mr tr4 Posted October 9, 2012 Report Share Posted October 9, 2012 I have a TR4 with dynamo. Did a 2 hour drive on Sunday evening with the lights and heater fan on, and when I managed to stall the engine at a set of lights the engine failed to turn over when I tried to start it. I switched off the fan and it did start, so I got home. So I now have a suspect battery/dynamo etc. - the battery is around 3-4 years old. Does anyone know if the loading put on the battery above is likely to run it down? Pretty sure the dynamo is ok as a) the red light isnt on and the lights get brighter when I rev the engine.- fan belt seems ok. I noticed that the ammeter was indicating slightly in the -ve during the journey - so I am sort of deducing that the loading was draining the battery, and that on future journeys I should turn the heater fan off. However, i suspect it isnt that simple..... Any comments welcome! Quote Link to post Share on other sites
Ashley James Posted October 9, 2012 Report Share Posted October 9, 2012 1. Modern batteries just seem to die, so I think yours may be okay. 2. Make sure the fan belt isn't slipping. 3. If the brushes are sticking, the ignition warning light will be slow to go out or may periodically flicker. 4. Make sure the battery wires are tight at both ends. My guess is that you've been driving comparatively slowly with the fan running and lights on and it has discharged the battery. Together they are probably close to the limit of the system. An expert will correct me. Quote Link to post Share on other sites
wayne taylor Posted October 9, 2012 Report Share Posted October 9, 2012 Concur - you can guess why dynamo's were phased out by their 'brighter' cousins the alternator! You must have been driving around for a while - in the red (-ve charge). You were lucky you got her started again! Mind you a gentle bump start would have sufficed, I suspect if all else fails. If the ammeter is ever in the -ve (except at tick over when it is inevitable with dynamo's) expect electrical trouble. Quote Link to post Share on other sites
mr tr4 Posted October 9, 2012 Author Report Share Posted October 9, 2012 Thanks for the comments. I have stuck the battery on charge, hopefully that will solve the problem. Just as well it wasnt raining! Quote Link to post Share on other sites
AlanT Posted October 9, 2012 Report Share Posted October 9, 2012 The whole reason they fitted ammeters is that you were supposed to watch it and turn stuff off to keep it on the right side. However I'd read up on adjusting the voltage-regulator because I would expect it to manage the lights and heater at the same time if you had enough revs. Wont do it at tick-over. Its just a question of how fast you need to go to get enough charging. Lucas generator and Control box tests from http://www.vitessesteve.co.uk/LucasStuff/LucasStuff1.htm Al. Quote Link to post Share on other sites
RogerH Posted October 9, 2012 Report Share Posted October 9, 2012 Hi Mr TR4 - have you a name , the dynamo is good for apprx 28 amps (if you are lucky) at about 2500RPM and above. dip headlights - 10amps front side lights - 1 amp Rear lights - 1 amp Stop lights - 4 amps Inst lights - 1 amp Ignition - 1 amp !!! heater fan - 5 amps Radio 4 - 16 amps!!! The poor dynamo doesn't like it unless it's a sunny, drt day. Roger Quote Link to post Share on other sites
AlanT Posted October 9, 2012 Report Share Posted October 9, 2012 Its not quite as bad as Roger says. These would be the currents if the dynamo had the battery "on charge" and the system would then be nearer to 14V than12V. I measured the currents when I fitted the new wiring loom using a 12V battery "starter" pack. Even though the battery is at 12V you wont get this at the headlight itself because there will be voltage drop in the wiring. This is about the stuation when the ammeter is showing negative. I got 8A for dipped and 10A for main headlights. Side lights ran 1.5A. About 4A for the fan. A proper medium/long-wave radio of the period wouldn't run more than 1.5A I should think. Stuff like horns doesn't count because its only intermittent. Just as well they took 8A. If you have a rheostat then of course you will dim the panel lights! We all used to manage with these things everyday. It got tricky when heated windows and big audio appeared. Truth is a dynamo-regulator is OK when set up and working perfectly. But only just! What maybe happening to you is that the regulator cuts off before the charging current reaches a high enough value. This means you dont collect enough charge when the going is good. These systems basically overcharge the battery somewhat to make up for the fact that it will be discharging shortly. In other words the battery is working harder and has a shorter life. This reflects the spirit of 50/60s Britain perfectly. Al. Quote Link to post Share on other sites
4AIRS Posted October 9, 2012 Report Share Posted October 9, 2012 After facing 2 "blackouts" in the middle of nowhere by rainy nights (heater + wipers + lights) I decided to fit an alternator. I lived >10 years with the standard dynamo, but I have to admit I feel more secured now. And the wipers go (a bit) quicker! Quote Link to post Share on other sites
ianc Posted October 10, 2012 Report Share Posted October 10, 2012 As suggested earlier, when all of us drove on dynamos we used lights only when it got really dark, did not use headlamps in towns and had very few auxiliaries. I was stopped in Chelsea by a PC in about 1964 and told to switch my headlights OFF. As it was obvious that I was not going to win the argument, I turned them off, drove 100 yards and turned them ON! Nowadays, I drive my TR on dipped headlights in gloomy/rainy weather, as it's safer and - because I have an alternator - I never seem to see any discharge since even at 850 rpm, it seems to cope. May not be original, but it has to be worth it! And the fan belt is so much easier to handle! Ian Cornish Quote Link to post Share on other sites
AlanT Posted October 10, 2012 Report Share Posted October 10, 2012 When you fit an alternator what do you do with the regulator box? What happens with the ignition warning light? Al. Quote Link to post Share on other sites
stuart Posted October 10, 2012 Report Share Posted October 10, 2012 You can delete the regulator box or remove the guts of it and use it as a junction box for the rewire. Ignition light functions exactly the same. Stuart. Quote Link to post Share on other sites
ianc Posted October 10, 2012 Report Share Posted October 10, 2012 See my article in Section J4 of the Technicalities CD and also the article about the Moss alternator kits, written jointly with Jim Christie, and which appeared in TR Action 248 (March 2011). Incidentally, Revington now has stock of the very useful 4-way Lucar connector block 150640, which allows up to 4 of the large connectors to be linked together. As Stuart states, the warning light works in exactly the same fashion, but you are unlikely to see it lit once the engine starts! Ian Cornish Quote Link to post Share on other sites
wayne taylor Posted October 10, 2012 Report Share Posted October 10, 2012 OK question for you as we are on this theme. Is it better long term value for money to go directly to an alternator conversion, or medium term go for narrow belt conversion and then when the wife isn't looking go for the full monty with an alternator mod? (Price comparison for narrow belt Vs Alternator kit?) Ta Quote Link to post Share on other sites
North London Mike Posted October 11, 2012 Report Share Posted October 11, 2012 (edited) When you fit an alternator what do you do with the regulator box? Al. Al Like Ian, LNK is on an Alternator (45 due to lots of extra kit) and I also condition the battery when in the garage. To answer your question regarding the Regulator Box, it is surplus to requirements and most people use it to re-wire as previously stated. However, its 'function' is now handled by the alternator diode pack, which, due to location is subject to heat damage from the exhaust manifold and fails after a couple of years. You really need a heat shield. I have a 'Roger Mk1' which is doing a fine job Edited October 11, 2012 by North London Mike Quote Link to post Share on other sites
TR 2100 Posted October 11, 2012 Report Share Posted October 11, 2012 (edited) I was stopped in Chelsea by a PC in about 1964 and told to switch my headlights OFF. Ian Cornish Yeah, those were the days of the mini skirt. Great viewing from a low driving position! Better from a TR2/3 rather than a 4, though I think you were driving a TR2 in those days? Back to the original post - you should be OK with heater and lights only on a dynamo, but if something isn't up to scratch, you could run down your battery, especially if it is a bit old. Alternator (and the necessary change to negative earth is one solution, but it's not the only one. AlanR Edited October 11, 2012 by TR 2100 Quote Link to post Share on other sites
ianc Posted October 11, 2012 Report Share Posted October 11, 2012 The alternator itself is not an expensive piece of kit, so I see no point whatsoever in taking two bites - just change to narrow belt AND alternator at the same time. Unless you have a great load of auxiliaries, a 34 amp alternator is quite sufficient (it's what I have), and it means that you need not worry about the capacity of your car's wiring. Go for a 65 amp beast and you could make your wiring quite warm at times! If you use a battery isolator when the car is not in use, there really should be no need to use a battery conditioner, even if the car is out of use for a month. Just prime the carburettors and the car should start. Four pot TRs are like Morris Minors, although the electric SU petrol pump can cause starting/running problems for Minors, so TRs are probably even more reliable. Of course, TRs with 6 cylinders and PI are an entirely different matter! Ian Cornish Quote Link to post Share on other sites
wayne taylor Posted October 11, 2012 Report Share Posted October 11, 2012 So - laying it up at the end of this month for several weeks/months. What is the best battery management for me to employ (haven't got a battery isolator?). Bearing in mind I may need to switch the ignition on, occasionally. Quote Link to post Share on other sites
ianc Posted October 12, 2012 Report Share Posted October 12, 2012 There is a cheap type of battery isolator called a Dis-Car-Nect (or something like that), which fits onto the battery terminal. This permits easy disconnection of the battery by unscrewing a knurled knob. Such a device makes it easy to enliven the ignition when required. If the battery has not been used for several weeks, any old battery charger (mine dates from about 1960) should restore it to full charge overnight. Unless the garage is dry (doesn't need to be heated - mine is not), laying up a car for a long time invites problems such as brake/clutch seizure, degradation of fuel (big problem with modern fuel - see elsewhere on the Forum), flatting of tyres (must get the wheels off the ground) and so on. Cars are best used all the year round - just avoid roads which have been coated with grit and salt. Ian Cornish Quote Link to post Share on other sites
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