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Tales of a Hay Hauler: Blood and DC current flows

Brad Nelson for Progressive Forage Published on 09 July 2021

Positive and negative. Not as in right versus wrong but as a direction, like north versus south, right versus left. (“Left turn here?” “Right.” So, I turned right. “No, no. Correct, not turn right!”)

My wife, a native of Minnesota, claims she’s so bad at directions because here in the western U.S., all the rivers run the wrong direction. I’ll admit to getting my directions tied in knots mentally.

Rowland, Nevada, is a prime example. It took studying it on a map for a long time to realize that after all the switchbacks on that last three miles of steep canyon getting down to the river and ranch that my directions were daffy. I had north and south reversed, and the ranch was set so deeply among the mountain terrain it wasn’t obvious from which direction the sun came up. It just felt like the Bruneau River should be running south instead of north toward the Snake River in Idaho.

Another day, I discovered one of the trucks I had was wired goofy. It had a positive-ground system. In most automotive applications, the electricity is direct current (DC) as opposed to AC, or alternating current, we’re familiar with for normal household use. I can make AC work, but I’m not sure I totally have my mind around it.

DC flows in a circle. Like blood in the body, it goes around and around the system, the blood carrying oxygen to the body and bringing carbon dioxide out.

DC moves, usually from the positive anode (post) on the battery, follows wires and does something (makes a light shine or a fan turn or an engine start) and then returns via wires and/or the frame of the vehicle to the negative anode of the battery. Unless there’s been a breakthrough in the last few days, my understanding is that scientists have been able to make, somewhat control and get work out of electricity, but they still don’t know what it is. Similar to magnetism – which, by the way, has a massive part in controlling and getting controlled energy from electricity.

Back to the truck. Installing a CB radio in the truck, I noted that the radio specified positive and negative on the power leads and had a caution that it wouldn’t work on a negative-ground vehicle.

I called the guys at Murray Electronics, where I got the CB, and asked for help. They said all I had to do was to isolate the body of the radio from the body/frame of the truck, run the positive wire from the radio to a positive wire from the truck and the negative wire from the radio to a negative wire from the truck.

Seems that the internals of the CB don’t care whether the truck is positive- or negative-ground as long as the radio gets the correct polarity as it is attached to the truck. Where a “normal” negative-ground setup would assume the body of the radio contacting the truck would only amount to another ground, or negative connection, frame or body contact wasn’t an issue.

I was halfway there. I had a bracket, so I could use the same CB radio in the truck or in my pickup. A base was anchored and hard-wired to each vehicle. The CB radio was hard-wired to an adapter which slid into and locked into either base unit on the rigs.

In a “Hold my Mountain Dew” episode, I got both base units wired correctly, to the pickup’s negative-ground system and to the truck’s positive-ground system so the adapter on the radio slid in and locked on either and worked correctly on either. All without blowing fuses or frying a radio in the process.

As a side note, most automobiles and trucks once had generators, with DC output. Modern vehicles have alternators, which produce AC, which is channeled through electronic wizardry to send DC to the vehicle. Note that a number of newer vehicles offer an option of available house current, 120-volt alternating current plug-ins to run alternating current tools from the rig.

I gotta share this: Someone posted a picture of a hybrid wheelchair/motorcycle. I remembered John Sachtjen commenting about what my wheelchair might look like, so I had to reply.

“One of my hay grower friends, who’s also a tinkerer/fabricator/inventor, told me it frightened him to imagine what my wheelchair could look like and include. Air horn. Wheelie bar. Twin Sachs-Dolmar chainsaw engines with reversing hydrostat drives. Cooler. Radar detector/jammer. Visible BS meter. 360-degree swivel 12-gauge disguised as an umbrella and rack. Personalized license plate, ‘You make my great-granddaughters cry and you won’t have time to cry.’ Attached camo canopies in various colors so I can have peace and solitude as needed.”

It’s high on the project list. end mark