I am converting to 12 volts neg ground on m,y 51. My stock wiring is in good shape but I want to add a fuse block for all the add ons like radio,turn signals, tach,gas gauge, fuel pump, etc. I thought I would run the hot feed through a toggel switch direct from the battery. What size wire should this feed be and do I need a certain amp switch. One reason I want to go this way is my bad back I have a hard time working under the dash. I thought an easy to get to and install fuse block would help. Any advice would help. Thanks Pete

 

Pete, how is your fire insurance? Even with a fuse or circuit breaker, direct from the battery is not such a good idea, the hot portion of the wire prior to the fuse/cb is not protected and any short will definitely let the factory smoke out of the wire.

I understand the problem with your back (yep) and you can mount an accessory power fuse bar anywhere but you should pick up power from a fused location and use a circuit breaker and/or a relay that is preferably ignition switched so that in the off position there is no power.

If possible, could you fill in your location when you get a moment, thanks!

 

Wouldn't a fuse or fusible link at the battery eliminate this problem?

 

Hi Pete!, The size wire you will need from the battery to your new fuse-box depends on the load required to operate "all" of your new accessories.."at the same time", or total load,..then just to be safe..go one wire-size larger.Add together the expected load/current draw of all your new "add-ons"..this will be your total current draw. A large "Maxi" fuse would be recommended at the point of power/source/ access,possably at the starter solenoid..or at least a switched source...
Once you have 12v to your fuse box ( which is protected by the Maxi fuse), be sure and add the correct fuse "from the fuse box" to each individual circuit..depending what that requirement may be...radio 10amp,fuel-pump 20amp,etc..label them so you know what is what.Sounds like you could be in the 40-50 amp range..that's alot of amps.
Why the Toggle swx??..so you can turn it off and not drain the battery? You may have a hard time finding a toggle swx in this range, the larger ones can carry 30 amps..besides, you know everyone forgets to turn those off... LoL!
Thought of a main battery disconnect instead?? just my .02$ Good Luck!

 

Yes, absolutely!

For some reason (I don’t know why, corrosion, appearance?) I just find the battery tap repulsive, hot terminal on the solenoid would be more tidy.

 

True. Very true.

 

50 amp toggles

JEGS 11028 JEGS 50 Amp Toggle Switches

Hi Amperage Toggle Switches

 

You will have to elliminate the 6 volt circuit breakers attatched to the instrument cluster which currnetly are the hub of your power distribution.

And your generator as currently wired runs there. So you have a little more work cut out for you than you might think.

First, you will need two circuit breaker panels - not one. If you have problems getting under the dash then you can mount them in the engine compartment on the fire wall.

Use NAPA 10 place fuse blocks part number BK7823208. Plan to give every component it's own fuse.

The first fuse block will be hot - powered all the time. The "Hot Bus" will include your headlights; running lights; brake lights; horn; door/courtesy light; cigarette lighter; and ignition switch. Power from the battery runs from the "BATT" position of the Starter Solenoid with a fuseable link in line through the amp meter, to the input lug on the hot bus.

The ingnition switch is powered off the hot bus, then a return line from the "ACC" post of the ignition switch powers the input lug of the "Switched Bus."

The "Switched Bus" powers: Radio; wipers; heater; signal lights; and fuel pump, etc.

Your charging circuit will originalte at the "BATT" post of the voltage regulator (or single wire on the alternator if using a "one wire"), through a fuseable link to the input lug of the hot bus. Then, the wire will continue to run from that same input lug on the hot bus, through the amp meter, to the "BATT" side of the Starter Solenoid (same wire as mentioned above).

In a charging state, the generator is supplying current to the busses, then on to the battery - the AMP guage shows the flow TO the battery as a "Charge.".

In a discharging state, the generator can not keep up the power demand, and power will flow FROM the battery to the hot bus showing a "Discharge" on the AMP guage.

I have two recommendations: First since you have to get rid of the 6 volt generator and get something else anyway, I strongly suggest a "one wire" alternator rated at 70 or more amps. Food for thought for the future - an electric fan will draw 40 amps.

Second, I would replace all the major (charge system, and power wires to/from the busses) wires. 10 guage from the generator all the way to the starter solenoid, and 10 guage back and forth to the ignition switch.

If you keep your stock electric wipers and heater, you will need to use one side of the "Switched Bus" as a 6 volt distribution - these fuse blocks actually come with 7 posts on one side and 3 on the other. For an all 12 volt buss you simply wire a bridge between the two inputs. On your switched bus you don't bridge them and run the 12 volt power to the 7 post side input lug as I described, then run one wire out of the 12 volt switched bus up to a "Vol-ta-drop," and back down to the three post side input lug supplying that side with 6 volt power. Then run your wiring from that (through the fuses) up to your wipers and heater. 6 volt wires should be one gauge larger (run 12 guage) up to the 6 volt accessories as they require twice the current to satisfy a given wattage at half (6) the voltage.

I have a gallery that has color Power Point wiring diagrams of the conversion and the busses. It's gallery #4 - Electrical Components (or some such faddle).

Take a look and if you need any of the originals or have any questions, write me a note.

Good luck