Need help - batteries not reaching full charge - adding more

[robbertwilliams]

The banks are successfully paralleled.  I've been watching EA via the exported LA Excel data and they've been leveling off around 6.9. 

Been operating the CC in Legacy Mode and have been getting to this charge (float) point after about 2hrs of charge (8:45-10:45am).  My current usage has only been approximately 70ah/night (drains down to about 91% SOC). 

Plugged the mini fridge in tonight.  Looking forward to seeing how much of a drain tonight/recharge we get tomorrow. 

[Westbranch]

Robbert, I just reread your #1 Post....
6.9 is not very different from where you ended up, good  ...,
only the Absorb time has increased IIRC...
so I would expect that your bulk time will increase as a factor of the additional  number of Ahrs of use you get from the fridge as might the time needed for Absorb.....
see if you can estimate that and compare to what happens tomorrow or the day after.. good hunting.

[WizBandit]

I quickly read through the thread and didn't see it so I will mention ENDAMPS can use the CLASSIC AMPS or WBjr AMPS.
If you want it to use the WBjr you need to set ENDAMPS to use SHUNT.

In the BATTERY MENU under ADVANCED where you set the REBULK in the lower left corner it will say "CLASC" or "SHUNT".

Unless it is set to "SHUNT" you are using the CLASSIC's AMPS and that is not good for battery ENDAMPS.
Toggle the choice with the LEFT SOFT KEY. Press ENTER to SAVE.

[robbertwilliams]

A little update:

I've been keeping an eye on the EA of the shunt via exporting to excel and checking out the graphs/tables.  So, with my battery bank capacity of 740ah and a suggested EA setting of 1% of the 740, that would be 7.4.  Well, I currently have it down to 5.7, and it could possibly go a tad lower. 

Any thoughts?  I think the setting is correct by checking SG's, etc.  But it seems a fair bit lower than the suggested starting point.  I'm guessing a lower EA finish suggests a healthier bank. 

Anyways, all has been good.  Again, thanks for all the feedback and the help getting my system set up and the understanding of it. 

One thing that's been a bugger is charging with the generator via the SE Conext Inverter/Charger.  It kept throwing faults as if I were feeding it triple phase (208v).  I found that when the fridge would kick on, there was enough of a voltage drop that it would throw a fault and the generator would kick out (become unloaded) and then start back in again.  I now just unplug the fridge, and also have lowered the output amps of the charger to 40a (was 65amp - the max of the charger - seemed to be running the generator hard, and probably not the best for the charger as well).

[Westbranch]

It is a given that excess energy presented to a battery in the final stages of charge creates heat in the battery.  Is your battery temp rising? Also is the batt performing as expected?

I know that my winter setting 1% EA setting may be a bit lower than needed in the summer when I get enough sun hrs and intensity to reach Absorb by 11:00.. but right now the basement is sold enough that I only get about a 1 to 2 degree rise in batt temp at the end of the day... Mind you the interior temps are also rising day to day so that ambient temp and batt temps rise somewhat in sync..

[Vic]

In general  the Flooded battery banks in use here,   have been running below 1% of C for a number of years.  This has been about 0.9%  of C,   when using the lower end of the recommended Vabs from the battery manufacturer.

IMO,  young batteries tend to need a lower Vabs.   This factor alone  will tend to reduce the required EA.  The needed Shunt EA will vary in direct proportion to Vabs.   A higher Vabs will dictate a higher EA setting,  generally.

There are other factors that will affect the ideal Shunt EA value.   One of these additional factors seems to be how deeply the battery is being discharged  --  deeper discharge seems to dictate a somewhat higher EA,  particularly if deep discharges occur daily.

Shunt EA is a very good approach to manage ending Absorb,  on Flooded batteries.   But,   like most things involvolving batteries,  it will not always result in a perfect Absorb time.

Of course,  there is also the tradeoff in the amount of time spent in Absorb for each charge cycle,   verses  EQ frequency,   voltage,   and duration.   You can set EA a bit higher,  to shorten the amount of time spent in Absorb,   but then one will need to EQ more frequently,   and perhaps need to increase EQ time.

With young FLAs,   it is good to note the Shunt current value,  when near the end of an EQ.   This can be used as an indicator of when the EQ has done its job,   and on a battery that has Hard Sulfation,   but is otherwise relatively healthy,   the Shunt current will never diminish to the current value for healthy battery.   And,  again,   the EQ voltage will affect the magnitude of this EQ Finishing current.

All just my opinions,   FWIW,  Vic

[EW Zuber]

I have searched this thread to see if system balance has been addressed but haven't read all the posts.
The balance between 740 AH of battery and roughly 41A of solar generated current is not a practical balance unless you are content getting most of your power with a generator. If you are going to double your battery bank it will require at least a 3.6KW array to generate enough current to charge a 1480AH battery bank @24 volts at a C/10 rate.
The idea of balance in a RE system is one of the most overlooked fundamentals of system design.

[Vic]

Hi Eric,

This IS a long Thread.

IIRC,  the relatively small amount of PV was covered.   The battery bank was doubled some time ago,   although,   again from distant memory,  each battery string was being charged individually.   Perhaps there was a Marine type battery switch being used,  or at least considered.

Robert was peppered with a lotta opinions and info,   and it seemed that for much of that,  the loop was not closed.

In some regards,   during Dakota Winters,  there may not ever be enough PV power to avoid a lot of genset run-time.

FWIW.   73,   Vic

[Vic]

In general  the Flooded battery banks in use here,   have been running below 1% of C for a number of years.  This has been about 0.9%  of C,   when using the lower end of the recommended Vabs from the battery manufacturer.

IMO,  young batteries tend to need a lower Vabs.   This factor alone  will tend to reduce the required EA.  The needed Shunt EA will vary in direct proportion to Vabs.   A higher Vabs will dictate a higher EA setting,  generally.

There are other factors that will affect the ideal Shunt EA value.   One of these additional factors seems to be how deeply the battery is being discharged  --  deeper discharge seems to dictate a somewhat higher EA,  particularly if deep discharges occur daily.

Shunt EA is a very good approach to manage ending Absorb,  on Flooded batteries.   But,   like most things involvolving batteries,  it will not always result in a perfect Absorb time.

Of course,  there is also the tradeoff in the amount of time spent in Absorb for each charge cycle,   verses  EQ frequency,   voltage,   and duration.   You can set EA a bit higher,  to shorten the amount of time spent in Absorb,   but then one will need to EQ more frequently,   and perhaps need to increase EQ time.

With young FLAs,   it is good to note the Shunt current value,  when near the end of an EQ.   This can be used as an indicator of when the EQ has done its job,   and on a battery that has Hard Sulfation,   but is otherwise relatively healthy,   the Shunt current will never diminish to the current value for healthy battery.   And,  again,   the EQ voltage will affect the magnitude of this EQ Finishing current.

All just my opinions,   FWIW,  Vic

Hello Robert,

Was ANY of the above of ANY use to you ?? ?

For some of us,  it can be a bit disappointing to spend 15,  or more minutes composing a Post,   and receive NO feedback at all whatsoever.

This can result in some folks who try to help members here,  becoming convinced that our efforts to help,  are of NO use to you whatsoever.

I am finally getting the message ...   am a bit slow.

Just trying to give some feedback.    Perhaps this is a bit of a sharp comment.
Good Luck !!   All the best,   Vic

[robbertwilliams]

Vic -

Yes, a bit sharp, and yes, a bit useful.  I don't think I've ever read anything you have posted that wasn't useful or of value to me.  Thank you!!

I guess you could say I've been spread a bit thin - and this forum/thread had only sent me 'new post' notifications via email for the first 2 or so pages.  So, from there on out, it's up to me to manually go and check out this forum, which is not part of my daily routine.

Not sure if any of you are familiar with Maslow's Hierarchy of Needs?  Well, as selfish as I might seem, I haven't hit the pinnacle of 'Self Actualization'; I'm still building my foundation. 

Again, I DO APPRECIATE your 15 minute long's work to type/formulate a worthy post. 

[russ_drinkwater]

Maslow's, ha, have not heard that spoken of since I did my health science degree

[Westbranch]

I see it (Maslow's)  every day in my mixed breed Chow/Border Collie... no need to remember who is at the top and self actualized! 
The Hemp oil ( not from MJ)  for his creaky bones helps actualize him too

[Vic]

Hi Robert,

Thanks for returning.

Good Luck with the off-grid power system.    Vic

[Matrix]

Found this thread and read most of it ....  I noticed the OP has an Schneider Conext SW Inverter/Charger.  I am having a hard time getting my SW 4024 to finish a charge for my Trojan L16 435 amp hour batteries (x4 in series) .  I get to an SG of 1.266-76 (depending on the cell) and the Classic says I am at 99% SOC with only 433 amp hours.  Trojan says 100% is 1.277 and when I did an EQ last week,  I noted the SG in all cells stopped rising between 1.286 and 1.295 according to my Hydro,  so I took the average of those hi numbers and have tried to use  that as a target for 100% charged (because my hydro may be off).

I have raised the Absorb timer to max so it is not timing out ... and have raised the Absorb voltage to 31.2 and temp comp to -5 (so today they were charging at 31.5 +/-).  That is getting near EQ voltage.   

So I was wondering,  the SW does not have an end amp setting like the classic.  BUT it does ask for the Battery Bank Capacity in Amp Hours.  I cannot see a reason why the SW would need to "know" the amp hours (it does not report SOC) except to set End Amps.  I did kinda confirm that is the case noting that the charge seemed to kick to float from absorb at about 8.7 amps which equals 435 ah x 2%.    So I tried setting the AH in the SW to 100 and it ended at about 4.5 amps.  But the batteries were already about 99% charged. 

So to the OP .... have you had any experience now since last spring with the SW and charging?

I ask here not to hijack this thread ... or resurrect an old thread (only to get a response from the OP) I am starting a new thread here.