How do I check the alternator?
Discussion
Apologies for this basic question, but I fitted a cooling fan to reduce warming up time and this seems to use up the battery faster than the alternator is able to charge it up. It works well in reducing warm up time but the second or third time it is used during the day there is insufficient power to start the engine (SR3 24v).
The batteries are on trickle charge whilst in my garage at home so they read 13v at the outset. Three warm ups with the fan running the Aim is telling me just 10.5v left.
What revs are needed for the alternator to recharge the battery? I have tried testing by connecting a voltmeter to the engine compartment battery and running the engine with the fan on, and it shows a slow fall in voltage at tickover (about 1250rpm) and no appreciable difference at 4000rpm.
Is there a better way of testing it? Any ideas?
Thanks
David
The batteries are on trickle charge whilst in my garage at home so they read 13v at the outset. Three warm ups with the fan running the Aim is telling me just 10.5v left.
What revs are needed for the alternator to recharge the battery? I have tried testing by connecting a voltmeter to the engine compartment battery and running the engine with the fan on, and it shows a slow fall in voltage at tickover (about 1250rpm) and no appreciable difference at 4000rpm.
Is there a better way of testing it? Any ideas?
Thanks
David
Unrelated to your question, but how does a cooling fan reduce warm up time?
I guess this is all complicated by the 24v starting system, but basically you need to measure the voltage at the battery that is supplying the 12v. That will likely tell you whether that battery is being charged enough when the fan is on you'd be looking for 14v+.
Bert
I guess this is all complicated by the 24v starting system, but basically you need to measure the voltage at the battery that is supplying the 12v. That will likely tell you whether that battery is being charged enough when the fan is on you'd be looking for 14v+.
Bert
In simplistic terms as long as your alternator produces a voltage higher than at the battery then current flows into the battery and slowly charges it. Lead acid batteries will be around 12.3v normally when charged. Ideally you want then around 13-14.8v max at the battery, with engine running and usual loads connected. Anything less than about 12.4v or so in that situation isn't good and the alt isn't going to recharge that battery really.
Some alternators are lazy and won't charge until 2 or 3k revs but generally the above voltages give or take will see it right.
Some alternators are lazy and won't charge until 2 or 3k revs but generally the above voltages give or take will see it right.
That makes sense Josh, I will try and find the charging loom. Any clues? It is a 2011 SR3 1500.
Bert, the water heats up faster than the oil to the point where the max water temperature is reached before the oil reaches the minimum temperature, so I have to keep switching the engine off to let the water cool down then start again, repeating until both are in range. The fan keeps the water cool enough to allow the oil to rise, halving the warm up time. It also keeps the water temp down whilst sitting in a queue.
The battery reads about 12.5v whilst on tickover, shows a drop when the fan is switched on and falling to 11.5 after about ten minutes. Switch the fan off and it rises to 12.1 / 12.3v.
Bert, the water heats up faster than the oil to the point where the max water temperature is reached before the oil reaches the minimum temperature, so I have to keep switching the engine off to let the water cool down then start again, repeating until both are in range. The fan keeps the water cool enough to allow the oil to rise, halving the warm up time. It also keeps the water temp down whilst sitting in a queue.
The battery reads about 12.5v whilst on tickover, shows a drop when the fan is switched on and falling to 11.5 after about ten minutes. Switch the fan off and it rises to 12.1 / 12.3v.
Definitely sounds like your alternator isn’t charging. Had similar on my PR6 recently and it ended up being the voltage regulator but as stated above check the fuse first, then the wiring and relay. I believe it is reasonably rare for the actual stator (alternator) to fail on the hayabusa. There’s a load of you tube videos about how to test the hayabusa (or similar bike) stator charging system which could help.
Cheers,
Dunc.
Cheers,
Dunc.
petroleum bone-apart said:
That makes sense Josh, I will try and find the charging loom. Any clues? It is a 2011 SR3 1500.
Bert, the water heats up faster than the oil to the point where the max water temperature is reached before the oil reaches the minimum temperature, so I have to keep switching the engine off to let the water cool down then start again, repeating until both are in range. The fan keeps the water cool enough to allow the oil to rise, halving the warm up time. It also keeps the water temp down whilst sitting in a queue.
The battery reads about 12.5v whilst on tickover, shows a drop when the fan is switched on and falling to 11.5 after about ten minutes. Switch the fan off and it rises to 12.1 / 12.3v.
your alternator isnt working. Bert, the water heats up faster than the oil to the point where the max water temperature is reached before the oil reaches the minimum temperature, so I have to keep switching the engine off to let the water cool down then start again, repeating until both are in range. The fan keeps the water cool enough to allow the oil to rise, halving the warm up time. It also keeps the water temp down whilst sitting in a queue.
The battery reads about 12.5v whilst on tickover, shows a drop when the fan is switched on and falling to 11.5 after about ten minutes. Switch the fan off and it rises to 12.1 / 12.3v.
Most common reason is the connector referenced earlier which connects the output of the alternator to the loom. It can end up with burned contacts. Take a look at the plug and replace if necessary. I had this on mine although it was a long time ago so my memory may not be serving me all that well, but I think the connector was white? ISTR I found the direct replacement on the shelf in Halfords of all places.
It's a common problem on Busa's in general, not just Radicals.
It's a common problem on Busa's in general, not just Radicals.
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