Introduction: Alligator Leads With Integral Fuse Holders for Safe Connections to Lead Acid Batteries
I don't like fires. I especially dislike fires in my tent or on my sleeping bag. This instructable details the steps I used to create a pair of alligator leads with integral fuse holders so that anything I hook up with the alligator leads is protected with some fuses. The fuses are part of the handles of the alligator clips. This makes it so that it is nearly impossible to have a short circuit before the fuses. I terminated the alligator clip leads with Anderson PowerPole Connectors. They are THE STANDARD for 12V connections in my home and automobiles. They are great to put on all of your 12V stuff because when I made the pictured alligator leads, I didn't just get them for one 12V device. They can now be used with my little air compressor, my inverter, my ham radio, my CB radio, another battery, a power supply to charge batteries, my 12V box fans, my 12V lighting, my UPS, or my lawn sprayer. On with the instructable!
Step 1: Gather Materials
First, collect a pair of alligator clips (perhaps from your inverter or something you already have that has a suitable pair). Then scavenge a pair of chassis mount fuse holders. Find a little wire and a pair of Anderson PowerPole connectors. randl.com has them, but any ham radio or RC car shop should have them. They are a little pricey, but when you consider how much more useful a compressor is when it can be used with alligators on the lawn mower AND with a 12V lighter plug in the car OR a pair of quick lugs on a little 12V security light battery the added versatility is well worth the cost.
Step 2: Remove Existing Wires From Alligator Clips.
In this photo you can see me desoldering the existing wires from the alligator clips. I also removed the crimp portion of the clips because I wanted to solder the fuse holder lug directly to the clip handle for the best mechanical connection possible.
Step 3: Solder the Fuse Holder to the Alligator Clip
Be sure to insert a fuse before soldering as it may change the position of the terminals on the fuse holder. With a soldering gun or other high heat iron, solder the tab at the exit of the use holder directly to the handle of the alligator clip. I also crimped over the sides of the handle to improve the mechanical connection between the clip and the fuse holder.
Step 4: Solder Wires to the Alligator Clips
Next, I soldered the wire lead to the fuse holder. I separated the wires about 8" back so they were long enough to reach each terminal on a typical car battery. I also put a wire tie on them to keep them from separating further.
Step 5: Make Handles From Epoxy Putty
This is the novel part. I used the maker's secret weapon #36 -- PLUMBING EPOXY. Home Depot has it in the plumbing isle. This is FANTASTIC stuff. Go buy a tube of it now. It is hardener and epoxy in on package. You cut off the amount you want to use, knead it, and then form it into the shape you want. It sticks to glass and everything else. It can be drilled and filed after it hardens. I cut approximately 1.25" of the stuff from the 3/4" diameter tube for each handle. I then formed it around the clip and the fuse holder to make them into one solid assembly. It is forms a nice solid bond and the fuse holders are ONE with the handle after it cures in about 5 minutes.
Step 6: Crimp the Anderson PowerPole Connectors Onto the Cable
First, strip back just enough insulation to be able to extend the full depth of the crimp portion of the wiring terminal. Next, orient the cable and connectors. Be sure to hold the wire so the red is on your right if you point the connector away from you. Then make sure the curve of the contact tip is curved downward. This will save wire twisting when you slide the plastic shells over the crimped on terminals. After orienting the terminals as described above, crimp on the contacts. Then, slide the covers over the terminals. They are a little counter-intuitive. The tip of the metal contact should curve toward the metal tab in the connector body. The connectors click when the terminal is fully inserted into the shell. If they don't click, you aren't done pushing. When the plastic shells are pressed on, slide the connectors against each other to engage the dovetails on the side of the connector shells. This will lock them together and make them ready for use.
Step 7: Enjoy!
Now your new SAFER alligator clips are ready to use. Don't forget to install the fuses in the holders. I typically use 30A fuses for them. These would blow if there is a short, but shouldn't affect normal use. Be sure to reduce the fuse size to be just adequate for your loads. Too large a fuse is just as bad as not having one.
Thank you for the time you spent looking over my instructable. If you have read this far and are thinking, "This was great and totally worth a buck" You can help me continue to make more instructables by making a donation using this link to my ebay store. Thanks, and keep building! -- Yeltrow