charging batteries

[solar blue]

    hi vic  well wired panels to 48v  input went from 34v  to 69  best i rember under that watts went to 54 below that is kwh   rite side says 32v i set it at that under that says 1,7v below that says absorb  eq is set 32v  now two questions does charge controler show the amount of charge in battery  the controler is in pv mode  how might L&Q mode help if any  what does it do to help i have bts coming  could i possibly have eq and absorb to hi and does the controler absorb power at nite when resting

[Vic]

Hi solar blue,

Are there any loads on this system,  are you using an inverter to power loads,  etc?

Could you post a photo of the main status screen,  when the Classic is in Absorb?

Do you know the approximate battery temperature?

EDIT:  So you have wired the PVs as two in series,  right?   What is the total number of PVs that are weird into the system?

If there are no loads on the system,  then the Current display on the right side of the display is close to the amount of current going into the batteries.  There is an optional accessory for the Classic  --  the WhizBang Jr (WBjr),  this plus a 500 A  50 mV Shunt will show a very accurate measurement of the current going into the battery.

Generally,  the Solar Mode for the Classic will be the best for PV charging of a battery.  Sometimes,  with passing clouds,  Legacy P&O  can be better.

What version of Classic Firmware is the Classic running?   This can be seen by pressing the small round Status button on the display about 7 or 8 times.  It will show the Classic,  MNGP,  and Network Firmware Version numbers ...
Be back in an hour or two.   Thanks,   Vic

[solar blue]

   vic   no loads on system   cant do a pic no camera  batteries probly bout 36f  yea rewired panels have five strings 48v  making 69.4 v in  for every degree f   how much do i need to add to Mv
   2054 mngp
   2096   03/26/16 classic
   rev sl4294967295
   if i found the right thing   hope this is right

[Vic]

Hi solar blue,

No problem on no photo.

Regarding manually setting the Absorb voltage,  to compensate for the battery temperature,   for every degree C that the battery is below 25 C,  you should add 0.06 volts to the recommended Absorb and Float  (and EQ) voltages.

You should probably take SG readings on each cell of the battery,  and write those down.   This is probably a good time to start a new Battery Logbook.   You would record the date,  SG readings for each cell  --  number each battery and letter each cell of the battery,  unless your battery is like most forklift batteries and all of the cells are in one metal container,  then just number each cell.

You would also want to record the amount of water added,  EQs  and their length,  etc.   All of this info will help  you monitor trends in battery behavior,  note any action that has been taken to try to correct anything that appears to be going amiss.

Since your system has no loads,   you can use the Classic output current  on the lower right of the display,  as a very close reading for the current that is going into the battery.   When this current reaches a value (around 9 Amps  -  about 2% of the 450 Ah battery Capacity IIRC),  begin watching this current closely.  When this current no longer is going down,  this is about the proper Absorb time,  and you could also use it as a good start for setting the Classic's End Amps,  in the Charge>Advanced menu.

EDIT:  Previously  it was suggested that you should probably set your Absorb time to 3 hours.  But  with no loads on the system,  you could reduce this time setting.  You should be able to shorten the Absorb Time,  to about 30 minutes,  or so.

If your system continues with no loads,  then you would probably to not recharge the battery every day.   But,  let's not talk about this now,  and wait until you measure the SG of each cell,   and get more comfortable with your system.


Vic

[solar blue]

  Vic

       i have put system back on line 9:35 tonight. Ihave made a log to keep records on batteries
  I have put in it all the things to check and keep up with with.
  you spoke of end amps what might this be and its use?  Thanks for all your help.
 

[Vic]

Hello solar blue,

Think that I forgot to mention that your Classic Firmware is up to date,  thanks for checking.

End (or Ending)  Amps is a setting in the Charge menu,  that will allow the Classic to end the Absorb stage,  when the current from the Classic (or the current measured by the WhizBang Jr)  comes down the value that is set for this menu item.

With no loads on the system at all,  the current that the Classic is supplying on its output will only be the current that is going into the battery.

When the current going into the battery (the battery charge current) reaches a fairly low amount,  and this current does not change for a number of minutes,  then the battery can be considered,  fully charged.   The Absorb voltage setting must be in the range of voltages that are suggested by the battery manufacturer,   and must be correctly Temperature Compensated,  for this Ending Amps value to indicate that the battery IS fully charged.

Usually,  this Ending Amps value is in the range of 1 to 2 percent of the 20-hour Capacity of the battery bank.   In the case of your battery,  believe that this Capacity value is 425 Ah.   So 2% of this is about 8.5Amps,  and 1% is about 4.2 Amps.

There is a setting for "  Ending Amps  ",  in the Charge menu  --  go to Charge,  and then scroll over once,  and down once,  to the Advanced menu.   At the left of the Advanced menu,  there is the  Ending Amps selection.  If you press  Enter then the Ending Amps selection is highlighted,  you will be able to enter a value for this.

The benefit of using Ending Amps,  is that  with a battery bank that is discharged by different amounts on every discharge,   the proper amount of Absorb Time need for a full-charge will differ,  compared to  a battery discharged by a different amount.

Finding the proper setting for Ending Amps can require quite a bit of time,   as  SG readings must be monitored to verify that the Ending Amps setting is correct.

With no loads of any kind on your system (not even an Inverter without any loads),  you  could probably only fully charge your battery once per week.   And,  then,  if your batteries are new,  and in good condition,  only for a fairly short time.   You could possibly begin using Ending Amps at a time when your system has a reasonable amount of loads on it.

You appear to have Grid power,  so this system may be intended as a backup power system,  for when the Grid power fails?

More later,   Vic

[solar blue]

    Hi Vic
thanks for end amps info I understand that pretty well . The bts should be here friday or tuesday when I plug it in all i need to do is set Mv back to Mv5 then that will adjust chage for temp of battery so after that I need to set end amps correct?
battery sg is staying at 1.275 a little above maybe



                                                                          Many Thanks
                                                                          Solar Blue

[Vic]

Hi solar blue,

Yes,  your battery needs a compensation of -- 5 mV/cell/C,  so make sure that this is set.   The Classic will know that there is a BTS installed,  when you plug it in.

Think that you have been manually Compensating for low battery temperatures,  so you may need to adjust the Absorb and Float voltages,  if this has been the case.

YES,  you can set the Ending Amps in the Charge > Advanced menu.  You could start with about 8.5 Amps,  and watch the SGs,  to make sure that you are maintaining good SGs.

Also,  check the Absorb time setting.  The way that Ending Amps works is  that either the End Amp setting,   OR,  the Absorb time setting is what will end Absorb,  so make sure that the Absorb time is set to a fairly long time,  like several hours,  until your system has some loads to discharge the battery.

Your 1.275 SGs are probably fine ...   forgot what the battery dealer or manufacturer says is the SG for a fully-charged battery.

Also,  SG measurements need to be temperature compensated  by a fairly small amount.   SO if your batteries are still fairly cold,  the SG readings will be a bit on the high side,  and could have about 3.5 points subtracted from the readings for every 10 degrees F change from about 77 - 80 degrees F.

There is a Hydrometer  --  the Hudrovolt  --  which compensates for the temperature of the electrolyte of the sample.

Also,  am sure that you know,  that batteries will emit Hydrogen,  an explosive gas,  and some acid vapor when being charged,  and EQed,  so please keep that in mind when you find a permanent place for your battery bank.  Some ventilation with a vent at or near the ceiling of the room where your batteries are located.

With the BTS installed,  the " Temps "  menu will show Battery temperature on the lower left of the display.

There are a few things that should be mentioned,  to help keep your system as safe as it can be,  but later for those,   Vic

[Vic]

Hi solar blue,

A couple of comments regarding circuit protection for your system;

You probably know this,  but,  since you have five strings of two 220 watt PVs,  you will need a Combiner,  which has  one DC  circuit breaker for each string of PVs.

Also,  you will need a DC circuit breaker for the input of the Classic,  and,  the most important DC breaker,  is the one on the output of the Classic to protect the cable that connects to the battery.

You may have already done this.  The PV breakers in the Combiner are often sized at the Maximum Fuse rating that is on the label on the back of the PVs,  and in the specification that can be found online.

The Classic's input and output breakers are sized to protect the cable that it is connected to.

FWIW,   Vic

[solar blue]

   Hi Vic
           Christmas greeting to You and Family
    Got the combiner bx coming what size breaker should I use for each circuit
     Im using number8awg is that large enough

   

[Westbranch]

Thee CB size should be on the back label on the panel,  this link says 15A CB is needed...http://www.solardesigntool.com/components/module-panel-solar/Canadian-Solar-Inc./382/CS6P-220P/specification-data-sheet.html

You will need one per string feeding the combiner. 

[solar blue]

  hi westbranch 
thanks for info   hope this is a great holiday season for all thnks again.
If i use 15a for each string of 5  what would be the rite amp size for input to cc and output to batteries and can i place in same bx if possible what is the rite bx for them

[Westbranch]

It is possible to put the other CB in the same box but will require you to make some modifications to the combiner that comes with the MNPV6.

As to the CB to the controller what voltage are you settled on?

[Vic]

solar blue,   Thanks for the Christmas wishes.   Hope that you are enjoying Christmas,   best wishes to you,  and your family.

It might be time for all of us to slow down a bit.

Previously,  most of the details of your system did not matter so much,  compared with the situation you were in,  in trying to get your batteries recharged,  ASAP.

Now  that this situation appears to have been resolved,  most of us trying to help you will need some more details about what you want your system to do.

For example;
1.  What is the purpose of this system?   Since you have Grid power,  is this a system to back up your grid power?

2.  Is this really for an off-grid cabin,  but you have the grid power elsewhere?

3.  What will be the daily loads on the system,  and when will these loads occur?   You may need to measure the loads with a device,  like the Kill-A-Watt,  for 120 VAC loads.

4.  Do you have plans to add onto this system?

It is the usual approach to design a system,  first,  based upon load on it,  when these occur,  and also what is the maximum load (like a deep well pump,  etc).

Knowing all the info about loads on the system,  the size of the battery,  its voltage,  the size of the PV array,   the size of the inverter,  cable sizes,  etc,   will become much more clear.

Also,  the way the system is laid out could depend upon any upgrade plans.   These things include where the Combiner (for the PVs) is located,  cable sizes,  and the type of box/es that could be chosen now,  instead of needing to tear out things if an upgrade is to be done.

You could do a quick but safe system,  very quickly,  as a temporary setup,  and do a more permanent system later,  but,  things like good quality inverters are fairly expensive,  so,  knowing the system size requirements is important.

Here are a few Links to examples of some of the boxes, breakers,  etc;

Six string Combiner:
https://www.solar-electric.com/mnpv6.html

Small breaker boxes-
Big Baby Box that uses DIN Rail DC breakers:
https://www.solar-electric.com/misobigbabox.html

Four breaker box that uses Panel Mount breakers:
https://www.solar-electric.com/misobigbabox.html

MidNite DC breakers-
Din Rail for the Combiner,  and the Big Baby box:
https://www.solar-electric.com/catalogsearch/result/?q=mnepv&_antispam=antispam_694

Panel mount DC breakers:
https://www.solar-electric.com/catalogsearch/result/?q=mnedc

There are several larger metal boxes that will collect more breakers than the above two boxes,  have space for the large inverter breaker etc.  The largest of these are in a group called e-panels,  which will usually allow the Charge Controller and inverter to be mounted to this panel,  and contain all,  or almost all of the wiring ...  will post those later.

Vic

[Vic]

solar blue,

Here are a few of the larger metal boxes that can collect many of the needed breakers and associated wiring in one place,  for convenience and safety.

The MidNite MiniDC is the smallest,  and least expensive of these boxes that are larger than the Big Baby Box,  and the DC Quad box:
https://www.solar-electric.com/midcdipocepl.html

Then,  there are the larger boxes that  have more room for breakers,  and for mounting the CC,  inverter,  etc:
https://www.solar-electric.com/catalogsearch/result/?q=e-panels

I do realize that choosing from this wide array of alternatives may well difficult for you,  as it is difficult to know what is really necessary for your system,  and which capabilities  might never be needed.

However,  for those of us who are trying to help you with your system,  it is also difficult to know just what you want and expect from your battery-based system.   So,  the above is some information on some products that will help collect most of the pieces in one place,  use breakers and other hardware that is designed to work safely and well while working reliably for many years.

The first series in this Post,  the Mini DC boxes are for small systems,  that need few breakers,  and not much space for mounting the power producing hardware.   The e-panels are for larger systems.

But,  these boxes are designed to do the job,  meet Codes,  and be safe,  when used appropriately.

All of the Links are to the Northern Arizona Wind & Sun store.  I have no affiliation with them,  but they are honest,  knowledgeable,  have very good pricing,  will deal with individuals,  ship quickly - usually from stock.   Have used them a number of times,  and  will do again ...   FWIW.

Am not in the business of trying to sell anything to anyone,  but just my quick attempt of a summary of some parts that will help construct a system that uses quality components,  has good documentation,  and is reasonably priced.

Vic