Electrical Power Management
All of our off-road machines are probably running more electrical gizmos, widgets, and junk than we really need. We think it has something to do with the fact that we are becoming too reliant on the fine appointments and creature comforts of the late-model vehicles we run around town in. Whatever happened to the Jeeps that only had a gas gauge, a speedometer, taillights, and headlights?
We’re finding that our Scrambler project is turning into a quest for an early-model Jeep/late-model hybrid fitted with enough fancy contraptions to accommodate a fussy old woman! It would be nice to monitor only the fuel gauge, speedometer, temp gauge, and a few other electrical accessories that run off one low-maintenance battery, but that’s not happening on this build. By the time we’re finished the CJ-8 will have a slew of electrical gadgets and components that will definitely need a properly controlled dual battery setup.
We installed the Digital Power Manager from Painless Performance so the deep-cycle Optima YellowTop batteries will be running in dependable form. The solid-state Power Manager will help keep the batteries from prematurely draining due to an overloaded electrical system that’s pulling too many amps. The system will regulate the batteries, automatically distributing more power only when needed.
The Digital Power Manager is far less complicated than the old dual battery manager systems of yesteryear. It is a four-wire hookup, and there are no levers, buttons, or switches to flip. The system will regulate any dual battery setup and automatically engage the second battery when enough load is placed on the main battery.
The manager is great for hardcore off-road machines because it is weatherproof and resists vibration and dust. However, the unit shouldn’t be placed close to any heat source like exhaust manifolds. We had room above the Optima batteries, so we mounted the control unit there. This reduces running a lot of cable from one side of the firewall to the other.
The system comes with six high-quality gauge cables for connecting between the two batteries and the control unit. The kit also comes with all the mounting and installation hardware. The cool heat shrink that’s included has adhesive inside it that forms a strong bond when heated with a heat gun. We won’t have to worry about them pulling apart while out on the trail.
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We have all arced a battery terminal and electrical connection while swinging a wrench around under the hood. The kit comes with rubber boots to cover the connections at the control unit. These help keep us from wrecking the unit and also allow it to be mounted in compact spaces without worrying about shorting out and burning the vehicle to the ground.
We protected any cables running to the Optimas or the control unit with a Power Braid and heat shrink from Painless. This protects the cable from chafing against other parts. We placed the braid over the cable and the heat shrink over the braid, then heated it up. The added protection is worth taking a few minutes to do it right.
If you have noticed a lot of orange, red, and blue tools in our stories lately, it’s because we have found ourselves with a Harbor Freight hookup! These tools work, and they fit our budget. We picked up this tap and die set for $19 and it has helped us work our way through a number of steps on the Scratch-Built Scrambler.
Taps and dies are simple to use. Just drill the proper size hole according to the bolt size that’s going to be used, and run the tap through it. If you’re tapping thick metal, don’t force the tap. A little oil will help it thread easier without breaking. We started using the tap set after breaking off one too many self-tapping stainless steel bolts.
We drilled and tapped the frame of the Jeep from bow to stern. After tapping our holes along the framerail, we used stainless steel bolts and clamps to secure any wiring or brake lines. The clamps we used to secure the cables have a rubber cover so they won’t cut into the insulation. The clamps beat the heck out of zip-tying cables and wires!
The main (upper) and auxiliary Optima batteries are ready for service. We’ll hook the winch cables directly to the auxiliary battery. The power control module will keep them charged and will only pull power from the main battery until heavy loads are placed on it, at which time it will pull power from the auxiliary battery. The power control unit is capable of switching up to 280 amperes of direct current for large loads, such as winching, and for the other electrical accessories we will be running (HID lights, Lowrance nav unit, radiator fan, A/C, stereo, and so on).