Equalizing over winter absence?

Freewilley
Freewilley Solar Expert Posts: 228 ✭✭
Leaving on Friday for sunny Arizona....home is empty for 7 months.

A friend, who knows nothing about my system will check my system as requested...but given that he lives 45 minutes away, and will have to fight the last 500 feet in on snowshoes, I would only ask him to come by once or twice.

The panels will be fully covered by snow at times, but 60% of the array can be adjusted to vertical to shed snow and to pick up the solar refection off the snow ( snow will be on ground from December 15 to April 15, approx). No power draw on system except inverter and CCs.

So, questions for knowledgeable folks,
should I set the auto equalize function, and if so, how often? If so, then should I leave the caps loose?

Should I make any adjustments to my settings? Normally I would leave them at 14.8 absorb for 5.5 hours and 13.2 float.

thanks for your help
Mate, VFX 2812, FM 60 & MX 60, 2 Full River AGM 400 6v, 1400 watt Solar Array, Yamaha 3000iSEB inverter gen
12 volt Flojet water pump
off grid summer home in northern Ontario
«1

Comments

  • Mountain Don
    Mountain Don Solar Expert Posts: 494 ✭✭✭
    Re: Equalizing over winter absence?

    Have you calculated the end amps for the CC? That would be good to know and to have that programmed in.

    When you state the inverter will be 'on', does that mean there are some loads that will be running? If no loads why not disconnect it / turn it off?

    When we leave our cabin system and there is no power being used for anything at all, I pull the disconnect on the inverter - battery line in. We do leave the CC active and it does keep the batteries up all winter.
    Northern NM, 624 watts PV, The Kid CC, GC-2 batteries @ 24 VDC, Outback VFX3524M
  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: Equalizing over winter absence?

    I agree with Mountain Don, and yes, the inverter should definitely be disconnected if at all possible.
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Equalizing over winter absence?

    I see you have Surrettes, If you have used them this summer and they have had plenty of cycles and the SG are acting normal they should be OK. I took a brand new set last year ( Factory to me ) and commissioned them and the SG were all at 1.265 and put them on float @ 13.4 with no loads. I went back to CK them in early February and they had a SG level of 1.210. After 12 + hrs of Equalization, I got them back up to 1.265. I went back in March and they again had fallen to 1.230. There has to be something with batteries that have unformed plates that only use a partial plate charging that will allow part of the plates to Sulfate. I ruled out stratification because that will correct itself with a short EG.

    I have now used them all summer and have many cycles on them and they have been discharging and charging all summer and don't expect the same issues this year. Early in the spring it was taking 11 amps EA to get back to 1.265 and now after the battery plates have fully formed it has moved up at 30 amps EA to get there. This makes me believe the plate theory.
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Equalizing over winter absence?

    If the batteries are fully charged, and you run an EQ a day or two before you leave, top off with distilled, disconnect the loads and inverter, and let the charge controllers float it all winter. Without cycles, the batteries wont get too unbalanced, and the PV should keep it topped off. Charged batteries have to get REALLY cold to freeze, so if nothing bad happens (charge controller blowing out with overvoltage some frosty morning) things should be fine.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    Re: Equalizing over winter absence?
    mike95490 wrote: »
    If the batteries are fully charged, and you run an EQ a day or two before you leave, top off with distilled, disconnect the loads and inverter, and let the charge controllers float it all winter.

    I would add the water before the EQ so that the EQ will stir the water into the electrolyte. --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • Freewilley
    Freewilley Solar Expert Posts: 228 ✭✭
    Re: Equalizing over winter absence?

    I was under the impression that my CCs go off if I shut off the inverter....I will check that when it is a good time to shut down power in the house.
    Mate, VFX 2812, FM 60 & MX 60, 2 Full River AGM 400 6v, 1400 watt Solar Array, Yamaha 3000iSEB inverter gen
    12 volt Flojet water pump
    off grid summer home in northern Ontario
  • Freewilley
    Freewilley Solar Expert Posts: 228 ✭✭
    Re: Equalizing over winter absence?
    Have you calculated the end amps for the CC? That would be good to know and to have that programmed in.

    When you state the inverter will be 'on', does that mean there are some loads that will be running? If no loads why not disconnect it / turn it off?

    When we leave our cabin system and there is no power being used for anything at all, I pull the disconnect on the inverter - battery line in. We do leave the CC active and it does keep the batteries up all winter.

    No, I have not calculated end amps, and have no idea what that means....can somebody help with that?
    Mate, VFX 2812, FM 60 & MX 60, 2 Full River AGM 400 6v, 1400 watt Solar Array, Yamaha 3000iSEB inverter gen
    12 volt Flojet water pump
    off grid summer home in northern Ontario
  • Freewilley
    Freewilley Solar Expert Posts: 228 ✭✭
    Re: Equalizing over winter absence?
    I see you have Surrettes, If you have used them this summer and they have had plenty of cycles and the SG are acting normal they should be OK. I took a brand new set last year ( Factory to me ) and commissioned them and the SG were all at 1.265 and put them on float @ 13.4 with no loads. I went back to CK them in early February and they had a SG level of 1.210. After 12 + hrs of Equalization, I got them back up to 1.265. I went back in March and they again had fallen to 1.230. There has to be something with batteries that have unformed plates that only use a partial plate charging that will allow part of the plates to Sulfate. I ruled out stratification because that will correct itself with a short EG.

    I have now used them all summer and have many cycles on them and they have been discharging and charging all summer and don't expect the same issues this year. Early in the spring it was taking 11 amps EA to get back to 1.265 and now after the battery plates have fully formed it has moved up at 30 amps EA to get there. This makes me believe the plate theory.


    I have had problems with sulphation and lack of full cycling since I put the bank in service mid-June. They seem to be fine now, but I anticipate deficit cycling....that is why I thought I should do an EQ cycle every 60 days or something...
    Mate, VFX 2812, FM 60 & MX 60, 2 Full River AGM 400 6v, 1400 watt Solar Array, Yamaha 3000iSEB inverter gen
    12 volt Flojet water pump
    off grid summer home in northern Ontario
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Equalizing over winter absence?

    Disconnect inverter. It will not affect the charge controllers. If it does, the system is wired wrong.

    Leave the charge controller connected. You may want to reduce the Float Voltage. There should be no deficit charging problem because there will be no loads to discharge the batteries to begin with.

    End Amps is a function of the controllers that cancels Absorb stage when output current drops below a certain level. It can be advantageous, but it is not strictly necessary. You will have to check the instructions for each controller to find where the settings are as they differ between the MX and FM controllers.

    You should not need to do an EQ cycle while the batteries are not in service. A good system will rarely require EQ even when in use, but Surrettes are problem batteries.
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Equalizing over winter absence?
    Freewilley wrote: »
    I have had problems with sulphation and lack of full cycling since I put the bank in service mid-June. They seem to be fine now, but I anticipate deficit cycling....that is why I thought I should do an EQ cycle every 60 days or something...
    It would be tempting to do a short EQ or two if it was done through the Charge Controller without any additional tare on the system, if for nothing more than to stir the electrolyte. I tried to set mine up that way but I couldn't get it to work right. The lesser of the two evils could be to deal with them next spring rather than a unwatched EQ, that you might not trust to shut off.

    You saw my issues last year, but like I said they have now dissipated. I never could find a mention of it anywhere that it was a potential problem.
  • Freewilley
    Freewilley Solar Expert Posts: 228 ✭✭
    Re: Equalizing over winter absence?

    What should I set the End Amps at?

    Blackcherry certainly found that he needed to EQ over the winter....so in theory it might not be necessary but his experience showed it was. Makes me wonder....what is the downside of an EQ every 2 months (providing the water is checked)?
    The only thing I can think of is that I would have to leave the caps loose which allows for loss of more water...but is that not pretty marginal???? My system does not take much water even when cycling and EQing. I have been doing a lot of that over the last 2 months and each cell took 200ml to top to MAX.
    Mate, VFX 2812, FM 60 & MX 60, 2 Full River AGM 400 6v, 1400 watt Solar Array, Yamaha 3000iSEB inverter gen
    12 volt Flojet water pump
    off grid summer home in northern Ontario
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Equalizing over winter absence?
    Freewilley wrote: »
    What should I set the End Amps at?
    I have more battery than you, but mine are at 30 Ending amps. That is from a full charge that is about 1.250 SG, but they will rise to 1.265 after a overnight rest. Thats how they work, if you run them to low you'll end up at 1.280 the next day. You have to give them that rest period to get the true SG level.
  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    Re: Equalizing over winter absence?
    Freewilley wrote: »
    What should I set the End Amps at?

    First of all, you cannot use end amps on your system with any loads, unless you have Outback's flexnet DC. If the inverter and all loads are discaonnected, your FM60 can do end amps. You have to watch your battery current while it is charging in absorb stage. The current slowly declines. When it stops declining, that is your end amps. Its different for every battery and changes some during the life of the battery.
    Freewilley wrote: »
    The only thing I can think of is that I would have to leave the caps loose which allows for loss of more water

    What happens if the caps are not loose?

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Equalizing over winter absence?
    vtmaps wrote: »
    First of all, you cannot use end amps on your system with any loads, unless you have Outback's flexnet DC.

    This is not true.
    If it were, the End Amps function would not have been included with the MX controllers which existed before the FNDC.
    It is a bit trickier with loads as a load allowance has to be made, but it can be done and does work.

    In any case it is not relevant here because there will be no loads.

    End Amps is typically 2% of the Amp hour capacity.

    The problem with doing unattended EQ is that there's no one there to make sure nothing has gone wrong. EQ is at higher Voltage: it stresses batteries and increases water loss. It is therefor not a good idea to do it unless you know it is needed and the batteries are able to undergo the process (i.e. fully charged and with sufficient water in them).

    As it is batteries that are fully charged when disconnected will probably not suffer enough self-discharge over half a year to go below the point where they really start to sulphate. They are not going to lose 25% of capacity in that time unless they are already old and suffering (like me).
  • Freewilley
    Freewilley Solar Expert Posts: 228 ✭✭
    Re: Equalizing over winter absence?

    So I have 4 S550 at 12 volts, 400ah at 20 hr, so I set at 16 amps?
    That seems high?

    On the loose caps, all I know is the EQ instructions say loosen the caps when EQing....that said, I have forgotten to loosen them, at least once, and nothing happened...
    Mate, VFX 2812, FM 60 & MX 60, 2 Full River AGM 400 6v, 1400 watt Solar Array, Yamaha 3000iSEB inverter gen
    12 volt Flojet water pump
    off grid summer home in northern Ontario
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Equalizing over winter absence?
    Freewilley wrote: »
    So I have 4 S550 at 12 volts, 400ah at 20 hr, so I set at 16 amps?
    That seems high?

    On the loose caps, all I know is the EQ instructions say loosen the caps when EQing....that said, I have forgotten to loosen them, at least once, and nothing happened...

    :confused: S550 is a 6 Volt 428 Amp hour battery I think? Four would be 856 Amp hours @ 12 Volts. 2% would be 17 Amps in fact.

    Should I ask why this isn't a 24 Volt system? It would work much better.
  • Freewilley
    Freewilley Solar Expert Posts: 228 ✭✭
    Re: Equalizing over winter absence?

    because I bought a 12 volt inverter 7 years ago...and started with 2 6v batts

    the FM has the absorb end amps setting, which I set at 17...the MX does not have that option, so is not set. about 70% of my solar comes thru the FM.

    I do not understand the end amps function tho, could somebody give me a more detailed explanation for a dummy? What is that doing to the absorb cycle?

    On the EQ, my buddy will check the SG in 2 months, as well as top up cells. If it is below 1.250 I will get him to start an EQ and check back later.
    This is a test run for me with these new batts.
    Mate, VFX 2812, FM 60 & MX 60, 2 Full River AGM 400 6v, 1400 watt Solar Array, Yamaha 3000iSEB inverter gen
    12 volt Flojet water pump
    off grid summer home in northern Ontario
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Equalizing over winter absence?

    Actually the MX does have that function, it's just harder to find. But you wouldn't need it on both if the MX is a 'minor contributor' to charging (although it may try to stay in Absorb past the End Amps point on the FM; if unable to maintain the higher Voltage it will drop back to Bulk, otherwise it could keep Absorb going despite the FM's discontinuation).

    What End Amps does is terminate Absorb stage when the output current of the controller falls below the set point. In this case EA = 17, so if current <17 Amps Absorb stops regardless of time settings.

    You can experiment to find the best setting by running long Absorb time and observing the current to see where it plateaus - the point where the battery has done all the Absorbing it is like to do. Check against SG if possible to see if the battery truly is charged. This is a necessary procedure when running a controller without any battery monitor, especially with concurrent loads.

    Running over your sig description I see 1050 Watts of PV. On a 12 Volt system that is about 67 Amps of current. Yet you have it divided between two 60 Amp controllers. Different spec panels?

    Given that, you are going to have trouble with that much battery as the peak current available is too low. Frankly your system needs some serious re-designing. It needs more PV for one thing. You should consider some possible changes such as using an FM80 or Classic 150 to replace the two controllers you have now (if PV will allow) and selling off the others. Or selling the 12 Volt inverter and getting a 24 Volt one, thus eliminating one controller as well (if possible). As it is the batteries are inevitably going to suffer without regular gen run time.
  • Freewilley
    Freewilley Solar Expert Posts: 228 ✭✭
    Re: Equalizing over winter absence?

    Thanks, good advice.
    I have two controllers because it is too much PV for one....800 watts is the max recomended on 12 volts bank. When I added a panel I was told, after the fact, that I was over and should add another CC. And yes, I have two different arrays, one of 2 240 watt panels fixed on the roof facing WSW, and the other 3 that pivot (on the ground).

    I have already decided that I need to add more PV, and will add 2 240 watt panels next spring.

    Any idea where to find the end amps on the MX? I went through the ADVANCED tab, which is where it was on the FM
    Mate, VFX 2812, FM 60 & MX 60, 2 Full River AGM 400 6v, 1400 watt Solar Array, Yamaha 3000iSEB inverter gen
    12 volt Flojet water pump
    off grid summer home in northern Ontario
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Equalizing over winter absence?
    Freewilley wrote: »
    Thanks, good advice.
    I have two controllers because it is too much PV for one....800 watts is the max recomended on 12 volts bank. When I added a panel I was told, after the fact, that I was over and should add another CC. And yes, I have two different arrays, one of 2 240 watt panels fixed on the roof facing WSW, and the other 3 that pivot (on the ground).

    Who told you that? 800 Watts on a 12 Volt system might make 52 Amps. A 60 Amp controller can handle around 900 Watts, but not 1050.

    Two different arrays isn't as much of a problem as two different array specs: i.e. Voltage not the same between them.
    I have already decided that I need to add more PV, and will add 2 240 watt panels next spring.

    You need about 1340 Watts minimum for that battery bank so another 480 Watts would be good.
    Any idea where to find the end amps on the MX? I went through the ADVANCED tab, which is where it was on the FM

    Which is not where it is on the MX. :p It is under the miscellaneous screen, page 3.

    Note that where you have two controllers supplying enough current each to exceed the desired End Amps setting you should divide it between the two: 8 Amps from one a 9 Amps from the other. You will still have to watch it for a cycle or two to see how it behaves. Ideally both will drop Absorb at about the same time, but it really depends on how the current is divided up between the two. If more comes from the MX when charging then its End Amps setting needs to be the higher portion of the total.

    I hope that's not too confusing.
    At least is shows why the MidNite Classic has the "Follow Me" function and WhizBang Jr. - makes things much easier for multiple controllers!
  • Freewilley
    Freewilley Solar Expert Posts: 228 ✭✭
    Re: Equalizing over winter absence?
    Who told you that? 800 Watts on a 12 Volt system might make 52 Amps. A 60 Amp controller can handle around 900 Watts, but not 1050.

    Nope, the outback manual gives the 800 as the optimum. Did not matter in any case because by the time I read it I had the 1050.
    As you note, I went over the line when I added the last panel. I chose not to go the FM80 as 2 60s gave me more room to expand.

    My 2 arrays do have very different voltage. I do not see any evidence that this is a problem. In any case, they will be closer when I add the 2 new panels.
    Mate, VFX 2812, FM 60 & MX 60, 2 Full River AGM 400 6v, 1400 watt Solar Array, Yamaha 3000iSEB inverter gen
    12 volt Flojet water pump
    off grid summer home in northern Ontario
  • Photowhit
    Photowhit Solar Expert Posts: 6,002 ✭✭✭✭✭
    Re: Equalizing over winter absence?
    Note that where you have two controllers supplying enough current each to exceed the desired End Amps setting you should divide it between the two: 8 Amps from one a 9 Amps from the other. You will still have to watch it for a cycle or two to see how it behaves.

    I like to argue that, since, when you reach absorb your reducing the current going to the batteries, let the controller with the smallest array time out and only set the one with the largest array to end amps. I don't know if 'Coot expressed an opinion on this last time I suggested it. I would be curious to what he things about this.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Equalizing over winter absence?
    Freewilley wrote: »
    My 2 arrays do have very different voltage. I do not see any evidence that this is a problem. In any case, they will be closer when I add the 2 new panels.

    It is a problem if the two arrays are on the same controller.
    Output of two different controllers would not be a problem.
    Photwhit wrote:
    I like to argue that, since, when you reach absorb your reducing the current going to the batteries, let the controller with the smallest array time out and only set the one with the largest array to end amps. I don't know if 'Coot expressed an opinion on this last time I suggested it. I would be curious to what he things about this.

    If that works. It would depend on what is the "smallest array" and whether they need to work together into Absorb in order to complete the cycle. If there's not much difference in the array sizes both may be needed at least initially; being able to predict where in the charging half the PV is no longer needed is difficult to say the least.

    That's why I suggest trying it, seeing how it behaves, and adjusting accordingly to get the desired results.
  • Photowhit
    Photowhit Solar Expert Posts: 6,002 ✭✭✭✭✭
    Re: Equalizing over winter absence?
    If that works. It would depend on what is the "smallest array" and whether they need to work together into Absorb in order to complete the cycle. If there's not much difference in the array sizes both may be needed at least initially; being able to predict where in the charging half the PV is no longer needed is difficult to say the least.

    I would have the 2nd controller do a timed absorb, so it should assist in the early stages...

    ...as you said try and see how things work out...
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • Freewilley
    Freewilley Solar Expert Posts: 228 ✭✭
    Re: Equalizing over winter absence?

    And what would happen if I do not set end amps?????

    I am a little reluctant as I am leaving today and have no chance to see how it works.

    The two arrays do not face the same direction, larger one is southwest, small is more west. Also, rooftop units will be covered with snow for days, if not weeks in mid winter. The other array is going to be 90 degrees so should be more active in Jan-Feb.

    There really is no way to predict how these will work together.....and with no loads, all I want is to avoid any kind of deficit cycling building up....
    Mate, VFX 2812, FM 60 & MX 60, 2 Full River AGM 400 6v, 1400 watt Solar Array, Yamaha 3000iSEB inverter gen
    12 volt Flojet water pump
    off grid summer home in northern Ontario
  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: Equalizing over winter absence?
    Freewilley wrote: »
    all I want is to avoid any kind of deficit cycling building up....

    If all your loads are disconnected, your wish should come true.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Equalizing over winter absence?

    Without End Amps set the Absorb cycle will simply time out. In the case of the Outback controllers Absorb time ramps up according to how long the Bulk stage lasts with a maximum limit set. This should not be a problem when there are no loads as the Bulk stage should go fairly quickly owing to the batteries not being discharged to begin with.
  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    Re: Equalizing over winter absence?
    If all your loads are disconnected, your wish should come true.

    The controller itself is a load and then, of course, there is self discharge. When the panels are covered with snow, tare losses and self discharge can be significant. Hopefully Willey's vertical panels will make the battery's day.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • Freewilley
    Freewilley Solar Expert Posts: 228 ✭✭
    Re: Equalizing over winter absence?

    I have read that self discharge is much slower when cold....it is going to be very cold for at least 5 of those months.

    So the consensus is I am better to set end amps than not??
    Mate, VFX 2812, FM 60 & MX 60, 2 Full River AGM 400 6v, 1400 watt Solar Array, Yamaha 3000iSEB inverter gen
    12 volt Flojet water pump
    off grid summer home in northern Ontario
  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    Re: Equalizing over winter absence?
    Freewilley wrote: »
    So the consensus is I am better to set end amps than not??

    End amps is probably best, but I don't suggest you set it and then leave town without seeing how it works. --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i