Would it be possible to add the absorb time to the list of daily values stored in the Classic and have them where they can be viewed and downloaded to your PC in a speadsheet format.
I have 16 S530 Surrette batteries in a 48volt system.
With my system, the absorb value is more important in determining the state of charge the batteries are at, without using a Hydrometer. Surrette recommends Absorbing for 10 hours, but I have found that I can bring them to a full charge in just over 7 hours. It would be nice to have these values at a glance. Most of the time I will reach absorb setpoint of 58.4 by 10:30 or 11:00 am this time of year. I am out of sun by 4:30, this only leaves 6 hrs at best to absorb. So once a week I watch the weather for a sunny day and bring the batteries to 58.4 with the generator just before daylight and then let the solar array keep it at the absorb setpoint for the required time.
With all of this being said, you can see that having this info at a glance would make it easier to manage and track day to day production.
Hi Joe.
Adding Absorb time to the Classic could be done but usually the Float time will tell you if it finished its Absorb or not.
Were you wanting the actual amount of time between minimum and maximum absorb time ? For instance, if minimum
absorb time was 30 minutes and maximum was 2 hours and it Absorbed for 60 minutes, is that what you want to see ?
The rest of the time for the day the Classic will be in Float so that will give an indication. One of the problems with the minimum
and maximum absorb times is that even if there is say, 50 Watts during a Bulk cycle, the absorb timer will rack up the minutes.
There are ways around this but isn't implemented in the Classic yet...
Another thing you can see, at least in the recent history in data logging is the charge stage the Classic is in along with a time stamp which will also give you a good indication of Absorb time as well as the amount of power the Classic is producing out its battery terminals.
Will think more about this.....
As always, thank you for the input.
boB
Thinks Bob,
This time of year I never reach float stage to know that I am at full charge. That is why it would be nice to know how long it has been in the absorb stage. I have my max absorb time at 7 hours is that way to long, I have check state of charge with hydromerter and it take about 7 hours in absorb stage to reach 1.260 SG in the battereis.
Thanks Joe
I can see where a "Time in Absorb" would be real handy for us Off grid guys that seem to never get to float in the winter. I could vote for this addition.
Ryan
yikes, 7hrs of time absorb charging would have trouble reaching float in the warmer months!!!
OK then, we'll just have to see what we can do for logging Absorb time...
Now, I have to ask, what is your batteries' Amp-Hour rating and much available power do you have to charge them ?
But maybe a better question is, (because of DC loads on the batteries), what is the typical amount of current going
into the battery bank during the day ?? Can you look at the hourly (recent) data logs to get an idea of what voltage
the batteries are getting to and a ball park on how long they are staying there ?
Will the system ever go to float if you set the Absorb time for, say, 2 hours ?? If not, then are you sure you have
enough power for that size of battery bank ? Or, how about 1 hour of Absorb ?
boB
Rolls / Surrette has always recommended a real long Absorb charge not sure how they anticipate Off Grid people actually getting that many hours in Absorb though ::)
Midnite,
THis is exactly what I had asked for in another post where you guys had asked what additional feature one would like to see in the app. I was remarking on how I would like to access absorb time so I would know from a design perspective if I need to add more panels or remove loads etc.
Further to this point I would wish to know why is it that the timer for absorb and equalise start counter up (when it was previously counting down) when passing clouds make the input power decrease. My layman thinking is that it should stop or pause until input power increases again and the timer would continue to countdown. If one had a high percentage on clouds on a sunny day it is concievable that one would never complete the count down since it alway counts up when power levels decrease. Tell me I am missing something here as it seem illogical to me.
Cheers..
Damani
1/2,
I have noticed the same ting with S/R. How do you generally set your absorption time in the field when(or if) you use S/R batteries given what they ask for.
Cheers...
Damani
I never used R/S batteries they are just to hard to charge off grid.
1/2,
That is an interesting comment. I even raised my eye brows. So what are you batteries of choice then? Trojans (ya know if you use trojans in another conversation they mean a complete different thing).
Hi All,
Well, to me, as a Surrette user, long Asorb times are only required when a large bank is cycled to a lower SOC. on my current system, use about 1:10 Asorb time, and almost always get into Float by noon, unless stormy.
Larger banks that are cycled to/below 80-85% SOC need more charge time, oh,, that is obvious.
The bank at the new project site runs an inverter and few internet radios plus some power tools, and needs about 1.8 Kwh per day do reach Float. But it just has a 1.1 Kw STC array to float the bank. Takes about 2 hours in Asorb, due to low charge I.
Just my experience.
ANd I'd also like to have Asorb time logged, as it is an aid in setting the charger. EIther in using Return Amps (End Amps), or perhaps in setting Asorb V. Not essential, but a help for those of us who have no other logging data, and cannot watch the CC when it transition from Asorb to Float.
On the venerable MX-60, had thought if it could just keep the Asorb countdown timer value as it was at the transition to Float (until next sunrise), instead of zeroing it out ... but that might have upset Rebulk or semething else ... dunno.
Thanks, Vic
OK then, it's unanimous ! Absorb time logging will be coming. I think that most of you know that you can view the present Absorb/Bulk timer value and select between HOURS:MINUTES or MINUTES:SECONDS in the timer/view sub-menu.
It starts out counting up with the MINIMUM Absorb time setting and counts up to MAXIMUM time which you all appear to know about.
This method has worked fine for many (10+) years now so it won't change too much, however, I do have a way to make it work better
without just pausing or stopping when going back to MPPT mode as DapDan was concerned about. It is very similar to when the Classic
wakes up at dawn.
boB
Logging the absorb time would be super nice, but might it be possible to log the amps at the termination of the absorb cycle, since that is also a useful data point? When I see my batteries are taking in less than 10 amps I know they are nearly full, so that's my line of thinking here.
Hello Bob,
I have the pleasure of living in eastern Oregon where the sun is at a premium.
My array consist of 8, 210 watt sanyo hip panels, I have no problem reaching absorb in the summer months. I can reach float stage now in 2 hours but this leaves the batteries at 80 to 85 % charged. Typicaly I can produce a current of 25 to 30 amps in full sun.
In the winter months I use 7.0 to 8.0 kwh a day. In the summer that falls to 4.5 to 6.0 kwh a day. My float setpoint is 54.8 volts absorb setpoint is 58.4 volts.
I do scroll through the time stamps sometime's to determine the time at absorb but this process takes a while.
It would be helpfull to read and down load to a chart of the day to day absorb time for the past week to determine the state of charge the batteries are at.
Thank you for your ear, Joe
Joe, I love eastern Oregon ! Great country !
what kind of batteries do you have ?? If regular flooded, maybe you need to raise your Absorb voltage ? Trojan, for instance, suggests 60+ volts for their L16s for Absorb. You might check your battery specs closely anyway just in case. You have to watch the water level though because it will go away a bit faster. it's usually better to boil off some electrolyte and not undercharge to help avoid sulphation.
For logging, have you tried looking at the battery voltage in a graph ? You might be able to more easily tell where it went to float.
Not too long now, the Local app will be looking at the classic's logs so should be easier to look at on the PC screen.
And Laszlo, you should be able to see amps out (or power) at any time, but the problem for most people (maybe not you) is that there may be other loads and the current from the controller may not all be going into the batteries.
boB
Bob
I have 16 S530. I use about 100 amp hr a night out of 800 available amps where I draw only 10% of my capacity a day from the batteries, do I need to cycle through an absorb stage every day? How is this affecting the longevity of my batteries. I might add, that for a 12 month cycle I log 108 hrs on the generator.
I power a 1800sq foot home off grid and am so far very happy with my system. Even happier yet with the new Classic.
By the way, when does a person stop wanting more power and a larger system?
One last question, can the daily values be veiwed by the pc and also will these values be viewable on Mymidnite.com when it is up and running?
Joe
I've been following this thread because I have similar interests with absorb time, plus it sounds like my system is very much like the original poster. I'm still learning about my Midnite 250and don't want to hijack, but have a question about the midnite operation.
If you set the absorb time way up to like 7 hours and it reaches the absorb volt setting in say 4 hours, does it go to float? Or does it just keep plowing away until the timer runs out?
I'm having an issue getting SG up and this is very interesting to me.
Thanks!
Paul
you may be misunderstanding about absorb charging. in absorb the voltage is held constant and the current is allowed to diminish. some go by time and some go by a preset current that is hit before going to float. with the surrettes if you put in say 4hrs or 5hrs of bulk time to the batteries they may not see the full cycle in absorb as daylight time can be limited. maybe try to bring it up with a generator and charger early in the morning to allow solar to top it off or stay off your batteries all together with the generator being used for the ac loads to allow the batteries the chance to come up all of the way, whichever way shows the results you need.
Ok, Got it! Thanks for clearing that up for me niel. Like I said, still learning and appreciate all the help...
Paul
Quote from: Joe on January 18, 2012, 08:00:29 AM
Bob
One last question, can the daily values be veiwed by the pc and also will these values be viewable on Mymidnite.com when it is up and running?
Joe
The daily values will soon be viewable on the PC with the local app and I think that will be included on the Mymidnite because the
applications are very similar. Then, USB at some point.
The only other way that may be done on a PC earlier than we get it done will be for someone to write their own PC modbus software.
I think I would just wait for now.
To give the batteries a long life, 2 things. Don't let them boil dry and expose the plates and do not let them stay undercharged.
What are the charging specifications for those batteries ?? Remember too that the Surrettes and Rolls batteries (same thing) will
not usually have full spec'd capacity when brand new. They have to be used for so many cycles first. That's what I hear and Jamie Surrette
seems to agree on that point.
So, you need to get the absorb voltage up and leave them there long enough. The question is, how high and how long ?
Some people never have enough battery or money. It's probably different in every situation.
boB