Author Topic: Power usage per day  (Read 450 times)

asdex

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Power usage per day
« on: July 20, 2019, 10:59:31 PM »
Hi, I can't figure out the best way to find our power usage per day on average.
I have a classic and wbjr and also get values from the app.
I have attached a screenshot of the daily app page.
I want to get a daily usage to size a new bank of batteries or maybe look at capacitors.
Thanks
6 x JA Solar 320w solar panels, 2 x Solarex MSX-83, 3 x Helios H750 panels, 4 x Suntellite 260w.
4 x 6v Crown CR430 batteries (24v), Classic and WBJr, FX2024 inverter and Mate, Trimetric monitor, Soma 1000 wind generator (to install), Alibaba solar pump. Air X 400w wind generator.

ClassicCrazy

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Re: Power usage per day
« Reply #1 on: July 20, 2019, 11:42:43 PM »
Get Grahams android Classic Monitoring app - it will give you more information.
Not sure where you are but here in the overcast midwest I greatly oversize my PV to be able to keep up with my baseline power usage even on cloudy days because it cuts down on generator run time.
Sizing the batteries really depends on not only your power usage but also on how many days you want to have in reserve for low light days.  Also it depends on the type of batteries - for example if you want lead acid to last a long time they are sized to use 20% of the capacity .

It would be hard for me to find an average power use because when it is sunny I try to run as many loads as I can . The baseline is what I would use when I am being conservative with power and that changes according to the season too.

Larry
system one
Classic 150 , 5s4p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system two
Classic 150 ,5s 135 watt Kyocero , 16s Calb 100AH LiFePO4 , Outback VFX 3648 inverter
system three
Midnite KID MPPT 24 DC in to  12 volt AGM batterie

asdex

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Re: Power usage per day
« Reply #2 on: July 21, 2019, 01:06:27 AM »
Hi, thanks for your reply. Yes, I have the app and that is where the screenshot is from. Just not sure if the figures show daily kWh usage. We would want three days coverage for bad weather.
Cheers,
6 x JA Solar 320w solar panels, 2 x Solarex MSX-83, 3 x Helios H750 panels, 4 x Suntellite 260w.
4 x 6v Crown CR430 batteries (24v), Classic and WBJr, FX2024 inverter and Mate, Trimetric monitor, Soma 1000 wind generator (to install), Alibaba solar pump. Air X 400w wind generator.

ClassicCrazy

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Re: Power usage per day
« Reply #3 on: July 21, 2019, 01:01:00 PM »
The top figure is basically your daily KWh usage - that is what it takes to fill up your batteries from whatever you used from the day before and what you are using that day.  So that is the figure I would use.
Oh - yeah I didn't recognize that screen from Grahams app !
If you use Mymidnite you can look at the graph where it shows kwh from full and that would help you know exactly how much you drained out of your batteries each night.

Larry
system one
Classic 150 , 5s4p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system two
Classic 150 ,5s 135 watt Kyocero , 16s Calb 100AH LiFePO4 , Outback VFX 3648 inverter
system three
Midnite KID MPPT 24 DC in to  12 volt AGM batterie

Vic

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Re: Power usage per day
« Reply #4 on: July 21, 2019, 02:49:29 PM »
Hi, I can't figure out the best way to find our power usage per day on average.
I have a classic and wbjr and also get values from the app.
I have attached a screenshot of the daily app page.
I want to get a daily usage to size a new bank of batteries or maybe look at capacitors.
Thanks

Hi Al,

Am not familiar with Graham's App,   but,  the Classic MNGP,   and the MidNite App  (LA)   both show the amount of power and Ah produced by the Classic/s.   This is the power used by the battery charging,   and the AC loads on the system inverter.

In the morning,   the Classic and the MN App show the number of AH removed from the battery bank.   The "usage"  will depend on your definition of that term.   But,  if the battery was fully-charged in the previous day's charge cycle,  then,  this Net Ah value should be fairly accurate,  as to the amount of power (Ah) removed,   BUT,   the Rate at which this current was removed can have a large effect on the Remaining Capacity of the battery,   and the Classic/WbJr does not track this Rate.

But for determining if your battery bank is appropriately-sized for your use patterns,   then,  the Net Ah value in the early morning,   and the Remaining Capacity  should be a good guide.   Just to watch that the battery was essentially fully-charged on the previous day,  AND,   watch that the Net Ah on that previous day was very close to zero,   at (or near) the end of significant charging  --  ie,  late in your Solar charging day.   The accuracy of this Net Ah value,  shown by the LA,   is affected by the relative Float voltage value,   battery Efficiency setting,   etc.

If necessary,   one could make the trek to the location of the Classic,   and reset the Net Ah value to zero,   manually,   on the MNGP  --  the MN LA,   appears to have NO provision for stetting this value to zero (and expect that Graham's App does not either ...   dunno).

FWIW,  Vic
Off Grid - Two systems -- 4 SW+ 5548s, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 3X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  Thanks MN for Great Products/Service/Support!

asdex

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Re: Power usage per day
« Reply #5 on: July 22, 2019, 07:22:28 PM »
Hi, thanks for that information. I'll look into that further. I have all the monitor programs and app.
A further issue I have always had a problem with is the state of charge figure on the Classic. It is incorrect when compared to hydrometer readings. I have adjusted battery efficiency and AH but this doesn't help. This has caused my bank to be seriously undercharged for some time. I now have a higher than standard charge voltage and 18 hours absorption time to compensate.
Is there any way to get the soc figure more correct?
Thanks,
6 x JA Solar 320w solar panels, 2 x Solarex MSX-83, 3 x Helios H750 panels, 4 x Suntellite 260w.
4 x 6v Crown CR430 batteries (24v), Classic and WBJr, FX2024 inverter and Mate, Trimetric monitor, Soma 1000 wind generator (to install), Alibaba solar pump. Air X 400w wind generator.

ClassicCrazy

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Re: Power usage per day
« Reply #6 on: July 23, 2019, 01:46:46 PM »
You have something wrong if your batteries won't charge full . Maybe a bad cell ? You should be able to spot that with your hydrometer though.  How accurate is  your hydrometer ? Might be worth to check with a different one or an inexpensive refractometer.  It should never take 18 hours absorb time to fully charge a battery pack of your size.

The SOC reading wouldn't effect the charge - only the charge settings you have it set for.  At 18 hours absorb time your batteries would be bubbling all the time and using a fair amount of water. 

How deep do you discharge your batteries ?

Larry
« Last Edit: July 23, 2019, 01:48:35 PM by ClassicCrazy »
system one
Classic 150 , 5s4p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system two
Classic 150 ,5s 135 watt Kyocero , 16s Calb 100AH LiFePO4 , Outback VFX 3648 inverter
system three
Midnite KID MPPT 24 DC in to  12 volt AGM batterie

Vic

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Re: Power usage per day
« Reply #7 on: July 23, 2019, 11:09:52 PM »

   ...   I have always had a problem with is the state of charge figure on the Classic. It is incorrect when compared to hydrometer readings. I have adjusted battery efficiency and AH but this doesn't help. This has caused my bank to be seriously undercharged for some time. I now have a higher than standard charge voltage and 18 hours absorption time to compensate.
Is there any way to get the soc figure more correct?
Thanks,

Hi asdex,

Believe that you are in NZ,   so an 18 hour Absorb  should not be a large problem in your Winter.

Battery Monitoring devices are usually not particularly accurate,   as there are SO many variables with Lead Acid batteries,   especially Flooded batteries that so many of us use.

IMO,   the SOC indication on monitoring devices,   including the WbJr,   is a rough approximation.   As Larry mentioned,   your high quality Hydrometer is THE tool to use for determining SOC.

Selecting several Pilot Cells in the battery bank (usually chosen from the cells with the lowest SG readings,  on average) will allow you to quickly determine the general SOC of the bank,  quickly.   Always RINSE,   RINSE,    and   RINSE yet again with Distilled Water when you are done measuring SGs,  to keep the Hydro accurate.

If your battery is not getting fully-charged on each charge cycle,   the first thing to change,  is the Absorb voltage  --  raise it 0.5  Volts for several charge cycles and see what is the change in SGs.

In quickly looking at the Crown spec for charge voltage,   their recommendation is fairly low,  for solar-charged systems.   Almost all of these charge parameters are for Grid-charged batteries.

Personally,  would ignore the SOC shown on the Classic MNGP,   Local App,   Trimetric, etc,    and use your SG readings.   Later,  when your battery is getting a real full-charge,   you can use the Net Ah as a guide of the SOC at the beginning of each day.

Use -3 millivolts/C as the Temp Compensation of charge voltage.

Generally,  with reasonable Absorb voltages,  3 - 4 hours of Absorb should charge a battery,  fully,  unless it has been deeply discharged.

What Absorb voltage are you using?
What is the EQ voltage?
How often do you EQ the battery?
Are you using Wb End Amps to end Absorb?
What is the charge Efficiency setting that you are using?

EQs should only be done after the battery is fully-charged,  or as fully charged as Absorb can charge it

Thanks for the added info.    Vic

« Last Edit: July 23, 2019, 11:12:00 PM by Vic »
Off Grid - Two systems -- 4 SW+ 5548s, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 3X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  Thanks MN for Great Products/Service/Support!

asdex

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Re: Power usage per day
« Reply #8 on: July 24, 2019, 05:40:46 AM »
Hi, thanks for your replies.
Just checked the settings:
Absorb 29.5 volts
Float 27.9 volts
EQ 31 volts
Wbjr end amps 3 amps
Eff 70%
SOC normally doesn't go under 80%.
Temp Co. 0.1% and 20deg
I don't equilise often as absorb voltage is quite high anyway.
Yes I'm in the lower South Island NZ and in winter I need to charge the batteries as quickly as possible with limited sunlight.
I do have a refractometer and have checked my hydrometer with it.
Early in our batteries life I switched battery voltage to a 24 volt element to heat the water. This was using the Classic aux and SOC. as the SOC wasn't correct as I thought it would be I was undercharging the batteries for at least 6 months until I bought and tested them with the hydrometer.
I don't really want to add more panels if possible as I'll need to get a second Classic.We have a vacuum tube solar hot water now.
Cheers,
6 x JA Solar 320w solar panels, 2 x Solarex MSX-83, 3 x Helios H750 panels, 4 x Suntellite 260w.
4 x 6v Crown CR430 batteries (24v), Classic and WBJr, FX2024 inverter and Mate, Trimetric monitor, Soma 1000 wind generator (to install), Alibaba solar pump. Air X 400w wind generator.

ClassicCrazy

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Re: Power usage per day
« Reply #9 on: July 24, 2019, 11:14:47 AM »
Curious how you got 0.1% / C  for the battery meter efficiency .  And 20 degrees ?
I think most batteries would use 1%  - and it seems like most battery specs use the 25 degree for their specs don't they ?

What is your Temperature Compensation set for - that should be around -3 mv  to -5mv range for most flooded lead acid. This would make a big difference if you batteries get cold.

The day chart you posted earlier shows your batteries going to Float most days .
The thing is you can only fill up batteries so quickly once they go into Absorb and they start to get charged and the internal resistance goes up you can only force so much power into them - you can't make them charge more quickly at the end - only when they are in bulk and all available power will go into them.

Larry
system one
Classic 150 , 5s4p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system two
Classic 150 ,5s 135 watt Kyocero , 16s Calb 100AH LiFePO4 , Outback VFX 3648 inverter
system three
Midnite KID MPPT 24 DC in to  12 volt AGM batterie

Vic

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Re: Power usage per day
« Reply #10 on: July 24, 2019, 05:25:22 PM »
asdex,

Thanks for the added info on your system settings,   and how it is used.

Am completely unfamiliar with the Graham App,  so the June summary is ambiguous to me:   kWh is clear,   but most of the rest is not   ... what is the Watt value shown,   average for the day,   max for the day ...  or ??

What is the degree value?   It must come from the Classic,  seems too warm for a battery temp,   not FET temp   ...   and cannot be the water temp (how does the Classic read this?),   and so on.   Do not need to understand all of this.

BUT,   using the battery for opportunity loads,   can make it difficult to know when your system is operating well,   and fully charging the batteries.

From that summary,  it would seem that you have very light loads,  when there is little,  or no PV power.

Your settings,  generally look OK.   THe EA value is fairly low,   but if that low a value is what is required to get batteries fully charged,   then this is fine.  It can be a bit difficult to actually see when the Wb current has truly stopped decreasing,  during Absorb.   59.5 V  is a bit of a high Absorb,   but  the spec for full charge SG is,  1.275,  which is a bit high,   and dictates a bit higher charger voltage settings.  The following is a CR430 Data sheet:|
https://www.wholesalesolar.com/cms/crown-cr430-flooded-battery-specs-2834660653.pdf

The Crown spec for Temp Compensation of charge voltages  IS -3 mV/C (as we sit in the Classic).

Because you may have been undercharging your battery banks for some time in the past,  you may want to EQ it again,   while monitoring the SG of the lowest cell,  or two.   Keep EQing until these SGs stop rising,   and continuing the EQ for 30 -  60 minutes after that point.

We have always Temp Comped the EQ voltage,   but this is open to debate by some.   With the EQ voltage compensated,  you should notice that the WB battery charging current diminishes during the EQ.   Your batteries may not need an EQ at this point,   but it is difficult to remove residual Sulphates on the plates,  without a charge/EQ voltage somewhat above the customary Absorb voltage.

EQ at 31 V,  seems a bit low to me,  but,  it seems that your batteries may not be the old traditional Lead - Antimony chemistry   ...   perhaps Lead - Antimony - Selenium (?)   .

Anyway  just a stream of unconsciousness from here.   Please let us know how you are doing.    Vic
Off Grid - Two systems -- 4 SW+ 5548s, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 3X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  Thanks MN for Great Products/Service/Support!

asdex

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Re: Power usage per day
« Reply #11 on: August 01, 2019, 11:40:36 PM »
Hi, thanks for your reply. Sorry I havent got back sooner.
I have adjusted some settings as you recommended and find the SOC on the classic is possibily more accurate now. As I changed a number of settings I'm not sure which helped but previously the Trimetric value was always lower than the classice but now its swapped. I'm checking with the hydrometer and compairing with the SOC.
I was wondering if updating the Classic software would give any performance improvement?
Its 1821 and MNGP 1849. Rev CL1491.
Thanks,
6 x JA Solar 320w solar panels, 2 x Solarex MSX-83, 3 x Helios H750 panels, 4 x Suntellite 260w.
4 x 6v Crown CR430 batteries (24v), Classic and WBJr, FX2024 inverter and Mate, Trimetric monitor, Soma 1000 wind generator (to install), Alibaba solar pump. Air X 400w wind generator.

Resthome

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Re: Power usage per day
« Reply #12 on: August 03, 2019, 03:57:50 PM »
Hi, thanks for your reply. Sorry I havent got back sooner.
I have adjusted some settings as you recommended and find the SOC on the classic is possibily more accurate now. As I changed a number of settings I'm not sure which helped but previously the Trimetric value was always lower than the classice but now its swapped. I'm checking with the hydrometer and compairing with the SOC.
I was wondering if updating the Classic software would give any performance improvement?
Its 1821 and MNGP 1849. Rev CL1491.
Thanks,

That's pretty old firmware, since 2193 is current.  Don't think there were any changes for SOC but not every change is documented. So yes I would definitely take advance of the latest firmware.
John

10 x Kyocera KC140, Classic 150 w/WBJr, Link10 Battery Monitor, 850 AH @ 12v Solar One 2v cells, Xantrex PROwatt SW2000
Off Grid on Houseboat Lake Don Pedro, CA

SolarMusher

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Re: Power usage per day
« Reply #13 on: September 03, 2019, 08:30:21 AM »
These Crown CR batteries are not that great... The Crown CRP525 395Ah is far better for solar system.
In your Trimetric/Wbjr, I would set the efficiency in the 85/90% range, 70% is very low!
Erik
Off Grid with 3.2kw PV | Classic 200/WBjr + Classic lite 200 | 2x Outback VFX3648 Epanel | 3x SPD300 + 1x Schneider HEPD80 | Hub + Mate + PSX-240 | 750Ah Rolls S-480 battery bank + Trimetric | 1200 watts DC water heater | 8000 Generac and 7200 watts Champion gas generators