TR6 Up-date to Bolt On 72 amp Alternator for TR6

[PeterK]

Re: Update to Bolt On 72 amp Alternator for TR6

I agree. I fit a 63 amp Delco unit on my TR3a and, instead of running the charge through the 30amp gauge, I ran the output directly to my battery + terminal/starter solenoid hot. I used 8 gauge wire. So none of the dash, etc. gets the full amps of the alternator. I have a volt gauge for my 4a with the same setup.

Also agree re:relays for add-ons to your system. Relays isolate the fragile switches from increased amps required for the uprated lights, stereo amplifier, electric fan. Also give you full power to the devices, reducing voltage loss.

So bolt-on isn't totally bolt-on, you also have to do the wire from the alt to the batt.

 

[Brosky]

Re: Update to Bolt On 72 amp Alternator for TR6

The only process difference that I see with some of the above suggestions, is that both Dan Masters and the alternator manufacturers recommend running a new 8ga wire to the starter solenoid, rather than directly to the battery. I happen to agree with that logic. I also have a voltage gauge, so the charge reading issues that occur with amp gauges don't affect my car.

So, while it's technically not a 100% "bolt on", I was referring more to the R&R of the alternator itself, as apposed to the alternator case and bracket mods needed for some Delco swaps.

 

[RobT]

Re: Update to Bolt On 72 amp Alternator for TR6

I agree. I fit a 63 amp Delco unit on my TR3a and, instead of running the charge through the 30amp gauge, I ran the output directly to my battery + terminal/starter solenoid hot.

But then dosn't the ammeter always register (-ve) "drain"?

Agree - its only the wires from the alt to the ammeter and then to the starter solenoid (brown and brown/white as I remember) that are sibject to overload, and then only when the battery is charged. Fusing & relaying any additional circuts (fans, driving lights, air horns) a must too. Don't want that expensive Lucas smoke leaking out!

 

[martx-5]

Re: Update to Bolt On 72 amp Alternator for TR6

I'm installing Dan Master's wiring harness in my TR3. The issue with the ammeter he deals with in a couple of differnet ways. One is, of course, use a higher rated ammeter. Another is to put in a 12 gauge shunt. The ammeter will read approximately 1/2 the current, but everything won't be going through it.

 

[Brosky]

Re: Update to Bolt On 72 amp Alternator for TR6

The alternator pictured above (72 amp) does have an internal voltage regulator, but has NO static suppressor built in.

"Stayin alive at 55" for now.

Remember that catchy little phrase for the gas crunch era of the 70's?

 

[martx-5]

Re: Update to Bolt On 72 amp Alternator for TR6

The only thing that is used to suppress alternator whine in radios is a small electrolytic capacitor. They are normally around 0.5 uF. That can be easily attached to the outside of the unit like Bosch does on alot of theirs.

 

[PeterK]

Re: Update to Bolt On 72 amp Alternator for TR6

I agree. I fit a 63 amp Delco unit on my TR3a and, instead of running the charge through the 30amp gauge, I ran the output directly to my battery + terminal/starter solenoid hot.

But then dosn't the ammeter always register (-ve) "drain"?

Rob

A. - yes. That's why I fitted a volts gauge in my 4A. But on the 3A, the needle still moves but on the - side.

I connected to the + side of the solenoid mainly because it was easier to make look clean. Didn't realize that it is preferred.

 

[Guest]

Re: Update to Bolt On 72 amp Alternator for TR6

If the idea of an alternator is to keep the battery charged, what purpose does it serve to connect a high-output aftermarket alternator to the starter when the purpose is to charge the battery, and not the starter. The battery's duty is to kick the starter over, not the job of the alternator. I found one of those multi-connector positive battery post connections and rewired my whole stock harness in this area with an 8 gauge wire. The big wire from my Delco-style 66 (really 69) amp alternator goes directly to my Optima battery and the wire to my high-torque starter is of equal size. I insulated the whole thing with a super-heavy-duty shrink tube. I also have my Spal fan wired direct to the battery (with its own GM-style fuse from Spal, inline), so I have 3 connections to the battery.

Am I wrong. No smoke yet.

 

[poolboy]

Re: Update to Bolt On 72 amp Alternator for TR6

I wondered the same thing. The starter and alternator are on opposite sides of the engine on a TR6; so why go to the starter even though the starter is wired to the battery? That just seems like taking a longer route. What am I missing?

 

[PeterK]

Re: Update to Bolt On 72 amp Alternator for TR6

On the TR3a, the starter solenoid is mounted on the bulkhead shelf to the left of the + terminal of the battery. About 12" or less.

It's already direct connected to the batery + terminal with the battery cable. I wouldn't think that there's much loss over the large gauge 14" long battery cable.

 

[Brosky]

Re: Update to Bolt On 72 amp Alternator for TR6

<div class="ubbcode-block"><div class="ubbcode-header">Quote:] I wondered the same thing. The starter and alternator are on opposite sides of the engine on a TR6; so why go to the starter even though the starter is wired to the battery? That just seems like taking a longer route. What am I missing? [/QUOTE]

I really don't know the answer to that, but I'm not a wiring whiz, so I know that I'm not qualified to answer that question accurately from my built in knowledge base.

However, I do remember reading back on one of the electrical threads here on the forum, that a direct wire from the alternator to the battery was bad for one reason. That reason was, that in the event that the battery went dead and the alternator was to pump out full charging, it "could" melt down the wiring between the two.

I could be wrong, but that's what I seem to remember reading either here or on the 6-Pack forum.

 

[PeterK]

Re: Update to Bolt On 72 amp Alternator for TR6

From what I know, alternators don't play well with a dead battery like generators do.

So maybe this has something to do with having an indirect route from the alt to battery. Not sure how it really differs though. It's the same cable just the other end.

 

[Opa]

Re: Update to Bolt On 72 amp Alternator for TR6

check the wiring schematics on Advance wiring web site for your particular car under stock wiring and you will see that the alt wire(brown on a late 6) goes directly to your battery cable about midway between batt. and starter.If you go directly to starter with your new wiring you eliminate the possibility of a problem in that particular connection,but you would be making the same connection.

Alt. has nothing to do with starter, just sharing a connection and using batt,cable to charge battery,when engine is running as soleniod is dormant until key is turned and solenoid is energized making connection to starter motor. hope this helps .....

 

[TR3driver]

Re: Update to Bolt On 72 amp Alternator for TR6

Since the battery clamp is normally not designed to accept side connections, the starter solenoid makes an excellent place to connect other high current devices to the battery. It already has a very heavy gauge cable, capable of handling hundreds of amps, connected directly to the battery. The starter has no other relationship to the alternator (since they are active at different times) except as another high current device connected to the battery.

That said, I routed my 60 amp Ford alternator through the stock ammeter on my 59 TR3A, with the stock wires (and a shunt as Art mentioned). Worked great for nearly 20 years; no signs of overheating or any problems at all. Using the original control box as a junction probably was a poor idea, it only lasted some 15 years in that configuration.

But, I created a new tie point in the new heavy gauge wire from the alternator to the control box, to tie other high current devices into. That means, under normal circumstances, the current to operate the radiator fan, headlights & stereo went directly from the alternator through the new tie point and to the new devices. The existing wires only had to carry current when the battery was being charged, or was supplying power to run the devices.

FWIW, the stock charging circuit on a TR3A is considerably heavier gauge wire than my Chevy with an 80 amp alternator had. It's in no danger of "burning up".

 

[TR3driver]

Re: Update to Bolt On 72 amp Alternator for TR6

From what I know, alternators don't play well with a dead battery like generators do.

A myth, IMO, albeit a popular one. Alternators are inherently current limited, and should be able to operate at full current all day long. Again IMO, the fable about them not being able to charge a fully discharged battery is mostly spread by rebuilders (and their resellers) offering excuses for their shoddy work and inferior materials. Automotive grade diodes will take the heat, but cheaper, industrial grade components won't.

And actually, the TR generator setup IS somewhat sensitive to a deeply discharged (but still low resistance) battery. That's because generators are not inherently current limited, and the TR setup uses a single relay to control both current and voltage. If the battery voltage is very low, it will let the generator over-current to some extent.

 

[martx-5]

Re: Update to Bolt On 72 amp Alternator for TR6

From what I know, alternators don't play well with a dead battery like generators do.

A myth, IMO, albeit a popular one. Alternators are inherently current limited, and should be able to operate at full current all day long. Again IMO, the fable about them not being able to charge a fully discharged battery is mostly spread by rebuilders (and their resellers) offering excuses for their shoddy work and inferior materials.

This was true in the past with alternators such as Delco's 10SI unit. But with modern alternators, the package may be the same size as a 10SI, but capable of twice the amperage. The heat build-up is just too great for them to run full bore for an extended period of time without components failing. As far as why rebuilders (and I work for one) say not to use the alternator for charging the battery has nothing to do with shoddy workmanship or inferior parts. It has to do with the fact that when the battery is fully discharged, voltages from the alternator can rise significantly, and this can play havoc with modern car electronics. It's the reason that many OE manufacturers are now installing avalanche (zener type) diodes in their units to control this over voltage. It's stated as a precaution against fried electronics.