TECHNOFILE
LRM workshop
by Lindsay Porter
in association with Mobile Centre Limited
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8 JUMP START FACT FILE
Jump To it
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put to the test
Why waste money on expensive jump leads when you can buy them for a song on eBay? Well, here’s what happens if you take the cheap and nasty route. And by contrast, here’s how you can fit permanent, pro-quality, jump lead connection points to your Land Rover.
For many years now we’ve got used to
the idea of goods becoming cheaper and cheaper. But some things simply can’t and won’t, not unless you accept a cut in quality. Jump leads are a perfect example. Their main cost lies in the expensive copper core of each cable. If a manufacturer reduces the size of the cable, it reduces the ability of the jump lead to do its job. Cheap jump leads have one advantage, and one advantage only. They don’t take up much storage space in your vehicle. On the other hand, they’ll be sure to let you down when you need them. Which means, you’ve spent your
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money on pretty decorations and a false sense of security. Tim Consolante of MCL came up with the idea of trying to find out just how much use cheap and nasty jump leads would be if you put them to the test. I think you’ll agree that the results were quite spectacularly interesting. PicTURE 1 Tim’s initial plan was to make jump lead connectors permanently fitted to front and rear bumpers using Anderson connectors. This is the grade of cable he selected. It’s 40mm2 cable, rated at
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anti to £8.99. These eBay leads were rated at 600A, used 8mm2 cable and were classed as Extra Heavy Duty in the description. As a rule of thumb, each 1mm2 will carry 8A. So, using our rule of thumb these would be capable of actually carrying around 65 Amps continuous and definitely not 600. The croc clips are only rated at 250A anyway!”
300Amps continuous, similar to that of the jump leads that MCL supply. PicTURE 2 Tim, who is a leading vehicle electrics expert says, “The battery clamp is a vitally important link in the chain, the one on the right in the picture is rated at 600A, the one fitted to the jump leads is rated at 150A. These leads cost £3.99 and are laughably classed as ‘Heavy Duty 200A’. These were made using 6mm2 cable which is actually rated at 42A continuous, and NOT 200A!” PicTURE 3 Again from Tim: “We upped the
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PicTURE 4 In order to simulate what would happen if a fully charged battery was connected to the flat one on a stranded vehicle before cranking the engine, Tim connected my Defender’s battery to his battery tester with a cable from the set of slightly heavier duty cheap and nasty jump leads in the circuit. PicTURE 5 He wound the tester up to 225 amps (by no means the maximum amount that you could expect to use when cranking a Land Rover with a flat battery) and within less than a minute, this is what happened. PicTURE 6 We let it singe for perhaps 60 seconds, turned off and gave it all time to cool down. In this location, the insulation simply burned away. PicTURE 7 Here, and this wasn’t preplanned, where two cables crossed each
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other, the insulation melted and allowed the cables to touch. If we had been using both positive and negative cables and this had happened, we would have had a dead short which, Tim tells me, frequently happens when people try to start a vehicle using these dangerously inadequate jump leads. The result is very likely to be a fire or an exploding battery, or both. PicTURE 8 When you come to compare the cheap jump lead cable with one of MCL’s safe and acceptable ones, you can spot the difference in an instant. Not only is there much less copper in the cheap one but the strands of cable are much coarser. The cheap cable contains around 40 strands whereas the MCL cable has 565 strands, each 0.30mm thick. More, lighter strands are far more flexible than fewer, thicker strands and so are less prone to breaking. PicTURE 9 And then there are the clamps themselves. This one has taken up smoking at an early age… PicTURE 10 …while results are similar at the other end. But in both cases, note that only one side of the clamp has overheated which means that only one side of the clamp is conducting electricity.
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More pearls of wisdom from Tim Consolante: “All batteries have ratings on such as ‘650 CCA’ This would mean 650 Cold Cranking Amps, so the battery is able to deliver 650 Amps for a pre-determined amount of time. As a battery becomes discharged and voltage drops, current rises. In a jump start situation you will be trying to start the flat-batteried vehicle and charge its battery at the same time using current running down the set of jump leads. As a rule of thumb, if you have a set of short jump leads, for example 2.5m long, the cable should always be at least as thick as the earth lead on the vehicle. To see an inrush of current in the region of 500A is easily possible for the first few seconds as your starter motor starts work on a cold engine while the battery is powering up glow plugs and other areas.” PiCTURE 11 The clamps fitted to heavy-duty jump leads, such as MCL’s, should have an integral strap to carry the electrical current equally to both sides of the clamp. Cheap and nasty ones can only conduct current through the hinge holding the two halves together. the right connections PicTURE 12 Grey Anderson connectors are, I’m told, frequently used for the charging connections on electric fork-lift trucks in the
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TECHNOFILE
LRM workshop
by Lindsay Porter
in association with Mobile Centre Limited
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UK, where grey is for use on 36V systems; yellow is for use on 12V.
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PicTURE 13 MCL can also supply handles for the male connectors and plastic, weatherproof shrouds. PicTURE 14 Tim’s first job was to cut the legs on the shroud so that the correct size for the jump lead cable was accessible. PicTURE 15 Next, he took one of the Anderson connector pins, to establish the length of the ferrule, and marked the end of the cable accordingly. He made a cut all around the insulation at this position. PicTURE 16 After making another cut lengthwise down the cable… PicTURE 17 …the redundant insulation was simple peeled away. PicTURE 18 You’ve got a choice of two different methods of attaching the pin to the end of the cable, as we’ll show in a tick… PicTURE 19 This bit is easy to forget. Push the cable through the shroud and slide the
latter well along the cable, especially if you’re going to be using solder and applying heat. Tim also slid a piece of shrink-fit insulation onto each cable end. You’ll see why later… PicTURE 20 This is where Pound Shop grips are ideal. Tim twisted several strands of electrical solder together and, applying the flame to the ferrule on the pin rather than the solder itself, he half-filled the ferrule with molten solder. PicTURE 21 Keeping the solder molten, he also pre-heated the end of the cable (without damaging the insulation) and then inserted the end of the cable into the ferrule. It took
ANDERSON CONNECTORS It can be difficult to find connectors
capable of taking the currents used with winches or for jump starting. MCL supplies connectors from Anderson, an American company that makes a wide range of high quality electrical connectors. We used SB175 connectors which are rated at 175A continuous but will carry much higher loads for shorter periods. They are made by Anderson Power Products and are of much better quality than the various ‘pattern’ parts offered by others. Tim’s company MCL has used them extensively with commercial and military customers, including Mercedes Benz Commercial Vehicles. These are colour-coded, preventing two different voltages from being connected in an industrial environment. Colour coding for the SB range is Colour Yellow Orange
Voltage 12V 18V
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Red Grey Blue Green Black Brown Purple White
a couple of minutes for the solder to freeze, during which time Tim was careful not to disturb the cable within the ferrule. PicTURE 22 Another way of fixing pin to cable is to use a crimping tool. The jaws are adjustable to accept different sizes of cable clip, similar in principle to those small-scale ones you use with regular vehicle-wiring cables. PicTURE 23 Tim held another connector onto the end of this cable while Ian Baughan applied the crimping tool. PicTURE 24 This cable had been fitted to
the vehicle and cut to length in situ, so the crimping tool was ideal for use here. PicTURE 25 Tim’s preference is to carry out a double crimp as an extra precaution so crimp the terminal in one place then move the crimpers along the terminal slightly and crimp again. Literally a double check. PiCTURE 26 Not satisfied with a connection that was only crimped, Tim and Ian applied a smaller amount of solder than before, to the opening in the connector-end. The trick is to heat a little way away from the opening and allow the heat to pull the solder in, by capillary action. Tim adds, “Applying the solder in the
end it works as a safety latch because the end of the cable is of a greater diameter than the terminal, which has been crimped smaller but now, it’s soldered solid.” PicTURE 27 Back to the Anderson Multipole Connector; Tim offered up the protective shroud to the connector body. PicTURE 28 There are two holes in the connector body, each with a recess to grip a fixing nut. PicTURE 29 Each of the pins was inserted into the rear of the body, the correct way up and pushed home firmly until it clicked into
position. The shroud, if nothing else is to be fitted, can simply be pushed on at this juncture. PicTURE 30 But in this case, Tim was going to be fitting a handle to make using the jump lead connector much easier when fitting it to and removing it from the vehicle. So he used a sharp craft knife to cut a pair of neat holes in the shroud, aligned with those in the connector body. PicTURE 31 He then slid the shroud back off again, popped a couple of nuts into the recesses, refitted the shroud… PicTURE 32 …and pushed the fixing screws
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24V 36V 48V 72V 80V 96V 120V 144V
Their main benefits are: • The ones we used actually have silver plated contacts for extra durability and lower contact resistance. • Avoids the need for unfastening ring type terminals. • Wiping action cleans contact surface during disconnection. • Capable of 10,000 mating cycles (honest, missus, that’s what it saye ‘ere…) • Helps prevent fingers (or probes) from accidentally touching live contacts. • E xcellent resistance to hydrocarbons and solvents.
LAND ROVER monthly June 2011 85
TECHNOFILE
by Lindsay Porter
in association with Mobile Centre Limited
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through the holes in the handle, the shroud and the Anderson connector body…
PicTURE 33 …and once the screws had been located in the nut threads, he tightened each one with a screwdriver. PicTURE 34 Now, each of those pieces of shrink-fit tubing that he’d slid into position earlier was pushed over the joints between the cables and the ends of the shroud. PicTURE 35 The shrink-fit tubing that Tim uses has a coating of sealant on its inner surface so that, when heat is applied to shrink the tubing down and make a tight fit, the sealant is also temporarily melted by the heat. When it cools, the sealant does its job. Superb! PicTURE 36 Earlier, we saw Tim and Ian crimping and soldering a ring for the earth cable to be fitted to the female Anderson connector, mounted on the front bumper. Tim drilled pilot then clearance holes… PicTURE 37 …for the fixing bolts holding the female Anderson connector in place.
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PicTURE 38 At the rear, a simple, rightangle bracket was used to attach another female Anderson connector to the trailer socket mounting point on my NAS rear step. Here, the male Anderson connector has been inserted and you can see the Anderson connector’s protective cap temporarily dangling down. PicTURE 39 So, here endeth the saga of why it’s necessary to have good quality jump leads, such as those from MCL and how fitting one or a pair of female Anderson connectors can make a huge difference both to the speed of connecting up and – most importantly – to the quality and lack of resistance in the connections you make. Tim says, “The jump leads we supply are made of either 35mm2 or 50mm2 cable. The 35mm2 on the left & 50mm2 are on the right. Our jump leads are also covered in an expandable braided sleeving that offers protection for the cables, but also keeps them neatly together without tangling.” It really is lovely kit!
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costs • Prices for MCL jump leads start at around £100 for 4.5m long, 35mm2 jump leads, fitted with Anderson connector, handle and supplied in a carry bag. • MCL can also supply the heavy-duty crimping tool used here for around £85 + VAT. Coming soon, we’ll show how the fitting of an Anderson connector kit from MCL can add versatility to the way you use your winch. No longer do you need to have a winch permanently mounted to your Landy; now you can just connect one up, plug it in and go, wherever and whenever you need to. LRM
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CONTACT Mobile Centre Limited (MCL), Tim Consolante, PO Box 222, Evesham, WR11 4WT 0844 578 1000 www.mobilecentre.co.uk Thanks to IRB Developments for use of workshop facilities. Ian Baughan, Unit C, Middleton House Fm, Middleton, B78 2BD 0121 342 6460 0773 092 0431 www.irbdevelopments.com
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