Roverdrive Posted January 14, 2015 Share Posted January 14, 2015 Hi Not wishing to hijack the other thread, I have an issue with the charging on my 300tdi. On starting the charge light goes out, and when left at tick over the voltage gradually recovers to about 14.2Volts. So far so good. If the revs are increased, the voltage will gradually reduce The higher the revs, the bigger the drop. Typically down to 13.6 Volts without lights,heater etc, and 12.8 Volts with all auxiliaries on. I am suspecting worn brushes, but any other ideas before I start taking things apart? I had thought of upgrading to the 100A alternator at some point but will the original cable handle the increase in current? Quote Link to comment Share on other sites More sharing options...
western Posted January 14, 2015 Share Posted January 14, 2015 If you upgrade always increase the cable from alt to starter motor/battery feed, I run a 100amp on my 200tdi, I fitted a extra thicker cable between those 2 items, haven't had any problem also have a split charge for 2nd batt. New brushes would be a good move. Quote Link to comment Share on other sites More sharing options...
Roverdrive Posted January 16, 2015 Author Share Posted January 16, 2015 Thanks Western, I guess I already knew the answer to that one :-) Nice to have a confirmation though. Quote Link to comment Share on other sites More sharing options...
deep Posted January 16, 2015 Share Posted January 16, 2015 I've already displayed my ignorance in another alternator thread but I am curious here. Those figures don't actually seem low in themselves but I wonder if the voltage goes up again after you've revved it and let it go back down to an idle for a minute or two? To follow up on Western's comment re a thicker cable: I am rewiring a diesel 110 at the moment (well, trying to make sense of what the previous owner supplied). One of the original wires still fitted to this ex-military 24v was a huge cable which ran from the generator to the battery isolator. It's like a starter cable! However, it seemed to be a good idea to use it for the 100 amp alternator I am fitting, even if it looks like overkill. The sparkies I have talked to reckon it's a good plan and will help when the winch is running and the alternator is working hard. Quote Link to comment Share on other sites More sharing options...
Roverdrive Posted January 17, 2015 Author Share Posted January 17, 2015 Deep The figures at higher rpm are a bit low. Once the rpm drop to idle, the voltage starts to recover straight away eventually reaching the initial value. Quote Link to comment Share on other sites More sharing options...
deep Posted January 18, 2015 Share Posted January 18, 2015 It will be interesting to see how you get on. Another chance to learn something! I am just about to head into the shed and connect up my newly mounted alternator (had to modify the huge generator bracket to take the relatively small alternator, a fairly straightforward job using a valve guide as a sleeve). No point worrying about the output too much until I've got the ignition light to magically work... Quote Link to comment Share on other sites More sharing options...
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