I forgot about the heat factor. I’ll go 10 gauge...👍

Thanks.

 

My mistake...I’ll need to go with a 4 gauge (120 amp) wire to cover the higher amp alternator. Am I correct here?

Thanks.

 

That seems to be huge for an alternator.

 

I’m thinking the same. 8 Gauge seems more in-line with what the members are posting....

 

You can relate an alternator to an engine-

The engine can make 500HP- but it's not putting that amount of power all the time.
And at idle - the engine is not going to make near that amount of HP either.

The same goes for an alternator-

In fact the alternator at idle- might be able to put out 60-65 AMP- the 130A capacity won't happen till around 1500-1800 RPMs- and that also is limited due to heat-
The alternator is only going to put out the power required - controlled by the voltage regulator.


You don't have a bunch of extra electrical stuff- 8GA is fine 6GA is better-

I look at it as the cost is not that much more- it certainly won't hurt.


The diagram above is to keep it simple and cost effective- as I have helped several members with this upgrade.

$30 for a battery fuse/holder and the WHOLE car is protected- say if you jumpstart it and reverse the cables- replace the fuse to fix. I have read many threads re that problem...

6-8 feet of good 6GA or 8GA is about $20-

I'd do it right- the first time-

Richard

 

Awesome. Thanks much. I’ve learned a whole lot about alternators with this post....👍

 

Just a small issue with the drawing. If the link blows your not making it home.

 

👍👍👍

 

The fuse at the battery would blow first if you reversed polarity with the jumpers-- If a fusible link burns- then you have another issue with your electrical system.

On my car- I have removed all the fusible links and running fuses-

I'm even running Blade fuses that lite up when they blow and relocated my fuse box- so I have less of a chance of being stranded!!!

 

For an alternative, the link for the alternator should be parallel with the other links feeding the car. In the drawing if you have a slow starter drawing 400 amps or a shorted alternator you have to call for a tow and possibly be stuck in traffic with your hood up which sucks. Moving the link may get you home or to a safe spot to be towed.

 

Just sayin- technology has changed in 50 years-

Having the alternator routing its power all with the other electrics is not a great idea. See the BMW design below.

In running the wires as I have pictured above mimics the 'better' way new car use to connect the alternator.

The alternator - think of it as income- the battery as your bank account. You'd rather have your mortgage payment come from the bank account NOT your paycheck,

Same idea- plus the battery not only starts the car - but stabilizes the voltage and cleans up the power, A much better source than the alternator for stable-ripple free power.

The 200A fuse at the battery will handle a 400A (I have never seen that high a number...) for about 5 minutes... Pulling that much current could melt the battery cable so popping the fuse would be a good thing.
Have a spare fuse if the situation does arise - you can replace it in a few minutes.

As far as running parallel wires is not a great idea- best stated by Big2bird-





Notice the starter and alternator run to the battery and FUSED there- then everything else is powered off the battery-

 

That wire chart is rather conservative for automotive use. All the gauges from about the #6 and smaller need to shift up one row to get more realistic ratings.

The fuse blowing times don't apply at all to those Bussmann CBBF marine fuses - that's what the Blue Sea fuses are. The 200A fuse would blow in about 10 minutes @ 135% current and about 10 seconds at 200% current. A 50A fuse would blow in about 10 minutes @ 135% current and about 2 seconds at 200% current. So, nothing close to those times. You have to look at the fuse characteristics, they are all different.

 

The main power distribution point at the battery has a paraelle circuit isolating starter and alternator from the cars functions as the engine ,abs,srs,ps,gauges etc will not shut down with an alternator (shorted) failure. As a note in 04 bmw came out with can controlled power distribution system to limit essential circuits only to function when charging system issues arise. Even parasitic draw strategies have a special design to address abnormally high numbers after 1 hour same as Merecedes.

 

Those reasons make way more sense for the wiring than using the battery for filtering does. A battery is a lousy filter. Great bulk storage device but lousy filter, especially of higher frequency switching noise from things like the 6-pulse alternator output or a DC-DC converter.

 

Like I said-technology has changed in 50 years-

These cars don't have canbus- so upgrading the wiring as I have suggested will minimize problems.

I try to keep it simple- the easiest way to improve on the car's old design- the KISS principle.

Sure there are better ways to to do it- rewire the entire car-but for the average car guy- it's above their pay grade.

Here are several ways to do it- inexpensive and straight forward-

I'm offering solutions - show me up yours








High current panel

 

It's pretty simple to do an alternator upgrade on a 78.

Install a new 6 gauge solenoid to alternator wire with a 10 gauge fusible link at the solenoid end.

Take the original charging wire which goes from the alternator to the bulkhead connector and use it only for voltage sensing.- connect it to terminal 2 of a 10/12SI type alternator or terminal S of a CS130/144 type alternator.

The car is a 78 which has an alternator indicator light, so the brown wire at the alternator can be connected directly to terminal 1 of a 10/12SI type alternator or terminal L of a CS130/144 type alternator.

If you want to run other accessories, then bring the 6 gauge wire to a big stud terminal and then continue it to the alternator. Connect your new accessories to the stud with the proper fusing for each wire.

 

1st of all I like your presentations. Keep in mind though the alternator and starter units in the European cars are expensive run on lin buss and have a low failure rate. There are better ways as you say. As far as say 60s-70s-80s GMs I will move the power distribution off the starter solenoid away from all the monkey business that location reveals over time with a remote distribution block. From that point all the fusible links will attach. Depending on the alternator output and gauge size choice will feed off that point. If a remote is not used I use a 4 gauge and 8 gauge link directly to the starter solenoid to provide power distribution for electric radiator fans at the alternator. Otherwise I will generally use 6 gauge. As a rule I try to keep parasite wiring off the battery posts due corrosion and intermittent charger / jumper use damage over time plus it looks messy and unorganized. If headers really make it tough to run 1/2"+ insulated coverings to fit to the starter causing heat damage as laying on them. I will run The 6 or 4 Gauge directly to the battery and only have the S and or R wiring running there. And as a must I will add a 4 gauge ground strap to chassis and or frame from the engine block. Radiator fans, hd fuel pumps, stereo amps will exploit inadequate original grounds.

 

So just like this? But use a fusible link versus on the side of the road serviceable fuse?

 

http://www.pvv.org/~syljua/merc/TooSeptST07.pdf

It would seem the engineers at Mercedes Benz disagree.

 

I like that approach. Easy, solid. If a fusable link melts, you have had a catastrophic failure. Replacing a fuse is the least of your concern at that point. You have bigger issues that need addressing first.