Is there a way to program how long the classic stays in these modes?
Or is it controlled by the battery voltage the classic analyses results?
Quote from: russ_drinkwater on March 15, 2016, 04:41:21 PM
Is there a way to program how long the classic stays in these modes?
Or is it controlled by the battery voltage the classic analyses results?
It stays in Bulk Mode until it reaches the Absorb voltage set point. It will stay in Absorb how ever long you have the Absorb Timer set to as long as you are not using END AMPS.
Hi,
I have not set the absorb timer.
All I set was the voltages as per the trojan guide for the L16 batteries.
Not sure about end amps I do not recall seeing that when I setup and fired up the regulator.
I have not been able to find absorb times from any trojan websites or resellers.
Just spoke to the trojan shop I buy from and they said there is no set time for absorb.
Any suggestions as to the best approach?
Russ
got this reference by googling 'Trojan battery Absorb time'
US BATTERY CHARGING RECOMMENDATIONS - Trojan ...
www.trojanbattery.com/.../U.S.%20Battery%20Charge%20Profile%20Fu...
Notes: Charge time from full discharge is 8-12 hours. Absorption charge time is determined by the battery but will usually be "3 hours at 2.40 volts per cell.
I only have 20% discharge overnight. When i try the link it comes up at the trojan website and says page not found!
So 3 hours of absorption for the bank each day.
Can I/or will the classic have the absorb times stored so I can retrieve that info?
Mine have not been updated.
Did a search and found what I assume is the link and downloaded the pdf.
Will have a look today.
Thanks Russ
I believe the default absorb time on the Classic is 2 hours IIRC. I believe the settings are right next to the Volts menu and called CHG Time. I'm not near a Classic at the moment but I believe this will be located under the Charge menu.
End Amps by default is set to zero or off. The WBjr has to be connected and set up for this to work correctly.
Had a read today John.
I have set the absorb to 3 hours and it was default at 2 hours.
No whizbang jnr connected as yet.
End of the month it should all be a goer.
Quote from: russ_drinkwater on March 17, 2016, 05:56:22 AM
Had a read today John.
I have set the absorb to 3 hours and it was default at 2 hours.
No whizbang jnr connected as yet.
End of the month it should all be a goer.
So how does CC knows when to start with 2 hours charging interval. Do we need to specify that time? 11:00 AM to 13:00 PM for example.
I thought it would be automatic process, whenever there is enough sun on the sky. I am total beginner in this.
Quote from: sigp2101 on June 21, 2016, 04:12:35 PM
So how does CC knows when to start with 2 hours charging interval. Do we need to specify that time? 11:00 AM to 13:00 PM for example.
I thought it would be automatic process, whenever there is enough sun on the sky. I am total beginner in this.
For Solar charge modes, at least, the Classic begins each day charging batteries in Bulk, Unless a number of Skip Days have specified.
The Bulk stage continues, until the Absorb voltage setting is reached This is when the Absorb stage begins, and the Absorb timer (another setting) begins to count down. When the Absorb timer reaches the end of the time that has been set (that is, reaches 00:00), the Classic transitions to Float, which keeps the batteries charged, until there is too little input power (usually from the PVs).
The Classic does come from the factory with generally-safe settings (Default settings) for Lead Acid batteries, but one should set voltages and times as recommended by the manufacturer of YOUR batteries.
There are some fine details that can change some of the above, but this is the general nature of the Classic operation.
FWIW, Vic
When you get the Whizbang connected watch where the amps going into the batteries stops decreasing. Then set that as your end amps, still leave the 3 hours there but if you are only lightly discharging the end amps will come up a lot sooner than that.
Quote from: Vic on June 21, 2016, 06:26:20 PM
Quote from: sigp2101 on June 21, 2016, 04:12:35 PM
So how does CC knows when to start with 2 hours charging interval. Do we need to specify that time? 11:00 AM to 13:00 PM for example.
I thought it would be automatic process, whenever there is enough sun on the sky. I am total beginner in this.
For Solar charge modes, at least, the Classic begins each day charging batteries in Bulk, Unless a number of Skip Days have specified.
The Bulk stage continues, until the Absorb voltage setting is reached This is when the Absorb stage begins, and the Absorb timer (another setting) begins to count down. When the Absorb timer reaches the end of the time that has been set (that is, reaches 00:00), the Classic transitions to Float, which keeps the batteries charged, until there is too little input power (usually from the PVs).
The Classic does come from the factory with generally-safe settings (Default settings) for Lead Acid batteries, but one should set voltages and times as recommended by the manufacturer of YOUR batteries.
There are some fine details that can change some of the above, but this is the general nature of the Classic operation.
FWIW, Vic
Hi Vic,
Trojan specifies for their T-105s
Bulk at 44.5V,
Float 40.5V, and
EQ too be 48.6V for 36V battery bank configuration.
How do I setup classic accordingly when Classic 150 only has Absorb and Float.
Hi sigp2101,
Very few Solar CCs have a Bulk voltage setting. So, would set the Absorb voltage to 44.5 V.
Good Luck, Vic
Quote from: Vic on June 22, 2016, 12:17:37 PM
Hi sigp2101,
Very few Solar CCs have a Bulk voltage setting. So, would set the Absorb voltage to 44.5 V.
Good Luck, Vic
OK, what should I set my absorb time to be then? 1 hour, 2 hours or else?
Thanks!
Hi sigp..,
The required Absorb for the battery depends upon how deeply-discharged the battery happens to be. This is a variable.
End Amps from the Classic might be able to do a good job managing the end of Absorb, but, without the WBjr and a Shunt, the Classic's EA function (where Absorb can be ended by the current that the CC providing to the battery AND any loads) will use all of the current being provided to the battery, and all loads on the battery (inverter, and any direct DC loads).
If your loads on the battery are fairly constant during the time that the Classic is near the end of Absorb, or if the loads are fairly constant, and a larger load is intermittent, CC EA (without WB & Shunt), can still work fine.
The EA function relies on the fact that as batteries become fully-charged, the amount of current that the battery needs tapers. When this tapering battery current diminishes to a value where the rate of change is quite small, Absorb can be terminated.
You can set a Maximum Absorb time in the Charge> Time menu. This max time will end the Absorb, even if the EA current value that you have entered in the Advanced menu has not be been reached.
With Flooded batteries (FLA), the SGs can be checked, and any small error is the EA setting can be compensated for by changes in Absorb voltage.
The Shunt + WBjr is an inexpensive option for the Classic, and seems to me to be well worth the small additional cost. This option will allow a more accurate termination of the Absorb stage, using Shunt EA.
This might be a bit too much detail at this point ...
FWIW, Vic
Quote from: Vic on June 22, 2016, 03:22:20 PM
Hi sigp..,
The required Absorb for the battery depends upon how deeply-discharged the battery happens to be. This is a variable.
End Amps from the Classic might be able to do a good job managing the end of Absorb, but, without the WBjr and a Shunt, the Classic's EA function (where Absorb can be ended by the current that the CC providing to the battery AND any loads) will use all of the current being provided to the battery, and all loads on the battery (inverter, and any direct DC loads).
If your loads on the battery are fairly constant during the time that the Classic is near the end of Absorb, or if the loads are fairly constant, and a larger load is intermittent, CC EA (without WB & Shunt), can still work fine.
The EA function relies on the fact that as batteries become fully-charged, the amount of current that the battery needs tapers. When this tapering battery current diminishes to a value where the rate of change is quite small, Absorb can be terminated.
You can set a Maximum Absorb time in the Charge> Time menu. This max time will end the Absorb, even if the EA current value that you have entered in the Advanced menu has not be been reached.
With Flooded batteries (FLA), the SGs can be checked, and any small error is the EA setting can be compensated for by changes in Absorb voltage.
The Shunt + WBjr is an inexpensive option for the Classic, and seems to me to be well worth the small additional cost. This option will allow a more accurate termination of the Absorb stage, using Shunt EA.
This might be a bit too much detail at this point ...
FWIW, Vic
Huh, OK, I have to digest all this info first. Your contribution I highly appreciated.
SIGP2101
Have two more whiz bang's in the mail.
$326 for the 2 including postage. But that is cheaper than the $400 plus dollars to get them locally!
Splitting my 2 classic 150's between 2 battery banks has killed off my follow me plans.
Next job is the build a covered enclosure for the last lot of batteries.
Quote from: Vic on June 22, 2016, 12:17:37 PM
Hi sigp2101,
Very few Solar CCs have a Bulk voltage setting. So, would set the Absorb voltage to 44.5 V.
Good Luck, Vic
I was watching videos last night and it was mentioned in one of them that Classic's Absorb = Bulk. That is rather interesting because in the same videos customers are often instructed to consult with manufacturers data for various settings.
Here is instructions from Trojan for example on how to properly recharge their batteries.
Voltage 6 Volt 8 Volt 12 Volt 24 Volt 36 Volt 48 Volt
Bulk Charge (2.47 VPC) 7.4 9.9 14.8 29.6 44.5 59.3
Absorption Charge (2.35 â€" 2.45 VPC) 7.05 â€" 7.35 9.4 â€" 9.8 14.1 â€" 14.7 28.2 â€" 29.4 42.3 â€" 44.1 56.4 â€" 58.8
Finish Charge (2.70 VPC) 8.1 10.8 16.2 32.4 48.6 64.8
Equalize Charge (2.70 VPC) 8.1 10.8 16.2 32.4 48.6 64.8
Float Charge (if desired 2.25 VPC) 6.75 9.0 13.5 27 40.5 54
So according to Trojan we have 5 different charge regimes and our classics offers only two/three. That is what confuses me a most. So Bulk and Absorption voltages are pretty close and that takes care of that but Finish and Float are significantly different. This is all very important for longevity of our systems and how to properly set those values is question I am struggling to find the answer.
Quote from: sigp2101 on June 23, 2016, 09:49:54 AM
Quote from: Vic on June 22, 2016, 12:17:37 PM
Hi sigp2101,
Very few Solar CCs have a Bulk voltage setting. So, would set the Absorb voltage to 44.5 V.
Good Luck, Vic
I was watching videos last night and it was mentioned in one of them that Classic's Absorb = Bulk. That is rather interesting because in the same videos customers are often instructed to consult with manufacturers data for various settings.
Here is instructions from Trojan for example on how to properly recharge their batteries.
Voltage 6 Volt 8 Volt 12 Volt 24 Volt 36 Volt 48 Volt
Bulk Charge (2.47 VPC) 7.4 9.9 14.8 29.6 44.5 59.3
Absorption Charge (2.35 â€" 2.45 VPC) 7.05 â€" 7.35 9.4 â€" 9.8 14.1 â€" 14.7 28.2 â€" 29.4 42.3 â€" 44.1 56.4 â€" 58.8
Finish Charge (2.70 VPC) 8.1 10.8 16.2 32.4 48.6 64.8
Equalize Charge (2.70 VPC) 8.1 10.8 16.2 32.4 48.6 64.8
Float Charge (if desired 2.25 VPC) 6.75 9.0 13.5 27 40.5 54
So according to Trojan we have 5 different charge regimes and our classics offers only two/three. That is what confuses me a most. So Bulk and Absorption voltages are pretty close and that takes care of that but Finish and Float are significantly different. This is all very important for longevity of our systems and how to properly set those values is question I am struggling to find the answer.
Some Mfg show/call the Equalize set point Finish as you can see they are the same. I would not recommend that you Equalize (Finish)your batteries after every charge cycle. More like once a month or less unless the S/G between cells a far apart. Normal operation is it go from Absorb to Float. Bulk is max current required to achieve Absorb voltage set point. The voltage is held constant in Absorb while the current will decline. End Amps is the absorb current where it flattens out and does not drop any farther this is the point where you should go to float an maintain float voltage. You need a WBjr and shunt attached to use End Amps.
Quote
Some Mfg show/call the Equalize set point Finish as you can see they are the same. I would not recommend that you Equalize (Finish)your batteries after every charge cycle. More like once a month or less unless the S/G between cells a far apart. Normal operation is it go from Absorb to Float. Bulk is max current required to achieve Absorb voltage set point. The voltage is held constant in Absorb while the current will decline. End Amps is the absorb current where it flattens out and does not drop any farther this is the point where you should go to float an maintain float voltage. You need a WBjr and shunt attached to use End Amps.
Thanks for your input, really appreciated.
sigp2101 said, "So according to Trojan we have 5 different charge regimes and our classics offers only two/three. That is what confuses me a most. So Bulk and Absorption voltages are pretty close and that takes care of that but Finish and Float are significantly different. This is all very important for longevity of our systems and how to properly set those values is question I am struggling to find the answer"
Those types of battery charge profiles are for Grid Charging, and are often used for batteries that are used on Floor Scrubbers, Forklifts, etc. Charging from Renewable Energy (RE) power sources is generally much different.
You have Trojan batteries, what is the exact model number of the battery?
You should probably try to contact Trojan, for specific charge instructions for charging them from RE power sources, like from PVs.
With the model number of your batteries, we can probably find some good info on-line, but would help if you tried to also get that info from Trojan.
Agree with John, that, generally you will not want to use that Finish charge, on every charge cycle.
Regarding using EA without the WBjr and a Shunt, this works quite well on systems with relatively constant loads, and for systems that also have varying loads that cycle, and will remain off for five or so minutes -- like fridges, freezers, A/Cs, etc.
. Have used CC EA for many, many years ... really have NEVER used a fixed Absorb time. But if the system has completely out-of-control, large loads (ie with several others in a household running vacuums, hair driers/curlers, large pumps and so on), then CC EA (without the WBjr) is probably not a good approach.
Thanks, more later, Vic
Quote from: Vic on June 23, 2016, 08:07:00 PM
sigp2101 said, "So according to Trojan we have 5 different charge regimes and our classics offers only two/three. That is what confuses me a most. So Bulk and Absorption voltages are pretty close and that takes care of that but Finish and Float are significantly different. This is all very important for longevity of our systems and how to properly set those values is question I am struggling to find the answer"
Those types of battery charge profiles are for Grid Charging, and are often used for batteries that are used on Floor Scrubbers, Forklifts, etc. Charging from Renewable Energy (RE) power sources is generally much different.
Quote
You have Trojan batteries, what is the exact model number of the battery?
T-105 T2 technology
Quote
You should probably try to contact Trojan, for specific charge instructions for charging them from RE power sources, like from PVs.
I will eventually.
QuoteWith the model number of your batteries, we can probably find some good info on-line, but would help if you tried to also get that info from Trojan.
Agree with John, that, generally you will not want to use that Finish charge, on every charge cycle.
Regarding using EA without the WBjr and a Shunt, this works quite well on systems with relatively constant loads, and for systems that also have varying loads that cycle, and will remain off for five or so minutes -- like fridges, freezers, A/Cs, etc.
. Have used CC EA for many, many years ... really have NEVER used a fixed Absorb time. But if the system has completely out-of-control, large loads (ie with several others in a household running vacuums, hair driers/curlers, large pumps and so on), then CC EA (without the WBjr) is probably not a good approach.
Thanks, more later, Vic
This CC EA you talking about is so far away from me at this point, I am slowly chewing this up. One weekend at the time. Thank you for your tremendous support. More questions coming in separate thread.
Hi sigp..,
Thanks for adding a Signature, and for the model number of batteries and the inverter size.
You said, "... This CC EA you talking about is so far away from me at this point, I am slowly chewing this up. One weekend at the time. Thank you for your tremendous support. More questions coming in separate thread ... "
The Classic can End Absorb, based on the output current of the Classic, WITHOUT the WBjr and Shunt. I call this CC EA, (as opposed to Shunt EA). This can work fine, if your larger loads cycle on and off, and are off for about five minutes or more per cycle.
Will look for charge parameters for that model of Trojan T-105.
It seems that the running load from your fridge is not excessive. An unknown, presently, is the idle load from your inverter. This inverter idle load can be fairly substantial in a 24 hour period. If you were looking at running the fridge 24/7 in your absence, this could possibly be a bit of a concern, without you being there to monitor your battery SOC.
Do you have the Idle, or Tare power (or current) consumption of the inverter, a Link to a data sheet for it, or perhaps the brand and model number for it?
Thanks, Vic
Quote from: Vic on June 28, 2016, 02:18:34 PM
Hi sigp..,
Thanks for adding a Signature, and for the model number of batteries and the inverter size.
You said, "... This CC EA you talking about is so far away from me at this point, I am slowly chewing this up. One weekend at the time. Thank you for your tremendous support. More questions coming in separate thread ... "
The Classic can End Absorb, based on the output current of the Classic, WITHOUT the WBjr and Shunt. I call this CC EA, (as opposed to Shunt EA). This can work fine, if your larger loads cycle on and off, and are off for about five minutes or more per cycle.
I would not mind at all using that feature if you say is good one. But I do not know much about it. What it is, what it does, and how to program it into Classic. My main concern on this small system is over or undercharging batteries.
QuoteWill look for charge parameters for that model of Trojan T-105.
Thanks!
Quote
It seems that the running load from your fridge is not excessive. An unknown, presently, is the idle load from your inverter. This inverter idle load can be fairly substantial in a 24 hour period. If you were looking at running the fridge 24/7 in your absence, this could possibly be a bit of a concern, without you being there to monitor your battery SOC.
Do you have the Idle, or Tare power (or current) consumption of the inverter, a Link to a data sheet for it, or perhaps the brand and model number for it?
Thanks, Vic
Idle load for inverter according to specs is 0.7A. It is Chinese made unit and it was custom made just for 36V. Price was right. Fridge and Inverter will be disconnected completely in unintended state. That is for now, first I have to learn system and gain confidence before I even start to experiment leaving things on one week the time. Winter months all will be definitely disconnected. Only BB will be connected to CC <=> PV.
Quote from: Vic on June 28, 2016, 02:18:34 PM
Hi sigp..,
The Classic can End Absorb, based on the output current of the Classic, WITHOUT the WBjr and Shunt. I call this CC EA, (as opposed to Shunt EA). This can work fine, if your larger loads cycle on and off, and are off for about five minutes or more per cycle.
Thanks, Vic
OK I think I started to grasp the concept of this. What do I need to do to come up with EA number in order to take advantage of this possibility? My system will have no loads between weekends.
Thanks!
Looks like you are getting great advice here, Sig...
I would add that Ending Amps AE works best when using the Whizbang Junior shunt sensor because then
it know what is going into and out of the battery and doesn't look at inverters and other chargers and loads
in the system.
There is also (in the newest firmwares) an Absorb "Skip Days" feature where the Classic will do an Absorb
cycle every so often. This is because an Absorb isn't absolutely necessary every single 24 hour period
and it "can" actually be harmful for longest battery life by hitting that high voltage too often.
Absorb is kind of like a mini EQ and helps to reduce sulfating. I have heard that some batteries can
go a month or more without an Absorb. I do not really know what the optimum time or period
would be so the manufacturer should know.
boB
Quote from: boB on July 19, 2016, 01:02:36 PM
Looks like you are getting great advice here, Sig...
I would add that Ending Amps AE works best when using the Whizbang Junior shunt sensor because then
it know what is going into and out of the battery and doesn't look at inverters and other chargers and loads
in the system.
There is also (in the newest firmwares) an Absorb "Skip Days" feature where the Classic will do an Absorb
cycle every so often. This is because an Absorb isn't absolutely necessary every single 24 hour period
and it "can" actually be harmful for longest battery life by hitting that high voltage too often.
Absorb is kind of like a mini EQ and helps to reduce sulfating. I have heard that some batteries can
go a month or more without an Absorb. I do not really know what the optimum time or period
would be so the manufacturer should know.
boB
Sure I do Bob, and I am grateful for that. This forum is a friendly bunch and all contributors are great. I feel like at home.
Summer was great as well and I had a chance to feel and experiment with my little system. I learned a lot. System is running my fridge, my lights and TV. Occasionally I can/can't run vacuum cleaner but that is another topic discussion.
Generally my system is 5 days recharge 2 days of use. During those 5 days there is absolutely no load on the system. During 2 days we do not use up even 1KWh daily. BB is fully charged every time I checked with hydrometer. I am happy, now it is time to find out how far I van push what I have. But there is still entire winter ahead of me.
Quote from: boB on July 19, 2016, 01:02:36 PM
There is also (in the newest firmwares) an Absorb "Skip Days" feature where the Classic will do an Absorb
cycle every so often. This is because an Absorb isn't absolutely necessary every single 24 hour period
and it "can" actually be harmful for longest battery life by hitting that high voltage too often.
Absorb is kind of like a mini EQ and helps to reduce sulfating. I have heard that some batteries can
go a month or more without an Absorb. I do not really know what the optimum time or period
would be so the manufacturer should know.
boB
Trying to keep up with this post but You lost me here. Are you saying that absorb every day is a bad thing for batts life? How can the CC goes directly from bulk to float without passing through absorb? Doesn't the bulk voltaje higher than absorb? I have actually noticed something on my classic: voltaje rise when reaching absorb so maybe you are referring to that. Does that means that during absorb current is lower but voltaje is higher?
Quote from: dapago on October 30, 2016, 09:05:35 PM
Quote from: boB on July 19, 2016, 01:02:36 PM
There is also (in the newest firmwares) an Absorb "Skip Days" feature where the Classic will do an Absorb
cycle every so often. This is because an Absorb isn't absolutely necessary every single 24 hour period
and it "can" actually be harmful for longest battery life by hitting that high voltage too often.
Absorb is kind of like a mini EQ and helps to reduce sulfating. I have heard that some batteries can
go a month or more without an Absorb. I do not really know what the optimum time or period
would be so the manufacturer should know.
boB
Trying to keep up with this post but You lost me here. Are you saying that absorb every day is a bad thing for batts life? How can the CC goes directly from bulk to float without passing through absorb? Doesn't the bulk voltaje higher than absorb? I have actually noticed something on my classic: voltaje rise when reaching absorb so maybe you are referring to that. Does that means that during absorb current is lower but voltaje is higher?
Hi dapago,
For systems that have relatively large battery Capacity, verses the average Depth Of Discharge (DOD), doing a full recharge every day is not needed. And, generally, there are only so many charge cycles that a battery will endure, until end of life for the battery.
Also, many batteries will do well with cycling between 50 or 60% State Of Charge (SOC) and let's say 85 - 90 % SOC, with only several full recharges per week.
Some batteries will essentially never need a complete recharge.
So, Skip days can help keep from depleting the number of rated discharge cycles, of many battery types.
Many CCs, like the Classic and KIDs have NO setting for Bulk voltage. There IS an Absorb voltage setting. The Bulk stage continues with the Renewable Energy (RE) power source providing maximum current available, until the Absorb voltage is reached. At this point, the Absorb stage begins. Absorb continues until the set Absorb time setting is reached, EA setting is reached, or, perhaps, the CC reverts back to Bulk, if there is insufficient RE power available to maintain the Absorb voltage. When the set Absorb end point is reached, the CC transitions to Float.
The Absorb voltage is regulated to the Absorb set point (but is usually compensated for the measured temperature of the battery via the BTS). If the CC stays in Absorb, the Absorb voltage will remain constant (except for changes in temp compensation when the battery temperature changes).
In Absorb, the battery charge current DOES diminish as the battery charges. Near the end of a full battery charge, the rate of change in the battery charge current levels off, and at some point, simply stops diminishing. This is usually considered to be the point where the battery is fully-charged.
In Absorb, the only thing that would change battery charge voltage, would be a change in battery temperature.
The battery charge current can most easily be measured by the WBjr and a Shunt. Looking at the current from the CC can be misleading, as this current display includes any/all loads on the battery, usually all from loads on the inverter.
Vic
Hi Vic,
Reading your post meanwhile taking my morning coffee so be forgiving ;-).
I understand that batt have a cycle life but doesn't cycles rise depending on DOD?
In order to understand the skip day function, First I need to know how cycles are calculated.
If during a day with a load, batt charging pattern goes from absorb to float several times a day (from let say 80%SOC to 100% SOC), does that means every time batt goes from absorb to float it counts for 1 cycle or some kind of a portion of a cycle? From what I can see on the Trojan cycle curve, I understand that it should count for only a portion of a cycle and the skip absorb function is then valid only when a minimum load is put on the batt, i.e. WE cabin
Quote from: dapago on October 31, 2016, 08:25:40 AM
Hi Vic,
Reading your post meanwhile taking my morning coffee so be forgiving ;-).
I understand that batt have a cycle life but doesn't cycles rise depending on DOD?
In order to understand the skip day function, First I need to know how cycles are calculated.
If during a day with a load, batt charging pattern goes from absorb to float several times a day (from let say 80%SOC to 100% SOC), does that means every time batt goes from absorb to float it counts for 1 cycle or some kind of a portion of a cycle? From what I can see on the Trojan cycle curve, I understand that it should count for only a portion of a cycle and the skip absorb function is then valid only when a minimum load is put on the batt, i.e. WE cabin
Hi dapago,
When you said, "If during a day with a load, batt charging pattern goes from absorb to float several times a day ..." Then, you must have set ReBulk (RB) to some voltage above the Default of 8 V, and somewhat below the Float voltage setting. The RB function allows for several charge cycles in one day, if the battery becomes discharged to or below the voltage setting for RB.
If you are seeing more than one charge cycle in a single day, very often, then your system is not a candidate for Skip Day charging.
Skip Day charging for Lead Acid (LA) batteries is usually best for larger Capacity banks that are not cycled very deeply on the average day. Shallow-cycling LA batteries (to a SOC that is not below 90%) is generally not good for them. So Skipping charges allows the battery to cycle below 90%, and reduce the total time above Gassing Voltage (Absorb is above Gassing V, which causes positive plate erosion, which is not so good for those plates).
It is possible that every battery manufacturer has a somewhat different idea of what is a Cycle. The bottom line for Flooded batteries, it would seem that every hour spent in Absorb will extract some life from the battery. AND every hour spent in EQ will extract even more life from the battery.
BUT, repeatedly cycling LA batteries without fully charging them once or twice per week can be more damaging to batteries than Absorbing and EQing them when they need it, and Absorbing and EQing them, doing so within the range of voltages for these stages that are recommended by the battery manufacturer is what really counts.
There are other mechanisms which will help determine when the end of battery life occurs. Batteries that are well cared for, will still have a Calendar life -- months since manufacture, but this also depends upon a number of variables.
Chronically undercharging LA batteries is very bad for battery life. Not keeping batteries relatively cool also takes much life from them. The rule of thumb, that for every 10 degree C rise in average temperature of a battery will remove one half of its life, also applies.
There are few absolutes when dealing with batteries, and what is the "best" thing to do in a certain situation ... many times, depends upon many variables.
So, bottom line, IMO is, if your Flooded batteries really need to be recharged more than once per day, and/or, your system does cycle to 80% SOC, or below on the average day, the system does not the Skip Day function.
Occasionally, it can be healthy for Flooded batteries to be cycled down into the 50 -60% SOC range, and then recharged in a relatively short time period. Doing this would normally require the ability to charge at a rate of about 10% of 20 hour Capacity, or having a generator which can help get the battery above 80% SOC within about one day, and fully charge by the end of the following day ... from memory, believe that you have enough PV power to do this recharging (about 2400 W STC, IIRC). Guess that your PVs could charge at about a 37-ish amp rate, without any loads. Which may be about 15-ish percent of battery Capacity with no loads ...
Opinions, FWIW, Vic
Vic,
these surrettes I have here only get 40 amps max charge ( per 24 volt bank) during the day as the classics go through their cycle.
So 24 volts @ 1350 amps there should not be any concerns for the battery life as the input charge will never get to 10-20% of rated capacity?
Even though I have a lower input amperage daily charging (cycle) will reduce the life of the cells?
I have noticed the temps of the surrettes never seem to get higher than the ambient temp here.
I am assuming this is because they are not getting the recommended 100 plus amps of charge per bank.
Vic,
That is a complete answer to my question. For the moment I haven't all the load I will have when place is fully equipped and I believe my SOC now is between 80/90% in the morning. Can not be sure until a batt meter is installed, hopefully in a few week. I bought a device to check gravity and try to know the SOC in the morning but not sure it is of good quality as the meter inside sometime seems to get stuck at the bottom.
ReBulk set shows <8v so that should be ok and eq being at 64.8v it gives 8.1v per batt so >8v. On that side everything seems ok.
Quote from: russ_drinkwater on October 31, 2016, 04:41:59 PM
Vic,
these surrettes I have here only get 40 amps max charge ( per 24 volt bank) during the day as the classics go through their cycle.
So 24 volts @ 1350 amps there should not be any concerns for the battery life as the input charge will never get to 10-20% of rated capacity?
Even though I have a lower input amperage daily charging (cycle) will reduce the life of the cells?
I have noticed the temps of the surrettes never seem to get higher than the ambient temp here.
I am assuming this is because they are not getting the recommended 100 plus amps of charge per bank.
Hi Russ,
There various opinions about many of these aspects of battery charging.
The charge rate on your standalone system would be a bit below 3% of 20 hour Capacity of 1350 Ah (folks like me, believe that these 4KS25Ps have an actual Capacity of about 1280 Ah IMO).
For batteries with some loads while being charged, 3-ish percent of C charge rate might not be enough on a number of days, to finish a charge, and one could get into deficit charging (never, or almost never fully charging the batteries).
But, if you are monitoring SGs, and your DOD is not too great, this rate can be just fine.
Most Flooded battery heating during charge comes when the charge voltage is above the Gassing Voltage. The deeper the discharge, the longer will (or should) be the Absorb time, and therefore greater heating of the batteries. EQing produces even more heating than does Absorb, as water in the electrolyte is broken down ah a faster rate, for Flooded batteries. This breaking down on the water is very inefficient, and creates a lot of heat).
Generally there is very little heating of Flooded batteries, until the Gassing Voltage is reached. The more that the charge voltage exceeds Gassing voltage, the greater the rate of heating. So, most of the Bulk charge stage generates little heat.
I DO believe, that occasional high rate (high current) charging (10 - 13% of Capacity), can be healthy for batteries, just as are occasional discharges into the 60 to 50 percent DOD range for FLAs, and a fairly rapid full recharge (within one day) .
If you can fully-charge your Surrettes when they need it, with your 40-ish amp max charge rate, then this should be OK.
With this 40 A charge rate, you might have trouble EQing your battery, even with your probably wall-to-wall sun, on many days per year.
FWIW, the main battery banks here are charged at about a 70 - 75 amp max rate, which has worked fine, on most days. EQing on a partly cloudy day can need a smallish genset for a bit of help.
Just my opinions, Vic
Thanks Vic,
The 2 x 24volt banks are less than 10% discharged from sunset to 5 am in summer.
Each array has another 4 panels to go into them.
So once I get organised the bank I will be keeping will be getting close or better than 50 amps charge at peak.
The classics show on average around 5kw into each bank per day.
Have had a new satillite dish for the internet installed so I can install the rest of panels now as the shading issue I had has been resolved!
Now that the days are longer the sg's on the cells all sit around 1275 by 1200 hrs.