36V Battery voltage and time settings?

[sigp2101]

Are not described in Classic 150 Manual. What are these recommendations for

Absorb Minimum time in minutes,
Absorb Maximum time in minutes,
Equalize time in minutes,
Equalize time intervals,

and what are those battery  1, 2, and 3 you are referring to for flooded type?
What happens if I do not set these values?

Also, how does Classic know when is my BB 100% so it can switch to float. Where do I set that Voltage value? In my case that would be 38.22V according to Trojan.

Thanks!

[Vic]

Are not described in Classic 150 Manual. What are these recommendations for

Absorb Minimum time in minutes,
Absorb Maximum time in minutes,
Equalize time in minutes,
Equalize time intervals,

and what are those battery  1, 2, and 3 you are referring to for flooded type?
What happens if I do not set these values?

Also, how does Classic know when is my BB 100% so it can switch to float. Where do I set that Voltage value? In my case that would be 38.22V according to Trojan.

Thanks!

Hi sigp..,

You will need to Update the Firmware in your Classic,  if it has Menu settings for Max AND Minimum Absorb times.   The Firmware in your Classic appears to be a number of years out of date.

What is the Firmware version number for the Classic and the MNGP,  if your Classic has the LCD display with buttons?

Have you ever updated the Firmware on any Classic?

The Absorb time required to recharge batteries depends mainly,  upon the Depth Of Discharge (DOD) that the battery bank experienced in the previous discharge cycle.

The Absorb voltage is set in the Charge >  Volts menu.   The EQ and Float voltages are also set on that same menu page.

The Classic "knows" to stop charging in the Absorb stage,  based upon the time that is set in the Charge > Time menu page.   There is also an optional device that allows measuring the battery charge current into the battery bank (the Whizbang Junior + a Shunt)  that allows ending Absorb,  based upon the charge current to the battery,  OR if the Absorb timer has counted down to zero.

Consult the manufacturer of YOUR batteries for recommendations on all voltage requirements,   as well as the frequency and duration for any EQs.

Are your batteries Flooded Lead Acid (FLA)?   FLAs will need EQs,  usually based on a certain length of time,  or for some batteries,  based on the amount of variation in the Specific Gravity (SG) measurements  between each cell in the battery bank.

Am not certain just what is meant by battery 1,  2  and 3 is referring to ...   have not seen this in any manual for Classics.

Does any of this help?   Vic

[tecnodave]

Vic,  &. sig2101

Those battery types 1,2, & 3 appear in early manuals referring to the MNLP display on the Classic lite.
They are the options with the non graphical display type used in the lite.

There are 7 entries total 1 for gel , 2 for sealed and 3 for FLA. And one for custom as set with external software.

The lite does not allow exact setting of charge points, you must use one of the built in profiles or use external software to set to a custom value.

This is totally non revelant in the full Classic

Sig2101,

I assume that you do have a Classic 150..... NOT  a Classic Lite.
The Classic lite does not have a setup for 36 volt battery bank.......must be done as custom


David

[Vic]

Vic,  &. sig2101   ...

Those battery types 1,2, & 3 appear in early manuals referring to the MNLP display on the Classic lite   ...

David

Hi David,

OH !!,  had noted that sigp2101's Signature mentioned a "Classic 150",   so was not thinking at all about a Classic Lite.   Have not ever touched a Lite,   or even seen one.   So,  have not paid much attention to the details of configuring them,  and avoid trying to address any questions about setting up one.

As you noted,  perhaps sigp2101  has noticed those references to the Lite in a manual,  but was unaware of just how a Lite differs from the Standard Classic.

Dunno,  but thanks David for adding some clarity to the situation.

Vic

[sigp2101]

Hi Vic,

first of all thank you for writing back, appreciated!

I will start with little background. CC is Classic 150 purchased in February this year. Serial number is #CL 27075. Firmware I do not know yet since it is at remote location I will get to it this weekend. BB is 6X6V Trojan 105 in 36V configuration. As I was going through manual I was using Classic 150 available on your web for download. Now to address some of your questions.

Hi sigp..,

You will need to Update the Firmware in your Classic,  if it has Menu settings for Max AND Minimum Absorb times.   The Firmware in your Classic appears to be a number of years out of date.

What is the Firmware version number for the Classic and the MNGP,  if your Classic has the LCD display with buttons?

Have you ever updated the Firmware on any Classic?

No, didn't have a chance to do that yet.

The Absorb time required to recharge batteries depends mainly,  upon the Depth Of Discharge (DOD) that the battery bank experienced in the previous discharge cycle.

How does classic knows about that?

The Absorb voltage is set in the Charge >  Volts menu.   The EQ and Float voltages are also set on that same menu page.

I would like classic to bulk charge as soon as battery bank drops to 50% and to stay that way till it is 80%. At 80 SOC I want it to switch to absorb till 99% SOC and then switch to float for the rest of the sunny day. How do I set my Classic to do just that? There is only absorb and float in charge many + EQ setting.

The Classic "knows" to stop charging in the Absorb stage,  based upon the time that is set in the Charge > Time menu page.   There is also an optional device that allows measuring the battery charge current into the battery bank (the Whizbang Junior + a Shunt)  that allows ending Absorb,  based upon the charge current to the battery,  OR if the Absorb timer has counted down to zero.

I do not have Whizbang. How do I set time, what is the value here for time.

Consult the manufacturer of YOUR batteries for recommendations on all voltage requirements,   as well as the frequency and duration for any EQs.

I did, Trojan specify Bulk, Float and EQ voltage, Classic has EQ, Absorb and Float as set-able variables in CHARGE menu. There is disconnect somewhere.

Are your batteries Flooded Lead Acid (FLA)?   FLAs will need EQs,  usually based on a certain length of time,  or for some batteries,  based on the amount of variation in the Specific Gravity (SG) measurements  between each cell in the battery bank.

Yes they are Flooded Lead Acid Trojan T150 GC2 batteries. Thanks!

Am not certain just what is meant by battery 1,  2  and 3 is referring to ...   have not seen this in any manual for Classics.

PAge 58 of this manual - http://www.midnitesolar.com/pdfs/classic_manual_Rev_1933.pdf
This is the one I downloaded since mine is at the remote location along with CC

Does any of this help?   Vic

Tremendously, as you can all see I am total rookie here trying to put my system together. Last weekend I put it together and did quick start and accepted all default values and left. This coming weekend I want to continue tweaking whole setup and that is why I downloaded manual of the line start reading through it but lots of questions start to pop up.

THANKS a lot for all of your guys dedications.

SIGP2101

[sigp2101]

Vic,  &. sig2101

Those battery types 1,2, & 3 appear in early manuals referring to the MNLP display on the Classic lite.
They are the options with the non graphical display type used in the lite.

There are 7 entries total 1 for gel , 2 for sealed and 3 for FLA. And one for custom as set with external software.

The lite does not allow exact setting of charge points, you must use one of the built in profiles or use external software to set to a custom value.

This is totally non revelant in the full Classic

Sig2101,

I assume that you do have a Classic 150..... NOT  a Classic Lite.
The Classic lite does not have a setup for 36 volt battery bank.......must be done as custom


David

THANKS! that explains it.

SIGP2101

[sigp2101]

Vic,  &. sig2101   ...

Those battery types 1,2, & 3 appear in early manuals referring to the MNLP display on the Classic lite   ...

David

Hi David,

OH !!,  had noted that sigp2101's Signature mentioned a "Classic 150",   so was not thinking at all about a Classic Lite.   Have not ever touched a Lite,   or even seen one.   So,  have not paid much attention to the details of configuring them,  and avoid trying to address any questions about setting up one.

As you noted,  perhaps sigp2101  has noticed those references to the Lite in a manual,  but was unaware of just how a Lite differs from the Standard Classic.

Dunno,  but thanks David for adding some clarity to the situation.

Vic

Thanks both!

SIGP2101

[Vic]

Hi SIGP..,

From this Page on the MN Solar site,  you could find the latest Classic Manual  --  for FW 2056:
http://www.midnitesolar.com/documents.php?productCat_ID=21&productCatName=Charge+Controllers+-+Classics&model=CLASSIC 150&product_ID=256&act=

It is not possible to know just what version of FW your Classic is using,   but it might be good to have a copy of the latest Manual.

You may not need to Update that Classic.
Do you have Internet access at the site where the Classic is located?

Thanks,   Vic

[Vic]

In regards to having a CC start a charge cycle,  based upon State Of Charge (SOC),   I do not know how to make any CC do that.

The later versions of Classic Firmware (FW),  have a Skip Days function,  in the Advanced charge menu,  but  this  just skips a number of days that you set.

Generally,  the user of the system needs to monitor SOC (as shown by SG readings,  for Flooded batteries),  and manually change CC settings to achieve as close to the desired results as is possible.

Remote sites can be a bit difficult to manage,  especially if those sites have varying Depth Of Discharge (DOD),  from one day to the next.   With Flooded batteries,  this is not such a large issue,  as Flooded batteries are quite forgiving of a bit of overcharge,  and some undercharge,  if this undercharge is not chronic,   and so on ...

You might want to study the benefits of adding the WhizBang Junior and a 50 mV Shunt to your system.   These,  together will allow you to monitor the actual battery charge current,  and  the WBjr  can tell the Classic to switch from  Absorb, to Float,   based on the actual battery Finishing current,  also called End Amps (EA).

WBjr at a reliable reseller:
http://www.solar-electric.com/midnite-solar-whiz-bang-jr-current-sense-module.html

A good 50 mV Shunt:
http://www.solar-electric.com/mkb-500-50.html

FWIW,   Vic

[sigp2101]

Hi SIGP..,

From this Page on the MN Solar site,  you could find the latest Classic Manual  --  for FW 2056:
http://www.midnitesolar.com/documents.php?productCat_ID=21&productCatName=Charge+Controllers+-+Classics&model=CLASSIC 150&product_ID=256&act=

It is not possible to know just what version of FW your Classic is using,   but it might be good to have a copy of the latest Manual.

That is the one I have

You may not need to Update that Classic.

Good

Do you have Internet access at the site where the Classic is located?

Thanks,   Vic

Unfortunately totally off the grid, no Internet yet. Maybe one day with satellite link.

In regards to having a CC start a charge cycle,  based upon State Of Charge (SOC),   I do not know how to make any CC do that.

I do not understand, what is the point of having all this settings for Absorb, Float, EQ when CC can't sense when BB  reach those crucial setting points?
What you are saying is that CC keeps charging regardless of SOC. Am I missing something here?

Thanks!

SIGP2101

[Vic]

Quickly,

For most of our history,  off-grid systems attempted to have PVs fully charge batteries EVERY day.   Flooded batteries can take some overcharge.   Some undercharge on some days is OK,  due to weather conditions,  etc,  as long as the battery gets fully-charged several times per week.

If that does seem like the correct approach to you,  the Classic is the only CC that I know of,  that has the Skip Day function.   This allows YOU to set the number of days the you estimate that will reach the DOD that is good for your system,  and only charge one day,  and then  Skip that same number of days,  again,  and so on.

There are some projects that some users of MidNite CC are working on,  for additional monitoring and control functions ...   so if you are interested in Programming some external computer CC controlling and monitoring gadgets,  there are several of those listed it their own section of this Forum.

This topic area is called,  "  The Open Source software/hardware corner  ".   I am not actively doing any of these types of monitor and control functions at this time,  so I am of no help.

Later,   Vic

[sigp2101]

Quickly,

For most of our history, off-grid systems attempted to have PVs fully charge batteries EVERY day. Flooded batteries can take some overcharge. Some undercharge on some days is OK, due to weather conditions, etc, as long as the battery gets fully-charged several times per week.

If that does seem like the correct approach to you, the Classic is the only CC that I know of, that has the Skip Day function. This allows YOU to set the number of days the you estimate that will reach the DOD that is good for your system, and only charge one day, and then Skip that same number of days, again, and so on.

There are some projects that some users of MidNite CC are working on, for additional monitoring and control functions ... so if your are interested in Programming some external computer CC controlling and monitoring gadgets, there are several of those listed it their own section of this Forum.

This topic area is called, " The Open Source software/hardware corner ". I am not actively doing any of these types of monitor and control functions at this time, so I am of no help.

Later, Vic

Thanks a bunch!

The Challenge for me then is to find best configuration settings for my off-grid weekend cottage. I will be running few lights and small fridge (up to max 1KW per day) but only during weekends. Occasionally will be extended stays up to 5 days. Any suggestions?

[Vic]

Thanks a bunch!

The Challenge for me then is to find best configuration settings for my off-grid weekend cottage. I will be running few lights and small fridge (up to max 1KW per day) but only during weekends. Occasionally will be extended stays up to 5 days. Any suggestions?
[/quote]

Hi sigp..,

OK,  so when you are not at your cabin,  the fridge is not running,  correct?
And,  do you leave your inverter running during your absence?

Are there ANY loads running when you are absent from the cabin?

Without knowing quite a bit about your system,  like type and amount of PV or other charging power available on an average day,  average loads when you are at the cabin,   etc,  etc ...

A battery that is lightly discharged may well only need about an hour of Absorb,  at  a reasonable Absorb voltage.   More deeply discharged,  probably a longer Absorb.

And,  as an aside,   even the best Battery Monitoring devices available are not terribly accurate,  in an absolute sense.   It is nearly impossible to make a very accurate model of the way batteries behave,   as Ah Capacity remaining depends on just how,  and at what rate the energy happened to have been removed from the battery,  and just how  that battery happens to be recharged,  and so on.

So,    IMO,   the reported SOC and Ah remaining shown by essentially any battery monitoring device  is really,  just a fairly rough estimate.   Not a bad approximate guide to SOC and Ah remaining,  just not that exact,  on average.   Therefore trying to wait to recharge a battery when it is at 50% SOC,  could,  possibly disappoint.

For systems using Flooded batteries,  with very regular discharge and charge patterns,  there is a better chance that the user of the system can monitor the SGs of the battery,  and do a better job in setting the important battery parameters into the battery monitoring device ...

Just my opinion,   FWIW,  Vic

[sigp2101]

Hi sigp..,

OK,  so when you are not at your cabin,  the fridge is not running,  correct?

Correct

And,  do you leave your inverter running during your absence?

All is disconnected except CC.

Are there ANY loads running when you are absent from the cabin?

NO

Without knowing quite a bit about your system,  like type and amount of PV or other ...

Panels are  3 X 235W 36V 8A SolarWorld

[Vic]

sigp2101,

Thanks for the info on your system.

So,  you are running the three SW-235 PVs in series,  for a String Vmp of about 90-ish volts (at STC) to the Classic,   assumed.

With absolutely no loads on the batteries,  except the Classic itself,  you could expect to run a number of weeks with no charging at all.

In your absence,  you could Float the batteries at the suggested Float voltage.   Or,  even Float at a somewhat reduced Vfloat.   Some of the strategy depends upon just how long will your absence be.

You could set a number of Skip Days,  and do a full,  or partial charge on the charge day.

Looks kind of like you have the batteries and inverter in a Root Cellar type of location.   This is often a very good idea,  as it does moderate the range of temperatures experienced by the batteries.   There can be considerations of how to deal with low temperatures in Winter,  in the Northern climes,   where there is some risk of freezing the batteries and ruining them.

You will become more familiar with the way your system operates,  and how your charge strategy is working,  as,  when you return you can check the SGs when you first arrive.

Vic