Engine Bay Blower voltage cycling between 14V and 10V - voltage regulator issue ?

[PaulRainbow]

Copied and pasted from my post No 6:

"To get to the bottom of it, you need more information. The first thing to do is check the voltage directly on the battery."

Each other point of your post can be discussed indefinitely, if the the objective is to prove how smart either of us is.
As my objective is more to help the OP to solve the problem, I am resting my case .

In post #6 you repeated my suggestion from post #2 to check the battery voltage, pointless. You then went on to dismiss out of hand any suggestion it could be the alternator, whilst suggesting it could be the glow plugs or a faulty battery.

If you are trying to help the OP, why not just wait until he posts back with the results of some more voltage checks ? Rather than keep arguing that i'm wrong.

 

[jiris]

Thank you for guidance. I will now do voltage measurements at the both engine + service batteries while engine is running. Not too sure about the safety of measuring voltage across alternator while engine is running as sounds dangerous ?

Nothing dangerous about measuring voltage when the engine is running - as long as you keep your fingers from the belts and pullies .

 

[PaulRainbow]

Thank you for guidance. I will now do voltage measurements at the both engine + service batteries while engine is running. Not too sure about the safety of measuring voltage across alternator while engine is running as sounds dangerous ?

Your initial tests only need to involve checking the battery voltages. If you find that the battery voltages are stable with the engine running, but fluctuate at the fan, there is no need to check at the alternator.

If the battery voltages do fluctuate, check at the alternator. There is no danger in checking at the alternator as long as you keep your fingers away from moving parts. If it is difficult to do so safely, attach a multimeter probe to the B+ terminal before starting the engine.

 

[VicS]

Nothing dangerous about measuring voltage when the engine is running - as long as you keep your fingers from the belts and pullies .

and hair and loose clothing ... and meter leads

 

[PaulRainbow]

and hair and loose clothing ... and meter leads

Don't worry, you'll be safe in your armchair

 

[Alex_Blackwood]

If the battery voltages do fluctuate, check at the alternator. There is no danger in checking at the alternator as long as you keep your fingers away from moving parts. If it is difficult to do so safely, attach a multimeter probe to the B+ terminal before starting the engine.
[/QUOTE]
I would do that any way and stop the engine before removing. Make sure it is securely attached and won't fall off with the engine running. (Grandmothers and eggs)!

 

[diversp]

Ok. Measurements taken. Engine battery at rest 13.3V. Service batteries at rest 13.3V. Engine started. Service batteries at constant 14.1V. Engine battery cycling between 14.1V and 13.8V in the same cadence that the fan is cycling louder and quieter. I did not feel confident to measure directly at the alternator as a lot of wires coming out the back.

Could this cause the fan voltage going from 14V to 10V. I don’t know. Thoughts please.

 

[PaulRainbow]

Ok. Measurements taken. Engine battery at rest 13.3V. Service batteries at rest 13.3V. Engine started. Service batteries at constant 14.1V. Engine battery cycling between 14.1V and 13.8V in the same cadence that the fan is cycling louder and quieter. I did not feel confident to measure directly at the alternator as a lot of wires coming out the back.

Could this cause the fan voltage going from 14V to 10V. I don’t know. Thoughts please.

What do you have for split charging, VSR, diode or what ?

 

[jiris]

Ok. Measurements taken. Engine battery at rest 13.3V. Service batteries at rest 13.3V. Engine started. Service batteries at constant 14.1V. Engine battery cycling between 14.1V and 13.8V in the same cadence that the fan is cycling louder and quieter. I did not feel confident to measure directly at the alternator as a lot of wires coming out the back.

Could this cause the fan voltage going from 14V to 10V. I don’t know. Thoughts please.

The steady voltage on the house battery pretty much eliminates the alternator. The fact the voltage fluctuation on the engine battery is lower than the fluctuation on the blower terminal suggests the problem is somewhere between the battery and the blower. If there is nothing connected in parallel with the blower on the same wiring, it has to be the blower as such. Is it just a straight motor or does it have some kind of control?

 

[VicS]

The steady voltage on the house battery pretty much eliminates the alternator. The fact the voltage fluctuation on the engine battery is lower than the fluctuation on the blower terminal suggests the problem is somewhere between the battery and the blower. If there is nothing connected in parallel with the blower on the same wiring, it has to be the blower as such. Is it just a straight motor or does it have some kind of control?

If the alternator is maintaining a steady voltage on the house battery how can it be fluctuating on the engine start battery ?

A very large fluctuating load on the engine start battery ? If so what can it be ?

Something peculiar happening in the charge splitting . ....... How is the charge split between the batteries ? VSR, diode splitter, Sterling A to B or something else ?

 

[jiris]

If the alternator is maintaining a steady voltage on the house battery how can it be fluctuating on the engine start battery ?

A very large fluctuating load on the engine start battery ? If so what can it be ?

Something peculiar happening in the charge splitting . ....... How is the charge split between the batteries ? VSR, diode splitter, Sterling A to B or something else ?

You don't really want me to answer this, do you . Do you call 0.3V fluctuation on the start battery a "very large fluctuation"?

 

[Alex_Blackwood]

Ok. Measurements taken. Engine battery at rest 13.3V. Service batteries at rest 13.3V. Engine started. Service batteries at constant 14.1V. Engine battery cycling between 14.1V and 13.8V in the same cadence that the fan is cycling louder and quieter. I did not feel confident to measure directly at the alternator as a lot of wires coming out the back.

Could this cause the fan voltage going from 14V to 10V. I don’t know. Thoughts please.

Just a thought, is the fan itself subject to any mechanical restriction. i.e. bearings? Could be that mechanical load is causing slow down with resultant increase in current and drop in voltage. This may explain difference in volt drop at battery and fan terminals. Note I said May!

 

[PaulRainbow]

Just a thought, is the fan itself subject to any mechanical restriction. i.e. bearings? Could be that mechanical load is causing slow down with resultant increase in current and drop in voltage. This may explain difference in volt drop at battery and fan terminals. Note I said May!

Something like this is worth investigating. My next check would be to disable the fan (should be a fuse that could be removed), then see if the engine battery voltage still fluctuates. If it does it further points to an issue with the fan itself.

 

[VicS]

You don't really want me to answer this, do you . Do you call 0.3V fluctuation on the start battery a "very large fluctuation"?

Its a fluctuation, while the voltage measured at the house battery is steady, but I did not qualify it or quantify it in any way.

How do you explain this fluctuation?

 

[jamie N]

Something like this is worth investigating. My next check would be to disable the fan (should be a fuse that could be removed), then see if the engine battery voltage still fluctuates. If it does it further points to an issue with the fan itself.

I thought that myself, but saw in post #1, that this IS a new fan, where the symptoms have followed precisely the pattern of the original item.

 

[jiris]

Its a fluctuation, while the voltage measured at the house battery is steady, but I did not qualify it or quantify it in any way.

How do you explain this fluctuation?

Copied and pasted from your post:

"A very large fluctuating load on the engine start battery ? If so what can it be ?"

Anyway, what if you, instead of asking me for explanation of the different behaviour of the house and starting battery, look at how split charging works? The only "peculiar" thing happening with this one is, it is doing its job.

 

[PaulRainbow]

I thought that myself, but saw in post #1, that this IS a new fan, where the symptoms have followed precisely the pattern of the original item.

Thanks for reminding me of that Jamie, i'd forgotten he's changed the fan.

In this case, i'd still check the battery voltage with the fan disconnected. I'd also temporarily connect the fan directly to the battery, buy using a length of cable.

 

[Alex_Blackwood]

Thanks for reminding me of that Jamie, i'd forgotten he's changed the fan.

In this case, i'd still check the battery voltage with the fan disconnected. I'd also temporarily connect the fan directly to the battery, buy using a length of cable.

+1 I missed that.

 

[VicS]

Copied and pasted from your post:

"A very large fluctuating load on the engine start battery ? If so what can it be ?"

Anyway, what if you, instead of asking me for explanation of the different behaviour of the house and starting battery, look at how split charging works? The only "peculiar" thing happening with this one is, it is doing its job.

Yes I asked if a very large and fluctuating LOAD could be what is causing the fluctuating voltage.

No where have I referred to a "very large" fluctuating voltage

 

[diversp]

Hi. Thanks for all the feedback. In response to a question the alternator is attached to a ECS163 quick charge separator.