Re: More battery/electrical drama
- From: "Phil, Squid-in-Training" <phil_leeIHEARTBASHGUARDS@xxxxxxxxxxx>
- Date: Thu, 6 Apr 2006 02:01:49 -0400
FB wrote:
Phil, Squid-in-Training wrote:
This is about a 1993 CBR600 F2.
So after putting in a new battery and riding the bike around for the
last
week or so, I invested in a battery charger. I actually bought a
tender,
but the stupid seller sent me the wrong, bigass charger with clamps,
etc.
Yeah, well the strategy of the new "smart" chargers seems to be to
sell the charger to somebody who knows *nothing* about batteries and
chargers. The so called "smart" charger will shut off if it senses
that the battery isn't charging or if it's sending to much current to
the battery and might damage itself.
This is the thing... I believe that this charger might actually have some
real function (Schumacher SC-6000A) because it seems to put the battery
under load for a couple of seconds to measure some current/voltage drop, and
then from there determines a percentage capacity rating. Then it takes off
the load and begins charging.
I hooked up the charger up to my old, dead battery. It charged up
real
quick and was stated to be full fast. Surface charge, I guess.
What you really need to charge a dead battery is a *variable voltage*
charger that you can crank up to about 20 to 25 volts and observe an
ammeter for a minute. That definitely wakes up a dead battery.
Hmm... When I turned it to the 10-30A range on the charger, the voltage
bumped up to around 16V. I only did it for a couple of seconds, though.
I told you before once that you could take two car batteries and hook
them in series to get 24 volts to wake up a dead battery. Just put a 1
amp amp in series with the two batteries and wait five minutes to see
if the fuse blows. If it does, you can start charging the dead battery
with a real charger that has a big rheostat on the box.
You mean like the 10/30A charging function that's on the charger?
If it starts charging within a minute or two, you then reduce the
voltage to 16 or 17 volts and monitor the charge rate. After a few
minutes, you can adjust the voltage to charge the battery slowly, at
about 1 amp for 6 to 8 hours.
Hmm... I tended to leave it on 2A because that's what the manual said. I
figured I'd rather not acidify or blow up things. ;)
I ran it down with a turn signal connected to the battery.
Reconnect the charger. This time it takes a long time to charge back
up. Good.
Yeah, well, you just *deep-cycled* the battery. Lead-acid batteries do
not like to be deep cycled any more than they like to be quick
charged. They shed lead from the plates and they sulfate if you don't
recharge the battery.
Oops, I didn't put enough detail. I ran the battery down a couple of volts
in several minutes with just one 18W turn signal. The charger manual said
to turn on some accessories to burn off the surface charge so that real
charging could occur. It seems to have worked.
I set it aside and
go to the bike, get to the new battery, and top off the charge. I
notice a
loose quick-connector (yay!) and squeeze it closed.
Yup.I've seen that happen many times. It's amazing how riders won't
check out the simplest possible problems, like loose connection.
So I'm wondering how
the old battery would do.... I throw it in the bike, turn the kill
switch to
on, and crank it up to see how well it cranks for 10 cycles or so.
Bzzzzt! The starter isn't designed to keep starting the engine over
and over and over.
Oops, I didn't mean 10 cycles as in 10 starting cycles. I meant 10 cycles
as in 10 crank revolutions. With the kill switch engaged.
Although it only dissipates about 500 watts, that 500 watts is trapped
inside the starter and it takes a while to dissipate the heat. You can
burn up a very expensive starter if you overheat it. You should only
crank the engine for about 5 seconds, give the starter about 20
seconds to cool and then try again for 5 seconds.
Yes, yes... it would have been just dumb to run a starter that long.
A better way to do a capacity test on a battery is to disconnect it
from the motorcycle and hook a known wattage light bulb across the
terminals and observe the battery voltage. An 8 ampere hour battery
will supply 8 amperes for 1 hour without the voltage dropping below 12
volts. If it only takes half an hour for the voltage to decay below 12
volts, the battery is approximately half used up.
Interesting... I always forget the simple math in electrics.
Then I check the voltage at
the battery across the RPM range. It looks like at <1300rpm the
voltage
drops below battery voltage (12.7V). At >1700, the voltages stay
within
specced range (13.3V-15.5V). So regulator/rectifier should be okay,
right?
I dunno. The question you should ask is *does the regulator CYCLE
voltage*, from high to low when you increase the engine RPM past 3000
RPM to 5000 or 6000, and does it CYCLE back to high voltage when you
decrease the RPM back to around 3000 RPM
Yep, that's exactly what I saw. At around 2500, the voltage dropped.
There are two basic types of alternators, excited field and permanent
magnet.
The excited field type of alternator will take power from the battery
and run it through a transistor with a voltage sensing circuit. When
the battery voltage rises too high
the transistor will shut off the excitation current to the alternator
field and you will see a sharp voltage drop as the transistor stops
conducting.
But that type of regulator CYCLES from high to low and back.
The other type of alternator is a permanent magnet type. When the
voltage rises too high, the voltage sensor causes a silicon control
rectifier to *shunt* excess voltage to ground, burning the excess
power up by changing it to heat.
I think this is what the CBR is. I mean, it's called a regulator/rectifier.
Again, the question is, *does the regulator CYCLE from high to low and
back, over and over and over?"
It's entirely possible for the voltage sensing circuit to fail and the
regulator never cycles, it just allows the voltage to stay too high
and the wiring harness connectors eventually melt.
No connectors looked burnt or yellowed or browned or brittle...
I find the RR and check the continuity where it should be. However,
I check
the red/white and ground voltage, which should match battery
voltage, and it doesn't work. I get 0V. Not sure if this is okay,
but the RR does have the
words CBR 95 chalked on it. I'm wondering if this was a replaced RR
because
the original one went bad.
In the realm of shunt type regulators for permanent magnet
alternators, there are FIVE wire regulators that take three AC phases
and convert them to DC, and there are SIX wire regulators that have
an extra wire that senses battery voltage at a remote location.
The six wire regulator is known for causing charging system problems.
So, count your wires, and if you have a sixth, sensing wire, relocate
to so it senses battery voltage, not the voltage drop across the wire
harness.
Hmm... just three yellows, one red/white, one green ground.
This is what I don't get. If the frame is ground, how come the frame
doesn't build up excess charge and statically shock me from time to time?
Or if I'm connected to the frame, and I touch the ground, isn't the frame
ground and earth ground not at the same voltage since the tires insulate?
Thanks for the details and charging lessons!
--
Phil, Squid-in-Training
.
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