ABS strange behaviour.

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andys
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ABS strange behaviour.

Postby andys » Fri Jul 20, 2018 8:05 pm

I've mentioned before that most of the time when starting my 1100RS, the abs lights blink alternately until I stop after a few hundred yards, and switch off and back on again, whereupon the lights will blink in unison as they should, and the ABS set's fine.
However, I've noticed that while it's the weathers been hot, even when the bikes been left a few days, the ABS set's fine first start.
So why does the ambient temperature make a difference.

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Jaythro
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Re: ABS strange behaviour.

Postby Jaythro » Fri Jul 20, 2018 9:41 pm

Its the starter drawing too much voltage

Somewhere recently I did a post about linking the ABS out in such a way so that it only does its self checks after the engine is running
"Put your Ass on a motorcycle and ride with an attitude and the "Grim Reaper" will ride in your shadow!"

Islandmagee in case you're interested?

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Galactic Greyhound
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Re: ABS strange behaviour.

Postby Galactic Greyhound » Fri Jul 20, 2018 10:09 pm

……...I've noticed that while it's the weathers been hot, even when the bikes been left a few days, the ABS set's fine first start.
So why does the ambient temperature make a difference.

On the ABS2 system, the designers set the 'ABS Fail' trip-out point at too high a voltage.
The result is that when the engine is cranked over, the high Starter Motor current can drop the voltage across the battery to as low as 9.0v in winter even with a good battery which causes the ABS2 start-up fail.
Even summer temperatures can cause ABS2 start-up failure if the battery, Starter Motor or battery leads/connections are not up to scratch.

In the Summer, the battery is able to supply more current and still keep its voltage up when the electrolyte (acid) in the battery is warmer.
In the winter, when the electrolyte is colder, the battery is not able to supply the same amount of current and the voltage falls as the battery struggles at its limit to supply the necessary current for cranking.

This effect is most noticeable when starting as the Starter Motor takes the most current (up to 200 Amp initially) of any circuit on the bike.
Starting energy requirement is compounded in the winter by colder thicker sump and gearbox oil.
An aged battery can be given an easier time by pulling in the clutch lever when starting.
This may also help with the ABS2 start-up failure even in the summer.

If you look at the specifications for a battery, the most important spec for motorcyclists who use their bike in the winter is the Cold Cranking Amperes (CCA) which states the amount of current the battery can supply at a nominal -18C.

If you experience regular winter ABS2 start-up failure with an aging battery, you can often get another season out of it by adopting the following procedure:

ABS2 RUNNING RESET
1. ABS2 failure on start-up (ABS lights flash alternately).
2. Ride off.
3. After about 1 mile and on a straight, level, traffic-free road with good surface conditions, close the throttle and coast the bike when in 4th gear - do NOT pull in the Clutch.
4. Switch Off the ignition for at least 2 seconds.
5. Switch the ignition On and the ABS2 should set normally and the flashing ABS lights go off.

This procedure works by not using the Starter Motor (which drops the battery voltage) to restart the engine and saves battery energy and time by not having to stop and do an engine restart to reset the ABS2 when the engine/oil has warmed up and the Alternator has had time to give the battery a slight boost.


Ref: https://en.wikipedia.org/wiki/Automotive_battery
Ced.

R1100RT 1996.
Sent by Boson Quantum Transmission from the Starship 'Galahad'.
http://www.researchgate.net/publication ... ing_bosons" - It works!

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sykospain
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Re: ABS strange behaviour.

Postby sykospain » Sat Jul 21, 2018 7:32 pm

Brilliant comprehensive reply Ced, as always. Right on the button.
But this problem of falling Voltage doesn't arise with the magnificent Li-Po latest generation of 'new technology' polymer-based batteries.
A third of the weight, five times the cranking power and virtually no self-discharge.

I'm a great believer in the Li-Po system in its latest realisation, after several years of experience using these more expensive but far more reliable and durable units on three different bikes.

Now in the EU the most recommended brand, "Shorai" is available from the Czech Republic, avoiding the customs hassle of trying to import one direct from the maker in the USA.
Better get one before the Czech and other EU republics become as foreign as the USA !

Look at the current giant strides being made in non-lead-acid battery technology by automotive manufacturing giants all round the world. It's the present AND the future.

Reasonably up-to-date info at :-
https://en.wikipedia.org/wiki/Lithium_polymer_battery

AL in s.e. Spain
This is the list of people I'd trust with my bike.

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Galactic Greyhound
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Re: ABS strange behaviour.

Postby Galactic Greyhound » Sat Jul 21, 2018 8:45 pm

.........….But this problem of falling Voltage doesn't arise with the magnificent Li-Po latest generation of 'new technology' polymer-based batteries.
A third of the weight, five times the cranking power and virtually no self-discharge...………....
Hi Al,

That is interesting about the Li-Po batteries.

I have always been wary of using Lithium-based batteries - even my iPhone is never left unseen when it is charging in case of fire.

As you say though, there are great strides being made in non lead-acid batteries and I don't think it will be long before lead-acid batteries are consigned to museums.

Nice to hear that you have been using these Li-Po batteries for a few years with no problems arising so that is good progress! :grin:
Ced.

R1100RT 1996.
Sent by Boson Quantum Transmission from the Starship 'Galahad'.
http://www.researchgate.net/publication ... ing_bosons" - It works!


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