Tricking-up the alternator’s boost
QI have an advanced alternator regulator but I am wondering if it is worth using. It appears to boost alternator output by ‘tricking the regulator’: does a modern alternator need this? The voltage at the batteries when charging is 14.3 volts. SIMON, via email
ATONY REPLIES... The reading of 14.3 volts indicates that the volt-drop on your charging cables is well within limits and the alternator’s regulated voltage will be around the 14.4 volts. So any time reduction in charging given by the device will be small. As you already have one you might as well fit it, so long as the voltage boost it provides is still less than the batteries’ maximum charging voltage.
Such devices do nothing for the first stage of charging when the alternator is running at maximum output, but once the charging voltage reaches the regulated voltage it will short-out the alternator’s regulator and boost the charging voltage a bit.
They cover up deficiencies in the charging system and the volt-drop caused by split-charge diodes, neither of which apply to you.
All alternators are supposed to be self-limiting for maximum current, so unless there is an alternator fault or you starve it of cooling air, the device should not be able to damage it.