Alternator and Solar living in perfect harmony!

[GHA]

Completely agree, my original wind/solar regulator pretty much stopped charging my T105s around 85% (based on temp. corrected SG). I checked for a few days to get a baseline and tweaked the defaults to stop regulator throwing away useful sunshine. Panels weren't large enough to get to 100% at that time but huge improvement in performance after adjustment.

I was always surprised to find how many people just accepted defaults.

Agree to your agree
I set float & absorption to 14.8v, still only just gets full with 300w on 2 x t105's. There was a paper published a while ago occasionally mentioned which concluded over 15v could be better as any corrosion/damage from the high voltage would be less harmful than not getting fully charged regularly.

 

[PaulRainbow]

The Sun is shining nicely here.

Voltage at the batteries is 14.38 and the solar controller is outputting 9.5a, 6a of which is going to the batteries for charging.

I'll start the engine......

Initial output from the alternator about 15a. After 3 or 4 minutes it's down to a barely readable current. The voltage at the batteries and the solar output remain unchanged.

Using the Victron connect software i've disabled the solar controller. Showing 12.8v at the batteries after a short wait, -9a I'll restart the engine......oh, the alternator is putting out 25a. Leave it for a while and it's down to 16a

So, the alternator did not cause the solar controller to shut down. The alternator output was substantially reduced (almost nothing) when the solar controller was on.

Solar only 9.5a
Solar and engine 10a
Engine only 25a falling to 16a after a time

 

[geem]

The Sun is shining nicely here.

Voltage at the batteries is 14.38 and the solar controller is outputting 9.5a, 6a of which is going to the batteries for charging.

I'll start the engine......

Initial output from the alternator about 15a. After 3 or 4 minutes it's down to a barely readable current. The voltage at the batteries and the solar output remain unchanged.

Using the Victron connect software i've disabled the solar controller. Showing 12.8v at the batteries after a short wait, -9a I'll restart the engine......oh, the alternator is putting out 25a. Leave it for a while and it's down to 16a

So, the alternator did not cause the solar controller to shut down. The alternator output was substantially reduced (almost nothing) when the solar controller was on.

Solar only 9.5a
Solar and engine 10a
Engine only 25a falling to 16a after a time

If you set your charge voltage on your victron controller above the set point voltage of the engine alternator the solar wont stop charging. Its not rocket science...

 

[PaulRainbow]

If you set your charge voltage on your victron controller above the set point voltage of the engine alternator the solar wont stop charging. Its not rocket science...

If you read the post you will see that the alternator does not stop the solar charging.

Reading, it's not rocket science.

I'm completely aware of what is happening and none of the results i've posted surprise me at all. Thanks.

 

[noelex]

Voltage at the batteries is 14.38 and the solar controller is outputting 9.5a, 6a of which is going to the batteries for charging.

I'll start the engine......

Initial output from the alternator about 15a. After 3 or 4 minutes it's down to a barely readable current. The voltage at the batteries and the solar output remain unchanged.

If I understand correctly the alternator is trying (and succeeding) to maintain a voltage of 14.38v. The question is why?

For a flooded battery a smart alternator regulator will maintain the absorption voltage which should be set at around 14.7v for an hour an half or so.

If you have set the alternator regulator to the Gel settings ( or sometimes the manufacturers conservative flooded settings) a typical absorption voltage might be 14.4v so 14.38v would be fine. It would be correct for the settings that the voltage is held at 14.4v (and 14.38v is close enough) so the alternator should reduce current if this voltage is reached.

If you can detail the set points of the alternator regulator (absorption voltage and time) it should be easy to see why the regulator is trying to maintain a 14.38v absorption voltage.

The alternator regulator has no idea if another charge source is connected or not. It simply trying to maintain a set voltage for set time.

 

[GHA]

Showing 12.8v at the batteries after a short wait, -9a

what's the -9A mean?

 

[PaulRainbow]

If I understand correctly the alternator is trying to maintain a voltage of 14.38v. The question is why?

No. The voltage is at 14.38v before the engine is started, with the solar controller on. It's the solar controller that is at 14.38v

For a flooded battery a smart alternator regulator will maintain the absorption voltage which should be set at around 14.7v for an hour an half or so.

I don't have a smart alternator regulator.

If you have Gel batteries a normal absorption voltage might be 14.4v so this voltage would be correct. It would be in the best interests of the battery that the charging is held at 14.4v (and 14.38v is close enough) so the alternator should shut down if this voltage is reached.

I don't have gel batteries.

if you can detail the set points of the alternator regulator (absorption voltage and time) it should be easy to see why the regulator is trying to maintain a 14.38v absorption voltage.

Again, the alternator regulator is not trying to maintain 14.38v.

The solar controller is at 14.38v. Actually, the solar controller absorption setting is 14.4v, 14.38 v is shown by the battery monitor. When the engine is started the alternator is sensing the solar controller voltage and the regulator is reducing the alternator power output, as it should, unless the regulator is also set to 14.4v or greater.

 

[geem]

If you read the post you will see that the alternator does not stop the solar charging.

Reading, it's not rocket science.

I'm completely aware of what is happening and none of the results i've posted surprise me at all. Thanks.

Reading your first post on the subject leaves me with some doubt.....

 

[PaulRainbow]

what's the -9A mean?

Not heard of amps

It means, that as i had (at that time) disabled the solar controller and the engine wasn't running, the battery monitor would show the current being drawn from the batteries. -9a.

 

[PaulRainbow]

Reading your first post on the subject leaves me with some doubt.....

Have you tried reading ?

Have you tried reading the set of results i posted, that you commented on ?

Have another look and you will see that (despite your comments) the solar controller does not shut down when the engine is started.

Why do you think it does ? Why do you think i said it does ?

I said

So, the alternator did not cause the solar controller to shut down.

You then said

If you set your charge voltage on your victron controller above the set point voltage of the engine alternator the solar wont stop charging. Its not rocket science...

 

[noelex]

Again, the alternator regulator is not trying to maintain 14.38v.

So why is doing exactly this and maintaining a voltage of 14.38v?

The settings on a smart alternator regulator (for flooded batteries) should be telling the alternator to maintain about 14.7v. If you do not have a smart regulator a typical set point is 14.4v so the alternator is doing just what you would expect and maintaining this voltage.

There is an explanation why it is behaving like you have indicated. The alternator regulator, even if it is smart device, will only maintain a set voltage over a set time. It has no idea if you have connected solar power or not. They are simple devices.

If you could indicate the type of alternator regulator, and the set points (if it is a smart regulator) then I think the explanation of the behaviour wll be clear. A change in settings might solve your problems.

 

[PaulRainbow]

So why is doing exactly this and maintaining a voltage of 14.38v?

This is getting tiresome now. The alternator is not maintaining a voltage of 14.38v. That's the reading at the batteries beofe the engine is even running. It's the voltage of the solar controller, at the time i took the measurements. It's the absorption voltage setting of the controller.

The settings on a smart alternator regulator (for flooded batteries) should be telling the alternator to maintain about 14.7v. If you do not have a smart regulator a typical set point is 14.4v so the alternator is doing just what you would expect and maintaining this voltage.

One last time, i do not have a smart alternator regulator.

There is an explanation why it is behaving like you have indicated. The alternator regulator, even if it is smart device, will only maintain a set voltage over a set time. It has no idea if you have connected solar power or not. They are simple devices.

There is a simple explanation and i have already given it. The solar controller absorption setting is 14.4v, this is greater that the alternator regulator set point, so the alternator regulator is reducing the output power.

[/quote]If you could indicate the type of alternator regulator, and the set points (if it is a smart regulator), I think the explanation of the behaviour wll be clear. A change in settings might solve your problems.[/QUOTE]

I keep saying i do not have a smart regulator.

I also don't have a problem. My system is performing exactly as i would expect. I posted some figures to highlight how different charging systems can conflict with one another. I'm perfectly happy with how it all works, i rarely use the engine so i see no need for a smart regulator, my solar panels give me enough power.

 

[noelex]

One last time, i do not have a smart alternator regulator

OK that is clear.

Without a smart regulator the set point is typically around 14.4v so the 14.38v your alternator is maintaining is typical.

So if the alternator will control its output to try and maintain a battery voltage of 14.38v. This is exactly what appears to happening.

If the battery voltage is above 14.38v the alternator will not deliver any current. This is not a conflict between different charge sources just a limitation of the simple alternator regulator.

14.38v is not a healthy maximum voltage to charge flooded lead acid batteries. The solar regulator will raise the voltage above this level but the output of the alternator will stop at 14.38v.

If you do not motor much I agree the extra cost of a smart regulator is in not justified, but it seems silly to blame a conflict between charging sources as the reason why the alternator stops producing power above 14.38v. This is just the way simple alternator regulators work.

 

[matthewriches]

U still running the Victron Paul? Can't remember exactly when you showed me but it was quite forgiving and clever as we set it to work with your battery charger though that relay IIRC.

The one I tested was a Chinese thing and couldn't be adjusted that I knew of.

 

[PaulRainbow]

OK that is clear.

At last !

Without a smart regulator the set point is typically around 14.4v so the 14.38v your alternator is maintaining is typical.

So if the alternator will control its output to try and maintain a battery voltage of 14.38v. This is exactly what appears to happening.

How many times must i say, the alternator is not charging at 14.38v, that reading was taken when the engine was not running.

the solar controller is set to 14.4v that is where the voltage comes from. The alternator cannot hold the batteries at 14.38 v if the engine is turned off, can it

If the battery voltage is above 14.38v the alternator will not deliver any current. This is not a conflict between different charge sources just a limitation of the simple alternator regulator.

Although you still do not understand the tests i posted, your theory is of course correct. BUt 14.38v is the solar controller voltage, not alternator. The alternator is lower than 14.38 so the alternator will not deliver any power.

14.38v is not a healthy maximum voltage to charge flooded lead acid batteries. The solar regulator will raise the voltage above this level but the output of the alternator will stop at 14.38v.

The alternator does not stop at 14.38v, that is the solar controller. The solar controller will NOT raise the voltage, it is set to 14.4v absorption and 13.4v float. Both of those are perfectly acceptable for FLA batteries.

If you do not motor much I agree the extra cost of a smart regulator is in not justified, but it seems silly to blame a conflict between charging sources as the reason why the alternator stops producing power above 14.38v. This is just the way simple alternator regulators work.

I know it's the way alternators work. That's the whole point of my original post. If the solar controller voltage exceed the setpoint of the alternator regulator it will stop the alternator output. Therefore, if the current from the solar controller is significantly less than the current the alternator is capable of producing you're better off turning the solar controller off. As those last figures prove, i was getting more current from the alternator alone than i was getting from solar and alternator together.

For me, this is not an issue. I motor little and have 260w of solar panels. My solar yield exceeds my consumption throughout the Summer. When i go sailing on a nice day the solar yield still exceeds my use, even with the autopilot and nav systems running, so i could care less if i have to run the engine for a while and don't get the full power from the alternator.

In the case of the OP, he has noticed a significant loss in alternator output when the engine is started and the solar controller is in absorption mode. As he has a large alternator and a small solar array he is losing a significant amount of power. Hence my suggestion of turning the solar controller off when the engine is running.

 

[GHA]

Not heard of amps

It means, that as i had (at that time) disabled the solar controller and the engine wasn't running, the battery monitor would show the current being drawn from the batteries. -9a.

Of course we all know what amps are - why keep barking? Can't you post nicely? :tranquillity:

So now current being used = 9A, 16A alternator output so 7A into the batteries.
Close to what the solar was putting in with a different 3.5A being used, 9.5A solar out > 6A going into batteries.

What's the alternator regulator set point voltage & voltage @ the batteries alternator only?

Given the limited data it sounds like the domestic draw could have been 5.5A more with the alternator only than with solar, solar/alternator.

Device output doesn't mean a great deal, amps into the batteries is where the action is

Solar only 9.5a
Solar and engine 10a
Engine only 25a falling to 16a after a time

 

[GHA]

If the solar controller voltage exceed the setpoint of the alternator regulator it will stop the alternator output. Therefore, if the current from the solar controller is significantly less than the current the alternator is capable of producing you're better off turning the solar controller off. .

Now we're getting somewhere

So how is the alternator going to put more amps into the batteries than solar if it can't push the battery voltage to as high a as the solar?

Doesn't matter at all how much the alternator is capable of producing, it's how much will the batteries take, if the alternator will peak at a lower voltage than the solar then the batteries will take less power from the alternator than the solar.

 

[RichardS]

The Sun is shining nicely here.

Voltage at the batteries is 14.38 and the solar controller is outputting 9.5a, 6a of which is going to the batteries for charging.

I'll start the engine......

Initial output from the alternator about 15a. After 3 or 4 minutes it's down to a barely readable current. The voltage at the batteries and the solar output remain unchanged.

Using the Victron connect software i've disabled the solar controller. Showing 12.8v at the batteries after a short wait, -9a I'll restart the engine......oh, the alternator is putting out 25a. Leave it for a while and it's down to 16a

So, the alternator did not cause the solar controller to shut down. The alternator output was substantially reduced (almost nothing) when the solar controller was on.

Solar only 9.5a
Solar and engine 10a
Engine only 25a falling to 16a after a time

That's interesting Paul. My combination of simple alternators (one 80A alternator on each engine) and 400W of solar through the Victron MPPT do not behave like that.

With mine, if I'm on solar alone and the solar has reached float voltage on it's own and I start the engines, then the engine alternators will put out just 5 amps or so.

If the solar panels alone have not reached float voltage but are still on the bulk stage they will be showing perhaps 10A going into the batteries at say 12V or 12.5V. If I then start the engines, the alternators totally take over the charging regime and both alternators will start putting 40A to 70A into the batteries which will be 80A - 140A if I'm running both engines. The alternators will then run the whole show until the battery voltages rise to over 14V and the Victron kicks into float.

Once I start the engine/s I can leave the solar panels connected or not .... it doesn't make any difference because the panels just throw in the towel as soon as the "big boys" join the party.

Richard

 

[PaulRainbow]

U still running the Victron Paul? Can't remember exactly when you showed me but it was quite forgiving and clever as we set it to work with your battery charger though that relay IIRC.

The one I tested was a Chinese thing and couldn't be adjusted that I knew of.

Yes Matt, still using the Victron controller and battery monitors. I still have it all set to automatically turn the mains charger on if the battery voltage gets low, but during the Summer it never comes on unless we have several cloudy days in a row, which we haven't had recently.

The solar panels do a great job, my total electricity consumption for the two Summer quarters last year was £15.70 That was just for boiling the kettle and some power tool re-charging.

 

[matthewriches]

So we can safely say it works! I keep contemplating fitting 2x 250w rigids on the flybridge which can be de-rigged when I go out as i have a mooring on the other side of the river to move onto in the next few weeks.

Yes Matt, still using the Victron controller and battery monitors. I still have it all set to automatically turn the mains charger on if the battery voltage gets low, but during the Summer it never comes on unless we have several cloudy days in a row, which we haven't had recently.

The solar panels do a great job, my total electricity consumption for the two Summer quarters last year was £15.70 That was just for boiling the kettle and some power tool re-charging.