Classic Car Booster Installation Instructions

Classic Car Booster Installation Instructions

6 or 8 Volt to 12 Volt Booster

Installation Instructions for both the 12 Watt booster and the 24 watt booster.  Please read completely before starting work.


Find the power cord.  It has a fuse holder with a 3 amp fuse installed for the 12 watt unit and a 5 amp fuse installed for the 24 watt unit.

Make connections to the power cable:

OPTION 1:  Non-permanent, booster can be moved from car to car, no drilling required.

Plan the connections so that the connector for the booster unit can be stowed behind the front panel with enough slack that the connector can be retrieved and connected to the booster unit easily.

OPTION 2: Permanently mount the power socket for the GPS or similar device

Plan the connections so that the power cable and the booster can be attached and hidden behind the instrument panel.

Step 1   Ground connection


Connect the red wire to ground.  The fuse will provide protection.  The black wire is the hot connection.


Connect the black wire to ground.  The hot wire is the red wire with fuse protection.

Step 2   Hot wire connection

The hot wire can be connected to a fused battery feed line (body feed). A handy place to connect is the light switch, if the booster unit is connected to the power cable, there is a small “standby” current through the booster even if nothing is plugged into the 12 volt socket.  This will eventually drain your battery.  If you reliably disconnect the booster, or use a cut-off switch, this problem is solved.

If you decide to connect the hot wire directly to the battery, please pay ATTENTION to this CAUTION: Obtain an inline fuse holder and place a second fuse in the hot wire close to the battery.  Otherwise a short in the wire between the battery and the power cable fuse could have catastrophic results. A fuse of 5 amps to 10 amps will protect against a short.

You may connect the hot wire to the instrument feed which is turned off with the ignition switch.  It also solves the current drain problem.

Step 3  Test the installation

Retrieve the power connector and plug in the booster.  Plug a GPS, or some other device, into the 12-volt accessory socket or the USB socket, as appropriate.  If necessary, turn on the ignition.  If the device does not power up go to the trouble shooting section.  If you are going to install the socket bracket, proceed to the next step.



Step 1  Bracket placement

Pick a spot to place the bracket.  You can mount the bracket on a return bend on the lower instrument panel, best locations are usually on the right hand side or near the center.  You may have to temporarily remove something, maybe a radio or glove box to gain access.  You might mount the bracket to the bottom side of the glove box with screws going through the glove box floor.  Keep in mind that you will want to hide the booster away and secure it somehow.

Step 2

Unscrew the large nut from the socket and pull the socket forward to gain access, leaving the wires connected. Use the bracket holes as a drilling template to drill mounting holes.  If you must remove the connectors from the socket, pull with the connectors, not the wire.  These connectors are quite tight.  Take note of where the wires are connected.  THE RED WIRE ALWAYS GOES TO THE POSITIVE TERMINAL AND THE BLACK WIRE GOES TO THE NEGATIVE TERMINAL.  The polarity is marked  ‘+’ and  ‘-‘ on the accessory socket and the optional dual USB socket.  If  the wires are connected backwards,  the USB devices are at risk.  If the USB socket wires are reversed, the damage is immediate when power is applied.

Step 3

Use the provided screws to mount the bracket.  Put the socket back in the bracket and hand tighten the large nut.

Step 4

Secure the booster in a hidden spot.  If you need more wire between the booster and the socket to do so, contact us.



Power up your booster and plug in your GPS or phone.  If it comes alive, you’re done.

The booster will produce no power if the polarity is backwards.  Double check that you have connected the power cable correctly.  If the battery is nearly dead such that the starter won’t crank, the booster will provide no power or reduced power.  You should charge the battery before proceeding.  The booster needs at least 5.6 volts.

Check that the power cable is pushed in all the way to the booster.  Check that the GPS cable is pushed firmly into the socket.  You might also plug the GPS into a modern car socket to see if it comes up.

If all that fails, get a voltmeter.  Unscrew the fuse holder on the power cable and check the 3 Amp or 5 amp fuse. If the fuse is missing or blown you have found the problem.  Otherwise, remove the fuse, and put the positive VM terminal on the power side of the red wire at the fuse holder. Put the negative VM terminal to the point where the black wire is connected.  If you are using instrument feed, turn on the ignition. If you have no voltage your “hot” wire isn’t hot or your ground connection is bad.  You need to investigate that.  If the voltmeter is reading negative voltage you have connected the red and black wires backwards.  You need to connect the red wire where the black wire is and vice versa.  You have done no damage to the booster, it protects itself, and should work properly once the proper voltage is applied.

If you have any questions, contact us at