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Growing misty-eyed, I can recall bikes whose batteries just kept their charge (allowing for self-discharge) - off meant off.
So I took the seat off and connected my Banner 'smart'charger
Explain to me, as you would to a child, why this doesn't happen when
you're actually riding the bike, say on long journey over a full day.
Surely the the alternator and charging system is 'continuing to pump
current into a fully charged battery'?
These days modern alternators are "smart" and switch off completely when
the battery is detected as charged. But, before then, the >regulator/rectifier was in control of such stuff, and dumps any excess >energy internally when the battery is full.
On Wed, 9 Jul 2025 09:07:58 +0100, Simon Wilson <siwilson@nodamnspamn.hotmail.com> wrote:
Explain to me, as you would to a child, why this doesn't happen when
you're actually riding the bike, say on long journey over a full day.
Surely the the alternator and charging system is 'continuing to pump
current into a fully charged battery'?
These days modern alternators are "smart" and switch off completely when >>the battery is detected as charged. But, before then, the >>regulator/rectifier was in control of such stuff, and dumps any excess >>energy internally when the battery is full.
'dumps any excess' - as heat, yes? Is this why certain Honda and
Suzuki reg/recs melt?
On 09/07/2025 08:59, Champ wrote:
On Tue, 8 Jul 2025 13:28:47 -0000 (UTC), Mark Olson
<olsonm@tiny.invalid> wrote:
It's not good
for a battery to have a charger continue to pump current into a fully
charged battery, which usually results in the battery being boiled
desert dry.
Explain to me, as you would to a child, why this doesn't happen when
you're actually riding the bike, say on long journey over a full day.
Surely the the alternator and charging system is 'continuing to pump
current into a fully charged battery'?
These days modern alternators are "smart" and switch off completely when
the battery is detected as charged. But, before then, the regulator/ rectifier was in control of such stuff, and dumps any excess energy internally when the battery is full.
On 09/07/2025 09:07, Simon Wilson wrote:
On 09/07/2025 08:59, Champ wrote:Of course, even old school charging resulted in the battery voltage 'lifting' to the point where it approached (but not necessarily
On Tue, 8 Jul 2025 13:28:47 -0000 (UTC), Mark Olson
<olsonm@tiny.invalid> wrote:
It's not good
for a battery to have a charger continue to pump current into a fully
charged battery, which usually results in the battery being boiled
desert dry.
Explain to me, as you would to a child, why this doesn't happen when
you're actually riding the bike, say on long journey over a full day.
Surely the the alternator and charging system is 'continuing to pump
current into a fully charged battery'?
These days modern alternators are "smart" and switch off completely when
the battery is detected as charged. But, before then, the regulator/
rectifier was in control of such stuff, and dumps any excess energy
internally when the battery is full.
equalled) that of the charger - and the current flow reduced
accordingly; as did the need for heat dissipation.
chrisnd @ukrm <chrisnd@privacy.net> wrote:
On 09/07/2025 09:07, Simon Wilson wrote:
On 09/07/2025 08:59, Champ wrote:Of course, even old school charging resulted in the battery voltage
On Tue, 8 Jul 2025 13:28:47 -0000 (UTC), Mark Olson
<olsonm@tiny.invalid> wrote:
It's not good
for a battery to have a charger continue to pump current into a fully >>>>> charged battery, which usually results in the battery being boiled
desert dry.
Explain to me, as you would to a child, why this doesn't happen when
you're actually riding the bike, say on long journey over a full day.
Surely the the alternator and charging system is 'continuing to pump
current into a fully charged battery'?
These days modern alternators are "smart" and switch off completely when >>> the battery is detected as charged. But, before then, the regulator/
rectifier was in control of such stuff, and dumps any excess energy
internally when the battery is full.
'lifting' to the point where it approached (but not necessarily
equalled) that of the charger - and the current flow reduced
accordingly; as did the need for heat dissipation.
A somewhat fine point not appreciated by everyone is that the typical
shunt regulator in a permanent magnet alternator bike charging system
doesn't have to dissipate the gross output rating of the alternator
minus the power consumed by charging the battery, and powering the
headlight, fuel injection, and ignition system.
It has to shunt to ground however much excess current the stator is
putting out, but at a small voltage[1], roughly on the order of ~1V
or less, rather than the system's ~14V, so the power dissipated in
the regulator is correspondingly less. This can still be a few watts
and without proper cooling, can result in overheating and premature
failure.
[1] These regulators work on the principle of varying their duty
cycle, when the load is higher, they stay off longer, when the load is reduced they are on for more of the (typically) 3 phase charging cycle.
A somewhat fine point not appreciated by everyone is that the typical
shunt regulator in a permanent magnet alternator bike charging system
doesn't have to dissipate the gross output rating of the alternator
minus the power consumed by charging the battery, and powering the
headlight, fuel injection, and ignition system.
It has to shunt to ground however much excess current the stator is
putting out, but at a small voltage[1], roughly on the order of ~1V
or less, rather than the system's ~14V, so the power dissipated in
the regulator is correspondingly less. This can still be a few watts
and without proper cooling, can result in overheating and premature
failure
On Wed, 9 Jul 2025 14:35:52 -0000 (UTC), Mark Olson
<olsonm@tiny.invalid> wrote:
A somewhat fine point not appreciated by everyone is that the typical
shunt regulator in a permanent magnet alternator bike charging system >>doesn't have to dissipate the gross output rating of the alternator
minus the power consumed by charging the battery, and powering the >>headlight, fuel injection, and ignition system.
It has to shunt to ground however much excess current the stator is
putting out, but at a small voltage[1], roughly on the order of ~1V
or less, rather than the system's ~14V, so the power dissipated in
the regulator is correspondingly less. This can still be a few watts
and without proper cooling, can result in overheating and premature
failure
Y'know up there I said "as if to a small child..." :-)
While I understand the individual words you've written, I'm afraid
this particular order of words conveys just about zero meaning to me
:-(
These days modern alternators are "smart" and switch off completely when
the battery is detected as charged. But, before then, the regulator/ rectifier was in control of such stuff, and dumps any excess energy internally when the battery is full.
On Wed, 9 Jul 2025 09:07:58 +0100, Simon Wilson <siwilson@nodamnspamn.hotmail.com> wrote:
Explain to me, as you would to a child, why this doesn't happen when
you're actually riding the bike, say on long journey over a full day.
Surely the the alternator and charging system is 'continuing to pump
current into a fully charged battery'?
These days modern alternators are "smart" and switch off completely when
the battery is detected as charged. But, before then, the
regulator/rectifier was in control of such stuff, and dumps any excess
energy internally when the battery is full.
'dumps any excess' - as heat, yes? Is this why certain Honda and
Suzuki reg/recs melt?
On 09/07/2025 09:07, Simon Wilson wrote:
These days modern alternators are "smart" and switch off completely when
the battery is detected as charged. But, before then, the regulator/
rectifier was in control of such stuff, and dumps any excess energy
internally when the battery is full.
Every day's a school day.
YTC#1 <ytc1@ytc1.co.uk> wrote in news:104jl70$3ml59$2@dont-email.me:It's a shade of grey, sits on the garage floor and gets attached to the
On 08/07/2025 15:31, chrisnd @ukrm wrote:
On 08/07/2025 14:28, Mark Olson wrote:[snip]'
Champ <neal@champ.org.uk> wrote:
Why does everything in the modern world have 'smart' in front of it? >>>>> Smartphones, smart watches, smart chargers...
[snip]
in its name?) and ended up boiling his battery by not taking it off
charge soon enough.-a My optimate is still going strong after ~15 years
without problems.
I think mine may be 25+ years ...
You probably have the original mk3, in the light coloured case (not the new v3 in a blue case)
I have one of the original Optimates, bought when I had a VFR750 that the original owner had fitted a Datatool alarm/immobiliser. That had to be connected to the charger frequently. 30 years ago.
On 08/07/2025 09:00, wessie wrote:
a dumb charger might remove many of the smarts in your expensive
motorcycle by supplying loads of unregulated voltage spikes at a
gazillion amps that were not of the right type to wake up the battery
Actually, I'd be delighted if motorcycles, well, motor vehicles in
general, didn't draw the sort of standby currents they do nowadays. Erm, come to think of it, the bikes I'm thinking of are 10+ years old. And Italian. The Guzzi's instructions actually advise removing the master
fuse if the bike is not to be used for more than (I think) 21 days.
Growing misty-eyed, I can recall bikes whose batteries just kept their charge (allowing for self-discharge) - off meant off.
On 09/07/2025 08:59, Champ wrote:
On Tue, 8 Jul 2025 13:28:47 -0000 (UTC), Mark Olson
<olsonm@tiny.invalid> wrote:
It's not good
for a battery to have a charger continue to pump current into a fully
charged battery, which usually results in the battery being boiled
desert dry.
Explain to me, as you would to a child, why this doesn't happen when
you're actually riding the bike, say on long journey over a full day.
Surely the the alternator and charging system is 'continuing to pump
current into a fully charged battery'?
These days modern alternators are "smart" and switch off completely when
the battery is detected as charged.
On 08/07/2025 18:38, YTC#1 wrote:
On 08/07/2025 08:38, Champ wrote:But everybody knows there is no such thing as 'the cloud'?
Why does everything in the modern world have 'smart' in front of it?
Smartphones, smart watches, smart chargers...
Just the latest fad.
We had .com for a while.
Then cloud[1], everything in the bloody cloud
[1] Still do
It's just somebody else's bloody computer![1]
Chris
[1] Therefore potentially as fickle as one's own - albeit there are
probably (hopefully?) better backup regimes in place.
On Wed, 9 Jul 2025 14:35:52 -0000 (UTC), Mark Olson
<olsonm@tiny.invalid> wrote:
A somewhat fine point not appreciated by everyone is that the typical
shunt regulator in a permanent magnet alternator bike charging system
doesn't have to dissipate the gross output rating of the alternator
minus the power consumed by charging the battery, and powering the
headlight, fuel injection, and ignition system.
It has to shunt to ground however much excess current the stator is
putting out, but at a small voltage[1], roughly on the order of ~1V
or less, rather than the system's ~14V, so the power dissipated in
the regulator is correspondingly less. This can still be a few watts
and without proper cooling, can result in overheating and premature
failure
Y'know up there I said "as if to a small child..." :-)
PipL <pip@nowhere.nul> wrote:
On 09/07/2025 09:07, Simon Wilson wrote:
These days modern alternators are "smart" and switch off completely when >>> the battery is detected as charged. But, before then, the regulator/
rectifier was in control of such stuff, and dumps any excess energy
internally when the battery is full.
Every day's a school day.
Especially when you're traversing the empty high plains of Wyoming in
a Subaru Outback, and watching[1] what you think is an intermittently
failing alternator when you are 75 miles from _anywhere_. System
voltage reported by the ECU and the OBD2 adapter was going as low as
12.0V or even a bit less, then suddenly jumping up to ~15V.
After we reached a decent sized town, and making a couple of panicked
visits to local auto parts stores to check if they had a replacement alternator in stock, and buying a digital voltmeter to confirm
what the OBD2 device was telling me, I decided to stop by a local
independent garage.
As soon as I described what make and model the car was, and the
symptoms, the mechanic broke into a smile and told me this was
'normal', and the behavior was as designed. Cue one big sigh of relief
from me and P.
When I got home I sent the mechanic a thank you card with a $20 note
in it. :^)
[1] via the Torque app on my phone, and a Bluetooth OBD2 interface.
A lead-acid battery[1] has an ideal voltage of about 14.4V. The
alternator is set to produce about 13V - 14V. As the battery charges up
it reaches the same voltage as the alternator and, since the voltages
are opposed, the net voltage in the circuit becomes zero and no current >flows. Since there is no current flowing, no more energy reaches the
battery so it can't be fried. Simples!
So what happens to the "excess" power being produced by the alternator
now that the battery is charged? Answer: there isn't any. Because no
current is flowing, by definition the alternator isn't producing any
power. (Not to battery - it's still powering the car of course.)
It's all a bit counter-intuitive.
Overcooking a battery by being left on a battery charger all night
happens when the charger charges at higher than 14.4V (in order to
reduce the charge time) but dumbly continues to do so after the battery
has charged.
It fooled me on the SO Renault. Kept getting a flat battery, replaced
the battery with a similar "flooded cell technology" battery that had
been fitted at the factory. But it still kept failing.
Someone told me I needed to fit an AGM, which I didn't believe.
Eventually I gave in and fitted one, problem solved. I looked up AGM
versus lead acid voltage/charge curves and it turns out they wre quite different. So the battery management system was obviously confused and
not properly charging the flooded cell[1] one.
I've still no idea how the original battery worked.
[1] whatever that means
A bit pricey IMHO, but it has worked unobtrusively and the ECU appears
to be happy.
On 08/07/2025 19:01, wessie wrote:
The XJR had an immobiliser. Fucking hated it. That was ripped out the
system about 20+ years ago
On 09/07/2025 22:06, YTC#1 wrote:
On 08/07/2025 19:01, wessie wrote:
The XJR had an immobiliser. Fucking hated it. That was ripped out the
system about 20+ years ago
Alarm too or just immobiliser?
I'm guessing with a remote fob? IMO, a proper immobiliser shouldn't even
be active unless the ignition or ECU are.