COLUMN GEOFFZONE BY GEOFF ANDERS
Charging into winter, mindfully using that winch We all know the importance of our vehicle battery. Run it down when camping and it won’t start the engine, use a winch too long, same result... oops! There’s lots of info about batteries, winches, fridges, capacity etc. It can be very confusing for a non-electrician. Vehicle batteries have five ratings: • Voltage: Usually 12Volts, the nominal rating of the vehicle’s electrical system. This is the pressure to move the electrical energy. When the engine is running this should rise to the charging voltage of about 14V. Below 12V is bad for the battery. • Ah: Ampere hours. Amps multiplied by time, i.e. 50Ah = 50 amps for an hour or 1 amp for 50hrs, after which it will be ‘flat’ and may not start an engine. the amount of useable energy it can store. It’s electrical energy capacity. Original vehicle batteries will be rated around 50Ah. Many vehicles cannot be hand or tow started, so need a charged battery. An electric winch may pull up over 500A under load so a 50Ah battery will be flat in just a few minutes of hard work. • CCA: Cold Cranking Amps. Starter motors need hundreds of amps when cranking, especially during winter. Diesel engines, being higher compression, usually need more amps than petrol engines hence their batteries are larger, with higher CCAs. The rating is for a short duration of very hard work. • Physical size: Will it fit? Is it a bit heavy? • Type: Usually Lead Acid, but AGM or other in some modern vehicles. • Amps: the current (amount) of electricity flowing. More amps require thicker wires. Consider Winches may drain your standard battery very quickly, hence the need for a dedicated winch battery. A charge controller will allow the alternator to charge both batteries while driving, maintaining the vehicle one as the most important. Alternator: creates the battery-charging electricity. It is driven by the engine and should produce between 50 and 100A, not enough to run a winch under load but will assist. Older winches had 2HP motors to pull 5000lbs. 6HP and over 10,000 lb winches are now available. One HP= 750Watts (3/4 of a kW) so 6HP=4.5kW. Getting that output from a 12V system is a quite a feat and requires fat cables and a battery with lots of CCAs. Many buyers of new 4WDs think ‘60k for the truck, what’s another grand?’ So they get a 10,000lb winch. 10K of pull will lift two 4WDs vertically! It will also put immense strain on chassis and winch mounts, never mind what you want to tow with it. Specific questions and considerations about winching How many new 4WDs get used seriously off-road? Few people
58 NZ4WD
AUGUST 2022
wish to risk their investment. If that is the case, maybe direct the accessory spend elsewhere? Any winch needs something to pull against. How many trees or fence posts will stand five tons of side-load? Use a tree protection strap or blanket. A mate of mine has owned a Warn 5000lb winch for about 40 years. He’s a serious, skilled, active 4WDer. I’ve seen his winch used multiple times hauling out 4WDs or logs and it has never failed to do the job, sometimes using a snatch block. The factory PTO winch on my Land Cruiser would haul as hard as the Warn, yet was only rated at one ton (2240lb) ‘safe working load’ (it didn’t need a battery so would do that all day with the motor idling)! Winch pull decreases as the rope drum gets fatter and will drop to about a quarter of the rating when on the outer rope layer. Full rating is only available on the inner-most layer. Getting rope off the drum is essential, and also much easier on its motor and power source. A snatch block will assist with that. Do you really need 100ft (30m) of rope? Steel wire is heavy, get synthetic rope and toss an extension length under a seat? Keep synthetic out of sun and heat.
