Monday, Jan 31, 2011 at 15:56
I like Steve's idea of putting an Anderson plug on the wire coming from the cigarette lighter plug too, so you can use it either way. (Sort of a general principle with changing connectors is that unless you're absolutely sure that you will never ever need the old connector, or if you absolutely need every last mm of cable length, don't cut off the wires to the "old" connector right at the connector - leave like 10 cm of wire on it. That way you can splice back onto it later if you need to.)
Having installed Anderson connectors (both the one and two-wire kind) and generic crimp connectors (red/blue/yellow sleeves) in various sizes on cars, here's some ideas.
As far as actually crimping the wire to the Anderson terminals: it depends on what gauge of wire you are working with and how big the "barrels" on the Anderson connector terminals are, but in general, the first thing to try is to strip the wire enough to fill up the barrel lengthwise, twist the strands together with your fingers, and then try the bare end in the barrel.
If it just barely won't go in, better twisting technique may help. As a last resort you can try cutting one or two strands out of the wire, but this is generally a sign that you need smaller wire or the next size up Anderson connector.
If the wire is way too big to go in, then you need smaller wire or the next size up Anderson connector.
If it fits snugly, you're in business... see below.
If it fits so loosely that it looks like you could fit two of the same size wire in the barrel, the absolutely correct thing to do is to use the next size down Anderson connector. The thing you do when you're already at the smallest size Anderson connector, or when it's 8 PM Sunday and you can't get parts, is: strip the wire so that two barrel lengths are bare on the end. (This can be hard to do if you've already twisted the strands; it may be simpler to cut off the twisted part and start again.) Twist the strands together, then use your fingers or some pliers to fold the bare wire back on itself. Then shove the folded bare wire into the barrel and it should fit snugly.
You have to at least crimp the barrel. The standard crimp tool (as used with those connectors with red, blue, and yellow plastic sleeves) will do an OK job. There seem to be two kinds of these in the world. One of them has a crimp station that looks like () - two concave curves. The other one has a crimp station that looks like }) - one of the curves has a bump in the middle. If you have a choice, I find that this latter kind makes a better crimp. It may help to use two hands on the crimp tool, or put one side of the tool against the table and push on the other - just to get more force on it. The barrel on an Anderson connector is usually long enough that you can get two crimps done along the length of the barrel.
After you crimp, you can give it a "pull test". This is simply holding the Anderson terminal in one hand and tugging on the wire with the other. This will show up a bad crimp pretty quickly (the terminal will come off the wire). You don't have to put a 300 pound pull on it, but give it a decent tug.
If you want to solder the connector, make sure you have flux-core (aka rosin-core) solder. The other kind is acid-core solder, which is meant for soldering (sweating) copper water pipes together. Pretty much all the solder that an electronics place sells will be the flux-core kind; it is kind of hard to buy acid-core solder by accident unless you are shopping at a plumbing supply. You will also need a stout soldering iron; a 30 W or so small "pencil" will sort of work, slowly, on the smallest Anderson terminals, but a 100 W or more "gun" or big pencil will work a lot quicker.
Arrange the wire so that the terminal is hanging down, with the wire coming up vertically out of it. Heat both the barrel of the connector and the bare part of the wire with the iron, until you can get solder to flow down in between the wire and the barrel. You will notice that it will suck up solder until you fill up the barrel, and then it will start pooling up around the top of the barrel and maybe running over the side; stop there. If you put in lots and lots of solder, it tends to "wick" up between the strands of wire, under the insulation, converting your flexible stranded wire to not-so-flexible solid wire. This is also why it works a little better to have the terminal hanging down, so solder doesn't flow under the wire insulation by gravity.
As has been noted, take care to get the polarity right. :) If you notice you have gotten it wrong, you can use a small flat screwdriver to release the retaining spring that is molded into the Anderson connector plastic body so you can get the terminal out.
Common Andersons are kind of protected against foreign objects but not as
well as (for example) a mains socket; there are "fingerpoof" Andersons that are a little better on this. If the Anderson on the end that is connected to the battery is going to flop around loose somewhere near metallic objects when the fridge isn't connected, it might be a good idea to put some kind of cap on it. This can be as simple as a strip of plastic tape, or as fancy as a rubber cap made for the job. Sometimes items that have plumbing joints (water valves, engine oil coolers, etc) are shipped with little vinyl caps over the ends to keep out dust or protect the threads; if you can find a big enough one of these you can usually squish it to fit around the end of an Anderson.
If you're feeling really scientific you can measure the voltage drop after you install the plug. Plug in the fridge and turn down the thermostat so the compressor comes on. Then set your meter on a low DC voltage range (like 1 or 2 or 4 volts, whatever you have) or let the autoranging kind do its thing. Stick one probe in the back side of one of the Anderson connectors, and the same probe in the back side of the other connector, on the same wire. Waeco says the CF-80 draws 7.5 amps, and Anderson says that the "50 amp" size Multipole has 200 micro-ohm contact resistance, so in super perfect happy world, you would measure about 0.0015 V (1.5 mV). In the real world it will be higher than this, but much over 0.050 V (50 mV) or so is probably worthy of investigation.
Was that far more than you wanted to know? :)
Matt R.
AnswerID:
443675
Follow Up By: Member - Kent M (QLD) - Monday, Jan 31, 2011 at 16:55
Monday, Jan 31, 2011 at 16:55
WOW!!! More info is better than none ay all I say. Thanks ever so much for your input - I'm sure it will make my job easier and more interesting.
Cheers - thanks again.
Kent
FollowupID:
715750