Local App - SNAFU :-|

[SolarMusher]

Funny how often the simple things like Whr in VS Whr each day out is overlooked

Kurt, Whr imbalance is only the result of what we are talking about and not the source... 
960W PV charging 240Ah/24V battery is a well balanced system, but two important items are missing here, battery monitor and charger. No matter from where we're looking at his problem, source or result, it is what it is.
Erik

[offgridQLD]

Yes sorry I agree .

Though  It doesn't sound like his PV its performing as a 960w charger in his location. Weather conditions and potentially how the PV has been installed determining this.

He already has a classic charge controller so he knows whats going into the battery every day and he mentioned before that he had a consistent 375w load each day. So it shouldn't be to hard to work out where he stands each day to determine if he has a battery issue or simply a imbalance input vs output. (That's what I mean by its often overlooked)

But yes i agree if he is in a location where 960w of pv isn't enough to sustain that load certain times of a year. Then another form of charging is mandatory during those times. If that's additional pv, generator, wind turbine is up to him.


Kurt

[dbcollen]

Well, lets do the math.... 375w x 24hrs = 9kwh/day load. 960w solar best case scenario lets say he gets the full 960w and has 5 sun hours/day = 4.8kwh/day, that is with no derating on the panels, no charge efficiency or inverter efficiency derating, it is no wonder why it won't keep up, he is pulling at least twice the power from the batteries than he is putting back in. Not the fault of the Classic, the batteries or the solar panels, purely a poorly designed system for the load.

[offgridQLD]

Sorry I think mistakenly I picked up on there error in quoting the units.

I try to make a habit of quoting consumption over time correctly as (whr and KWH) and was going to mention it earlier in this thread when I noticed consumption over time was being presented as just (watts) its misleading. Ends up even though I picked up on it I was fooled by it .

I think they were suppose to write whrs so 375whr 0.375kwh per 24hrs. Hopefully they will chime in and confirm this.

So 960w of PV should be able to cover this 375whr load easy as long as the panels are getting sun on them.

Kurt

[dgd]

So 960w of PV should be able to cover this 375whr load easy as long as the panels are getting sun on them.

Kurt

..and therein lies the problem, he isn't getting anywhere near 975w per hour for even a few hours per day. His immediate problem is that he is starving (to death) those batteries. I wonder if he has got that genny yet 

dgd

[dbcollen]

I wonder if he has got that genny yet 

dgd

Or just set his classic to Manual EQ at 2.6 volts per cell and about 10 hours to start, and repeat that treatment till the sp. grav. is up to 1.260- 1.280.

The ONLY real way to ACCURATELY tell state of charge of a lead acid battery is a hydrometer, and charge parameters should be set to get the batteries full according to the hydrometer.

[Lya72]

Hi All,

First of all, a lot of thanks for your numerous inputs. I will have to read them in detail and understand them !!


To be precise, actually my load is just 15.5W/hour so that's 375 watts  needed a day.
My first objective is a load up to 60W/hour, so that's          1 440 watts needed a day.


With the latest firmware, parameters are default parameters ( Varimax isn't documented is the manual and I have difficulties to understand what I found in the forum).
(I will have to speak in French with Erik)


Equalize is a state of charge that i never saw, the little time I was facing my Classic. Humm, if the logs could say the state of charge  :-(((((

Also I don't understand how Equalize comes ON.

With my little known, and in simple words :

BULK :  The CLASSIC pushs all the power from the panels to the batteries

ABSORB : When the Batteries hits a voltage point (for me, 29.2V, temperature compensated value), The Classic diminues the current going into the batteries. The objective is to complete the charge.

FLOAT : After a certain time in Absorb (for me Min : 03:45 - Max : 05:00), the Classic diminues the Voltage (for me, 27.6 compensated) and the current. This stage is rarely been seen. The objective is to maintain the battery charged.

EQUALIZE : It's after FLOAT.  In the documentation, there is a redirection problem : "refer to page Error! Bookmark not defined. for details on setting up EQ."


To follow...

Yann

[SolarMusher]

Yann,
BULK :  The CLASSIC pushs all the power from the panels to the batteries: Yes

ABSORB : When the Batteries hits a voltage point (for me, 29.2V, temperature compensated value), The Classic diminues the current going into the batteries. The objective is to complete the charge: 29.2V seems to be a good Absorb voltage for these batteries, but better check with you battery manufacturer/dealer.
FLOAT : After a certain time in Absorb (for me Min : 03:45 - Max : 05:00), the Classic diminues the Voltage (for me, 27.6 compensated) and the current. This stage is rarely been seen. The objective is to maintain the battery charged: Your Absorb time is too long, I would suggest Min 30mn/ Max 2hr30. Your float time seems too high to me, would suggest 26.8V but better check with you battery manufacturer/dealer.

To Equalize, you'll need first to set EQ voltage (31/32V) in the Classic CHARGE=> Volt menu and time in CHARGE=>ChgTime.
That's where you can set all Absorb, Float, and Eq time and voltage.
Then go to CHARGE=>EQ and press the upper arrow to start EQ or press lower arrow to stop it at any time.
You could set it to start automatically, but this is not very usefull because it's not a true EQ as it wouldn't start after a full charge (float) when batteries are really full  .
You have to understand roughly that Absorb time=Bulk time but it could be too long or too short for a given battery, so time limits Min/Max were added to be more accurate. Bob improved it and added Varimax to limit bulk and to be even more accurate (to not overcharge) when cloudly or in case bulk time would be too long because of specific reasons, ex: exposure, shadow, etc...
In the last firmware, you can use/set varimax or not. From what I understand, Absorb Time, say 2hrs with varimax disabled will result in a fixed 2hrs absorb time length (someone wil correct me if I'm wrong  ), With varimax enable, say Mintime 30mn, Maxtime 2hrs (5A current), Bulk time counter will count only when a 5A bulk current is available and the Classic will hold Absorb somewhere in a 30mn to 2hrs range.
Another Way to end Absorb is to set your Classic EA (end current) function to 1 or 2% of you battery bank, somewhere between 3A to 4.8A for you. You will have to take in account and add all of your DC loads amps (if steady) to not overcharge and set your absorb time longer, say 3hrs (with Varimax disabled) in order to have EA to end this Absorb.

To Equalize with your Classic, you'd need your array to produce enough energy to hold 31/32V for a given time, say 4hrs or more.
But you DON'T HAVE ENOUGH PV POWER TO DO THAT AT THIS TIME, because of a low PV production/exposure!
1.180 is below 50% SOC and your batteries are slowly but surely dying.
You'll have to follow an emergency process to save your batteries using a generator or grid with an inverter/charger or a simple 25A/24V charger (better than nothing, ex: Iota DLS2725). Disconnect all your DC loads. Start the generator or grid and let the Gen/charger run until your Specific Gravity rise to 1.265/75 (100% charged), it could take several hours, you will have to check water level and temperature and stop this charge when the temperature will approache 50°C to let them cool for a while.
You'll need to buy later (quickly) a battery monitor (with shunt) to know exactly what's your batteries state of charge, amps in and out.
But charge and EQ at first! And improve you PV exposure as soon as you can...
Erik

[dbcollen]

To be precise, actually my load is just 15.5W/hour so that's 375 watts  needed a day.
My first objective is a load up to 60W/hour, so that's          1 440 watts needed a day.


With the latest firmware, parameters are default parameters
Equalize is a state of charge that i never saw, the little time I was facing my Classic. Humm, if the logs could say the state of charge  :-(((((

Also I don't understand how Equalize comes ON.

We really need to work on terms, watts are an instantanious measurement, so you can't have "1440 watts per day"  what you require is 1440 watt hours per day. I understand the language barrier, it is just difficult to give proper advice if we don't get the correct info.

Default parameters are very conservative so they will not damage AGM or Gel Cells.  It is IMPOSSIBLE for the logs to ACCURATELY show state of charge. Any electronic component that tells you state of charge IS lying to you. It is not the fault of the device, it is just the fact there is no way to keep track of the variables of charge/discharge rate, temperature, Peukerts equasion, battery age...... The list of variables you would need to track is quite long. THE ONLY WAY TO ACCURATELY CHECK STATE OF CHARGE IS WITH A HYDROMETER.

If you have local status panel running on a computer you can set Eq parameters on the "Config-basic" tab

[SolarMusher]

If you have local status panel running on a computer you can set Eq parameters on the "Config-basic" tab

Does this work      ?
Erik

[SolarMusher]

Hi db,
Excuse me I couldn't resist  ,
1.44kw/hr daily load would need another battery string and roughly 1.5kw PV (with good exposure) to charge a 480Ah battery bank and a good charger with batt monitor/hydrometer for year round use. It's gonna be a long road...
Erik

[TomW]

dbcollen is right. Folks really need to use proper terms.

Watts is an instantaneous energy value

Kilo Watts or watt hours is energy over time.

This causes confusion on nearly every forum I frequent.

Just look at this thread for a prime example. Even after it has been pointed out motre than once.

Not to pick on anyone but there is a big difference between the two terms.

Just from here.

Carry on.

Tom

[Lya72]

Hi Tom,


I learnt English by reading Internet, because after the school, my known was just things like "The plane is behind the cloud". Things that you use every day !!!

For Electricity, it's the same.

So, don't hesitate to correct my mistakes by giving the correct spelling on my values, so I will learn !

Also, to be sure to be understood, I put a lot of images, it's international !


@db,
My need for the Logs was to include the charge state (Bulk, Absorb, Float, Equalize) in each record.
Maybe, I should say Charge  Step ??

If I understand you, no electronics component is able to give the battery state of charge, even the Battery monitor, recommanded by others ??

Are you OK that the Hydrometer is the thing that' give the Acid density (SG in English ?)? If Yes, I'm also using this (see the photo enclosed above)


@ Erik,
This afternoon, after the Float step, I plugged my charger 24V/10Ah. It's now running for two hours, putting 4 Amps. in the batteries.

Yes, it isn't a 24V/25Ah but it's the model that was in my garage.

And now, it isn't time to buy a biggest model, because money has gone in the Valentine's gift !

Yann

[Westbranch]

Hi Yann, I will try to answer some of your questions.

My need for the Logs was to include the charge state (Bulk, Absorb, Float, Equalize) in each record.
Maybe, I should say Charge  Step ?? YES that will work

If I understand you, no electronics component is able to give the battery state of charge, even the Battery monitor, recommanded by others ??  The battery monitor will tell you how many Amps have been replaced into your battery at the end of a Charge cycle and then it will show how many Amps have been removed.  It does not show the SOC of the battery

Are you OK that the Hydrometer is the thing that' give the Acid density (SG in English ?)? If Yes, I'm also using this (see the photo enclosed above)
  YES, SG means Specific Graviity, 

@ Erik,
This afternoon, after the Float step, I plugged my charger 24V/10Ah. It's now running for two hours, putting 4 Amps. in the batteries.

Yes, it isn't a 24V/25Ah but it's the model that was in my garage.

The charger should be used first, or over night to keep the battery topped up,  you really do need a good 3 stage charger to do a proper EQ as the process is long , much longer than the time the sun shines in this case.  The EQ is to 'over charge' the battery and remove any sulphate deposits on the battery plates. That is why it heats up the battery and you MUST NOT let the battery get too HOT or it can be damaged.   

What are the details on  your small charger?.  Is it a 3 or 4 stage charger or just 4 amp trickle charger (only 1 or no setting).

Check to see if you can get a Midnite BCM Battery Capacity meter http://www.midnitesolar.com/pdfs/MNBCM12.13a.pdf  it will visually tell you if the battery has been fully charged recently and the approximate SOC

[dgd]

This afternoon, after the Float step, I plugged my charger 24V/10Ah. It's now running for two hours, putting 4 Amps. in the batteries.

Yes, it isn't a 24V/25Ah but it's the model that was in my garage.

And now, it isn't time to buy a biggest model, because money has gone in the Valentine's gift !

Yann

So the PVs provided enough power today to complete an ABSORB cycle and go into FLOAT?   Did you check the acid SG after this and the batteries are now ok?  I would suggest you still need to do an EQUALISE cycle.

dgd