Bob Horner Posted October 21, 2013 Report Share Posted October 21, 2013 I have bought the revington lightweight alternator conversion for my tr4 and I think the wiring etc all makes sense per their instructions. However, I have a couple of questions re the wiring generally. I have read elsewhere that is it a good idea to run an extra heavy gauge wire from the alternator to the battery (or starter solenoid if the run is shorter which it will be) to ensure that the existing wiring doesn't impeded the charging capacity of the new alternator. The alternator has three terminals - one for the lamp, one to the ignition (IG terminal) and then the output terminal post. If I ran the extra wire presumably this would be an extra wire on the output post. otherwise revington wire this post to the battery via the ammeter. is the extra wire a good idea. I have fitted the extra loom kit from revington already. This is wired from the starter solenoid, via a cut out switch. Presumably this helps the wiring as any lamps, fan etc goes through their new loom wire to the fuse box and draws current independently of the existing wiring that goes via the ammeter to the battery. is my understanding correct and what effect does all of the above have the the ammeter and it's reading? Regards Bob Ps I have fitted relays recently per Roger's suggestion ( see post on tr4/4a forum) and these are wired from the starter solenoid via the ignition cut off switch) Quote Link to post Share on other sites
ianc Posted October 21, 2013 Report Share Posted October 21, 2013 You might wish to read my article in Section J4 of the Technicalities CD, and the more recent one which Jim Christie and I wrote and which was published in TR Action 248 (March 2011). Or PM me with your home e-mail address and I'll send them down the wire. Ian Cornish Quote Link to post Share on other sites
BlueTR3A-5EKT Posted October 21, 2013 Report Share Posted October 21, 2013 On my own TR with the Nippon Denso lightweight alternator I have added a cable from the output post to the starter solenoid. Did the kit you bought include the terminal plug for the alternator? If not see this supplier site for terminal kits and other alternator accessories. http://www.brise.co.uk/alternator_accessories.html Alternator types http://www.brise.co.uk/alternators.html Quote Link to post Share on other sites
AlfredHitchcock Posted October 22, 2013 Report Share Posted October 22, 2013 The alternator I recently installed had 3 terminals like yours. There was a small blade and 2 big ones. I took the alternator apart for mounting issues and noticed that the 2 big blades were joined so were effectively the same terminal. I used this extra terminal to run an extra wire straight to the solenoid battery terminal. Your ammeter will not see this current but so what. Of course I'm not saying yours is the same. Nick Quote Link to post Share on other sites
RogerH Posted October 22, 2013 Report Share Posted October 22, 2013 Hi Nick, if the ammeter does not see the charging current then if/when you have a problem you will not know what is happening. The normal charging current is just a few amps with the occassional peak of 20+ amps after starting that may last for 20-30 seconds. The normal loom cable should hold this with no problem. Age and mechanical damage are the downfall of the standard loom. Roger Quote Link to post Share on other sites
Bob Horner Posted October 22, 2013 Author Report Share Posted October 22, 2013 I have read the articles sent to me by Ian Cornish and the above replies and from these I conclude (or contend at least) (1) Adding an extra wire from the alternator output to the solenoid (ie in addition to the wire from the new alternator output via the ammeter to the battery and other loads) will bypass the ammeter to some extent but ensure the 40 amps will make it to the battery. Presumably it will also help to shunt the 40 amp output current around the 30amp reading ammeter - I suppose that will depend on the relative resistence of the wire to the solenoid and the wire through the ammeter? (2) As currently wired I have a cable running from the solenoid to a cut out switch and from this I have wired the headlamps and spots (using relays) and also revington's supplementary wiring loom. It would seem that the effect of this will be to bypass these loads from the ammeter. In effect, the ammeter will show a draw for eveything but the lamps etc. Does that make sense? Bob Quote Link to post Share on other sites
RogerH Posted October 22, 2013 Report Share Posted October 22, 2013 Hi Bob, if you fit a heavy cable from Alt to battery (via the S/solenoid attachment) the ammeter will not read at all. The battery will not take more than 30amps even after a difficult start and will drop to 2-5 amps very quickly. The ammeter should only show charge/discharge current. All the accessories should be tapped off before the ammeter. No matter what the output of the Alt is 40,60,75amps the battery will take only what it wants <30amps for a few seconds. Do not let the smoke out of the cables Roger Quote Link to post Share on other sites
MikeF Posted October 23, 2013 Report Share Posted October 23, 2013 Hi Bob, ........,SNIP........ Do not let the smoke out of the cables Roger Roger ; Does this mean you are another convert to the smoke theory of electricity and reliability? Quote Link to post Share on other sites
RogerH Posted October 23, 2013 Report Share Posted October 23, 2013 Hi Mike, most definately. I think it was the Greeks that first postulated this idea. We had the same thing at British Airways when we did Mag Particle testing with lots of current. The trainees were always told never let the smoke out. It this case it was to stop localised burning of the component. Roger Quote Link to post Share on other sites
TR Mitch Posted October 23, 2013 Report Share Posted October 23, 2013 trainees were always told never let the smoke out Did that work with Kapton cable as well? Quote Link to post Share on other sites
RogerH Posted October 24, 2013 Report Share Posted October 24, 2013 I get mine from B&Q. Roger Quote Link to post Share on other sites
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