Alternators and Regulators

[lw395]

I have a pair of these (or at least the prototypes for these). They work well enough, and get good output from a pair of regualr alternators. Alternators themselves have not chnaged much in the last 40 years, what has chnaged is the controller technocolgy.

WAKESPEED WS500 Advanced Alternator Regulator & Wiring Harness

We ought to stop calling common or garden ~14.4V alternators 'modern'.
My car is, I suspect, the olest in the street and it has a remotely regulated alternator linked to a microprocessor together with a current sensor on the battery lead. The charging voltage is anything but constant. Newer cars with stop/start do this even more.
My car was 11 years old when it 'needed' a new battery, I say 'needed' because it was only apparent the battery was getting old because I quite often go ten days without using my car, in daily use it might have done a bit longer, but I decided to change it before it let me down.
Cars with 90s alternators giving a plain 14.4V tended to have much shorter battery lives.

 

[Bobc]

Been reading this with interest. I had charging issues on my boat with an old Valeo 65A alternator which was charging at 13.7v.
After talking to a number of people, I decided to fir an AtoB charger instead of buying a bigger alternator.

The difference was dramatic. I was getting a bulk charge to the house batteries of 14.6v with plenty of amps. It has been so successful that when I fitted a new engine this year, I went with the 70A alternator (and stick with the AtoB) instead of opting for the 120A alternator, as I would still have a proper 3-stage charger.

 

[Bobc]

Duplicate post

 

[Malabarista]

I have a pair of these (or at least the prototypes for these). They work well enough, and get good output from a pair of regualr alternators. Alternators themselves have not chnaged much in the last 40 years, what has chnaged is the controller technocolgy.

WAKESPEED WS500 Advanced Alternator Regulator & Wiring Harness

Hi thanks for the link.
after wading through the specs and blurb ( why do even genuine ‘Merkin products sound like they are trying to sell snake oil?)
It appears, to my feeble grasp on the subject, that the Wakespeed does what an A to B does with the exception of the current measuring capability. At $600 each it seems a bit of a ‘nice to have’ unless of course you are using exotic batteries. Are they more of a belts and braces approach to protecting your bank or have you seen great gains in charging abilities from the alternator?

 

[Malabarista]

Been reading this with interest. I had charging issues on my boat with an old Valeo 65A alternator which was charging at 13.7v.
After talking to a number of people, I decided to fir an AtoB charger instead of buying a bigger alternator.

The difference was dramatic. I was getting a bulk charge to the house batteries of 14.6v with plenty of amps. It has been so successful that when I fitted a new engine this year, I went with the 70A alternator (and stick with the AtoB) instead of opting for the 120A alternator, as I would still have a proper 3-stage charger.

My poor ( unfitted) A to B is getting dizzy from all this attention. It’s in and out like a fiddlers elbow ?

 

[VicS]

Been reading this with interest. I had charging issues on my boat with an old Valeo 65A alternator which was charging at 13.7v.
After talking to a number of people, I decided to fir an AtoB charger instead of buying a bigger alternator.

The difference was dramatic. I was getting a bulk charge to the house batteries of 14.6v with plenty of amps. It has been so successful that when I fitted a new engine this year, I went with the 70A alternator (and stick with the AtoB) instead of opting for the 120A alternator, as I would still have a proper 3-stage charger.

The merits of the A to B charger are that it provides advanced charging of the domestic battery, without the alternator "modification" which other advanced add -on regulators require, and at the same time simultaneously provides basic charging of the engine start battery without needing diode splitters or VSRs etc
Unlike other advanced regulators it also incorporates a true "float" stage while the others only reduce the volts to the basic output volts of the alternator.

The trouble with your Valeo may have been that it needed a new regulator although 13.7 may have been within spec for a very old one .

 

[GHA]

With temperature my alternator seems to just track the engine temperature, though probably not pushing out that much power here -

 

[halcyon]

That has to be the most bass ackwards explanation of how a constant voltage alternator works ever. The alternator does not "cut back on the amps" .. it simply produces a constant output voltage, and the amps are simply whatever the battery will pull at that particular voltage (up to the maximum output current of the altnerator). The alternator's control circuit has no knowledge of the output current and does not use it in it's feedback circuit, it simply drives the field coil to try and achieve the pre-set output voltage, and thats all.

How do you think a basic alternator regulates the voltage ? it cuts feed to rotor, thus no output, alternators were designed to supply car electric power supply. Same theory I used for the mains battery chargers I used to design and make, it has no need to have knowledge of current, it just cuts back till it is below the set voltage. We were a little more advanced controlling thyristor firing angle, but still reduced current. There are alternate mays, but normally link to ECU, and may monitor current, temperature plus other factors.

Brian

 

[Iliade]

With temperature my alternator seems to just track the engine temperature, though probably not pushing out that much power here -

Superb! What kit do you use to capture and log this please?

It would now be very interesting to see this same exercise repeated with different starting conditions, e.g With the house batteries in different states of discharge. Especially if you could also record the voltage at the house and engine batteries and at the alternator output terminal. Even if we have to wait until the summer.

 

[GHA]

Superb! What kit do you use to capture and log this please?

It would now be very interesting to see this same exercise repeated with different starting conditions, e.g With the house batteries in different states of discharge. Especially if you could also record the voltage at the house and engine batteries and at the alternator output terminal. Even if we have to wait until the summer.

A raspberry pi running openplotter saves all the data and makes the plot, temperature sensors are ds18b20, cheap and waterproof, you can string a load together into the raspberry pi then it's easy to set up. It also records battery voltage and current which is really interesting. Would be interesting looking bat alternator temperature when it's really working hard but living aboard usually on the hook they're never allowed to run down too far. Maybe time to add some lithium

 

[halcyon]

Apropos the float charging above, I have just observed that my 14.nnV alternator* has boiled off some of the electrolyte from the 2018 sealed house batteries such that the green eye is now black... I have just bought a used Sterling A-B.

* Assuming that the wind and mains chargers were not the culprits, but they are both sophisticated jobbies, Sterlingling and Marlec respectively, so unlikely.

Remember the voltage you read on your meter is not the voltage the battery sees, the alternator output is rectified sinusoidal. So you get a series of charge pulses that are higher than the meter, 14.4 volt could be peaking at 15.5 volt. The charge takes place during the peak, which as the battery level comes up, so the current gets lower as the area above the battery voltage rises. So increasing voltage reading can give high charge voltages and water loss from excessive boiling. You need a scope to see it though.

Switch mode has a flatter / flat output, hence the charge phases and higher voltages.

Brian

 

[PaulRainbow]

Remember the voltage you read on your meter is not the voltage the battery sees, the alternator output is rectified sinusoidal. So you get a series of charge pulses that are higher than the meter, 14.4 volt could be peaking at 15.5 volt. The charge takes place during the peak, which as the battery level comes up, so the current gets lower as the area above the battery voltage rises. So increasing voltage reading can give high charge voltages and water loss from excessive boiling. You need a scope to see it though.

Switch mode has a flatter / flat output, hence the charge phases and higher voltages.

Brian

You misquoted Brian, i didn't say that.

 

[Iliade]

No, I did. I understand that the new forum's 'quote' function is a little screwy so it may not have been Halcyon's error.

In response to Halcyon: Yes indeed...