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Re: K75 Clock always on: Is this normal? Fri Jan 01, 2021 1:47 am
Point-Seven-five
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Perfectly normal. Digital clocks can run for years on a single AA battery, so I doubt the ones on our bikes draw anywhere near enough to run down the big batteries the bikes have. I seem to recall that the clocks on our bikes use less than 1 amp of power in a month and a half.
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Present: 1991 K100RS "Moby Brick Too"
Past:
1994 K75RT "Ilsa, She Wolf of the SS"
1988 K100RS SE "Special Ed"
1994 K75S "Cheetos"
1992 K100RS "Moby Brick" R.I.P.
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
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Re: K75 Clock always on: Is this normal? Fri Jan 01, 2021 3:21 pm
robmack
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Point seven-five is right. The PCF1171 clock chip in the dash draws 400uA (about 0.4mA) constantly from the battery. With the LCD on, that current draw is somewhere around 800 - 900uA (about 0.9mA). That's a total of 12 mW of power.
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Robert
1987 K75 @k75retro.blogspot.ca
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Re: K75 Clock always on: Is this normal? Fri Jan 01, 2021 5:59 pm
cycleman
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The amp draw down is enough that after several months of inactivity, like with winter storage it can lower the voltage enough that the bike won't start. That is why you put a battery tender on the battery.
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Re: K75 Clock always on: Is this normal? Fri Jan 01, 2021 7:44 pm
Rick G
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The current drain of the clock is as Robmack has stated and that is not sufficient to discharge a 18ah battery so that it wont start the bike after a winter lay up. The natural drain that any automotive battery suffers over a winter lay up is more than the clock draws ( probably 2-3 times that) it is this drain that causes the biggest need to use a battery tender charger.
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Re: K75 Clock always on: Is this normal? Sat Jan 02, 2021 12:02 pm
cycleman
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The clock on my R1100R would draw the battery down enough in 2 months that when you turned the ignition on, head lights on etc, the voltage was too low and the fuel injection pump wouldn't start. Non fuel injected bike not a problem and would likely start.
My rule of thumb has always been if the bike is sitting for more than a month, then I put the battery on a tender. Battery lasts much longer.
My rule of thumb has always been if the bike is sitting for more than a month, then I put the battery on a tender. Battery lasts much longer.
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