| Author | Message | ||
     Bob uk Unregistered guest Posted From: 94.197.122.92 |
One of the common alterations that owners of old cars is to fit an alternator because modern traffic conditions and extras such as radios will drain the battery down after a short while. I have done exactly the above but not because of traffic jams and radios but because modern batteries are different from dynamo batteries. Batteries come in two sorts deep cycle or starter batteries. And combinations of the above. To make a deep cycle battery supply enough to crank an engine it needs to be twice the size of the starter battery. Older batteries had more deep cycle bias than modern batteries. Which is why they were bigger. When I started driving in 1967 most cars were dynamo and I used to drive around London in heavy traffic and the battery never went flat even with radio and head lights. On elderly RR instead of fitting an alternator fit an older type of battery because it's a shame to alter a system that worked well and is part of the cars favour. Also dynamo are very bodgeable. I had a regulator cut box stop working. So I set the revs 900 rpm connected the field to the dynamo output then the two to the live on the starter solenoid after about ten minutes of charging flat out I put a indicator bulb between dynamo and field to lower the charge rate. And drove 250 miles home and fitted a used regulator. If am alternator goes down on a modern car it's car the recovery truck. (Message approved by david_gore) | ||
| Jan Forrest Grand Master Username: got_one Post Number: 642 Registered: 1-2008 |
Although dynamos may have advantages over alternators, the reverse can be successfully argued. As can the distributor/magneto ignition alternatives. As you say: Deep discharge leisure/traction batteries are far larger, heavier and rugged than 'ordinary' short term, high current output car batteries. My heavily modified mobility scooter almost groans under the weight of a pair of sealed 140 A/H batteries even before I plonk my 15 stone racing snake carcass onto it. However it can take me 3 miles into town, all round the shopping areas twice! (once to find the bargains and a second time to buy them), and all the way home against all the steep uphill stretches and only show one 'bar' out of 10 drain on the batteries. |
