We have some new Beta code. it has support for the now available WBjr current sense module and also has "Days between Bulk charges"
http://www.midnitesolar.com/firmwareReport.php?firmware_ID=5&firmwareProduct_ID=1&act=edit (http://www.midnitesolar.com/firmwareReport.php?firmware_ID=5&firmwareProduct_ID=1&act=edit)
boB will be doing the instruction sheet for the WBjr today and I will get it up on the website with the Classics.
Ryan
Hi Ryan and the MN Crew.
Thanks for getting the WBjr AND the Days Between Bulk in this new code.
Will be a week or so before I can get to a Classic CCed site, but will be working with the new FW very soon. Thank You very much! Vic
Under what circumstances would one use the "Days between bulk" setting? Just curious.
Hi Tons ..
Many of us with Flooded Lead Acid batteries, full recharge every day is not desirable.
Some off-grid systems do not have consistent daily loads and are not always taken below 90% SOC. It is generally best to cycle FLAs below 90% before recharging, but should be recharged every 5 - 7 days even if the batteries are not cycled below 90% SOC. There is some difference in opinion on the exact details of this. Furthermore, in Summer heat, daily recharge from shallow discharges does tend to dump quite a lot of heat into the battery bank, as the final charge stage -- Absorption -- is not very efficient. This efficiency loss occurs within the battery bank, and shows up as battery heating. Doing a full recharge from a lower SOC will extend the Absorption stage when one chooses to do it, but on average, quite a bit of battery heating can be avoided.
Some of us have been manually avoiding complete recharge by either shutting Off the PV input for some number of days, or have set the Absorption voltage on the Classic to Vfloat + 0.1 V or similar, to gradually reduce the SOC of the battery over a period of days.
Having an automatic way of delaying full recharge can be helpful in cases as noted above.
At unattended sites, delaying full recharge automatically is a great benefit (verses having to drive to the remote location to do this).
My opinions. FWIW, Vic
Some of us have been asking for having some level of doing some of this automatically.
Thanks for the explanation! And now I get it.
QuoteMany of us with Flooded Lead Acid batteries, full recharge every day is not desirable.
QuoteIt is generally best to cycle FLAs below 90% before recharging
Vic, this has got my attention!
I have a 1330Ah of flooded lead Acid batterys.Made up of 2volt Exide cells for 48v system. Being a reasonably big battery bank at 63kwh on paper and given that Monday - Friday there is only house base loads on the system. Perhaps 3kwh -maximum each day . The system spends a lot of its time in the mid to high 90% range. With lots of sun and a 4000w array. Every day after going through the bulk and absorb change it quickly reaches (end amps) by about 9:30 - 10:00AM and spend most of the weekdays in float.
Spending all this time cycling from say 95% full to 100% I have noticed my efficiency, as in Kwh consumed (around 3kwh) vs what the classic has to put back in each weekday to go through this cycle isn't to good. Perhaps 3kwh out vs 5-6kwh back so 50 - 60% efficiency . I'm sure with a deeper DOD the efficiency would be better and I usually find it is on the weekends when I am there.
So could you fill be in more on the theory behind not fully charging each day and whats a good plan for my system. It's always drummed into you that flooded cells like shallow cycles for example on cycle life graphs my cells are rated to 5000cycles at 10% DOD . So that's always been my rule and I don't think my cells have spent any time below 10% DOD.
So it would have you think its a good thing to keen them topped up each day. Or is the theory just not to go through the bulk-absorb stage every day and have them come up to 100% full slowly just using float voltage to charge and then only do a bulk-absorb charge every few days?
Or is this only for situations where you have no load at all on the bank ?
Kurt
It is not so much theory but fact that recharging in the 50 - 80% range is most efficient. the next is 80-90%,
the idea is if you float every 3 - 5 days you give your battery a good workout and a good charge through the range exposing surfaces that otherwise ( float daily) would never get touched.
IIRC it is Chris Olson that has written a lot over at NAWS BB.
Ok yes I agree that charging up to 80% soc is more efficient then from 80- 100% So yes sorry yes that part is fact not theory.
So this new setting "Days between bulk" if I was to set that to say 2 or 3 days what happens on the no bulk days? Will the classic just wont charge at all (effectively go to sleep) for a few days?
Can you set it for particular days of the week or is it just a ongoing tally? (Sorry my pc with the app isn't with me)
One part of me is thinking why not just increase the 24hr load on the battery's , at least the PV is being used each day then. Some kind of work could be done .Extra deep freezer, swimming pool pump, Pump water to high ground, something usefull. Rather than just have the 4000w of pv sit there for days while the pack SOC comes down.
What about salfation, is a few days at less than 100% not enough to bring that on?
I will give the setting a try just to see what difference it makes say charging every 2nd day just for a week. If it shakes my pack up a little and improves over all efficiency.
Kurt
The recent thread on optimum SOC is here:
http://www.wind-sun.com/ForumVB/showthread.php?20840-What-is-the-optimal-SOC-range-for-cycling-lead-acid-batteries&highlight=optimum+battery+charge
Its long and not completely resolved, but plenty to think about for sure.
Kurt, If I had loads to run that were not taking advantage of excess PV, OPPORTUNITY LOADS!, that is what I would run before going to a no Bulk setting, especially if they were in periods when you weren't there. The Classic can do this nicely, then if still not enough, go to the No Bulk, for a few days...
Well I just read through the 14 page discussion on the wind and sun forum. A few things I could agree on but a lot of it needed tweaking to my personal situation and system and a lot of it depends on so many factors and weighing up pro's and cons.
As soon as My 63kwh of lead is dead I will be going to a small 20kwh lithium lifepo4 bank. I have much more experience with this chemistry and its benefits are huge. Then all this black art of bubbling boxes of acid and watering the dam things like pot plants will be a distant memory.
One load we do have that is a great place to dump our excess PV energy is our EV (Mitsubishi Imiev) it has 16kwh lithium battery and puts a nice 2200w load on our system when on charge.It charges in the 90% + efficiency range and you get the energy back out of it at about the same efficiency ;) 10kwh in = 100km of driving for us. Its only a 16kwh battery but I can discharge the battery at 50kw rate! and recharge it at the same rate (public fast charger). I can let it sit for months at 50% SOC or work it in the 40 - 80% range and it will be doing it a favor not harming it like FLA.Other than a balance charge once a month of so there is no black art like FLA its simple. Even functioning at the high rates I get out of it about what I put into it so efficiency is way better. Lithium is just so much easier to work with and performs so much better than FLA. If Mitsubishi can give that battery a 8 year warranty when it gets abused that much then a similar battery will last a lot longer in a lightly loaded/charged off grid application.
Kurt
Hi Kurt,
Well, in my opinion, much of the exact ins and outs of recharging FLAs is theory, not fact. There are many variables, and many opinions.
In looking at cycle life of FLAs, almost all of the charts from different manufacturers stop at 90% SOC. This means that most of the manufacturers recommend that the batteries be cycled to 90% or lower SOC. Cycles to 80% for my banks seem about ideal. But, when one is not around to consume power it takes more days of no Bulk to reach this level of discharge. Discharge cycles that do not get to/below 90% SOC have been noted as causing earlier battery failure than cycles to 80%, for example. This is apparently due to Lead Dioxide clumping on the plates, rather than being evenly distributed over the entire positive plate. Those of us with larger battery banks, especially those of us who are not always present to consume life-style energy can run into this.
Many Opportunity Loads require for a human or more to be around to need to use these loads, like some A/C, hot water, running pumps for domestic water etc. One can run heaters to heat the great outdoors in the absence of humans, but, I do not like to have such functions run unattended.
I have not studied or tried the Days before Bulk function mentioned earlier in this Thread, so cannot comment. I have been using a manual change in Absorption voltage to around the Float voltage setting, and if time permits, on returning to the off-grid location, further depleting the battery by running heater loads with the PV shut off to get down to about 80% SOC, if that level has not been reached while away.
This is all a bit experimental. A poster on the Wind-Sun Forum that was the first person to mention delaying days between recharges was member "stephendv" on the Wind Sun forum, who noted that several European manufacturers of CCs (and perhaps inverters) had an algorithm to avoid recharging the batteries for N days if the battery voltage remained above V volts, or similar, and cited some supporting info on such an approach.
In days past, most of us off-gridders were quite satisfied to fully recharge our batteries each and every day.
I am happy that MidNite is beginning to allow multiple strategies for recharging batteries via the Classic CCs.
An added comment -- Off grid systems are not very efficient. FLAs are not very efficient. We all waste a lot of power almost every day, if our systems are well designed. And, to me, obsessing too much about any of this wasted power is personally inefficient -- life is to short. My opinions, Vic
Well I can use this new feature to once on lithium battery's. As they give the best service life running around the 50% soc mark Ideal would be 49-51% but only using 2% of the capacity isn't practical but in reality 30-70% or 20-80% would be a example option. With the odd 100% soc run just to balance them. So this new feature could be used to obtain that.
my FLA batterys would only get a 2.5% dod weekdays but on the weekends they would get about 5% DOD. Its just so hard as for me 10% DOD is 6kwh and I would have to use that 6kwh in a time that I am just running on battery's 5pm - 5am , or in reality 5pm - 11pm when we sleep.As soon as the sun comes up our system is pumping the power in and Not even charging the EV car and welding,washing and so on will take anything from the battery.Basically our battery is to big for our needs (previous owners choice) but being FLA chemistry I need that large capacity to give me the C rating to run my big workshop loads, plasma cuter, welder, lathe, air compressor and so on. A small lithium battery has a much better C rating than FLA. So you don't need the big reserve of defunct battery for the odd high C load.
Kurt
Quote from: offgridQLD on November 05, 2013, 07:52:15 PM
So this new setting "Days between bulk" if I was to set that to say 2 or 3 days what happens on the no bulk days? Will the classic just wont charge at all (effectively go to sleep) for a few days?
Can you set it for particular days of the week or is it just a ongoing tally? (Sorry my pc with the app isn't with me)
Kurt
On the no bulk days it just goes to Float - no bulk or absorb cycle. It's just a single number to set no choice of which days. And from what I could tell only tested it once. It is not recurring, in other words once it skips the set amount of days the counter reaches 0 and bulk & absorb restart. So you would have to reset this counter again to initiate a skip cycle again. It's a start but when you are like us and gone for long period of time in the winter months it would be nice if it could cycle for some number of cycles with charging occurring in between.
Edited 12/09/2013: I stand corrected per Ryan this function does reset and the cycle will reoccur.
http://midniteforum.com/index.php?topic=1541.msg13039#msg13039
Hi John,
Thanks for the summary for DBB. It is a start, and am happy to see MN beginning down this road.
Hope to get the WB installed within a week and the FW Updated to the latest.
Vic
This may not belong in this Thread ...
But, just re-installed a new Classic 150, in a position where one was removed some time ago.
Installed the WbJr board etc, and Updated the FW to the latest Production code -- 1609/1608; 10/04/13.
Have been running the venerable 6/29/12 FW on Classics, elsewhere.
Have been watching things, and it seems that the Vabs is NOT being Temperature Compensated. Have used the Default value of -5.0 mV/C setting.
Do not find a setting that would switch this Comp value on/off. Did try specifying EQ temp Comp = YES, but had no effect on compensating Vabs.
So for now, have manually set the Vabs to the correct value to Comp Absorption voltage.
I must be missing some added menu item.
The 6/29/12 FW has been Temp Comping Absorption correctly with other Classics at other sites.
I will try changing the 5 mV value to see if it must be changed by the user ...
Will try Removing and Reseating the BTS connector ...
Must be missing something(s) here, Thanks, Vic
Vic
Temp Comp still works fine here. Try 2 things for me:
1- Go to the Temp's Menu and see what it thinks the Battery Temperature is?
2- Go to the Charge menu and then to Tcomp Menu and then push the top right button labeled View and see what voltage it is trying to get to?
Ryan
Hi Ryan,
Thanks ... I had noted previously that in the Temps menu that there was 12.7C for the battery, which did seem a bit lower than I'd expected. But have NEVER seen what happens when the BTS is not installed, when writing the post above.
Did go back to disconnect the BTS, and noted that it knows and says that the BTS is not present and 25C value is being used.
Will go back to see what is Charge - Tcomp screen has to say. Thanks, Vic
OK, went back, and re-powered the Classic, it went into its Absorb stage, and now, Vabs IS Temp Comped.
The "more" screen on Tcomp menu does have the correct Comp voltage value.
But, just after updating the FW, in the initial charge stage, it quite clearly did not Comp Vabs -- the comp value is around 1.4 volts which is quite noticeable. But the value was settable by just going to the Voltage page in the Charge menu.
Had done the VMM just after the FW UD.
Had wondered if this issue might just have been the first time through the loop kind of thing (?).
There is one thing that has never been clear to me; when changing Charge voltage or EA settings, for example, does the Enter function save ONLY that screen's values, or all of the settings that are user changeable? Might guess it is only that screen.
OK, bottom line; Vabs is now Temp Comped.
Thanks. Am in transit now to another project. Vic
I have a question about the install for the 1608/1609 firmware upgrade. I borrowed a windows notebook to do this but I was unable to determine whether the downloader reset the notebook back to its previous setting of com 3 from the com 8 setting used by the Classic USB drivers to download the code to the classic.
I used the online instructions for windows 8 and when the process was finished I could not find the window for the configuration of the ports, first time in windows 8
Thanks David
The process for changing the port number is the same in all versions of windows. In device manager locate under ports, CDC serial emulator, if you see a boot loader device you did not install the driver and should follow those instructions again. Now I will describe page 11 of the windows 8 firmware instructions. Right click CDC serial and click properties. Now click on the port settings tab and then click advanced. At the bottom of this screen it says com port number. Change this to 8. Now just click OK on all the open windows and follow the instructions for updating the classic.
MidNite mike,
The Classic did get updated to 1608/1609 and it works fine, haven't got WBjr yet so I can't try yet. The question is about the borrowed laptop being restored to com 3. I was pressed for time but have since reread the instructions and now know where I need to go to reset it to com 3
The install routine is a bit different than the reset to original configuration I ran out of time and. Needed to return notebook
The boot loader device was gone so that is what confused me.
Thanks for response, David
I cannot think of a reason to set it back to 3. You could do it but the classic has to be plugged in. If something else he had used 8 it should not conflict unless the classic was also plugged in.
Quote from: Mike_Midnite on November 27, 2013, 01:35:49 AM
I cannot think of a reason to set it back to 3. You could do it but the classic has to be plugged in. If something else he had used 8 it should not conflict unless the classic was also plugged in.
Right. Windows knows what is plugged into it by the information given to it by the unit itself
after that setup. You can always change it if you want just like it was changed to com 8.
boB
Thanks boB and mike,
I didn't want to change my friends new notebook and I was worried that changing port to com 8 would interfere with its original com 3 configuration. I have been on Mac and iPad for a while now and could not find ports. I changed it in CDC emulator but need to change it back in ports LPT and COM. brain cells now reprogrammed to understand windows again.
Is MidNite going to support utilities in Mac OS? I might buy a new windows laptop to make this easier but I like my Mac PowerBook better
Thanks, David
Quote from: tecnodave on November 27, 2013, 08:11:12 AM
Is MidNite going to support utilities in Mac OS? I might buy a new windows laptop to make this easier but I like my Mac PowerBook better
Thanks, David
David;
In a way, they kind of already do. There is a Python script that is cross platform. I use it in Ubuntu Linux and others use it in various versions of OSX. If you have a USB port on your machine and Python you should be able to install Classic and MNGP updates just fine from a terminal window!
I think they support Winders because it is so widely used.
Anyway, that Python script is around someplace and it is actually quite easy to use. Toughest part may be getting the firmware file extracted from the archive they distribute. It was an .exe file and I use Wine to unpack it. Wish they just offered the file itself for us non M$ users.
If you need a bit of hand holding to run it from Python, I and several others can certainly help.
Tom
TomW
Thanks, I haven't got around to using other interfaces on the PowerBook yet as I have been in computer burnout but it does intrigue me. Just what is Python? There are other things that I would prefer to do in Windows so the dashboard and utilities are not the only things I would use windows for.
David
David;
Python is a programming language. This explains it better than I can:
http://en.wikipedia.org/wiki/Python_%28programming_language%29 (http://en.wikipedia.org/wiki/Python_%28programming_language%29)
To use it you would simply execute the provided script in a terminal window. If you don't know what a terminal window is then it probably is not for you.
Someone smarter than myself could probably wrap it in a typical Mac GUI but it is not really needed.
Difficulty is relative to the users computer ability but there is really nothing hard about doing updates with the Python script. Then, I am a bit of a geek.
Tom