Hello,
My Classic is entering float with the batts not totally charged (90%). Absorb time is set to 2 hours. Should I just add 30 mm more or are there other settings that need to be changed?
Thanks guys.
What does Trojan have for Absorb Time and do you have a WBjr? I don't see it listed in your sig line...
I don't have a WBjr..Trojan does not tell an absorb time, just a voltaje setting per cel. My settings are set at 58.5v. Sun every days during 8 months a year.
looks like you are too low on the Absorb voltage it should be 59.28V (59.3?) and Float at 54.00V... and yes you need to extend the time.
ADD: Please refer to this Trojan Publication. 59.28V comes from there.
http://www.trojanbattery.com/pdf/datasheets/T105RE_TrojanRE_Data_Sheets.pdf
Without a WBjr you can NOT use the End Amps setting in your Classic and get the above voltage values at the battery ADD: due to system losses,wire, connections etc.. It allows you to see just how many Amps are really making it into the batteries , not just what comes out of the Classic.
The End Amps point should be where the Amps going In to the battery finally levels out to a flat line, which is normally ~ 1 to 2% of the Ahr rating of your battery.
ADD: The Amps you can see in the MNGP are the total amps the Classic is putting out but not what gets into the battery
.
hth
Do you use the Local App? you can plot the Amps out on the graph...
So if you increase the time to 4 hrs, and watch it for a day to observe the flattening out of the Amps, that will give you a good ball park of the time needed ... then you can back off the time and adjust as needed...
Sorry for my poor knowledge but I don't understand. Trojan says 59.3 for bulk but does not say for absorb. Is it the same?
I do not use the local app but I can check directly on the midnite display. Basically if I well understand, absorb time must be set when voltage In is about ~1 to 2% of the batt amp. In my case ~5 amp In.
I can first increase voltage to Trojan spec for bulk (as suggested) and keep with the 2 hours absorb time and see what happen. If that is not enough, I can then increase the absorb time.
Now Isnt it better for the batts to absorb at a lower voltage (58.5) and increase the absorb time instead of increasing the voltage and a shorter absorb time?
Hi dapago,
First, the battery manufacturer will not be able to specify an Absorb time, as this time will depend upon how deeply the battery had been discharged in the previous discharge.
YES, just use that Bulk voltage setting as your Absorb voltage setting in the Classic.
How is it that you determining the SOC is 90%, with your Hydrometer?
You CAN use Ending Amps without the WBjr, by using the Classic output amps. With fairly steady loads on the battery (via the inverter), and Flooded batteries it is fairly easy to find a good EA setting. In a household with out-of-control loads, this will probably not work too well, without a WBjr, however.
You can set your Absorb time, based upon the leveling off of the Classic's output current, but fairly large changes of loads on the system can make this more difficult to see.
IMO, it is probably best to use the manufacturer's recommended Absorb, Float and EQ voltages. Much more damage occurs when batteries are chronically under charged, than when a bit overcharged.
Yes, why not try increasing the Absorb voltage first, before changing the Absorb time and voltage all at the same time.
Vic
Hello Vic,
Thank you.
Yes I use an hydrometer to check the SG.
How do I set the EA? Do I just enter the value that correspond to 1% to 2% of my batt rating (2.5/5 Amps)?
All the settings in the classic were made by the dealer/installer (absorb @ 58.5V). I asked Trojan about the absorb voltage and here is their answer:
The absorb voltage from the graph below is 2.35 to 2.45V per cell in 48V that is 56.4V to 58.8V. Absorb at 30C should be about 2.35v/cell. Float remains same. Equalization 2.70V/cell every 30 cycles.
Considering Trojan info and in order to get the correct absorb voltage at 25C (because I use Temp Comp in the classic) I calculated 2.35+0.025V (0.005x5)=2.375 per cel x 24=56.425V for absorb.
56.425V for absorb seems far away from 59.3V recommended here. Even if I take the highest Trojan recommended value (2.45V per cell) that makes 58.8V.
Because I did not get 100% SOC with 2.35V per cell, I raised it to 2.45 (58.8V/cell) as Trojan highest absorb voltage recommend but still i do not get 100% SOC entering float.
Sorry but I have to ask again: should I keep 58.8V as Trojan highest recommended voltage for absorb and increase absorb time or raise absorb voltage to 59.3 as recommend here and keep with 2 hours absorb time?
dapago, please re read post #3... I made some additional comments to clarify what i typed, some of it was not clear enough after I read Vic's comments. Sorry about that.
I would go back to Trojan and ask them which is correct the published document or his response to your inquiry. There is some inconsistency there.
My final sentence is what I believe you should do.
In addition I recommend a WBjr , it is a very good tool..
Thank Westbranch. I attached the diagram Trojan sent me. It seems absorb voltage should be between 2.35 and 2.45 per cell as showned on this diagram. Still confused.
Vic: could you please explain: You can set your Absorb time, based upon the leveling off of the Classics's output current...
dapago, you asked
could you please explain: You can set your Absorb time, based upon the leveling off of the Classic's output current...
Looking at the graph you posted, down on the right side, the red line is the Amps going into the battery.
The horizontal part of the line you see is what we are calling ''leveling off''.
It tells me that the EA is from 1 to 3% of the battery capacity.
You need to keep track of the time that Absorb started and when the leveling started.
That time, in minutes,IIRC, will be what you enter into the EA location on the MNGP.
Westbranch.
Thank. But what the point entering the EA set point in minutes if absorb time does the same thing? It might be a typo error and I suppose you were referring entering the EA set point in Amp.
To make sure I did understand correctly:
1. Set the absorb time limit by monitoring when the CC enter absorb stage until leveling off. Enter this time period (in minute) in the absorb time limit set point.
2. Set the EA set point to 1% to 2% (~1.5%) batt capacity. In my case 225Ahx1.5%=~3.5 Amps.
Is that correct?
An other question.
EA set point has the priority over absorb time limit. Does that means then when the EA set point is reached, the CC just does not charge anymore the batt (meaning 100%SOC) until absorb time set point is reached or does it enter float mode or bulk depending on the loads?
Hi dapago,
In general, using EA to end Absorb, is a good approach, because the amount of Absorb time to fully charge a battery depends upon the Depth Of Discharge (DOD) that the battery experienced in the previous discharge.
On many systems, the DOD will vary quite a bit from day-to-day. So the required Absorb time would also vary quite a bit from day to day.
The graph that you posted, shows measured battery charge current. IIRC, you do not have the WBjr, so, if your system has varying loads, using the output current of the Classic will not be a clear indication of the actual amount of that current that is flowing into the battery. Depending on the size of the other loads, the CC output current may give an adequate indication of the battery current plateau.
If you were not going to use EA to end Absorb, then, noting the amount of Absorb time required to reach that plateau, could be used as an approximate Absorb time setting in the CC (and not try to use EA). But, again, this required time may well vary from day-to-day, or week-to-week, depending upon the DOD that the battery has experienced, compared to the DOD of the battery when you observed the amount of time that took to reach the charge current plateau.
Without the WBjr, that actually measures the battery charge current, by using a Shunt, EA can still be used, when Flooded batteries are being used, and with systems that have either predictable loads, or with loads that cycle.
This may be too many words. Hope that some of it makes sense.
Vic
amps that were received by the battery ...
The CC will stop ABSORB when it reaches either the time set or the measured EA.
sorry have to go and I see most of my post disappeared, more later if needed.
YES, the EA function is an OR -- either the set Absorb time set ends the Absorb, OR, the EA reaches its set value, and ends Absorb, which ever one happens first.
AND should have also mentioned, that when using EA, one should set the Absorb time to a value that will usually be more than would ever be required.
Off to work. Vic
Vic. To make it simple. Should I just set the EA to 7.5 amp (~ 3% of 225ah allowing a small continuous load on the batts [2 fridges, sound system on all the time] and the absorb time to 3 hours?
Unfortunately in my location I can not get the WBjr or have to wait until somebody would bring it back to me from the US.
If you don't have a WBjr connected to your Classic then to keep things simple don't bother trying to terminate Absorb using any EA figure, just use the default 2 hour Absorb timer.
At least until you get a WBjr and then can measure with some accuracy the actual battery current.
dgd
Ok then. Will try to get the WBjr and start a new tread on that matter once I've got it installed. For the moment I will just raised the absorb voltage and/or time and try to get the batts 100% SOC at entering float with those 2 settings.
Hi dapago,
We do not know too much about your system.
Many systems already have the 500 A 50 mV Shunt installed in a DC Conduit box (called different things by different manufacturers).
If your system does not already have this 500 A Shunt, then you should order it as well:
https://www.solar-electric.com/catalogsearch/result/?q=500+a+shunt
The Deltec Shunt is quite common. MidNite also offers a shunt, that has two extra holes for the MN Shunt busbar, which might help you rewire things easily.
If you are not going to try using the Classic's EA function, then you may want to watch the SGs for a week or two, as you try to dial-in the Absorb time that will allow fully charging your batteries, at least twice per week.
Your battery bank is not huge, so, perhaps your system will really need to be recharged every day.
FWIW, Vic
My needs are not huge either. For now my needs are ~ 2.5 kwh daily and in the morning before the sun kick in, I am ~ 80% SOC. My needs will raised in the future to ~4KWH.
I'd like to try the EA function but still can't get my head around what figure in Amp I should enter. I still don't know if the EA function limits the Amp to the figure entered or does something else. On the other side, I don't see the reason to use the EA if without it,I am reading ~ 5Amp in the CC display near the end of absorb... But my batts don't get to 100% SOC.
What I know is that in float mode the CC shows ~ 2.5 Amp and near the end of absorb (I change the voltage to 59.3 and raised the time to 2h30 yesterday) it shows ~5Amp. Today took a SG reading at float and still not getting 100% SOC but better than yesterday. Today I raised the ABsorb time to 3 hours and will see tomorrow.
Quote from: dgd on December 29, 2016, 11:54:50 PM
If you don't have a WBjr connected to your Classic then to keep things simple don't bother trying to terminate Absorb using any EA figure, just use the default 2 hour Absorb timer.
At least until you get a WBjr and then can measure with some accuracy the actual battery current.
dgd
With 2 hours absorb time I enter float and my batts are not 100 % SOC in sunny day. This is the reason of my post. I could just raised the abs time but wanted to see if the EA function could help.
At the end I will certainly follow your advice and just not use EA.
Hi dapago,
Fine on your changes to Vabs and Absorb time.
Just wait a few days to see what effects the changes will make on the SGs.
BTW, what Hydrometer are you using.
Also, believe that you are in the Tropics, so, if your batteries are warm, SG readings will probably need to be Temperature Compensated.
What SG reading are you using as an indication of 100% SOC?
What is the Temperature Compensation value in the Charge> R-Comps are you using?
Sometimes we need to wait a few days of charging to see the effects of changes to Vabs and or Charge time, make with the your SG readings.
FWIW, Vic
Quote from: dapago on December 30, 2016, 09:05:05 PM
With 2 hours absorb time I enter float and my batts are not 100 % SOC in sunny day. This is the reason of my post. I could just raised the abs time but wanted to see if the EA function could help.
At the end I will certainly follow your advice and just not use EA.
So you are seeing the SOC increase to 90% while charging in Absorb, then the SOC changes to 100% when charging changes to float?
Where exactly are you seeing this SOC reading as I thought it was only calculated properly when using a WBjr with the Classic.
Or have use ascertained the SOC using a hydrometer to measuer the battery SG?
I would be confident that after a 2 hour timed absorb that you battery bank is 100% SOC
dgd
Quote from: Vic on December 30, 2016, 09:43:51 PM
Hi dapago,
Fine on your changes to Vabs and Absorb time.
Just wait a few days to see what effects the changes will make on the SGs.
BTW, what Hydrometer are you using.
Also, believe that you are in the Tropics, so, if your batteries are warm, SG readings will probably need to be Temperature Compensated.
What SG reading are you using as an indication of 100% SOC?
What is the Temperature Compensation value in the Charge> R-Comps are you using?
Sometimes we need to wait a few days of charging to see the effects of changes to Vabs and or Charge time, make with the your SG readings.
FWIW, Vic
I am using an hydrometer I bought in a battery shop. Could it be inaccurate? No many choices here.
I am using 1.277 SG for 100% SOC.
The CC is set to Compensate temperature in Temp-Comp setting (-0.005V per degree C)
My battes never get hot or warm even when EQ and that surprised me. But gazing all right (strong smell and bubbles sounds)
Dgd
I am seeing 90% in float using an hydrometer and since increasing absorb V + absorb time to 2.30h yesterday I am seeing ~95%.
It is sunny generally every day (I am in the tropics). I get float every day at ~1pm/2pm with still 2/3 good hours of sun to go. When cloudy (white clouds) I read ~1000 watts and with dark clouds ~500watts. At the end of the day, on average when CC is resting, I harvested ~4 to 5 KWh (CC display). If I EQ at 1pm, I read ~1800/1900 watts IN on the display.
With my CC 150 wired 3s,2p I always reached 100 SOC every day around 1pm whatever the weather conditions with max 2 hours absorb time. With my new 200CC, 2 more panels and just an other inverter fridge added to the load, 2 hours absorb time is not enough apparently and some cloudy days I am not getting float. I would have thought that with 2 more panels I would have got the same charging patern (float every day at 1pm whatever the weather condition)
I would still be intending to get a WBjr/Deltec shunt (or get an MN Epanel or MNDC) then use the battery monitor reporting in the local app.
I have set up a few systems using 225Ah FLA batteries and have never had an problems with the default 2 hour Absorb time (at 29.2v) getting the cells to 100%. But then I tend to size capacity ro never get below 75 to 80% capacity with FLAs.
If you are only seeing 90% after 2hr Absorb then I'm guessing the bank must be starting out at a well discharged state. If you are down to 50 to 60% SOC then that would make me think the capacity of the bank is too small.
Have you actually checked the SG in all of the cells?
What are your Absprb and float voltages and have you done any EQ yet?
dgd
Maybe you need to EQ the batteries to get some of that sulphate off the plates and back into the electrolyte ?
Also, while charging, are all of the batteries at the same voltage ? They should be fairly
well balanced.
Could some batteries be in better shape than the others ?
Make sure the water/electrolyte level is covering the plates and then some of course.
boB
Quote from: dgd on January 05, 2017, 04:38:35 PM
I would still be intending to get a WBjr/Deltec shunt (or get an MN Epanel or MNDC) then use the battery monitor reporting in the local app.
I have set up a few systems using 225Ah FLA batteries and have never had an problems with the default 2 hour Absorb time (at 29.2v) getting the cells to 100%. But then I tend to size capacity ro never get below 75 to 80% capacity with FLAs.
If you are only seeing 90% after 2hr Absorb then I'm guessing the bank must be starting out at a well discharged state. If you are down to 50 to 60% SOC then that would make me think the capacity of the bank is too small.
Have you actually checked the SG in all of the cells?
What are your Absprb and float voltages and have you done any EQ yet?
dgd
I am down ~75% SOC in the morning. Not check all of them but 1 in each batt. I raised Absorb to 59.3 and float at 54. I did an EQ and then I get 100% SOC. Now it is sunny every day every days and only then I get 100% SOC at noon and it stays like that until dark.
Quote from: boB on January 06, 2017, 12:09:31 AM
Maybe you need to EQ the batteries to get some of that sulphate off the plates and back into the electrolyte ?
Also, while charging, are all of the batteries at the same voltage ? They should be fairly
well balanced.
Could some batteries be in better shape than the others ?
Make sure the water/electrolyte level is covering the plates and then some of course.
boB
I did an EQ yes. 100%SOC after 20mn. Yes all the batts are the same voltage and 6 months old. Water electrolyte is well over the plates level so that is not the problem. Absorb is now set to 2h30 at 59.3. From now on, sun will be shinning every day for 6 months so maybe I should lower absorb time to 2h and see what happens.
dapago, you need to measure the SG and please post it here for review... so we can see just what happened...this should not be a one or 2 day recovery... :)