jumping out the ammeter? opinion

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swing69

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Since I have the dash and ALL the wiring out of the 65 Plymouth, now is the time to take the STOCK ammeter out of the circuit.

Why? I want to go to a 45+ or 50 amp alternator, and I don't want to cook the stock ammeter. Gonna drive a stereo amp and higher output lighting.....

Options:

1) install a more modern ammeter in the 65 place? Will it be any better than the stock one?
Any benefit? If not, leave it alone and do nothing?

2) simply tie the two wires together? I don't like this one....but its effective....

3) do the "Mad" wiring mod? I don't know of anyone who actually did this though.....

4) run a hot lead jumper from the + of the alternator directly to the + battery post. This should "half" the amp sending it to the battery....yes?

Like I said, I'm going to add more gauges, better lights, a stereo, back up light circuit, dash hot lead for "accessories" like GPS and phone charger.


Opinions??????
Mike
 
Ammeter bypass and install a voltage gauge. I have yet to do that, but it's in the works.

I did tie the two wires together when I last had the cluster out, I just haven't completed the rest.
 
I just cut and soldered the two wires together. And then ran a wire from the alternator to the starter relay battery post. My lights are brighter, blower motor is stronger... It's just better every way.
 
Wasn't worth the cost to me to convert the ammeter to volt meter. I decided to just connect everything to one post on the ammeter and run a volt meter under dash. I didn't want to hack up the factory panel to install it in place of the ammeter.
 
Leave gauge installed. Move the black wire over to red stud and you have bypassed it. No splices needed.
 
mderoy340 said:
Leave gauge installed. Move the black wire over to red stud and you have bypassed it. No splices needed.
Click to expand...

That's fine for most standard panels but not the best route for a rally panel.
If there is a hot wire connected to the amp gauge, the entire gauge is hot.
The rally panel has both a ground path through its fuel gauge and a conductor that can bridge the 2. Yes I've seen the results of this event more than once. Owners reported lovely bright red/orange arcs as those 2 gauge needles turned to ash.
 
I did option #4 but ran it to the starter relay instead of the battery. Been three years now and working great. I did add a voltmeter in my dash.
 
Just so you will know, the ammeter does not measure the full alternator output. It only measures the current flowing into the battery when charging and the current from the battery to any non-starter circuit when the lateranotr is supplying adequate current. So you can move up to a 50A or 65A alternator with the same ammeter and it will show little or no change in the ammeter indication. Just wire the new accessories into the dash or alternator output areas if you retain the ammeter.

Having explained that, your wiring and connections need to be in good shape to move up in alternator output to 65A and not have issues. Many of these olders car's wires and connnections are not in good shape, so the other alternatives are very good to consider. My car's original wiring is in good shape, so I keep it all stock, but it gets a lot of attention and inspection to keep things well cleaned, and corrosion free connections. (And I have some special conductive greases and treatments to help.) If I went to 65A, I would change the alternator connection through the firewall, as that will be a high current connection.
 
Left it connected. It remains in the near neutral position. If you look at a B-body wiring diagram, they show the alternate wiring routes for fleet vehicles (Cop, taxi etc) They did not use the bulkhead connector for the two high amp wires- they ran the wires through their own independent grommets through the firewall like nm9stheham mentioned in the last sentence. That eliminates one trouble area where the spade connectors at the BHC corrode and resistance and heat increases.

I have a B-body donor behind my garage which I'm sure was parked for good after the BHC got hot and everything melted together in one big mess. It looked like it had been half-assed repaired once before the main meltdown. It must have been kind of exciting.

View attachment donor wiring.jpg

View attachment BHC wiring.jpg
 
I just re-read the OP's post and see one thing; He has a '65 Plymouth (A-body) I presume. This year had the 'heavy duty' bulkhead wiring arrangement, where the alternator output wire and the battery feed wire through the bulkhead go through the heavy separate lugs in the bulkhead connections. '63 and '65 A-bodies had this arrangement. So the OP HAS the heavy duty connection already in his car, if it is original, and essentially already has part of the MAD electrical upgrade.

I would do this:
- Remove and clean these 2 screwed-on wire connections on both sides of the bulkhead with fine emery cloth and clean the ligs the same way
- Check the ring lug crimps to these wires on both sides of the bulkhead for anny corrosion in the wire ends
- Re-connect using dielectric grease (and even silver loaded dielectric grease if possible)
- Inspect the ammeter lug connections and wires; if all good, clean, use dielectric grease and re-use if he wants to use the ammeter. The older ammeters are not quite so trouble pone as the later ones, but look for any corrision possible.
- BTW, there is no issue to have both ammeter and voltmeter in the car. You can diagnose the charging system condtion with either but the voltmeter readings are easier for most folks to interpret.
 
Yes. There are the separate blades for the ammeter wires the are solid and located between the 2 BHC. There are 2, not 3 on the early As. Good call
 
If anybody does bypass the ammeter directly from the alt to the battery or the starter relay use a fusable link in the bypass.
 
swing69 said:
Yes. There are the separate blades for the ammeter wires the are solid and located between the 2 BHC. There are 2, not 3 on the early As. Good call
Click to expand...
One blade comes in from the alternator output, and goes through the welded splice in the dash where current gets distributed to various places. This blade is where other accessories would be connected. From the welded splice, the battery charging current passes through the ammeter and out the other blade to the starter relay big lug and on to the battery.

If one takes a wire direct from the alternator output to the starter relay big lug, then the ammeter may as well be bypassed as it no longer serves any good diagnostic purpose. Battery charging current goes direct to the battery from the starter relay big lug and bypasses the ammeter. Other system currents can flow in reverse through the ammeter to the welded splice for distribution to various loads, or may flow from the alternator through the original connection to the welded splice and on to the loads. So, the orignal function of the ammeter is completely disrupted.

And if the only lead from the alternator is taken to the starter realy big lug, then all current into the car's system flows backwards through the ammeter to the weld splice and then goes to the various loads, and the ammeter will show discharge in normal operation.
 
Best to bypass within the engine bay, so the high current doesn't route thru the bulkhead. However, as mentioned, the OP has a 65 w/ buss-bar feed-thrus (63 also). I put a 65 bulkhead in my 64 to get that benefit. Still, it is still easy and better to run a thick wire from ALT output to the big stud on the starter relay (BATT+).

You can have a bigger alternator, stock ammeter, and keep it all protected. See my posts on using parallel back-back diodes to bypass the ammeter as the alternator output increases. But don't try unless you fully understand basic electricity. Things melt fast when people don't understand P = I*dV.
 
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