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Posted to uk.d-i-y
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Battery not charging light
On 09/03/2020 16:45, wrote:
Hi All,
Back in the dark ages (60s,70s, 80s) cars had little bulbs that would come on to tell you your battery was no longer charging.
There have been a few people on the Peugeot007 self
Help FB group Im on whose alternators have died, but their cars not charging light hasnt illuminated (despite its passing its POST before the problem and after its been rectified (see what I did there).
Got me to thinking, how were these bulbs driven in the past (i.e, what electrics / electronics / circuit lit them when charging stopped)?
And how are they supposed to work in modern Cars?
On the 007, I believe its an LED and I SUSPECT its fed from the ECU??
Anyone know?
In the good old days of dynamos, there was a sort of relay known as a
cut-out that disconnected the dynamo output from the battery when the
dynamo voltage was less than the battery. The bulb simply sat across the
cut-out contacts. So if the dynamo was still working but its voltage was
low and the contacts opened, the bulb would illuminate dimly. The later
mods described for alternators in other posts were designed to give
similar performance since, in those days, most people knew about the
cutout. Everyone could change a plug, and most knew how to adjust points
or change a capacitor too.
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