Keefer Posted July 15 Report Posted July 15 (edited) Hello all.Want to install alternator on my 1939 P8 with ammeter but not quite sure how to wire it.Any info is very much appreciated.Thanks Edited July 15 by Keefer Quote
Plymouthy Adams Posted July 15 Report Posted July 15 the use of the older limited ampmeter with the use of new (normally high output) alternator is considered a risk to damage overheat/fire etc and why today they defer to a volt meter. In the early period of ampmeter and alternators these were changed to shunted (mopar) and sampled the current flow to show discharge and charge only with no true indication of actual current only direction of current flow. IF your alternator is an output equiv to stock and staying positive ground....should stay as is. Exceeding the capacity of your amp gauge is not considered wise. Quote
Sniper Posted July 15 Report Posted July 15 A couple of points to bring out. What determines current flow in the charging system is the load. Not the alternator not the ammeter. As long as th OP doesn't add any additional electrical items this should be no increase in current through the system. That said old systems tend to have dirty connections which increase the load. A properly designed and calibrated shunted ammeter can most definitely show you accurate current values. Which is not to say the factory ones are like that because frankly it's really unnecessary. All they need to be able to do is show you whether or not it's charging or discharging and the relative amount of charge which they do just fine. One other thing to understand is that the only two loads going through the ammeter and a properly functioning vehicle is the current necessary to charge the battery and for some odd reason the horn. So I don't really think this is a concern 1 Quote
Sam Buchanan Posted July 15 Report Posted July 15 3 hours ago, Keefer said: Hello all.Want to install alternator on my 1939 P8 b=with ammeter but not quite sure how to wire it.Any info is very much appreciated.Thanks I don't know the answer to the issue that has been raised in regard to whether or not your 1938 has the same type of ammeter as my 48. What I can tell you is the modern 6v alternator works beautifully in my car using the original ammeter. Connecting the alternator to your wiring architecture is straightforward because the new alternators are "single wire" and internally regulated which eliminates the old voltage regulator. There are several threads in the forum on this subject and we can walk you through this simple process if you decide to pursue it. Here is the vendor I and several other forum members have used to source our alternators: https://www.ebay.com/str/HowardEnt?_trksid=p2047675.l2563 1 Quote
Keefer Posted July 15 Author Report Posted July 15 Thank you.I have a one wire already installed in my var but not wired up yet.Also i have a fusible link in case i need it.Do i connect alternator to batt, terminal on voltage regulator or to battery or to battery lug on starter. Quote
Dave72dt Posted July 15 Report Posted July 15 The instructions from one vender shows it going to the voltage regulator BAT terminal with the FLD and ARM terminal wires disconnected. Your vender should have had instructions with the alternator or a tech number to call. Quote
Sam Buchanan Posted July 15 Report Posted July 15 (edited) 2 hours ago, Keefer said: Thank you.I have a one wire already installed in my var but not wired up yet.Also i have a fusible link in case i need it.Do i connect alternator to batt, terminal on voltage regulator or to battery or to battery lug on starter. BAT terminal on regulator or the actual battery terminal will work, they are electrically at the same potential. I'm not sure how the early stomp starters are wired. Most of us connect the single wire to the wire that was on the BAT terminal of the old voltage regulator. Your fuse can go between the alternator and where you connect the single wire. Its purpose is to protect the car's harness in the remote case something in the alternator shorts to ground. The link should be rated a little lower than the harness wires so it will open before smoke escapes from the harness. Get ready to enjoy bright lights at idle and a battery that stays fully charged with none of the aggravation of keeping an old genny and regulator in working order! Edited July 15 by Sam Buchanan 1 Quote
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