Hello All,
I am running a Classic 150 in 12V mode with a WB Jr and four 6V 230 AH FLA batteries. I have set end amps to 5 (1% of battery capacity) and absorb duration to 1 hr 15 min. The inverter and refrigerator keep load amps at 6-10. I've seen the charging amps at less than 5, total amps at 12 or so.
Does the classic differentiate between charging amps and load when monitoring end amps?
With a WBjr in the system, you are able to set the END Amps going into the battery, if you did NOT have a WBjr your end amps would be the amps leaving the Classic.... which may or may not be the Amps actually going into the battery bank... the difference would be any loads that are running at the time...
Add, that 1.5 hr Absorb may be a bit low, you want to watch it in the winter
Quote from: ScoobyMike on July 08, 2018, 12:28:12 PM
Hello All,
I am running a Classic 150 in 12V mode with a WB Jr and four 6V 230 AH FLA batteries. I have set end amps to 5 (1% of battery capacity) and absorb duration to 1 hr 15 min. The inverter and refrigerator keep load amps at 6-10. I've seen the charging amps at less than 5, total amps at 12 or so.
Does the classic differentiate between charging amps and load when monitoring end amps?
Hi ScoobyMike,
Yes, your WbJr will show the WbJr Amps that are going into the batteries -- on the Wb Status display, which, on the MNGP is three Status button presses from the first Status display. Or on the LocalApp, on the Status page just under Whizbang Jr. label on the right side of the App display System: .
Since your batteries are Flooded types, your Hydrometer will tell you if you have sufficient Absorb time, and if your Absorb voltage is in the correct range.
Absorb time really depends upon the Depth Of Discharge (DOD) in the previous discharge.
It will take a bit of study, to determine the best Setup details for your system. Depending on the efficiency of your refer, the inverter, and other loads, your one hour fifteen minute Abs time might be a bit low.
Most manufacturers of Flooded batteries note that the Charge Efficiency is about 85%.
Please note, that battery monitoring devices give approximate values for SOC, Remaining AH, etc. Your Hydrometer is THE thing that will give you actual SOC values.
What are your Charge voltage settings, and what value have you used for charge Temperature Comp?
FWIW, Vic
In the CHARGE submenu, ADVANCED I think it is.... On the lower left (soft key) under End-Amps setting (5A for you) it should give you the option of SHUNT or CLASSIC (abbreviated ?)... Choose SHUNT. It should toggle between one or the other. Then press ENTER to make sure that the Classic remembers this.
If it is set for CLASSIC, then it will be looking at the loads as well as battery current. SHUNT uses only the current into the battery for ending amps.
That is the one you want.
And then all the other good advice the others are giving too of course :)
boB
Thank you for the replies! I typed my absorb time wrong, it is 2hr 15min.
Vic, I use 14.4 for bulk and absorb, 13.2 for float. Tcomp and battery efficiency are the classic default (or maybe WBJr suggestion) I'll look when I figure out where they are again :-) I agree with the specific gravity yielding the best charge status however going to float with end amp = 5 should yield a fully charged battery. I have the classic reset to full whenever float is achieved. Now I may not get full absorb on cloudy days so should I push my absorb timer higher?
boB. It is set to shunt. I reloaded to make sure
I am occassionally checking when the system goes to float, I have seen it bin absorb below 5 amps charging tho. Seems to always go 2:15, but I can't swear to that. I typically take batteries down to 85%, but my power hog son is with me now and we go down to 70%. On sunny days the 5 end amps and 2:15 absorb time seem to be neck and neck.
Hi Mike,
Ok on your Absorb time setting being 2:15, that does seem better, for many off-grid systems. Assume that you are off-grid.
Why not leave your Absorb voltage (Vabs) and time where they are for now. Your SGs will tell you how that is working in general. When using EA to end Absorb, setting the Absorb time higher than generally required, is often good. This does allow for heavier discharges, on occasion.
Assume that you are running Golf Cart batteries. What brand are these, and do you have the manufacturer's recommended charge setting for them? Seems that your Vabs might be a bit on the low side, but it all depends ...
If you find that your Vabs needs to be changed, realize that the required EA setting will change, for the new Vabs.
New batteries often need 50, or more discharge/charge cycles to develop full Capacity, and settle in, and become more predictable. Your batteries may well have had these cycles.
You may have dealt with Flooded batteries for some time, but, please be certain to RINSE, RINSE, and RINSE your Hydrometer after each measuring session. Use Distilled Water ONLY for this and to add to your batteries to make up for lost water.
More later, it seems like you are off to a good start. Vic
Thank you Vic,
I have 230 AH Duracells from Batteries Plus. They were new this year, put into service mid May. I could not find specific Duracell charging instructions, I am following the instructions from US Battery. I am new to solar but have been using deep cycle batteries in boats and RVs for more years than I care to count.
I am very happy with the Classic. On sunny days the Iabs is on the order of 1% battery capacity and I get 2+ hours of float. Timed absorb on cloudy days short charge the battery, which is why I mention increasing absorb time. I have a 55 Amp Iota and generator for rainy days.
Mike
Quote from: ScoobyMike on July 09, 2018, 06:03:47 AM
Thank you Vic,
I have 230 AH Duracells from Batteries Plus. They were new this year, put into service mid May. I could not find specific Duracell charging instructions, I am following the instructions from US Battery. I am new to solar but have been using deep cycle batteries in boats and RVs for more years than I care to count.
I am very happy with the Classic. On sunny days the Iabs is on the order of 1% battery capacity and I get 2+ hours of float. Timed absorb on cloudy days short charge the battery, which is why I mention increasing absorb time. I have a 55 Amp Iota and generator for rainy days.
Mike
Those Duracells used to be made by Eastpenn Deka - look the tops and then compare to Eastpenn Deka of same type . East Penn Deka has a lot of info on their website for charging - this link and others . Look at column for Flooded Monoblock and use the lower of the ranges if they are new batteries. http://www.eastpennmanufacturing.com/wp-content/uploads/Renewable-Energy-Charging-Parameters-1913.pdf
Sweet! And that is why ClassicCrazy is a hero member!
Vic,
I checked my setup values and Temp Comp is 1 %, efficiency is 94%.
The Tcomp factor in the Deka document Larry pointed me to shows 3mV per cell per deg C.
.003V per deg / 2.4 V x 100 = 0.125% per deg C
Am I looking at this correctly? If so, 1% is high.
Efficiency â€" The WBJr instructions note FLA efficiency is typically 94% - 96% so I was surprised to see your 85% number. I poked around a bit and found the Stevens and Cory paper on FLA efficiency near top of charge. In their results section they reference the 85% efficiency as the commonly used value for charge efficiency and less than 60% efficiency when SOC is above 80%. Interesting… I will attempt to attach the paper.
Anyway, I have adjusted my parameters to:
Tcomp â€" still 1%
Efficiency â€" 85%
Float V = 13.8 (from Deka paper)
Tabs =3:00
EA still 5
When all is said & done it seems logical that when the battery stops accepting current then it is charged. It has been a bit cloudy lately and we are running down to 70% SOC lately (I have a power hungry guest) and I don’t want to short charge the batteries.
Mike
Hi Mike,
Thanks for the update on some of your settings.
Am at a location without a Classic, but, from memory;
In the Classic Charge menu, if your batteries are Deka-made, then under Temp Compensation, or similar, set the value as 3 mV. This is negative 3 mV per degree C compensation for each of the cells in your battery bank. The Classic will know the number of cells, based on the system voltage setting.
For the Whizbang Jr Setup, there is the Charge Effiiciency, and IMO 85 % is a good place to start. There is also a Temperature factor, that is what changes the Remaining Capacity display, and the T-capacity (or similar) that is displayed on one of the Wb Status pages of the MNGP. This factor is usually a small number, and IIRC, it is the percentage of Capacity reduction for each degree C that the measured battery temperature descends below the battery Reference Temperature (usually 25, or about 27 C).
Have always felt that the recommended 94% Charge Efficiency is a great value for AGM (and perhaps Gel batteries, but most Flooded batteries start around 85% (on an average recharge), and decrease from there with battery ageing.
Thank you very much for (successfully) attaching that Stevens - Cory paper on battery charge efficiency ! I had not seen this before ... THANKS !
Believe that the two main battery banks here have an efficiency of about 70% on the average recharge (almost 13 years old).
When a battery is fully charged, it still Accepts current when the charger is still at the Absorb voltage, but that charge current just essentially stops decreasing. When the charger switches to Float, (after some time, to allow the surface charge to diminish from the battery charge voltage having been higher, in Absorb), then the charge current is quite low. This low charge current continues, until the charger can no longer maintain the Float voltage, for solar charged systems.
Every resident in a household generally needs some individual power. Often, others do not appreciate the relative size of this amount, compared to what can be produced and stored.
Hope that some of this helps. Thanks again for the update, and that paper. Vic
Vic - I think you have to put the minus sign on the mv/C/cell setting so would have to enter -3 .
And as Vic said you just enter -3 in the temp compensation menu there and it will calculate out how many cells.
You can see the temperature compensated value temperature hidden away on some menu on the MNGP or in the Local Status App Advance screen to the right of where you enter the value . Or you can see it on Grahams Android Classic Monitoring App on the Message Screen or the Info screen - forget which one right now. Graham also put the Target voltage and timers for Absorb and Float so that is a real handy screen especially in winter here when batteries are cold and I want to know what is going on .
Larry
Quote from: ScoobyMike on July 10, 2018, 06:51:31 PM
When all is said & done it seems logical that when the battery stops accepting current then it is charged.
It may be though that if the battery needs a good 2+ hour weekly (or whatever) Absorb charge cycle that it may only draw this
very low current to mix up the mixture and give the plates a good de-sulfating.
I would love to hear about others' experiences with their charge current levels in these situations.
boB
Thank you for the input guys!
The Tcomp I was referring to is in WBJr setup-2. Here it is the percent capacity change per degree C.
Also, I was too loose with wording regarding completing the charge cycle. I meant to say that if the absorb amps decay to 1% of the battery capacity then the battery is charged.
Hi Larry, thanks for clarifying my earlier statement regarding the charge voltage Temp Compensation. The way that I worded it, it was ambiguous at a minimum, saying, "... set the value as 3 mV. This is negative 3 mV per degree C ... ".
Do not know for certain, but think that it may even be possible to set a Positive number in the Classic's Charge Temp Compensation menu ... forget.
And, boB, for the FLA Lead Antimony battery banks, here, we note the following, regarding the nominal EA values that maintain full-charge SGs:
When these batteries are young, and therefore, generally lower Vabs settings can maintain SGs, that an EA of about 1% of 20 hour Capacity do fine. BUT there seems to be an additional factor -- the DOD of the battery in the previous discharge. Deeper discharge seems to equate to a higher plateau point for the battery charge current. This can mean that the previously used EA for more shallow discharges simply cannot be met, and the Absorb timer will dictate the end to Absorb.
As the battery bank ages, it seems that a higher Vabs is required to return the battery bank to full charge. This, of course, means that the ideal EA setting will need to be raised.
Also, there is some ambiguity is choosing the point to say that the battery charge current has actually plateaued. We choose a point, where one starts to wonder if the EA will EVER be reached. This is fairly out on the tail of this current curve. This is also where WbJr current into the battery has a reasonable amount of Jitter, and cycling Opportunity loads change the charge voltage seen by the battery. Here, with a 10K BTU A/C will need one EA value if running, and a different one if the A/C is not running. This one load, makes about a 1.2 Amp difference in battery charge current.
IMO, the current jitter, is caused by voltage jitter. And, is probably caused, primarily by AC voltage Ripple, at the battery terminals. IIRC, this ripple is around 1 V peak to peak when the A/C is running. The PF of the A/C may contribute some to the magnitude of this.
The later comment about jitter, really is not on topic ...
The main battery banks here are about 12.75 years old, and this affects my perspective, and may not what others see on young battery banks.
FWIW, 73, Vic
Good stuff, Vic.
The voltage jitter could have a few causes. AC load or Classic regulation or something else.
boB