My hope here is that some incognito MidNite Engineer would take the time to read this Epistle. My goal is to better inform myself and other Forum readers of information not included in the manual for the MidNite 150. It is also, through my questions, rationale and suggestions, to help MidNite make a better "mousetrap". I fully realize that this may take you more than 15 minutes. I want to thank you in advance for any efforts you might take on my behalf.
Hi Barry, Welcome to the Forum.
Short of time now, but did skim your doc.
You may want to look at the Knowledge Base for some additional info, mostly Classic-related:
http://www.midniteftp.com/support/kb/faq.php?cid=1
With FLA batts, you might want to AVOID Al bussbars ...
Later, Vic
... a few additional thoughts, as breakfast, here, cooks:
Four parallel strings of LA batteries are generally not a good idea.
FLAs have needs for attention, and with 96 cells (!!), to tend, water, SG check, etc, as well as battery balance issues, this can lead to less, than needed attention. If you really need that much batt Capacity, one or two strings of larger batts is generally a better idea.
Also (IMO) AIMS has not had a stellar record of reliability, support, and parts availability. Please carefully check all specs, especially, what is the Standby power (Tare) losses with the inverter running, but delivering no power to loads, and so on.
EDIT: 6 kW, is a large inverter, forget all of your loads, but more inverter power is not always better.
Usually, one would do a Power Budget, which includes how much power needs to be provided, vs when it is needed<.
Also, if this is your first battery power system, it may be difficult for you to design it to meet your real needs.
Later, just sayin' ... Vic
[1] I presume the Absorb and Float set points are Battery Bank Temperature compensated values.TRUE?
[2] When the unit is in Absorb or Float, what voltage drop initiates Absorb(mppt) or Float(mppt) and a what voltage does the unit return to Absorb or Float?
[3] When the unit is in Absorb and a primary load drops the Bank voltage significantly, is the Absorb timer paused?
If TRUE, what are the parameters for pausing and restarting the timer? If FALSE, should it be?
[4] During ABSORB (constant voltage) or FLOAT(constant voltage) what are the reasonable expectation of the +/- voltage ranges delivered to the Battery Bank?
You set your absorb and float voltage, you set the temp compensation value. The absorb and float setpoints will adjust up or down automatically according to the battery temperature sensor . Example - batteries get colder , the absorb and float values go up.
If in Absorb the voltage absorb timer starts , if voltage drops below Absorb setpoint, it will
start again at the remaining absorb time once it rises again to absorb voltage.
If in Float and it drops below float setpoint it will go to Float Mppt . It will stay at float setpoint until next day no matter what the battery voltage is - so if battery dropped below float but then raises up it will go back to float.
During Float and absorb - power will always go to loads. You can use Aux settings to turn on and or control loads to use extra power above absorb or float . example - if in absorb or float you can have aux turn on a ssr relay to send just the extra power to something like a water heater .
Larry
regarding your aux questions -
Take a look at some of the videos I made of how I use classic aux 2 waste not to pwm ssr for water heater.
I made a few videos of how I got this going or updates.
Here is one
https://youtu.be/Non3H88UzPs
Larry
Quote from: Barry Fields on April 01, 2023, 09:12:26 PMQuote from: Vic on March 26, 2023, 03:53:05 PMHi Barry, Welcome to the Forum.
Short of time now, but did skim your doc.
You may want to look at the Knowledge Base for some additional info, mostly Classic-related:
http://www.midniteftp.com/support/kb/faq.php?cid=1
Barry - I was unable to find any of the voltage tolerance levels that I seek' questions 2,4,7,9,10,11,12 &13. Are you aware of any specific posts that might answer these questions?
With FLA batts, you might want to AVOID Al bussbars ...
Barry - My buss bars are 1ft from the batteries. The #4 copper connections from each Bank String are made with anti-corrosion compound. In 1 1/2 years of operation there is no evidence of corrosion, most likely due to the H2 detector properly venting the Battery Box.
Later, Vic
Quote from: Vic on March 26, 2023, 04:45:14 PM... a few additional thoughts, as breakfast, here, cooks:
Four parallel strings of LA batteries are generally not a good idea.
Barry - Why?
FLAs have needs for attention, and with 96 cells (!!), to tend, water, SG check, etc, as well as battery balance issues, this can lead to less, than needed attention. If you really need that much batt Capacity, one or two strings of larger batts is generally a better idea.
Barry - SLA's and AGM's would still need 96 cells without a way to check SG. Remember that some equalization occurs during ABSORB (per DEKA Batteries). SLA's and AGM's need about 1.5 volts less in ABSORB, therefore less equalization.
Also (IMO) AIMS has not had a stellar record of reliability, support, and parts availability. Please carefully check all specs, especially, what is the Standby power (Tare) losses with the inverter running, but delivering no power to loads, and so on.
Barry - Primary Inverter after 1 1/2 years of constant run (not stand-by) so far no problems. 80watt un loaded draw. Max load (everything on at once) = 6200 watts 104%overload.
Secondary Inverter is only on for opportunity loads. Max load = 5400watts
EDIT: 6 kW, is a large inverter, forget all of your loads, but more inverter power is not always better.
Usually, one would do a Power Budget, which includes how much power needs to be provided, vs when it is needed<.
Barry - Done - Max Buss bar load @ 42volts and 88% Inverter efficiency = 311Amps [buss bar rating 800A]
Max load per Bank String = 78A String wiring #4 copper (rated 85A @ 75 degrees)
Over the last 1 1/2 years, my average daily discharge was 1.2 KWH/string (10% of capacity). This fits well with my primary objective of running my Refridgerator, freezer, and waterpump for a minimum of 4-5 days.
Also, if this is your first battery power system, it may be difficult for you to design it to meet your real needs.
Later, just sayin' ... Vic
Quote from: ClassicCrazy on March 27, 2023, 10:45:21 AM[1] I presume the Absorb and Float set points are Battery Bank Temperature compensated values.TRUE?
[2] When the unit is in Absorb or Float, what voltage drop initiates Absorb(mppt) or Float(mppt) and a what voltage does the unit return to Absorb or Float?
[3] When the unit is in Absorb and a primary load drops the Bank voltage significantly, is the Absorb timer paused?
If TRUE, what are the parameters for pausing and restarting the timer? If FALSE, should it be?
[4] During ABSORB (constant voltage) or FLOAT(constant voltage) what are the reasonable expectation of the +/- voltage ranges delivered to the Battery Bank?
You set your absorb and float voltage, you set the temp compensation value. The absorb and float setpoints will adjust up or down automatically according to the battery temperature sensor . Example - batteries get colder , the absorb and float values go up.
Barry - Question 1 - Thank you.
If in Absorb the voltage absorb timer starts , if voltage drops below Absorb setpoint, it will
start again at the remaining absorb time once it rises again to absorb voltage.
If in Float and it drops below float setpoint it will go to Float Mppt . It will stay at float setpoint until next day no matter what the battery voltage is - so if battery dropped below float but then raises up it will go back to float.
Barry - Do we know at what voltage levels this occurs? (questions 2,3 and 4)
During Float and absorb - power will always go to loads. You can use Aux settings to turn on and or control loads to use extra power above absorb or float . example - if in absorb or float you can have aux turn on a ssr relay to send just the extra power to something like a water heater .
Barry - Kinda knew that but do we know the answers to questions 4,5 and 6 ?.
Larry
Quote from: ClassicCrazy on March 27, 2023, 10:53:07 AMregarding your aux questions -
Take a look at some of the videos I made of how I use classic aux 2 waste not to pwm ssr for water heater.
I made a few videos of how I got this going or updates.
Here is one
https://youtu.be/Non3H88UzPs
Barry - This was helpful. I was previously unaware of the capabilities of SSRs. Thank you.
Barry - Most of the rest of my questions deal with the following:
Can AUX1 waste not hi be be set with voltage levels that a "skimmer" circuit would not interfere with ABSORB and FLOAT performance yet still allow the "skimmer" to achieve 100% PWM?
Can AUX2 waste not hi be set so it minimally intereferes with ABSORB and Float performance?
If I had the numbers, I could answer these last 2 questions myself.
Larry
Quote from: Barry Fields on April 01, 2023, 09:34:47 PMQuote from: ClassicCrazy on March 27, 2023, 10:45:21 AM[1] I presume the Absorb and Float set points are Battery Bank Temperature compensated values.TRUE?
[2] When the unit is in Absorb or Float, what voltage drop initiates Absorb(mppt) or Float(mppt) and a what voltage does the unit return to Absorb or Float?
[3] When the unit is in Absorb and a primary load drops the Bank voltage significantly, is the Absorb timer paused?
If TRUE, what are the parameters for pausing and restarting the timer? If FALSE, should it be?
[4] During ABSORB (constant voltage) or FLOAT(constant voltage) what are the reasonable expectation of the +/- voltage ranges delivered to the Battery Bank?
You set your absorb and float voltage, you set the temp compensation value. The absorb and float setpoints will adjust up or down automatically according to the battery temperature sensor . Example - batteries get colder , the absorb and float values go up.
Barry - Question 1 - Thank you.
If in Absorb the voltage absorb timer starts , if voltage drops below Absorb setpoint, it will
start again at the remaining absorb time once it rises again to absorb voltage.
If in Float and it drops below float setpoint it will go to Float Mppt . It will stay at float setpoint until next day no matter what the battery voltage is - so if battery dropped below float but then raises up it will go back to float.
Barry - Do we know at what voltage levels this occurs? (questions 2,3 and 4)
During Float and absorb - power will always go to loads. You can use Aux settings to turn on and or control loads to use extra power above absorb or float . example - if in absorb or float you can have aux turn on a ssr relay to send just the extra power to something like a water heater .
Barry - Kinda knew that but do we know the answers to questions 4,5 and 6 ?.
Larry
Barry , for some reason I can't download or see your original question attachment.
Also as a side note - it would help if you answered outside the quotes since it would differentiate from original comment so we could see your reply easier. At least on my computer format.
So not knowing what your exact questions were - I think you asked when absorb timer or float starts - and that is when the Absorb voltage or Float voltage setpoints are reached.
I don't know what you mean by a skimmer circuit.
Using Waste Not or diversion pwm from Aux2 won't interfere with Absorb or Float performance since it only will use any excess power not needed to maintain Absorb or Float.
Larry
Classic Crazy Larry said,
"Barry , for some reason I can't download or see your original question attachment.
Also as a side note - it would help if you answered outside the quotes since it would differentiate from original comment so we could see your reply easier. At least on my computer format"
Larry, I will try to attach Barry's Question file. 73 VicBarry Fields' Classic CC Questions.rtf
Well, I was able to find ONE answer in the Hawks Bay manual. It states that the unit will enter Float(mppt) on a voltage drop of .3 v. I do not know if that also applies to the Classic 150.
If any of you reading this post feel that the information I have requested would also be of assistance to you, please make your voices known (peaceably and patriotically). I believe that my questions are reasonable and aimed at making more effective use of the Classic 150.
Thanks for ya'lls help.
Yes, the -0.3V is about the same as the Classic's.
Both Absorb and Float are temperature compensated.
When the battery voltage drops back to bulk from Absorb, the timer will just stop counting. It will suspend counting. Then, when the large load goes away or the sun comes back, the timer will continue counting from where it left off. This is if it all happens during the same day.
If it is the next day, then the Absorb counter will start from scratch... 2 Hours or whatever it is set for.
boB
Bob, Thank you for your response. You deserve a well thought out response. My cancer treatments leave me with just so much energy but I will get back to you. The Doctors say I have at least a couple of years left to aggravate people so I will persist in trying to leave something behind for others.
Thanks for your patience.
Barry, I am sorry about your cancer and low energy level.
I have had 3 cancers within the last 20 years but nothing in the last 13 years or so (knock on wood)
I understand the problems of course but really commend you on your great attitude and motivation !
We can chat anytime you are ready.
boB
On a personal note, I asked my oncologist if instead of taking inject-able testosterone blockers I could just start drinking Bud-Lite.
My goal is to divert uncollected PV power to my Cold water heater. I have capacity in my primary inverter to run a 50 ft 14-2 220v line to a SSR to a rewired CWH (2250w) and use AUX2 waste not hi PWM to control the SSR. I want it active in both absorb and float modes yet not interfere with their operation.
I understand the the Absorb timer will pause at -.3v below set point. Will it re-engage @ setpoint or something lower?
If width = 1v and vlow = -.1v ;
[1] Will that interfere with the absorb timer?
[2] Will the classic allow the unloaded bank voltage to rise to .9v above the setpoint? (100% pwm)
[3] Would settings of width =.5v and vlow = 0 be more appropriate?
Thanks for your time.
Quote from: Barry Fields on April 17, 2023, 03:04:12 PMOn a personal note, I asked my oncologist if instead of taking inject-able testosterone blockers I could just start drinking Bud-Lite.
My goal is to divert uncollected PV power to my Cold water heater. I have capacity in my primary inverter to run a 50 ft 14-2 220v line to a SSR to a rewired CWH (2250w) and use AUX2 waste not hi PWM to control the SSR. I want it active in both absorb and float modes yet not interfere with their operation.
I understand the the Absorb timer will pause at -.3v below set point. Will it re-engage @ setpoint or something lower?
If width = 1v and vlow = -.1v ;
[1] Will that interfere with the absorb timer?
[2] Will the classic allow the unloaded bank voltage to rise to .9v above the setpoint? (100% pwm)
[3] Would settings of width =.5v and vlow = 0 be more appropriate?
Thanks for your time.
You watched my video right ? Maybe I didn't link the correct video but I had a 120v AC line from my inverter going to SSR that was controlled by Aux2 Waste Not. It only will let the extra power above absorb ( or float) to the water heater coil. It doesn't interfere with absorb timer because it only turns on the extra power above Absorb or Float . I think I had Waste Not set up using default settings but don't remember. I had Waste Not High. But I made a few changes and Waste Not high didn't seem to work so I used Diversion now and it accomplishes the same goal of sending extra power over to hot water coil.
Larry
Larry, I just re-watched your video. I noticed your settings for Waste not high were width = 1v and Vlow= 1v. Did I read that correctly?
Why did you feel that Waste not didn't work well?
thanks for your input
Barry
Quote from: Barry Fields on April 18, 2023, 11:14:39 AMLarry, I just re-watched your video. I noticed your settings for Waste not high were width = 1v and Vlow= 1v. Did I read that correctly?
Why did you feel that Waste not didn't work well?
thanks for your input
Barry
I think I just used the defaults for waste not. It could be that other settings would work better. That was a few years ago so I don't remember much about the setup.
I change my system from two Classics that had lots of pv on each and were in follow me , changed it to less PV on one Classic and just two pv on the second Classic. I was using the Aux2 on the second Classic. My aim was to use extra power to hot water heating element. I don't know why the Waste Not did not work , but when I tried Diversion it did what I wanted it to and I just did not spend any more time trying to figure it out or mess around with it.
Larry
Quote from: Barry Fields on April 18, 2023, 11:14:39 AMLarry, I just re-watched your video. I noticed your settings for Waste not high were width = 1v and Vlow= 1v. Did I read that correctly?
Why did you feel that Waste not didn't work well?
thanks for your input
Barry
I think I went into more detail in this video and showed how pwm worked using Classic App
https://youtu.be/Non3H88UzPs
Larry
Larry, That is the one I watched. Still have the same questions.
thanks Barry
Quote from: Barry Fields on April 18, 2023, 02:32:19 PMLarry, That is the one I watched. Still have the same questions.
thanks Barry
Maybe this is the other one - I made a few videos
https://youtu.be/s7trVpHLts4
This is playlist with some of my solar videos in it
https://www.youtube.com/watch?v=ljxi-xDMW7E&list=PLyZ0F9SqMJulkcsoMABwloxRY9oPl5rqw&pp=gAQB
Larry
Larry, your second video yielded no additional information.
Thanks Barry
Just a summary of where we are
Questions Answered
[1] The Absorb and Float set points are Battery Bank Temperature compensated values.TRUE {thanks Larry}
[3] When the unit is in Absorb and a primary load drops the Bank voltage significantly, is the Absorb timer paused?TRUE -.3v (Thanks boB)
Un-answered questions
[3] If TRUE, what are the parameters for restarting the Absorb timer?
[4] During ABSORB (constant voltage) or FLOAT(constant voltage) what are the reasonable expectation of the +/- voltage ranges delivered to the Battery Bank?
[5] Are Aux 1 and AUX 2 inactive during bulk and rebulk?
[6] AUX 1 and AUX 2 setpoints automatically change from Absorb to Float settings. TRUE?
[7] In AUX 1 waste not high, what are the range of settings for Vhigh, Vlow, Delay and Hold?
[11] What are the range of settings for WIDTH and AUX 2 Vlow?
[12] If WIDTH is set to 1v and AUX 2 Vlow is set to 0, Will 100% PWM be achieved ? (see question 4)
[13] Would those settings interfere with the ABSORB TIMER? (see question 3)
Other Un-answered Questions
The rest of the questions apply to my peculiar system or are meant to prompt thought of a better mousetrap. If I had the answers to the above, I could solve my own system applications.
Do you have a Classic ?
Really the best way to answer your questions is to just hook something up to Aux and test it out.
Yes the Aux changes by itself from Absorb to Float stages.
The Absorb timer restarts when it gets back to Absorb voltage.
The only time the absorb timer stops is if it goes below absorb voltage setting, once it comes back up then timer starts again.
Larry
Larry,
No I do not have a Classic 150. I am trying to decide whether to spend $700 of my Social Security Check to improve my system performance. That is why I am asking these questions. I want to be sure that the 150 will satisfy my needs.
I do not believe that my questions are that difficult or involve trade secrets.
Thank you for answering
[6] AUX 1 and AUX 2 setpoints automatically change from Absorb to Float settings. TRUE
Can you confirm
[3] The ABSORB timer pauses @ ABSORBv-.3v and restarts @ ABSORBv. OR does it restart @ ABSORBv-.2v ? Important difference.
Thanks for your input
Barry
You might want to consider the Hawkes Bay too.
But if you are thinking of installing a smaller array the HB wouldn't work since it needs at least 185v pv to operate.
I have never paid close enough attention to the details that you are wanting to know about. It is also kind of hard to answer your question because I think the Classic does some averaging since the voltage can bounce around some. Why does that -.3 or -.2 v make a difference for your system engineering?
It also depends on the type of batteries you have in your system. With lead acid things are a bit more stable in the run up to absorb. But with lithium it can change to absorb and then to float very quickly before you might even notice it.
What kind of controller do you have now ?
Larry
Quote from: boB on April 12, 2023, 01:54:44 PMYes, the -0.3V is about the same as the Classic's.
Both Absorb and Float are temperature compensated.
When the battery voltage drops back to bulk from Absorb, the timer will just stop counting. It will suspend counting. Then, when the large load goes away or the sun comes back, the timer will continue counting from where it left off. This is if it all happens during the same day.
If it is the next day, then the Absorb counter will start from scratch... 2 Hours or whatever it is set for.
boB
Sorry to bother you. Is that ABSORB pause of -.3v the same for 12v, 24v, and 48v lead acid battery banks?
What voltage restarts the timer?
Thanks Barry
No bother at all !
It starts again when the voltage equals the Absorb target voltage again.
If it wasn't allowed to move around a little bit, then it would almost constantly be going from Absorb-bulk-absorb-bulk etc...
I think the -0.3V is the same for all voltages. The next version of code will be able to tighten that up more which is specially for Lithium batteries.
boB
Quote from: boB on April 21, 2023, 10:22:56 PMNo bother at all !
It starts again when the voltage equals the Absorb target voltage again.
If it wasn't allowed to move around a little bit, then it would almost constantly be going from Absorb-bulk-absorb-bulk etc...
I think the -0.3V is the same for all voltages. The next version of code will be able to tighten that up more which is specially for Lithium batteries.
boB
Thanks so much.
One more question before I share how this would work for me.
In AUX2 waste not hi, can the width be set for .4v or .5v?
(remember I have a 40KWH 48volt FLA battery bank that is not prone to wild fluctuations)
Also, good luck walking the Lithium voltage tightrope.
Thanks Barry
The waste not PWM is set to a 0.1 V resolution which gives that function the 1.0 volt width. The Classic's natural resolution is 0.1V and that is why it went that way.
I suppose it could have used a slower average for say, 0.5V width but would have taken more time to engineer.
Samples at 5 kHz and so that is why the output PWM is at 500 Hz for the 1V width.
boB
Quote from: boB on April 22, 2023, 04:54:48 PMThe waste not PWM is set to a 0.1 V resolution which gives that function the 1.0 volt width. The Classic's natural resolution is 0.1V and that is why it went that way.
I suppose it could have used a slower average for say, 0.5V width but would have taken more time to engineer.
Samples at 5 kHz and so that is why the output PWM is at 500 Hz for the 1V width.
boB
My hope was that a width of .4v would yield 0% 25% 50% 75% 100% PWM.
As I have no external drivers (wind/hydro) a 1volt width would either never reach 100% or it would interfere with the Absorb cycle.
Below is my dream. (@ 74 I still dream)
width setpoints.png
Barry - are you reading the range of absorb and float voltages that Deka recommends ?
My understanding of those ranges was that you used the lower of the range when the batteries were new, and then increased the voltages as the batteries aged. Or maybe due to the stress the batteries are under if they get too cold , hot , or are being deeply cycled compared to less deep .
If you have flooded lead acid and took specific gravity readings and SG wasn't what it should be , the you would increase the voltage setpoint which compensated for the condition of the battery.
Larry
Larry,
Yes. No mention of age/condition.img20230423_12463604.png
https://batteryuniversity.com/article/bu-403-charging-lead-acid
Larry
Barry, thank you for the charge stage pic. That is good.
Classic update software forging ahead. From 1.0V to 0.4V width and your percentage PWM references would be great to add. I don't know of any other requests for this feature change BUT I can certainly see the thinner width V as being an advantage for lithium battery chemistries as well.
Can't guarantee this will be added on the next round but I will definitely put a bit of thought thought into it in case there might be a quick and easier way.
i.e. We'll put this one on the list for sure :) I like it !
boB
Quote from: boB on April 23, 2023, 11:05:00 PMBarry, thank you for the charge stage pic. That is good.
Classic update software forging ahead. From 1.0V to 0.4V width and your percentage PWM references would be great to add. I don't know of any other requests for this feature change BUT I can certainly see the thinner width V as being an advantage for lithium battery chemistries as well.
Can't guarantee this will be added on the next round but I will definitely put a bit of thought thought into it in case there might be a quick and easier way.
i.e. We'll put this one on the list for sure :) I like it !
boB
boB,
Thank you for your response. You may not know how good it makes me feel to be validated by someone as competent as yourself. (says aw shucks and kicks dirt with foot)
Given the improvement discussed, I would love to acquire a Classic 150. Please keep me apprised as to progress.
If I could be so bold as to make some observations, without being overly negative or critical.
When I first addressed my questions to MidNite Product Support, I was told that they were not allowed to bother the Engineering Group and that the Classic 150 was approaching End Of Life.
Product Support not being allowed to bother Engineering left me (be polite Barry) bemused. That is something that should be handled by someone with a higher paygrade .
I am not a Marketing genius but I fear you take the chance of leaving behind a significant portion of your loyal customer base. Not everyone is going to follow MidNite to the Hawkes Bay unit for a varity of reasons.
It appears to me that the Classic 150 is a pretty rock solid unit that should be allowed to live. If I could make some further suggestions.
It seems that you are depending on ONE onboard firmware revision level to be "all things to all people". You may be running out of MCU capabilities to give you the flexibility you need. I am not a software/firmware designer so I won't pretend to say exactly what might be done.
If you could "offload" your battery algorithims to a memory stick on the USB port, you could free the up the onboard MCU for other stuff. A customer could install appropriate memory stick (for example) one for Lead acid or one for Lithium or one for the next generation of battery chemistry yet to be discovered. This would likely free up some flexibility in dealing with the tighter voltage tolerances 12v lead acid and Lithium systems.
I would also add a third timer to the AUX1 waste not high that would start at the end of delay. Delay could be set to say 5 minutes as a restart delay for compressors. The new timer could be used as minimum run timer (maybe up to an hour). and the hold time would remain as a "bounce out" delay.
I believe these suggestions could significantly extend the life and flexibility of the Classic 150. It wants to live.
Thanks again.
Barry
I hope my previous post was taken as positive and constructive as it was intended. I hope I did not step on anyones toes, but I can only be forthright in my assesments. I am pleased that VIC and Larry have not yet critiqued that post.
I realize that I have given you much to mull over and am certainly not asking for weekly updates. If I could add a couple of more observations that you may have already thought of.
Product Support has confirmed that after a firmware update the customer has to re-enter their parameters (absorb v, absorb time, Float v, etc). If those parameters could also be off-loaded to the memory stick it could make the update process a little more user friendly.
I have also seen requests on the Forum for a voltage resolution of better than .1volts. I do not know if that is a hardware or a firmware restriction. If it is a firmware restriction, off-loading MCU tasks could enable improvement. If it is a hardware restriction, never mind. You should want any Classic 150 improvements to be downwards compatible with your installed base.
Just a final note. I have never understood companies that say: "We have a really good product that many people are happy with, let's stop making it". Just saying.
Best regards
Barry
Barry, the 0.1V resolution is a hardware thing. The only way to get better, say, 0.05 V resolution would be an averaging method going very slow from the 0.1 V input when it toggles between 2 0.1V points. Not really all that easy to do at this point.
I really with that processor ADC had just ONE MORE bit !
Normally, updating the firmware does NOT over-write the Absorb voltage and other settings.
That may have been a thing during one of the older updates but I can't even remember when/if that happened ? I think I know though what that is from. Once in a while there would be some new registers and bits that needed to be initialized by the MNGP remote and THAT is probably where things had to get re-initialized.
The only way I know of to do a re-init from your saved numbers is from the local-app that connects via the Ethernet connection. Not sure if you have used that or not but I seem to remember it being able to save and recall Classic settings ?
boB
Yes you can use the Local App to save and restore the settings for the Classic.
Larry
boB,
After this post I promise to go away for a while.
Let me outline the "niche" that the Classic line of controllers could continue to play in MidNite's future. If I get anything wrong, please correct me.
Transitioning to the Hawksbay unit would require the following:
[1] Any Classic 150/200/250 user with a 24 volt battery bank would have to revamp the battery bank to 48v AND purchase 48v inverters.
{2} Any Classic 150 user would have to upgrade their solar array AND PV breakers to meet the minimum Hawksbay PV requirements.
Some of those users might opt for the Outback Flexmax 100 even though they would lose an AUX port.
I have no idea what the numbers are for Midnite's Classic installed base and what the permutations are. I would suggest that Marketing do a survey to find that answer. Only then could a rational migration path for existing customers be developed.
Hopefully that migration path is to MidNite products.
Again, my best assessment.
Regards
Barry
Quote from: Barry Fields on April 19, 2023, 03:02:11 PMJust a summary of where we are
Questions Answered
[1] The Absorb and Float set points are Battery Bank Temperature compensated values.TRUE {thanks Larry}
[3] When the unit is in Absorb and a primary load drops the Bank voltage significantly, is the Absorb timer paused?TRUE -.3v (Thanks boB)
Un-answered questions
[3] If TRUE, what are the parameters for restarting the Absorb timer?
Absorb timer will reset under 3 condiutions, 1- At midnight if the clock is set 2- 2hrs after resting if clock is not set 3- when rebulk is triggered
[4] During ABSORB (constant voltage) or FLOAT(constant voltage) what are the reasonable expectation of the +/- voltage ranges delivered to the Battery Bank?, Usually what you will see is the voltage will hit the actual target then it can drift to -0.3v but will not over shoot. Essentially it trys to stay at target but it can be allowed to drift -0.3. boB is working on tightening this up now
[5] Are Aux 1 and AUX 2 inactive during bulk and rebulk? it depends, Aux 1 and 2 have a lot of modes, If the mode is float for example yes it ignores the bulk but if its a simple diversion it triggers based on the voltage regardless
[6] AUX 1 and AUX 2 setpoints automatically change from Absorb to Float settings. TRUE? Depends, If it is something like Waste Not Hi yes, If its Diversion it runs n a single voltage independent of the target
[7] In AUX 1 waste not high, what are the range of settings for Vhigh, Vlow, Delay and Hold? I would have to go look on this one
[11] What are the range of settings for WIDTH and AUX 2 Vlow? I would have to go look
[12] If WIDTH is set to 1v and AUX 2 Vlow is set to 0, Will 100% PWM be achieved ? (see question 4)
[13] Would those settings interfere with the ABSORB TIMER? (see question 3)
Other Un-answered Questions
The rest of the questions apply to my peculiar system or are meant to prompt thought of a better mousetrap. If I had the answers to the above, I could solve my own system applications.
I do appreciate the time and effort you all have spent on this post. I hope it has been useful to many. Remember I do not yet own a Classic 150 but am looking forward to it. As I do not yet have a vested interest in MidNite, I can only hope I have helped generate an internal discussion of a "better mousetrap".
Best Regards
Barry
Quote from: FNG on May 04, 2023, 06:30:03 AM[4] During ABSORB (constant voltage) or FLOAT(constant voltage) what are the reasonable expectation of the +/- voltage ranges delivered to the Battery Bank?, Usually what you will see is the voltage will hit the actual target then it can drift to -0.3v but will not over shoot. Essentially it trys to stay at target but it can be allowed to drift -0.3. boB is working on tightening this up now
If trying to harvest uncollected solar power using AUX2 PWM, some overshoot is needed to indicate that excess power is there to be collected. I would think that SETPOINT +/- .2 volts would do that for lead acid batteries. I would start the absorb timer @ SETPOINT -.2 volts and pause it at -.4 volts. These setting should be well within the tolerances for a 24v or 48v lead acid bank.
I do not know how one would do what I want to do with Lithium which is another reason I did not choose them.
SO, please DO NOT tighten the lead acid regulation specs.
Regards
Barry
Quote from: boB on May 01, 2023, 04:34:15 PMI really with that processor ADC had just ONE MORE bit !
Pretty sure you meant wish.
As I previously said, I am not a Hardware/firmware engineer but am always willing to ask a dumb question and learn something new.
Is it possible to assume the value of the Most Significant Digit of the ADC depending on battery bank voltage?
That would free up the Least Significant Digit for a resolution of .5volts.
Just asking.
Barry
Yes, with = wish :)
Not sure what you mean by MSD in this context ?
0.05 volt resolution would be the goal. From a longer time average, if the 0.1 volt resolution were real accurate, we could probably derive an in-between average of 0.05V resolution maybe.
Think of a battery voltage for example toggling between, say, 48.3 V and 48.4 V at 50%... That could be interpreted as 48.35 volts
Like I say I am no engineer. I only have a cursory knowledge of the MCU used in the AIMs inverter.
If the following is of assistance to you, great.
MOTOROLA.COM/SEMICONDUCTORS
M68HC08
Microcontrollers
MC68HC908MR32/D
Rev. 6.0
MC68HC908MR32
3.3.2 Voltage Conversion
When the input voltage to the ADC equals VREFH , the ADC converts the signal to
$3FF (full scale). If the input voltage equals VREFL, the ADC converts it to $000.
Input voltages between VREFH and V REFL are straight-line linear conversions. All
other input voltages will result in $3FF if greater than V REFH and $000 if less than
VREFL.
My sense is you have no reason to accurately measure Bank voltages less than 3 or 4 volts.
I have no idea if your MCU has similar capabilities.
Just throwing it out there.
Barry
I used the M68HC08 line of controllers 30+ years ago. They were fine for the time.
Then became Freescale and now, Microchip ? I can't keep up with names and who bought who.
Another way to read battery voltages more accurately with a lower bit A/D converter would be to bias the input voltage down so that the low end you are measuring, say a 48V battery only reading down to maybe 35 volts, becomes zero for the ADC.
The Classic works from around 9 volts up to 100 V DC or so, so that can't be done enough to help its resolution.
Interesting engineering issues and I do like discussing these.
boB
boB,
Could you share with me which MCU the Classic 150 uses? I might then better educate my self and ask less dumb questions.
I have to stop dreaming about the 150 and get back to Gisele Bündchen.
Barry
The Classic uses an NXP LPC2366 ARM chip. Old technology by today's standards.
Not even a Cortex-M It was/is still a good processor but if I were changing it, I would probably go to an STM32F4xx Cortex M4 part.
boB
boB,
Thanks for the info. When I say something wrong, please correct me. These suggestions are made trying to avoid a total redesign of the 150.
As I read it there are 6 ADC inputs on pins 23, 24, 25, 26, 30 and 31. I do not know know which are used or might still be available.
My presumption is you are using ONE precision voltage divider on one ADC input to automatically determine BANK voltage and to control BANK charging parameters. This one divider is aimed at a 96volt Bank.
It would dramatically improve resolution if each BANK voltage had it's own divider.
If one more ADC input were available, It could be used to control BANK charging parameters. A user installable (plug in) BANK voltage specific voltage divider could solve most resolution issues. Unfortunately this approach is NOT IDIOT PROOF. The wrong divider could cause MCU POOF. I'm not sure how many 3.3v zeners would be required to preclude this.
IDIOT PROOFING would require an addition of a HV addressable analog switch. That would depend on remaining MCU resources and room inside "the box" for a jack board.
It might be that only two additional dividers are necessary. The existing divider used for 72v and 96v BANKS, another for 32v and 48v BANKS , and the third for 12v and 24v BANKS.
Me thinks I should retreat to the sidelines for now. Kinda feel I have thrown enough tennis balls to your side of the net to ponder.
I want to thank boB, Ryan, Vic and Larry for their contributions to make this post exceed 1000 views. All this Newby did was ask a few questions.
That 1000 views should be taken as an indicator of the interest in the future of the Classic 150.
I remain at your service,
Barry
Some where in the myriad of posts I have perused, I remember a request for averaging the Wizbang current measurement.
Would the addition of a 30-60 second Low leakage R/C network to the Wizbang output be a solution?
Just asking.
Barry
There is already an R-C filter on the WB Jr. but not 30 to 60 seconds.
Enough filtering to stop fast current spikes though.
30+ seconds would be way too much filtering.
A digital filter could of course keep the fast captures while doing what you are thinking. You can also request the WB Jr. samples continuously, 10 times per second through modbus. Then filter by external computer such as a Raspberi Pi.
Then, if wanted, that filtered information could be fed back to the Classic if you wanted to control it a bit differently based on that data. That is what is pretty cool about communications...
A fun project !
boB
I must have misunderstood. I thought the complaint was a premature dropout of ABSORB at end amps.
I suppose if the end amps reading is validated by an ABSORB setpoint voltage, then it should not be a problem.
Sorry for the misunderstanding.
Barry
Quote from: Barry Fields on June 12, 2023, 12:41:45 PMI must have misunderstood. I thought the complaint was a premature dropout of ABSORB at end amps.
I suppose if the end amps reading is validated by an ABSORB setpoint voltage, then it should not be a problem.
Sorry for the misunderstanding.
Barry
Oh !
THAT problem !
I understand that one. I will look to see if the newer firmware changes fixed that or not.
The problem was that when the Classic is sitting there in Absorb below the ending-amps setting, regulation or loads will change such that the current rises just above the ending-amp setting momentarily and resets the ending-amps timer which is 60 seconds or 90 seconds.
That is a software issue but might be fixed also by a LARGE R-C network.