with a range of suppliers for various electrical components as they are dealers for various brands of equipment. Installing is not a difficult job for an average person with minimal DIY or vehicle maintenance skills, doing it yourself allows you freedom of choice for sourcing the appropriate components required for your installation, the associated cost savings from better prices, and a saving in labour costs.
Before commencing with any purchases we need to begin by reading the instruction manual for an electric winch as this contains considerable information we need, this will often give a minimum battery size, minimum cable diameters required, and a wealth of other useful information.
Such information needs understanding, to begin we need to understand batteries because this is the area in which the most mistakes are made, too small a battery will not allow the full power of the winch to be attained and it will reduce winching time considerably. In addition to this it will hammer the battery and reduce its useful working life, replacing batteries on regular basis is much more expensive then purchasing the right size and type of battery, and let’s not forget the battery provides the motive power for our winch.
Manufacturers information will give us one or two useful pieces of information, one will be the minimum battery size in CCA or cold cranking amps, the other piece of information is the recommended CCA range, this is the minimum and maximum CCA’s required for the winch. If this is not in the instruction manual you can go to the winch manufacturer’s website and access their technical information which will give this information.
Many types of lead acid batteries exist, and the word compromise rears its head again as batteries are a compromise; automotive batteries are a compromise between performance and price, and are not generally suitable for winch applications, but why? Batteries are rated as amp/hours, a typical battery for a vehicle may be classed as type XXX, and so what does this mean. Battery types of a certain code number have to meet a specification, this will be a minimum A/H (amp/hour) rating which we shall call 60 A/H, and it will have a minimum CCA (cold cranking amps) of 560 CCA, and a specific type of battery post configuration, so what does this mean. Basically it gives a minimum specification for vehicle manufacturers and battery manufacturers alike so when they design a vehicle they know the batteries rating, post type and configuration, and sizes so they can design a vehicle to accommodate the battery, and an electrical system to suit it.
Amp/hour ratings are a misnomer, a 60 A/H rated battery should produce a continual supply of 60 amps for one hour; basically no is the answer, it will produce 60 amps for less than 15 minutes and then it will fall off dramatically and not last for one hour. Why? Because actual battery loads are measured on the 20 hour cycle and not over one hour, if we take our 60 amp hour rated battery and divide it by 20 hours we get the following figures.
60 amps divided by 20 hours = 3.
This 3 is the actual current or amperage the battery will provide over 20 hours, therefore we can say our battery will provide a guaranteed three amps for twenty hours, if we exceed this 3A discharge the battery performance will fall off dramatically, and not last for anywhere near twenty hours. If we apply the same formula to an average 100 A/H battery we can apply the same formula for its 20 hour rating; 100 A/H divided by 20 hours = 5 amps, therefore a 100 A/H battery will supply 5 amps for 20 hours.
CCA or cold cranking amps is the amount of, or maximum amps the battery will provide to the starter motor, once again these are measured over a prescribed time as with our A/H rating, for CCA this is for twenty or thirty seconds, usually 20 seconds for an automotive battery.
What does this mean, basically if we exceed the maximum A/H rating over the 20 hour period, or crank the engine for more than 20 seconds it will damage our automotive battery as it’s not designed to operate outside these parameters. It also means an automotive battery is not suitable for electric winches as they are cranked for much longer than 20 seconds at a time. We can also conclude that automotive batteries are designed to produce a low current output over a long period, but with very short periods of deep discharges for cranking engines, and they are designed to cope with this, but they cannot be deeply discharged without suffering terminal damage.
Leisure batteries are the next common type of battery, once again these are designed to operate on the 20 hour cycle, and some on a 40 hour cycle, and they are not designed for heavy discharging so cannot be used for cranking an engine or winch as it will damage them. Leisure batteries are solely designed for providing a fairly low current output for long periods of time, if we apply our calculations to an average or typically 80 A/H rated leisure battery we can conclude its designed to offer 4Amps for a 20 hour period. Leisure batteries are designed to tolerate deep discharges, unlike automotive batteries, and will cope with being flattened and can still be recharged without damage. At the time of writing a battery manufacturer, Fuller; is selling a combination battery which is a leisure battery but is suitable for automotive starting applications due to its robust construction, although defined as a leisure battery its more akin to a semi traction battery. As technology moves on its worth keeping a careful watch on these developments.
Having discounted both automotive and leisure batteries as being suitable for electric winches, we are left with one type of battery which is suitable, this is the traction or semi traction battery, these are designed to withstand long periods of heavy discharges and be run flat without damage. These are the only type of battery suitable for electric winches as they can provide their maximum CCA discharges for minutes or hours without damage, but this comes at a price, they can be recharged at much higher rates than automotive or leisure batteries without damage. In simple terms they can be abused in any way, in which an automotive or leisure battery cannot, and they will tolerate any abuse a winch can throw at them without complaint, and work for very long periods without needing replacing, but the price is they cost much more than other battery types. If we consider their heavy construction and long working life they work out much cheaper than automotive batteries as an automotive battery will need replacing many times before a traction battery will.
Now we know what type and size of battery we need for a professional installation we can search for a suitable make at the best possible price, many people make the mistake of buying a brand name because they have a reputation or image, this can be a mistake. Many of these popular batteries have a good reputation for durability, but lack the performance of many of their competitors offer for similar prices, so you are effectively paying top prices for a brand or name when you can buy the same type battery for much less now you are informed. Many battery manufacturers exist and they all have excellent websites which allow anyone to select a battery, these contain the technical performance information, also they contain the sizes and weights for a battery so you can select a battery to fit a space. This is more important if you intend to fit the battery purely as the winch battery, and retain your original vehicle battery.
This point raises another issue; do you swap the original vehicle for a traction battery which fulfils the needs of the engine and the winch? My instinct and experience says no for numerous reasons, modern vehicles rely on electronics and electrics to function, lose battery power and you lose your engine and with no chance of restarting it without another vehicle and jump leads; so if you are on your own you’re stranded. You have spent a lot of money on an electric winch, taken the time to select a secondary battery, so install this purely for the winch and fit a good split charging system, this will provide power for both batteries, is one flattens you can connect to to the other battery with jump leads and restart yourself. Many winch batteries will be rated much higher than the original vehicle battery, so selecting a dedicated winch battery means you are retain the original vehicle battery which is cheaper to buy than a much more expensive traction battery when it expires naturally through old age.
Split charging systems are moving at a rapid pace due to the rapid advances in high power control electronics systems, so buy the best type you can and install this using the manufacturer’s instructions. Many systems now offer the facility to programme, or pre-programme the split charging system to bias to the winch battery, but charge the main vehicle battery to its maximum and maintain it there, yet still run the alternator at, or near its capacity to charge the winch battery. Such systems use various forms of battery monitoring and many manufacturers offer a control panel to show the state of charge in each battery, these are permanently fitted to the vehicles dashboard or other convenient place, and are worth having as you can see the state of charge in both batteries. Having this visual reference allows you to stop winching and recharge your winch battery if its charge drops, we already know a discharged battery or one with too low an output means less winching power, so knowing how much charge a battery has sufficient output for maximum winching power.
Battery isolators are a piece of equipment which isolates the power from the battery, always obtain one which is a double pole type, and suitable to handle the maximum current the winch will draw, install this as close to the battery as possible so as much of the cables are isolated, Double pole isolators means it shout off both the live and earth cable from the battery, and double pole isolators are the safest type and cost little more than single pole breakers. Always leave them switched off unless the winch is to be used to prevent people interfering with your winch when your vehicle is unattended, or to prevent a vehicle fire if a cable is damaged while off roading.
Cables are often supplied with a winch, and often they are just adequate and often not long enough to reach the battery, other winches are not supplied with cables, in both cases you will need to refer to the manufacturer’s instructions for the size of cable, or cable rating you require. Where a minimum specification or size of cable is required, or you need longer cables, then go at least one size of cable larger than the minimum, or larger than this as this will allow the full power to be transmitted to the winch. Always have ends professionally crimped on; many auto electricians will do this for you for a nominal fee.
Mounting your electrical circuits
Begin by mounting your second battery in a convenient location, ensure it is securely fastened and bolted down securely, and that its mounting frame is substantial enough to cope with the rigours of off roading, and holds the battery without flexing or movement.
Fit the breaker switch as close to the battery as possible, this gives protection to as much of the cables as possible, and avoid mounting near hot exhaust systems, or fabricate and fit a heat shield to protect the breaker and cabling from the heat.
Measure the length of cables needed to connect the battery to the breaker switch and the size of ring terminals they require to connect to the battery and breaker. If your battery has tapered posts then have these fitted and crimped to one end of the cable instead of ring connectors.
Install the winch solenoid pack in a suitable location, and again ensure it’s not near the exhaust, or fit a heat shield to protect it.
Measure the distance from the breaker switch to the solenoid pack and have these cables made up with the correct ends crimped to the cables.
Measure the cables from the solenoid pack to the winch, again have these made up with the correct ring connectors crimped on.
Install a cable anchoring system for each individual cable which spaces them about 1’ (25mm) apart, never run them together or twist them together as any damaged cable may short against the other cable, and if one gets hot it may melt the insulation on both cables.
Install the cables loosely in position, fit appropriately sized rubber boots to each end of the cables, and battery post rubbers to the battery connection ends, attach each ring end to its connection and tighten up, fill the rubber boot with silicone grease and push it over the ring terminal to seal it. Run the winch to test it, switch the breaker on and off while running to ensure it works and isolates the winch. If you want to use the wander lead supplied, to operate the winch, but want it inside the vehicle you will have to drill a suitable hole in the bulkhead to pass the plug through, always paint the bare metal, and fit a rubber grommet to fit the hole and prevent cold air or water entering the vehicle.
If you want a permanent installation you will require the switch to be taken off the wander lead, power the winch by switching it on and identifying the common cable with a multimeter as it will now have 12 volts supplied to it. Fit a two way rocker switch to a suitable location in the vehicle, fit the identified live cable to the common terminal of the rocker switch, and the remaining two wires to the other two terminals.
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