Amongst the myriad of things I do not know is the following:
Are all End Amps equal?
CASE 1 Consistent PV input. Absorb voltage (say 58v) constant until 2% of AH rating is reached.
Case 2 Inconsistent PV input. Absorb voltage reaches 58v then hangs at 57.5 for 1hr until finally again reaching 58v and 2% AH rating is achieved.
Are both ending SOCs the same?
You would probably rather have it like case 1 where you have consistent Absorb BUT yes, the Absorb time is cumulative.
In fact, if the battery voltage is just under the Absorb voltage when it goes back to Bulk MPPT, you may get a bit more Absorb time for lead acid batteries, although it is not exactly Absorb voltage.
Doesn't matter quite so much for lead acid. And even lithium batteries in Absorb if that is being used so the BMS can do its balancing act for the lithium cells.
For the Classic and Kid controllers, the ending amps only works if the charging voltage is at the Absorb voltage or just above a few tenths of a volt below that absolute Absorb voltage setting.
I hope that makes some sense.
boB
Quote from: boB on September 01, 2023, 02:21:38 PMYou would probably rather have it like case 1 where you have consistent Absorb BUT yes, the Absorb time is cumulative.
In fact, if the battery voltage is just under the Absorb voltage when it goes back to Bulk MPPT, you may get a bit more Absorb time for lead acid batteries, although it is not exactly Absorb voltage.
Doesn't matter quite so much for lead acid. And even lithium batteries in Absorb if that is being used so the BMS can do its balancing act for the lithium cells.
For the Classic and Kid controllers, the ending amps only works if the charging voltage is at the Absorb voltage or just above a few tenths of a volt below that absolute Absorb voltage setting.
I hope that makes some sense.
boB
What I think I hear you saying is that Case 2 would likely yield a slightly higher SOC depending on how much time was spent just under Absorb V.
I am ready to be corrected. Barry
I would say you are correct, Barry.
You got it.
boB
Quote from: boB on September 01, 2023, 02:21:38 PMDoesn't matter quite so much for lead acid. And even lithium batteries in Absorb if that is being used so the BMS can do its balancing act for the lithium cells.
I hope that makes some sense.
boB
[/quote]
Bob -I am finally starting to figure out the lithium batteries and bms stuff. Most existing bms will balance at some point they are programmed for. But a lot of them are passive balancers shunting the high cells to resistors. The bms I have seen only shunt off 50 to 150 ma which isn't much when the cells are 100ah or more. My particular bms is on the lower range of like 50 ma but it only balances when charging - or if a cell goes to OVP overvolt protection , that shuts off charging but the balancing will stay on until the cell drops to whatever voltage it is programmed for. And my bms won't balance anything unless the cell differential is higher than 20ma. But still not much is going to balance at that low ma rate.
But there are a newer generation of bms or stand alone balancers - active balancers that can move 2 to 5 amps from high to low cells , and some of these can be programmed to turn on and off at specific cell voltages. You only want them to balance at the very top of the charge curve. So they would work better with the longer absorb if the charging current is lower than full blast. Of course as the cells get full , they take in less current so that will decrease.
The youtuber OffGridGarage Australian - Andy - does some thorough testing of each new bms and best voltages to charge to. He has a very nice charge / discharger that will graph the results and helps explain what is really going on. Watching his videos along with messing around with my own batteries is helping me to finally understand the lithium stuff. I did buy an add on active balancer for my battery which has the weak passive balancer and it works wonders to balance in comparison.
Here is a recent video where he shows all the graphs on charging / discharging . https://youtu.be/aiiJ1IWSWos?si=xOu2vuOx3vx7oh_t
Anyway what we really need with lithium is accurate reading of the voltages to controller, or ideally have the controller able to read the battery voltage data that many bms provide via rs485 or CAN.
Larry
Being elderly, I can only handle one battery chemistry at a time. For now I am concentrating on Lead Acid only.
I am asking these questions in consideration of a possible alternative to fixed Absorb Time or End Amps. If we can agree that our goal is 95% SOC at the end of the absorb cycle.
TO EAST PENN.
Barry: For the same replacement energy, 20 amp charging will yield anti-stratification bubbling at double the rate of a 10 amp charge rate. However that lower rate will occur for double the time. Therefore, stratification should not be a significant issue. (assuming a 95%-100% SOC is achieved at least every 3rd day).
EAST PENN: If the battery reaches 95%-100% SoC every 3rd day, it is reasonable to assume the sulphation can be avoided.
Consider the following also from EAST PENN:
Barry? If FLOAT is achieved, a FLOAT current significantly above 500ma (? 1amp ?) might indicate an incomplete ABSORB cycle.
EAST PENN The float current of a fully charged battery is dependent on battery capacity and charge voltage.
Fully charged float current of a GC10 would be around 450mA.
If the float current is above 480mA, it is an indication that the battery is not fully charged.
Additionally, if the current is above 800mA at the end of absorption charge, this is also an indication the battery is not fully charged.
Barry? If I were to take a GC10 that is verifibly at 95% SOC and put it into FLOAT, what might I expect for an initial Float current. ?
EAST PENN We temperature compensate the charge voltage to in order keep the polarization of the positive and negative plates the same as they would be at 25°C (higher temperature we lower the voltage, lower temperatures we raise the voltage).
Additionally, we say temperature compensation of the charge voltage should be only done in the range of 10°C to 35°C.
Abiding by these rules, the stabilization current will remain relatively the same, could fluctuate a couple of milliamps.
As the FLOAT voltage is temperature compensated (-3mv/cell/degree C), would the FLOAT current be reasonably consistent over a battery temperature range of 5 degrees C to 35 degrees C ?
My suggestion is to use a somewhat short ABSORB TIME, let it go to FLOAT, and measure the FLOAT CURRENT.
If the current is above what is expected for a 95% SOC, re-initiate ABSORB for another 1/2 hr and repeat.
My thought is that this is a way to effectively evaluate the preceding ABSORB CYCLE for completeness.
My take on this proposal is as follows:
It will assure a 95% SOC based on daily PV conditions with NO user intervention.
It will minimize battery over charging due to extended ABSORB times.
Both of these extend battery life and ensure that sufficient time is spent in the SOC range of desulphation and self equalization.
ISSUES TO RESOLVE
Low current discrimination - The 500A Wbjr most likely is insufficient.
I would suggest a 10A or 20A halleffect toroid in series with the Wbjr.
My understanding is that over-amping a halleffect device will not damage it.
Settling time between ABSORB and FLOAT - ?
Baseline FLOAT current - There are many combinations of battery chemistries. (flooded, agm, gel, alloys, electrolytes, etc) I suggest the following procedure:
Slightly overcharge the battery bank to assure 100% SOC
go to Float and record 100% FLOAT current
Discharge the Battery Bank by 10% of the rated AH capacity
go to FLOAT and record 90% FLOAT current
Select a current level between those data points and use that as the trigger for the "lather rinse repeat" process described in my previous post.
Note that some long term changes will occur with these FLOAT currents due to battery age and health. The BASELINE procedure may be required on a periodic basis.(?6mths/12mths?) Changes in the BASELINE might be helpful in predicting battery replacement.
One last thing
Is it too soon to ask for a promotion? I do realize that a raise is out of the question.
I think someone once mentioned that if people had kept as close track of each lead acid cell and balanced them like is now done with lithium , they probably would last a lot longer. I know that the place I used to get batteries from would load test each cell in older forklift batteries and then match the cells to make up a new renovated pack. The battery guy told me that heat was probably the cause of most of the cell degeneration since the cells in the center of the pack were the ones that most often failed.
If someone has a large lead acid battery pack with separate cells, an active balancer like is used with lithium would help them also since it can monitor each cell individually and adjust charge to them as needed. This may go a long way also to eliminate the equalization charges that try to do the same thing , though at the expense of overcharging the higher cells to try and bring up the lower ones.
I think the Neey active balancer may have lead acid setting or capabilities.
Of course there are so many variables with different systems and the loads on them that play into lead acid care and lifespan - like stratification if large capacity cells don't get a high enough charge to bubble up the electrolyte. That may not be an issue though with gel or lead crystal types of lead acid batteries.
Larry
Larry,
I appreciate your input. My take on battery balancers:
If as you say you are using 2volt LEAD ACID cells, there is a benefit to keeping the CELLS balanced. However, without an appropriate charge regimen that routinely puts the batteries in the 95-100% SOC range, I fear that all we have done is guarantee that all cells will sulphate evenly.
If the 2volt Lead acid cells are 2 to 3 times the height of a monobloc battery, then it seems to me that stratification of the electrolyte would be more of an issue. That can only be resolved by a more vigorous charge rate (independent of the SOC). Shaking the battery won't do it.
For a majority of us that are using 6v, 8v & 12v monobloc LEAD ACID batteries, a balancer would only balance the batteries, NOT the individual cells. I know of no other way of balancing the individual cells of a monobloc battery but through an appropriate charge regimen. Therefore, for monobloc batteries, balancers are an expense of little to no value.
I started this post in the LEAD ACID category in an attempt to find the best possible LEAD ACID CHARGING REGIMEN. I had kinda hoped to keep this chain centered on that specific subject.
Regards
Barry
Vic has made a lot of posts in the past about lead acid batteries.
His advice always suggested taking electrolyte sampling to determine the proper charging values are achieved. And then to keep taking the samples as regular maintenance to ensure that no cells are low and to be able to do equalizing and see if corrections have been achieved.
Of course this won't work for sealed lead acid batteries - only flooded where you can get samples .
I used that method to dial in the proper charging and ending amps - along with getting the SOC values on the Classic calibrated to be close .
Larry
Robin and I wanted to make an active lead acid battery balancer 20+ years ago.
boB
The company Multitel has an extensive explanation of FLOAT CURRENT MONITORING.
https://www.multitel.com/float-current-monitoring-a-complete-overview/
Below are two quotes I feel are worth highlighting:
Battery chemistry, battery design, quality of material, manufacturing process and battery capacity (AH) will ultimately influence the rate of self discharge of any lead acid batteries. Thus, the typical float current value will differ from one model to another.
Since the early 2000, float current measurements have been accepted for determining SoC (State of Charge) of VLA and VRLA batteries (see IEEE-450). As hygrometers are not easy to use and testing is time consuming, SG measurements can be replaced by float current measurements. Float current has an advantage in that it provides an indicator of the entire battery string, while specific gravity is measured on a cell-by-cell basis.
Should MidNite decide to pursue the CHARGING REGIMEN I have proposed, Multitel may be a valuable engineering resource.
I am surprised that I have not yet received ANY negative feedback on my proposal. I cannot possibly be that correct.
PS - Thanks for the promotion to Jr Member. At 74 it has been a while since I have been called Jr. Maybe ROJM (Really Old Jr Member)
Quote from: boB on September 04, 2023, 04:07:40 PMRobin and I wanted to make an active lead acid battery balancer 20+ years ago.
boB
The following is a question I posed to East Penn about a year ago and their response.
If I were able to compare all the battery voltages in a bank string, and one battery (6v 3cell) was more than 30 millivolts +/- from the average, would that be (while not perfect) an indicator that the string should be equalized?
Yes, that is a good trigger, but cell to cell equality is not our only goal. You must also regularly ensure the electrolyte in each cell gets mixed bottom to top by enough gassing time and get the plates fully charged all the way to the bottom.
Hope this might help.
PS I sent you a private message about 3 weeks ago. I know, nag, nag, nag.
Barry
Quote from: Barry Fields on October 06, 2023, 12:23:49 PMQuote from: boB on September 04, 2023, 04:07:40 PMRobin and I wanted to make an active lead acid battery balancer 20+ years ago.
boB
The following is a question I posed to East Penn about a year ago and their response.
If I were able to compare all the battery voltages in a bank string, and one battery (6v 3cell) was more than 30 millivolts +/- from the average, would that be (while not perfect) an indicator that the string should be equalized?
Yes, that is a good trigger, but cell to cell equality is not our only goal. You must also regularly ensure the electrolyte in each cell gets mixed bottom to top by enough gassing time and get the plates fully charged all the way to the bottom.
Hope this might help.
PS I sent you a private message about 3 weeks ago. I know, nag, nag, nag.
Barry
Yes, this is true ! Depending on the battery type, 30 mV may or may not be a problem. For lead acid, no problem IMO.
boB
Quote from: Barry Fields on September 05, 2023, 12:12:34 PMThe company Multitel has an extensive explanation of FLOAT CURRENT MONITORING.
https://www.multitel.com/float-current-monitoring-a-complete-overview/
Below are two quotes I feel are worth highlighting:
Battery chemistry, battery design, quality of material, manufacturing process and battery capacity (AH) will ultimately influence the rate of self discharge of any lead acid batteries. Thus, the typical float current value will differ from one model to another.
Since the early 2000, float current measurements have been accepted for determining SoC (State of Charge) of VLA and VRLA batteries (see IEEE-450). As hygrometers are not easy to use and testing is time consuming, SG measurements can be replaced by float current measurements. Float current has an advantage in that it provides an indicator of the entire battery string, while specific gravity is measured on a cell-by-cell basis.
Should MidNite decide to pursue the CHARGING REGIMEN I have proposed, Multitel may be a valuable engineering resource.
I am surprised that I have not yet received ANY negative feedback on my proposal. I cannot possibly be that correct.
PS - Thanks for the promotion to Jr Member. At 74 it has been a while since I have been called Jr. Maybe ROJM (Really Old Jr Member)
Hi Barry,
It is just me, but, any "Authority", regarding FLA batteries, that calls an Electrolyte Density-measuring device, a "Hygrometer" (which generally measures the proportion of water, present in, gas/es, like those in air, instantly loses 98.998% of any credibility, about all the other "info", provided.
IMO, there are many, many ... many variables when charging/discharging, and measuring/inferring SOC, and SOH of batteries. None of the methods used need to be perfect, just, perfectly adequate.
It is often proposed, that, when possible, a person needing a battery system, buy a set of batteries, ideally, FLAs, true deep-cycle, like GCs, and learn how to use them, and use accepted measurements -- a Hydrometer, and Pilot Cells, for quick readings on the average, nominal SOC.
Monitor, carefully, the amount of replenishment Distilled Water, for each battery ...
Create a Log Book, for that batt bank, record charge settings, EQ duration, and voltage, battery current, etc, then sit back, and enjoy the fruits of the labor, and wisdom that you have gained.
Over time, the battery current reduction, during EQ can imply battery SOH, and when further EQing will probably have diminishing effect.
IMO, again, USE A BTS, with FLA batts, AND, Temp Comp the EQ voltage ...
AND, as always, I am NO battery expert, am still practicing, though.
IMO, FWIW ... YMMV, and so on Vic
Quote from: Vic on October 06, 2023, 02:56:48 PMQuote from: Barry Fields on September 05, 2023, 12:12:34 PMThe company Multitel has an extensive explanation of FLOAT CURRENT MONITORING.
https://www.multitel.com/float-current-monitoring-a-complete-overview/
Below are two quotes I feel are worth highlighting:
Battery chemistry, battery design, quality of material, manufacturing process and battery capacity (AH) will ultimately influence the rate of self discharge of any lead acid batteries. Thus, the typical float current value will differ from one model to another.
Since the early 2000, float current measurements have been accepted for determining SoC (State of Charge) of VLA and VRLA batteries (see IEEE-450). As hygrometers are not easy to use and testing is time consuming, SG measurements can be replaced by float current measurements. Float current has an advantage in that it provides an indicator of the entire battery string, while specific gravity is measured on a cell-by-cell basis.
Should MidNite decide to pursue the CHARGING REGIMEN I have proposed, Multitel may be a valuable engineering resource.
I am surprised that I have not yet received ANY negative feedback on my proposal. I cannot possibly be that correct.
PS - Thanks for the promotion to Jr Member. At 74 it has been a while since I have been called Jr. Maybe ROJM (Really Old Jr Member)
Hi Barry,
It is just me, but, any "Authority", regarding FLA batteries, that calls an Electrolyte Density-measuring device, a "Hygrometer" (which generally measures the proportion of water, present in, gas/es, like those in air, instantly loses 98.998% of any credibility, about all the other "info", provided.
IMO, there are many, many ... many variables when charging/discharging, and measuring/inferring SOC, and SOH of batteries. None of the methods used need to be perfect, just, perfectly adequate.
It is often proposed, that, when possible, a person needing a battery system, buy a set of batteries, ideally, FLAs, true deep-cycle, like GCs, and learn how to use them, and use accepted measurements -- a Hydrometer, and Pilot Cells, for quick readings on the average, nominal SOC.
Monitor, carefully, the amount of replenishment Distilled Water, for each battery ...
Create a Log Book, for that batt bank, record charge settings, EQ duration, and voltage, battery current, etc, then sit back, and enjoy the fruits of the labor, and wisdom that you have gained.
Over time, the battery current reduction, during EQ can imply battery SOH, and when further EQing will probably have diminishing effect.
IMO, again, USE A BTS, with FLA batts, AND, Temp Comp the EQ voltage ...
AND, as always, I am NO battery expert, am still practicing, though.
IMO, FWIW ... YMMV, and so on Vic
I try to ignore spelling and punctuation when I am reading for content and the ideas behind that content. Just me.
My last conversation with Rolls Battery was instructive. The support rep stated that NO solar company charges batteries properly except for Outback. My interpretation is that they may be the only ones doing it the "Rolls way".
The rep also stated that he had been doing this for 30 years. That translates to "we have always done it this way and there is no reason to entertain anything new" IMHO
I certainly hope that MidNite does not feel the same way. I understand that the
perfect should not stand in the way
better.
Quote from: boB on October 06, 2023, 01:40:47 PMYes, this is true ! Depending on the battery type, 30 mV may or may not be a problem. For lead acid, no problem IMO.
Most of what I have read about balancers and East Penn is the goal is that more than 10mv per cell is an indicator of a problem. Lithium imbalances are a safety issue(smoke/fire). For lead acid batteries, it would be an alert to an imbalance. What to do to correct or prevent that imbalance is a separate discussion. One needs to know that an issue exists before you try to address it.
QED
boB [/quote]
Quote from: Barry Fields on October 07, 2023, 09:51:55 PMQuote from: Vic on October 06, 2023, 02:56:48 PMQuote from: Barry Fields on September 05, 2023, 12:12:34 PMThe company Multitel has an extensive explanation of FLOAT CURRENT MONITORING.
https://www.multitel.com/float-current-monitoring-a-complete-overview/
Below are two quotes I feel are worth highlighting:
Battery chemistry, battery design, quality of material, manufacturing process and battery capacity (AH) will ultimately influence the rate of self discharge of any lead acid batteries. Thus, the typical float current value will differ from one model to another.
Since the early 2000, float current measurements have been accepted for determining SoC (State of Charge) of VLA and VRLA batteries (see IEEE-450). As hygrometers are not easy to use and testing is time consuming, SG measurements can be replaced by float current measurements. Float current has an advantage in that it provides an indicator of the entire battery string, while specific gravity is measured on a cell-by-cell basis.
Should MidNite decide to pursue the CHARGING REGIMEN I have proposed, Multitel may be a valuable engineering resource.
I am surprised that I have not yet received ANY negative feedback on my proposal. I cannot possibly be that correct.
PS - Thanks for the promotion to Jr Member. At 74 it has been a while since I have been called Jr. Maybe ROJM (Really Old Jr Member)
Hi Barry,
It is just me, but, any "Authority", regarding FLA batteries, that calls an Electrolyte Density-measuring device, a "Hygrometer" (which generally measures the proportion of water, present in, gas/es, like those in air, instantly loses 98.998% of any credibility, about all the other "info", provided.
IMO, there are many, many ... many variables when charging/discharging, and measuring/inferring SOC, and SOH of batteries. None of the methods used need to be perfect, just, perfectly adequate.
It is often proposed, that, when possible, a person needing a battery system, buy a set of batteries, ideally, FLAs, true deep-cycle, like GCs, and learn how to use them, and use accepted measurements -- a Hydrometer, and Pilot Cells, for quick readings on the average, nominal SOC.
Monitor, carefully, the amount of replenishment Distilled Water, for each battery ...
Create a Log Book, for that batt bank, record charge settings, EQ duration, and voltage, battery current, etc, then sit back, and enjoy the fruits of the labor, and wisdom that you have gained.
Over time, the battery current reduction, during EQ can imply battery SOH, and when further EQing will probably have diminishing effect.
IMO, again, USE A BTS, with FLA batts, AND, Temp Comp the EQ voltage ...
AND, as always, I am NO battery expert, am still practicing, though.
IMO, FWIW ... YMMV, and so on Vic
I try to ignore spelling and punctuation when I am reading for content and the ideas behind that content. Just me.
My last conversation with Rolls Battery was instructive. The support rep stated that NO solar company charges batteries properly except for Outback. My interpretation is that they may be the only ones doing it the "Rolls way".
The rep also stated that he had been doing this for 30 years. That translates to "we have always done it this way and there is no reason to entertain anything new" IMHO
I certainly hope that MidNite does not feel the same way. I understand that the perfect should not stand in the way better.
Quote from: boB on October 06, 2023, 01:40:47 PMYes, this is true ! Depending on the battery type, 30 mV may or may not be a problem. For lead acid, no problem IMO.
Most of what I have read about balancers and East Penn is the goal is that more than 10mv per cell is an indicator of a problem.
Maybe that is because they sell battery balancers that can get the balance that close ?
Quote from: Barry Fields on October 07, 2023, 09:51:55 PMLithium imbalances are a safety issue(smoke/fire). For lead acid batteries, it would be an alert to an imbalance. What to do to correct or prevent that imbalance is a separate discussion. One needs to know that an issue exists before you try to address it.
QED
I think that for Lithium, I would not want them to be off balance by much at all, even for string capacity sake, as well as for safety.
I wonder what Outback does that they like so much ? I am guessing that it has to do with Outback's float cut-off time and re-float voltage settings to bring it back into float. The idea is that floating all the time can reduce the life of a LA battery.
Was it Steve Higgins that you talked to ?
Checking out the Multitel thing.
boB
Barry ,
Look up Lead Crystal type batteries. They are like gel but the electrolyte is never supposed to let the plates sulfate even if they go way below voltage.
Not sure if it is all hype or real tech.
I happen to have some though I bought them because that is what my battery dealer had at a nice price. He said he had heard good things about them being used in Africa.
Here is one link to a type - but there are others, maybe they are all made in the same plant in China and have different branding ?
https://greencrystalbatteries.com/pages/about-lead-crystal-batteries
https://soneil.com/products/battery/
Larry
Quote from: boB on October 08, 2023, 01:14:58 AMI wonder what Outback does that they like so much ? I am guessing that it has to do with Outback's float cut-off time and re-float voltage settings to bring it back into float. The idea is that floating all the time can reduce the life of a LA battery.
Was it Steve Higgins that you talked to ?
Checking out the Multitel thing.
boB
Yes is was Steve Higgins. I believe that Rolls wants end amps to last for 1 hour.
I do not approve because it could cause overcharging depending on the day's conditions.
I am trying to prevent both under and over charging for the sake of battery life.
I do not have the resources to effectively put a stamp of approval on my suggested process. I have the ability to physically monitor end amps and float current. I have adjusted absorb times and spent hours watching my system for transitions from absorb to float, I have no way to force that transition in either direction.
EastPenn has quoted my battery's 100% SOC float current @ 450ma (2.1ma/AHC).
In looking at the charge efficiency curve, I can only guess that the 95%SOC value would be approximately 2-3 times the 100% value. I have achieved values for float current between 600-1200ma which would be in that 95-100% range.
If I had the resources, I would verify the projected 95%SOC value through actual test of a battery. (overcharge, float stabilized, read 100%, fixed 5% discharge, float stabilized, read 95%)
I truly believe that my process would be a better mouse trap.
Thanks for your support
Barry
Quote from: ClassicCrazy on October 08, 2023, 12:12:58 PMBarry ,
Look up Lead Crystal type batteries. They are like gel but the electrolyte is never supposed to let the plates sulfate even if they go way below voltage.
Not sure if it is all hype or real tech.
I happen to have some though I bought them because that is what my battery dealer had at a nice price. He said he had heard good things about them being used in Africa.
Here is one link to a type - but there are others, maybe they are all made in the same plant in China and have different branding ?
https://greencrystalbatteries.com/pages/about-lead-crystal-batteries
https://soneil.com/products/battery/
Larry
Do they seem to work for you? I did notice that the web sites did not offer much in the way of tech data. Most of the support info I found were either from the manufacturers or sellers.
Understand that I am a skeptic. I sometimes doubt what I think I know.
I would hesitate until there are many more charts and graphs on performance.
?? Why did your dealer have such a good price ??
Hope to meet or talk to ya someday,
Barry
Quote from: Barry Fields on October 09, 2023, 05:46:18 PMQuote from: ClassicCrazy on October 08, 2023, 12:12:58 PMBarry ,
Look up Lead Crystal type batteries. They are like gel but the electrolyte is never supposed to let the plates sulfate even if they go way below voltage.
Not sure if it is all hype or real tech.
I happen to have some though I bought them because that is what my battery dealer had at a nice price. He said he had heard good things about them being used in Africa.
Here is one link to a type - but there are others, maybe they are all made in the same plant in China and have different branding ?
https://greencrystalbatteries.com/pages/about-lead-crystal-batteries
https://soneil.com/products/battery/
Larry
Do they seem to work for you? I did notice that the web sites did not offer much in the way of tech data. Most of the support info I found were either from the manufacturers or sellers.
Understand that I am a skeptic. I sometimes doubt what I think I know.
I would hesitate until there are many more charts and graphs on performance.
?? Why did your dealer have such a good price ??
Hope to meet or talk to ya someday,
Barry
I guess the dealer just happened to have what I needed in stock - the cost was around 4 thousand for 24v 540ah if I remember correctly. At the time I would have had to order the flooded forklift type ( the kind that came with studs so you can move each cell separately). It was nice to have the sealed batteries because you can move them around without having to worry about the juice in them spilling out. The other reason I got these is because they have very good low temperature performance and I had them in unheated place. One winter it was down to -40F and while they were not happy charging at that temp they got me through the extreme cold until it warmed up in a day or two. All in all they have performed okay for me -I tried to not take more than 20% out of them for better longevity. The nice thing is not having to mess around with taking SG readings and watering them. You are right - there is not a lot of technical or real experience with these though I haven't looked for awhile. I took the gamble getting them and it seems to have paid off in the long run. I have basically moved on to 48v lithium , I still have them on a separate system which I mostly use for supplying DC loads ( via 12v converter).
Larry
Before you read the attached, I need you to understand the following:
55 years ago on a day very much like today, I was studying Vacuum Tube design. Yes it was a time when we had TV repair men. You could take your # 27 vacuum tube to the hardware store and test it.
It was in that bygone era I was subjected to classes in FORTRAN and COBOL.
The attached is a proposed algorithm for "float current controlled charging". It is crude by today's standards but I hope it is illustrative. I have assumed some numbers that would have to be proven in the real world.
That being said, you are allowed to chuckle amongst yourselves, however I am sensitive to overt belly laughs.
Barry
Quote from: Barry Fields on October 10, 2023, 06:42:23 PMThat being said, you are allowed to chuckle amongst yourselves, however I am sensitive to overt belly laughs.
Barry
ROFL !
No, not at all. That is about right. We use fail days for Auto-EQing the battery so that it wouldn't keep trying to go high voltage day after day (for too long) if not quite enough sun was available.
Waiting 15 minutes for ending amps before going to Float is good too. We wait something like 90 seconds but either one is probably fine.
boB
Quote from: boB on October 11, 2023, 11:45:04 AMROFL !
Glad I was able to brighten up your day.
I chose 15 minutes because Rolls wanted 1 hour after end amps. 15 minutes would prevent too many loops back to absorb.
Again, real world testing beyond my skill set and resources.
Barry