Battery or starter...

marc11

Joined
Apr 3, 2024
Messages
108
Age
55
Location
Orange County, NY
Bike
2004 ST1300
Noticed when my 04 ST13 sits for a few days first push of the starter would either get no response from the starter or after a second or two the starter would engage. It always engaged the second attempt and always engaged perfectly the rest of the riding day.

Decided to put it on a tender for a few days, tender light was green, voltage shows 13.06, hit the starter voltage drops to 8 then back to 10, sometimes engages the starter, sometimes requires a second try where voltage will drop to 10-11.

To me it could be a weak cell in the battery or a bad starter or starter relay causing a high load.

I do not know the age of the battery.

Not sure how common this is, any thoughts?
 
Try cleaning the starter button first, they tend to wear and also get gunk in there. I would do that first with some electrical contact cleaner.

It does sound like the battery might be done for...
 
marc11 said:
hit the starter voltage drops to 8 then back to 10, sometimes engages the starter, sometimes requires a second try where voltage will drop to 10-11.

I do not know the age of the battery.
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If your battery voltage is dropping below 10 when the starter is pressed, that's an indication of a bad battery. The fact that it recovers back to 10 on the 2nd try suggests it might not be totally bad yet, but its probably on its way out. That plus the fact that you don't know the age of the battery suggests replacing the battery would be the best approach. Before doing that, take it to an AutoZone or similar and have it tested.
 
My 1300 has been intermittently not starting well (and it has abrand new healthy battery). I have cleaned the contacts on the diode (it lives in the fuse box, looks like a skinny three-legged fuse) and that helped, and I have recently replaced my neutral switch as when I tested that electrically it was quite intermittent.
 
TerryS said:
My 1300 has been intermittently not starting well (and it has abrand new healthy battery). I have cleaned the contacts on the diode (it lives in the fuse box, looks like a skinny three-legged fuse) and that helped, and I have recently replaced my neutral switch as when I tested that electrically it was quite intermittent.
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Hmmm interesting, I want to check all these things before just throwing a battery at it.
 
marc11 said:
Hmmm interesting, I want to check all these things before just throwing a battery at it.
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As mentioned before, auto parts stores will usually load test a battery for free, so you won't be "throwing a battery at it".

Also, if the 1300 starter circuit is like the 1100, and it probably is, all that other stuff is in the path that actuates the starter relay. The symptom when the problem is in that path is the starter relay doesn't energize reliably every time, but when it does, the battery is able to turn the engine over normally. Like Terry says, its intermittent, your failure mode description doesn't sound intermittent at all.

If the battery voltage is dropping down to 8 when the starter motor is energized, that suggests the starter relay is working normally, and the battery isn't capable of driving enough current to the starter motor without the internal resistance of the battery dropping the voltage too low.

Do you have a starter system schematic to trace things out with, you never mentioned it so far.
 
marc11 said:
Noticed when my 04 ST13 sits for a few days first push of the starter would either get no response from the starter or after a second or two the starter would engage. It always engaged the second attempt and always engaged perfectly the rest of the riding day.

Decided to put it on a tender for a few days, tender light was green, voltage shows 13.06, hit the starter voltage drops to 8 then back to 10, sometimes engages the starter, sometimes requires a second try where voltage will drop to 10-11.

To me it could be a weak cell in the battery or a bad starter or starter relay causing a high load.

I do not know the age of the battery.

Not sure how common this is, any thoughts?
Click to expand...

Do you have a booster/jump pack you could use to start the bike and compare?
 
Although testing the battery at an auto parts store is a great idea, I'd likely clean and inspect all the connections first- at the battery, solenoid, grounding point, etc. Corrosion can creep up on an unsuspecting rider pretty quickly.
 
Thanks everyone.

I ordered a battery tester and contact cleaner and will have them tomorrow,(gotta love prime day discounts) I also cleaned the terminals and do have a service manual to trace the circuit

I also have a jump pack however since this does not happen all the time and only happens once at a given attempt to start using the jump pack could give a false positive although in thinking could confirm if it is not the battery ie if it happens with the jump pack on it cannot be the battery...

This morning at 330 am bike started perfectly single press less than a full crank.

I'll clean the start and kill switches as that's a good idea on a 20 year old former Florida bike anyway and load test the battery and report back.
 
Jump it from your car, see if that makes a difference. Car battery has huge reserve power compared to the bike battery or the jump pack. If it starts flawlessly chances are the bike battery is done.
 
If the voltage drops as low as you are seeing stop now and fix it, as voltage drop amperage draw goes up and the starter begins to accelerate wear. A general easy way to test battery that is completely gone is to charge it put the lights on for a while and see if it recovers when lights are turned off, but that comes to a judgement call,
Your description is what I see when a diode in the alternator fails or the battery fails. The alternator drains overnight but is enough to charge during day, or the battery is charged enough to make it through the day. Quick check, what is the charging volage, if it is normal it probably is the battery.
 
What you can do also is put the positive lead of meter on positive side of battery and the negative probe as far down on the starter circuit as you can. When you hit the starter you will get the voltage drop reading through that circuit under load.
 
marc11 said:
if it happens with the jump pack on it cannot be the battery...
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.......that's the idea.

Although you cannot exclude that this battery is not far from the end of its life and may soon let you down.

Curious: Are you able to identify what battery it is? CA rating still visible on it?

If lead acid: topped up?
 
quick question on your voltage readings. Are you reading the voltage across the battery terminals with a multimeter when you see the 8 volts, or are you reading a panel voltmeter you installed in the circuit? If the answer is panel voltmeter in circuit, where is the positive tap located? The reason I ask is if you're reading 8 volts at the battery terminals under load, then that's independent of any corrosion induced voltage drops and cleaning the terminals isn't going to make any difference, the battery has gotten weak with age. If your positive tap for the panel voltmeter is downstream a bit from the battery terminal, then cleaning up corrosion may make a difference, and the battery may not be as bad as it first sounds.
 
MidLife said:
Good old Georg Simon may not quite agree with this one!
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Depends on the type of load. Most loads are resistive, so the current varies proportionately with the applied voltage.

Motor loads tend to be constant-power loads, so the current varies inversely with the applied voltage (within a range).
 
I found the text below (in italics) with a web search and cut/pasted it from some other forum. Its a good explanation of how a DC motor works. Based on this, it would appear that if your battery voltage gets too low and the starter motor turns too slowly, there is an explanation for how the current could rise. However, in that situation its also possible that as the battery voltage drops and the speed of the motor slows, the voltage lowers by enough that it effectively cancels out the current effect of the slowing motor speed based on the purely resistive I=V/R relationship. Seems like a good motor design would not allow a weak battery to be able to fry one of the field windings and destroy the motor, so the effects of low battery voltage on motor current are probably not something that we need to be concerned about as motorcyclists.

If a brushed motor was a resistive load, then it would fry whenever you hooked up a power supply across it because the winding resistance is so low. BUt it doesn't. A DC brushed motor accepts DC current, but inside the rotating brushes are commutating (switching the DC current back and forth across the windings) so that if you measured the voltage across the individual windings you would not see a flat constant DC voltage, but you would see a AC waveform (not necessarily the pure sinusoid AC waveform you get from the mains, more likely to be a trapzoidal waveform but AC nonetheless with no AC component).

THe winding inductance is slowing down the rise time of the current in the winding which is trying to reach to "infinite" due to the low resistance of the motor windings. But before it can reach "infinite" (a level of current that would fry the motor) the brushes commutate the current to another winding.

What it's actually doing is for every winding it is switching the voltage polarity of the winding to reverse the current flow so that it decreases to zero before it gets too high. BUt once it reaches zero it starts increasing in the opposite direction. The voltage polarity is reversed again before this gets too high (assuming the motor is running under allowable operating conditions). BUt it is doing this in a sequence so it appears as though the positive voltage across windings is jumping sequentially across the windings in one direction and the negative voltage is moving in the opposite direction across the windings taking the empty place the winding that the other polarity left behind.

If there is too much load on the motor the motor is spinning too slowly and the current polarity isn't reversed fast enough and is given too much time to rise to a level that overheats the motor. In the absolute worst case (stall) then, yeah, it appears as a resistive load since the inductance will allow the DC current flow through a single winding to eventually reach a level where the current is now limited by the resistance and thus no longer rises meaning the inductance then appears as a short.
 
The inverse current phenomenon applies within a voltage range, outside of which current is proportionate.
 
Larry Fine said:
Motor loads tend to be constant-power loads, so the current varies inversely with the applied voltage (within a range).
Click to expand...

Voltage drop is from higher IR on older battery, not from the battery somehow miraculously exceeding its rated CA.
 
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