System Does Not Seem to Be Set Up Correctly To Charge Fully from Panels

gridman · June 2013

I know now how to set up my system for Grid Support mode. The other mode I want to be familiar with is off-grid and that's what I'm working with right now.

For several days, I have had the grid turned off and I've been observing how the batteries are charging from just the output of the panels. What I've noticed is that during the day, the system is not fully charging the battery bank back up.

At what was probably the peak time today, I was producing 4300W. Earlier at 4:00pm, the system was only producing 380W with clear skies, full sun and no shade on the panels. I understand that was not the peak time of the day, but there has to have been more power available for charging than 380W. Therefore, I think I must not have the charging set up correctly for this mode.

Does anyone have any ideas?

vtmaps · June 2013

Re: System Does Not Seem to Be Set Up Correctly To Charge Fully from Panels

gridman wrote: »

For several days, I have had the grid turned off and I've been observing how the batteries are charging from just the output of the panels. What I've noticed is that during the day, the system is not fully charging the battery bank back up.

At what was probably the peak time today, I was producing 4300W. Earlier at 4:00pm, the system was only producing 380W with clear skies, full sun and no shade on the panels. I understand that was not the peak time of the day, but there has to have been more power available for charging than 380W. Therefore, I think I must not have the charging set up correctly for this mode.

Perhaps your batteries are charged up by 4 PM and therefore there is no where for the solar power to go. In that case you will only produce what you can use for your loads and floating the battery.

--vtMaps

gridman · June 2013

Re: System Does Not Seem to Be Set Up Correctly To Charge Fully from Panels

The reason I don't think it's fully charged is because the inverter just shows 2 out of 5 LEDS, the control panel shows 47.2v when the full charge is 53v to 54v. That's what I'm going on.

mike95490 · June 2013

Re: System Does Not Seem to Be Set Up Correctly To Charge Fully from Panels

control panel shows 47.2v

You have killed your batteries at that voltage :grr

Your PV charger should be putting 60V or so into the batteries to charge them.
What are your panel strings wired to ? Should be AT LEAST 75 or 80V to charge and EQ the batteries.

Charge those batteries - or they are toast.

NorthGuy · June 2013

Re: System Does Not Seem to Be Set Up Correctly To Charge Fully from Panels

gridman wrote: »

The reason I don't think it's fully charged is because the inverter just shows 2 out of 5 LEDS, the control panel shows 47.2v when the full charge is 53v to 54v. That's what I'm going on.

LEDs on XW6048 are not very accurate. Simply ignore them.

The voltage, besides the state of charge, depends on charging current and loads on the batteries.

At the peak, it should be somewhere 57-59V (depending on the settings). As soon as this voltage is reached, solar production will start tapering down. This is called "Absorb". When batteries are charged, controller drops voltage to 53V. This is called "Float".

Any single number doesn't tell much. You need to know current, voltage, loads, stage the charger is on.

You can use arrows on your SCC to find out "System" producton, "System" current, and battery voltage, as well as the stage - "Bulk", "Absorb" or "Float". Write all these numbers down along with loads displayed by XW6048. If you thing something is wrong, post all these numbers taken at the same time.

Blackcherry04 · June 2013

Re: System Does Not Seem to Be Set Up Correctly To Charge Fully from Panels

Sounds like you need to start charging from the Grid or your Generator. Tomorrow when you get sun, take a amp meter and see what the input is from the charge controllers. @ 47.2 your at or just below 50% dod.

Photowhit · June 2013

Re: System Does Not Seem to Be Set Up Correctly To Charge Fully from Panels

What is your array set up, number of panels in series? What is the panel vmp?

gridman · June 2013

Re: System Does Not Seem to Be Set Up Correctly To Charge Fully from Panels

Thanks for the replies.

I have only been running in this mode for 3 days. The week before that I was in Grid Support mode. I started running in Grid Support mode when I got my panels hooked into the system. The year before that I was running in grid backup mode or what used to be called on the Trace SW4024, Utility Backup mode. So hopefully, 3 days won't have harmed a year-old set of batteries.

I am charging from the grid now and when it's done, I will write down all the settings and post them. But here is the info on my solar panel bank:

32) Evergreen ES-A-210 panels

They are arranged in 8 banks of 4 panels. Each bank of 4 is connected in series. At the Midnite Solar combiner box, the 8 banks of panels are combined into 2 banks. Two DC lines go back to the house into two SCCs. Here are the panel specs:

Electrical Specifications at STC

Pmp 210
Ptc 190.0
Vmp 18.3
Imp 11.48
Voc 22.8
Isc 12.11

Just for info, my AC1 is the grid, AC2 is a generator.

My old system was SW4024 and 12 Trojan L16s and I ran in Utility Backup mode for 15 years. That's how long the inverter and batteries lasted. Or at least the inverter went out at the 15 year point and I got an entire new system, including batteries. So, I'm familiar with that mode. I'm just new to the solar aspect.

gridman · June 2013

Re: System Does Not Seem to Be Set Up Correctly To Charge Fully from Panels

I charged from the grid last night. The battery bank float voltage now is 53.8V, which is probably the temperature corrected value of 54.0V for float. I'm currently back in Grid Support mode until I figure this out.

To answer an earlier question, if I measure the voltage on the incoming DC lines from each bank of PV panels, they are both 84.5V (within a few tenths of each other).

Here are the menu settings for the XW6048 and the MPPT60 charge controllers. I am only listing one charge controller because they both have the same settings, just different device numbers.

XW6048 - Setup
Advanced Settings
Meters
Inverter Enabled
Search Mode Disabled
Grid Support Enabled
Charger Enabled
Force Chg Disabled
Equalize Disabled
Mode Operating

XW6048 – Inverter
Low Batt Cut Out 46V
LBCO Delay 10s
High Batt Cut Out 70V
Search Watts 50W
Search Delay 2s

XW6048 – Charger
Batt Type Flooded
Batt Capacity 840Ah
Max Chg Rate 100%
Charge Cycle 2StgNoFloat
Default Batt Temp Warm
Recharge Volts 50V
Absorb Time 180min
ChgBlockStart 12:00AM
ChgBlockStop 12:00AM

XW6048 – Custom Settings
Eqlz support Enabled
Eqlz Voltage 64.0V
Bulk Voltage 57.6V
Absorb Voltage 57.6V
Float Voltage 54.0V
Batt Temp Comp 108mV/C

XW6048 – AC
AC Priority AC1
AC1 Breaker 60A
AC1 Lo Volt 106V
AC1 Hi Volt 132V
AC1 Lo Freq 55Hz
AC1 Hi Freq 65Hz
AC2 Breaker 60A
AC2 Lo Volt 106V
AC2 Hi Volt 132V
AC2 Lo Freq 55Hz
AC2 Hi Freq 65Hz

XW6048 – Grid
Grid Supp Volts 64V
Sell Disabled
Max Sell Amps 27A
Load Shave Disabled
Load Shave Amps 48A
LoadShaveStart 12:00AM
LoadShaveStop 12:00AM

XW6048 – Gen
GenSupp Mode Disabled
GenSupp Amps 48.0A

XW6048 – Aux
Manual Aux ManualOff
Active Lvl Active High

XW6048 – Multi
Dev Name XW6048
Dev Number 00
Invtr Mode SplitPhMstr
Connections

XW6048 – Connections
DCConn HouseBatter1
ACOut ACLoad1
AC1 Grid1
AC2 Gen1

XW6048 – Adv Features
RPO Disabled
Power Save Distabled
Sell Dly 40s Disabled
GenSupp Plus Disabled

MPPT60 01 Setup
Advanced Settings
Meters
Force Chg
Equalize Disabled
Mode Operating

MPPT60 – Charger Settings
BattType Flooded
Batt Capacity 840Ah
Max Chg Rate 100%
Charge Cycle 3Stage
Recharge Volts 40V
Default Batt Temp Warm
Batt Voltage 48.0V

MPPT60 – Input Settings
MPPT Auto Track Enabled
MPPT Ref Volts 63.5V

BB. · June 2013

Re: System Does Not Seem to Be Set Up Correctly To Charge Fully from Panels

Which L-16 batteries do you have? The Trojan L-16 RE-A recommend 2.35 to 2.45 volt volts which could be upwards of 58.8 volts at 77F/25C.

You probably need to play around with the voltages and absorb timing a bit (probably higher voltage, especially for the solar charging which is time limited). And for the inverter/charger when operating from generator.

Have you been measuring specific gravity yet?

-Bill

gridman · June 2013

Re: System Does Not Seem to Be Set Up Correctly To Charge Fully from Panels

I have 16 Trojan L16 PA-C batteries connected to give 48V and 840Ah.

When I set the system up, I used the default values, set the battery type to Flooded, the capacity to 840Ah. Then set up the settings for Grid Support mode. So, when I wanted to run on solar completely, I just flipped off the grid breaker. But as I stated earlier, the settings are right for charging completely for solar.

If I change the solar charging settings, I would need some advice, since I haven't messed with that before.

Yes, I check Specific Gravity and have Equalized when I needed to. I just followed the equalize recommendations from Trojan, which I don't remember right now, I have them written down.

gridman · July 2013

Re: System Does Not Seem to Be Set Up Correctly To Charge Fully from Panels

Over the past 45 days, I watched and figured out what was going on here.

During the day with full sun, one SCC would be putting out 20w or so and the second would be putting out 1000w or the majority of the power that was needed. No matter what conditions, the first SCC would only put out an extremely small wattage.

I checked the two lines coming into the house, they both registered the same voltage, so the problem had to be with the first SCC.

A couple weeks ago, I got the bright idea to shut off the breaker coming into the first SCC from that bank of panels. I then turned it immediately back on and when it came back on line, the power produced from each SCC was close to the same.

Bottom line: That one SCC needed to be reset. Now, the whole system works great. Where before I was only getting half the power that my system could produce, now I get the full amount.

Happy days are here again.

BB. · July 2013

Re: System Does Not Seem to Be Set Up Correctly To Charge Fully from Panels

Glad you found the problem... We tend to forget the first rule of debugging a computer based system--Reboot and see if the problem "goes away".

On the other hand, collecting some debugging data before rebooting (and writing it down) can be helpful too (i.e., it has done the same thing X times before and here is what I keep seeing).

-Bill

inetdog · July 2013

Re: System Does Not Seem to Be Set Up Correctly To Charge Fully from Panels

gridman wrote: »

A couple weeks ago, I got the bright idea to shut off the breaker coming into the first SCC from that bank of panels. I then turned it immediately back on and when it came back on line, the power produced from each SCC was close to the same.

Bottom line: That one SCC needed to be reset. Now, the whole system works great. Where before I was only getting half the power that my system could produce, now I get the full amount.

Happy days are here again.

Happy indeed!

One thing to keep in mind is that most CCs require that the battery connection be made before the panel connection. If at any time the reverse happens, the CC could get into a state where it was behaving badly and needed a reset by applying power in the correct order.
It is interesting though that just having the panel voltage go to near zero at night did not allow the CC to reset.

Cariboocoot · July 2013

Re: System Does Not Seem to Be Set Up Correctly To Charge Fully from Panels

inetdog wrote: »

Happy indeed!

One thing to keep in mind is that most CCs require that the battery connection be made before the panel connection. If at any time the reverse happens, the CC could get into a state where it was behaving badly and needed a reset by applying power in the correct order.

Ooh! Don't say that 'cause someone will come along and tell you how they read right in the manual that it doesn't matter! Those of us who actually deal with the things know otherwise.

It is interesting though that just having the panel voltage go to near zero at night did not allow the CC to reset.

As long as it is connected to the batteries the charge controller will remain in its confused state because it is being powered. See your first statement.

inetdog · July 2013

Re: System Does Not Seem to Be Set Up Correctly To Charge Fully from Panels

Cariboocoot wrote: »

As long as it is connected to the batteries the charge controller will remain in its confused state because it is being powered. See your first statement.

OK. Now see gridman's statement that all he did was cycle the panel side breaker without ever removing the battery connection. How did that do a reset? And if it did, how was that different from the panels "turning off" at night, other than the timing?

Cariboocoot · July 2013

Re: System Does Not Seem to Be Set Up Correctly To Charge Fully from Panels

inetdog wrote: »

OK. Now see gridman's statement that all he did was cycle the panel side breaker without ever removing the battery connection. How did that do a reset? And if it did, how was that different from the panels "turning off" at night, other than the timing?

First, I have to admit I'm not clear as to how his system is wired, what controllers he's using, and mostly which breaker he flipped where.

Shutting off the panels on a the controller outputting low would not reset a confused controller, but it might change the "Last Voc" reading - a fun little number for MPPT controllers that is largely ignored. In essence "waking up" a controller that was partially asleep; stuck in Float mode for example and never realizing a new day had dawned and it was time to get down to the business of charging.

Normally the controller would expect low Voltage on input to indicate night, and then get a jolt of Voc from the panels which tells it its daytime again. If it can't pull current, it will go back to sleep. If the second controller is putting out more the current from the first can be low enough to keep sinking it to sleep.

Again, generalized statements about MPPT function. But ones which give a clue as to why MidNite Classics now have a "Follow Me" function which enables them to work so well in multiples.

inetdog · July 2013

Re: System Does Not Seem to Be Set Up Correctly To Charge Fully from Panels

Cariboocoot wrote: »

Normally the controller would expect low Voltage on input to indicate night, and then get a jolt of Voc from the panels which tells it its daytime again. If it can't pull current, it will go back to sleep. If the second controller is putting out more the current from the first can be low enough to keep sinking it to sleep.

As long as the two CCs are connected to different panel arrays, I can't see how the fact that the second CC is holding the battery-side voltage high could have any effect on the waking up of the first CC.
But strange things can happen in both hardware and software. :-)

Cariboocoot · July 2013

Re: System Does Not Seem to Be Set Up Correctly To Charge Fully from Panels

inetdog wrote: »

As long as the two CCs are connected to different panel arrays, I can't see how the fact that the second CC is holding the battery-side voltage high could have any effect on the waking up of the first CC.
But strange things can happen in both hardware and software. :-)

This is certainly true.

Remember I don't engineer these things, I reverse-engineer these things.
And hit them with large hammers when they fail to operate properly.

inetdog · July 2013

Re: System Does Not Seem to Be Set Up Correctly To Charge Fully from Panels

Cariboocoot wrote: »

This is certainly true.

Remember I don't engineer these things, I reverse-engineer these things.
And hit them with large hammers when they fail to operate properly.

As the old saying goes, "If at first you don't succeed, get a bigger hammer."

YehoshuaAgapao · July 2013

Re: System Does Not Seem to Be Set Up Correctly To Charge Fully from Panels

NorthGuy wrote: »

LEDs on XW6048 are not very accurate. Simply ignore them.

The voltage, besides the state of charge, depends on charging current and loads on the batteries.

At the peak, it should be somewhere 57-59V (depending on the settings). As soon as this voltage is reached, solar production will start tapering down. This is called "Absorb". When batteries are charged, controller drops voltage to 53V. This is called "Float".

Any single number doesn't tell much. You need to know current, voltage, loads, stage the charger is on.

You can use arrows on your SCC to find out "System" producton, "System" current, and battery voltage, as well as the stage - "Bulk", "Absorb" or "Float". Write all these numbers down along with loads displayed by XW6048. If you thing something is wrong, post all these numbers taken at the same time.

On my system, near the end of bulk and absorption have 5 LEDs lighted while 4LEDs light during float. Surrette has a lower float voltage than default, 52.5, so that may be why it is only 4.

What is your grid support volts set to? If you want to use enhanced interactive mode (charge controllers control grid support voltage), set grid support volts to be equal to your equalize volts.

How much voltage is your PV putting out? 210W panels may be less than 60 cells and may prefer 4 to a string rather than 3. If your PV isn't putting out enough voltage, your charge controllers will not charge the batteries because they can only step down voltage, not step up. My 240W panels are driven down to as low as 72V in the Arizona heat even though Vmp for 3 in series is 89.7V @ STC and 81.9V @ NOCT.

System Does Not Seem to Be Set Up Correctly To Charge Fully from Panels

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