Is the bulk,absorb,float intelligent or only procedure?

[Tinman]

Last night I connected to utility power because we ran some things that would have depleted battery power. I turned the mode off for the Classic and turned on the utility power. I then turned on the converter function of our Invert/charger with a draw limit of 25 amps from the 50 amp utility service. The inverter is then off by ATS function. I verified that.

Since the batteries weren't yet full charged, the converter went through bulk very quickly, then absorb until reaching float stage where it then stayed until this morning. With full sun and no longer needing utility power, I turned that off and turned the mode back in for the Classic. It started out in bulk and quickly went to absorb. There was no power draw at the time. After nearly two hours it is still at absorb. I set the minimum absorb time to 15 min but that was over an hour ago.

Shouldn't the Classic see fully charged batteries and take that into account and adjust the absorb cycle appropriately and go to float sooner? Seems to reason that if it doesn't then what whould be the purpose of a minimum time for absorb mode?

I'm asking because my inverter/charger does cycle through bulk,absorb depending on the charge of the batteries. For example, if I got through an hour of absorb on the Classic and then had to connect to utility power for some reason and turned the mode the off, the converter didn't run through a whole maximum absorb cycle, it goes to float faster which is what should happen.

Again, when I turned the mode to on, I know the batteries were charged and also know there was no power draw (inverter was off of course-ATS and no DC equipment was powered on)

[Tinman]

Ok, the Classic finally went to float but not before the maximum duration for absorb. That doesn't seem right to me since the min time setting should be there to allow the cessation of absorb between that and maximum depending on the charge in the batteries.

[boB]

Ok, the Classic finally went to float but not before the maximum duration for absorb. That doesn't seem right to me since the min time setting should be there to allow the cessation of absorb between that and maximum depending on the charge in the batteries.

OK, I will check on this.  In your situation, yes, the Classic should keep counting if it sees a secondary source keeping the battery at or above the absorb set point.   But that would have to be the temperature compensated voltage set point of course.  I remember going through
this but can't remember off the top of my head if I did what you are talking about or not.   There may have been a good reason not to but I will look at my notes and see.

Thanks for the input !

boB

[Tinman]

Ok, the Classic finally went to float but not before the maximum duration for absorb. That doesn't seem right to me since the min time setting should be there to allow the cessation of absorb between that and maximum depending on the charge in the batteries.

OK, I will check on this.  In your situation, yes, the Classic should keep counting if it sees a secondary source keeping the battery at or above the absorb set point.   But that would have to be the temperature compensated voltage set point of course.  I remember going through
this but can't remember off the top of my head if I did what you are talking about or not.   There may have been a good reason not to but I will look at my notes and see.

Thanks for the input !

boB

Is it possible that unless the Classic mode is set to on that it wouldn't track another charging source? My inverter/charger will not charge if it detects another charging source, therefore I turn the Classic mode to off, turning it on only after insuring the converter function of the inverter/charger is turned off. This situation doesn't happen after the sun goes down since the Classic isn't providing charge then.

I have yet to test out if the Classic will track the other charging source but I'll see in the morning since we're going to run the high amp draw again tonight but I've left the Classic mode in the "on" selection. At first sun, the Classic should start sending charge from the tracker array. Since the batteries will be at float from the converter, hopefully the Classic will get there pronto. If it does, then that will support tracking another charging source only when mode is on. If it doesn't, then the original question remains.

I'll post the results first thing AM.

[boB]

I have yet to test out if the Classic will track the other charging source but I'll see in the morning since we're going to run the high amp draw again tonight but I've left the Classic mode in the "on" selection. At first sun, the Classic should start sending charge from the tracker array. Since the batteries will be at float from the converter, hopefully the Classic will get there pronto. If it does, then that will support tracking another charging source only when mode is on. If it doesn't, then the original question remains.

I'll post the results first thing AM.

If the Classic wakes up in the morning and your other charging source has already gone to float, then the Classic will still start in Bulk/Absorb and stay in Absorb for at least the minimum programmed Absorb time.  You could set that minimum Absorb time to say, 5 minutes,  and  since the batteries were already charged, "ideally" the Classic should get to absorb quickly and only stay in Absorb  for that 5 minutes or so.
The reason it won't do that though is because when the Classic woke up, it will immediately start the Bulk/Absorb counting and since there is a very small amount of charging power at first dawn, it will take quite a bit longer than 5 minutes and who knows how long it will take to get to Absorb ?  This can eventually be dealt with in software though.

As far as tracking other chargers, the Classic doesn't know what the other chargers are doing.  All it knows is that it is a new day (solar) and it is starting a new Bulk/Absorb cycle.  If your other charger is on-line and keeping the battery at or above the Absorb voltage set point, then it
shouldn't even turn on because the battery is already full as far as the Classic is concerned.

Soon, with multiple Classics networked together, they will know what the others are doing and at some time, all the other chargers and inverters may very well be able to tell the Classics what they are doing too.  It would be real nice if THEY could also know what the Classics are doing, too.

boB

[Tinman]

I have yet to test out if the Classic will track the other charging source but I'll see in the morning since we're going to run the high amp draw again tonight but I've left the Classic mode in the "on" selection. At first sun, the Classic should start sending charge from the tracker array. Since the batteries will be at float from the converter, hopefully the Classic will get there pronto. If it does, then that will support tracking another charging source only when mode is on. If it doesn't, then the original question remains.

I'll post the results first thing AM.

If the Classic wakes up in the morning and your other charging source has already gone to float, then the Classic will still start in Bulk/Absorb and stay in Absorb for at least the minimum programmed Absorb time.  You could set that minimum Absorb time to say, 5 minutes,  and  since the batteries were already charged, "ideally" the Classic should get to absorb quickly and only stay in Absorb  for that 5 minutes or so.
The reason it won't do that though is because when the Classic woke up, it will immediately start the Bulk/Absorb counting and since there is a very small amount of charging power at first dawn, it will take quite a bit longer than 5 minutes and who knows how long it will take to get to Absorb ?  This can eventually be dealt with in software though.

As far as tracking other chargers, the Classic doesn't know what the other chargers are doing.  All it knows is that it is a new day (solar) and it is starting a new Bulk/Absorb cycle.  If your other charger is on-line and keeping the battery at or above the Absorb voltage set point, then it
shouldn't even turn on because the battery is already full as far as the Classic is concerned.

Soon, with multiple Classics networked together, they will know what the others are doing and at some time, all the other chargers and inverters may very well be able to tell the Classics what they are doing too.  It would be real nice if THEY could also know what the Classics are doing, too.

boB

My panels are on a 2 axis tracker and the sun comes up over some hills so it is about 15-20 minutes past dawn. As soon as the sun hits the panels they are producing nearly 70% according to the Classic, I'm taking its word for that.

I set the min absorb time to 5 minutes after an hour. Batteries were in float at 14 volts, higher than usual because of relatively low temps here. Checked and verified the Midnight temp sensor readings so all is good after my alternative sensor mounting method.

Classic went through bulk in about 2 minutes and then into absorb where it took battery voltage to 14.9 for an hour. That is when I set the min time to 5 min.  No DC loads during that time. Then it went to float at 13.9, consistent with temp correction here.

Turned off the converter and Classic retains float mode. I guess that is okay once in a while but I can't help thinking that this (holding absorb after starting from float) would be any good for the batteries if it became a regular thing. I don't know how long it would have stayed in absorb had I not changed the min setting but since yesterday it was the full max time who knows? I'm not going to experiment since my batteries are new and the most costly of his whole solar deal.

Maybe consider adding some info on this in FAQs or the manual. Lots of people like me might not know about setting a minimum absorb time and such. Having another charging source is often the case, especially in motor homes and rvs . Maybe not the biggest market for midnight but easy does sell.

[boB]

Maybe consider adding some info on this in FAQs or the manual. Lots of people like me might not know about setting a minimum absorb time and such. Having another charging source is often the case, especially in motor homes and rvs . Maybe not the biggest market for midnight but easy does sell.

OK, got Chya !!   We can do this.

Also, if you want the Classic to return to Bulk/Absorb within the same day, you can set the Re-Bulk Voltage to a value which will cause it so Re-bulk when the battery voltage goes below that value for a couple of minutes.

boB

[Tinman]

JFYI, after the full day of sun here and with the Classic sitting on float I turned on the charger function of the inverter. It immediately went to float as well, no lagging whatsoever.

It seems that once batteries are at float, another other charger including the Classic should also go to float, maybe not instantly (although my charger sure did) but surely it shouldn't take an hour unless the set voltages are quite different (they are not).

As we head to our bad weather season but with some sun, ideally I'd send a full charge to the batteries from another charging source, beit genset or even utility. Then if I had sun, I would use that power for day use or longer depending on sunshine forecasts.

What would be an example charge setting scenario for the Classic to avoid over charging where another charger takes the batteries to float before full sun?

[boB]

What would be an example charge setting scenario for the Classic to avoid over charging where another charger takes the batteries to float before full sun?

Well, not 100% related to that question but I think that an inverter has an advantage because it has enough power (the grid) to know almost immediately
that the batteries are full because it can give enough power to the batteries right away and see the voltage rise...  Unless there is some other large
DC load on the batteries.  The Magnum inverters' chargers already do this.

So the Classic can't quite do this upon first wakeup.  You said that your modules are in full sun and you get full power in 20 minutes ?
That's pretty darn quick !!  I would say there's nothing wrong with the Classic giving you and extra few minutes of Absorb charge to
the batteries.  It's undercharging that is really the killer.  Overcharging  (longer Absorb time) just uses water up faster so you have to
watch the level more often if they are flooded.

But then again, the Classic could watch the battery voltage to see if it got  a charge overnight from an external source OR
get a signal from the other source to tell it that it is charged or better yet. a battery monitor that knows the SOC of the battery !
That's something that's coming up anyway to connect to the network although other monitors could communicate that info
to the Classic on our network.

We are hoping that modbus becomes more of a standard  which can communicate information to many different inverters and controllers to
take care of all this.  It's just programming, right ??!!?

boB

[Tinman]

Okay, thanks for that. My biggest concern was overcharging.

On the panel performance:

I sit west of a shallow valley. The sun rises over that before hitting the panels, somewhere around 15 minutes to 20 I think. Within 20 minutes of sun on the panels the classic tells me my panels are producing 220 watts per series set (ran them independently to check each series set). That is from 300 watts (3 100 watt panels). 440 watts from 600, that is where the 70% approx comes from. Again, according to the Classic.

By 10 am I routinely see 270 and it heads to 285 per set (series array) for 540 and 570 as respective totals.

If we had a heavy fog, when it burns off I see 640 watts total or 320 per series array.

I'm using Grape monocrystalline panels and getting 300 or more from each series array isn't unusual. That isn't all day but it is almost always over 280 for most of the day. I've found the Grape panels to be very well made, produce what they claim and are very strong even though they are very light (16 pounds per panel). You call them, someone answers.

My panel tracker is set to adjust every 20 minutes and runs from its own small any battery charged by a 20 watt panel which keeps that battery between 12.9 and 13.8.