3 stage alternator regulator logic

[Fuss]

I am interested to know what logic is programmed onto 3 stage smart regulators. I realise that different manufacturers use different logic. If this was known it would help me understand how the alternator charging is affected when there are other charging sources such as wind and solar.
John

[Alan Wheeler]

Are you meaning, at what voltage points does the charge controller ramp to the next stage of charging????

[Hud3]

Hi, John.

I have Balmar two alternators on my boat, and each has it's own smart regulator. The manual explains the charging stages on page 7:

http://www.balmar.net/PDF/mc624manual.pdf

Is this the sort of thing you're looking for?

Regards,

[Fuss]

Hi Wheels and Hud,
Thanks for the replies, The reason that I have asked the question is that my 3 stage regulator (not from balmar), does not seem to output as many amps if the batterys have recently been charged from another source.

In bulk/boost mode, my fast charge 3 stage alternator regulator does not seem to sense battery condition correctly it senses only the voltage, I think it somehow should also sense the potential for more amperage acceptance and then calculate the amperage to deliver.

A Senario -
Battery bank discharged by 50 %.
Solar or wind generator are charging the battery bank or maybe the AC generator which runs the AC battery charger has only just been switched off after cooking breakfast.
(The result is that the battery bank shows a voltage that does not reflect the true amount that the battery bank is discharged.)
The engine is now started and the 3 stage regulator reads the voltage and
decides how many amps to deliver.
(as the voltage reading is higher than it should be at start up, the 3 stage regulator does not deliver as many amps as the battery could potentially accept.)

On my boat in this senario the alternator puts out 50 amps instead of 100 and takes very much longer to charge fully.
My solution is to have at least 20 minutes gap and some load on the battery bank after switching off the generator and then starting the engine.
I only have a generator and no solar or wind, so I imagine boats with these alternatives have the problem that they cannot easily switch off battery charging.

After looking at the link from Hud, it looks like the balmar regulator might not have this problem.

If all regulators only sense the voltage then I could imagine that they all would have this problem.

I hope that makes it a bit clearer as to why I asked.
Thanks
John

[Alan Wheeler]

What is the regulator? You are correct that not all regulators are created equal. As I understand it, the way the Balmar operates is to place a high current charge into the battery till it requires the Absorbtion charge. Cheaper or poorly designed charge regulators may not do it that way. Certainly the built in Alternator regulators do not.

[Rick]

The task of any regulator, be it for a shore power charger, alternator, PV panel, is to regulate voltage, period. If the algorithm that "sets" the voltage output is not "smart" then the voltage will be either too low or too high.

It is the battery that determines charge acceptance current. If the voltage is "correct" and the battery does not accept sufficient current according to its state of capacity (notice that I did not state, "state of charge" which is different...you can have a high state of charge AND have lost capacity which may or may not be permanent) then the battery has high internal resistance, low temperature, or lost capacity.

As a guideline, if you have a "real" battery monitor you can observe the number of Amp-hours missing from the battery and make the charge voltage (if variable) high enough to make the current equal to the number of Amp-hours missing. This will help recover lost capacity (except for that which is reversible ..called sulphatation). In general, one would rarely have to reach much more than 15Volts to do this when recharging a deeply discharged battery except when performing an equalization cycle.

There is no point in applying a dc load or discharging the battery after using a shore power charger to get an alternator to put out more current.

[Fuss]

The regulator is a 24v merlin ams. I get the feeling that it only works with voltage and on startup checks the voltage and depending on what it reads then decides on the power info to give to the alternator. The alternator then starts charging but not with the amount of amps that the battery could absorb. Thus resulting in a significantly longer charging time (3x longer if i have recently run the generator which powers the 220 volt battery charger). If I remove the surface voltage after the generator has been running then the alternator charges at the full 100 amps.

[Fuss]

When the condition occurs that causes the alternator to start charging at around 40 amps instead of 100 I assume that given time the regulator will see that the batterys could accept more charge but it never does. It seems that whatever the regulator decides at startup is the maximum charge that it will be putting in. This is why I was interested to know the programmed logic.
John

[Rick]

The regulator has nothing to do with the charge acceptance current of a battery. Check to see that your regulator "sees" the exact voltage that appears across the battery (measured directly at the battery) so that it can regulate the alternator output voltage to a "correct" value.

If the battery does not receive the same exact voltage that the charger delivers (when running the generator) then the same acceptance current will not flow.

Your whole problem is one of voltage regulation.

[Alan Wheeler]

To perhaps take a different view of what you have. Please Note Ricks comment

Check to see that your regulator "sees" the exact voltage that appears across the battery (measured directly at the battery)

This alludes to a possible cause. One of, do you have sufficient cable size for length between charger/Alt. and battery. Or, is it possible you have a poor connection. So you will want to make to voltage test measurments. One at the charger output and the other at the battery. There should be no or very little difference.

[Joe Okros]

I am not familiar with your setup- I have and Ideal 3 stage regulator with a Balmar alternator. BUT a few things spring to mind

1. Make sure that you have a "shunt" installed and working properly - this allows amperage to be measured accurately without being in series.
2. My regulator is "clever" in that it will not deliver current upon startup for a predetermined time--this is to allow the engine a warm up time before placing load on it.
3. Your batteries may be stuffed--showing a high voltage, but retaining/accepting no charge.
4. If you have any solar panels/wind generator connected, it might lead to incorrect voltage sensing--depending on where your alternator voltage sensing leads are attached and wether the solar panels are still working (I've seen 19V on my panels).

But at the end of the day, as one other poster explained, most multistage regulators function on voltage sensing. Typically they will provide maximum current till the voltage setting has been achieved-varies for different battery types, but in my case (AGM batteries) its set to 14.4V. The regulator will then lower the current whilst trying to maintain the voltage--at some stage the (this varies for different batteries) regulator will be only providing 2% of the batteries capacity (10 amps for a 500 AMP battery bank). Once again, this is something you have to tell the regulator in advance (programming). At this stage it is counter productive to continue charging.....

All of this fails to work if the battery is stuffed--I know this how?? been there and pissed around for days figuring it out. That said--it sometimes makes no sense to me either, and I studied this **** at college a long long time ago