Battery emergency

2

Comments

  • BB.BB. Super Moderators, Administrators Posts: 29,523 admin
    Re: Battery emergency

    Whoa--Basically 100% charge is when the battery specific gravity stops rising after 1-2 hours... You don't want to continue to charge unless you know that 1.275 SG is "low" and you are trying to "recover" the battery.

    Are you temperature correcting too? (hot batteries read lower SG than if at room temperature).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • zozomikezozomike Solar Expert Posts: 87 ✭✭✭
    Re: Battery emergency

    Thank you, I am not temperature correcting, but the temp has never seemed high, based on spot checking with a thermometer at least. It has always been near ambient, mid 80s since installation. The battery is in an outdoor, ventilated but insulated enclosure, and since I have been obsessing with it the doors have always been open during the day. The SG has never stopped rising, it just climbs VERY slowly, it has taken a full day of generator/inverter charging to get from the morning low of 1.250 ( as it was at 8 am today) to the 1.275. Per GB the sg of the full battery is 1.285-1.295. I wonder if I have permanently lowered capacity. I am trying to recover the battery.

    Off grid, all solar, passive and active ( winter wood heat supplements) solar DHW, no backup.

    Array 1 1980w,   12 Solarworld 165 w panels - Outback Flex max 80

    Array 2 1590 w, 6 Solarworld 265 w panels - Outback flex max 60

    Well array 600w, 6 Kyocera 130 w  with Grundfos sqflex11 and cu200 to elevated  storage, ( 2- 330 g tanks,) no battery storage at well

    GB industrial 510 AH battery 24 V

    Outback VFX 3525 inverter,


  • vtmapsvtmaps Solar Expert Posts: 3,738 ✭✭✭✭
    Re: Battery emergency
    zozomike wrote: »
    I am not temperature correcting, but the temp has never seemed high
    <snip>
    it has taken a full day of generator/inverter charging to get from the morning low of 1.250 ( as it was at 8 am today) to the 1.275. Per GB the sg of the full battery is 1.285-1.295. I wonder if I have permanently lowered capacity. I am trying to recover the battery.

    As you approach full charge the charging process becomes less efficient. That means more heat generation in the battery. Warm batteries will give you an artificially low SG if you don't temp compensate the reading you get from your hydrometer. You might be closer than you think to a full charge.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • NorthGuyNorthGuy Solar Expert Posts: 1,925 ✭✭
    Re: Battery emergency
    zozomike wrote: »
    Thank you, I am not temperature correcting, but the temp has never seemed high, based on spot checking with a thermometer at least. It has always been near ambient, mid 80s since installation. The battery is in an outdoor, ventilated but insulated enclosure, and since I have been obsessing with it the doors have always been open during the day. The SG has never stopped rising, it just climbs VERY slowly, it has taken a full day of generator/inverter charging to get from the morning low of 1.250 ( as it was at 8 am today) to the 1.275. Per GB the sg of the full battery is 1.285-1.295. I wonder if I have permanently lowered capacity. I am trying to recover the battery.

    It took me 16-hour equalization at 64V (32V yours) to bring SG to where it should be. I measured it every hour. It was rising for 10-hours. It didn't keep steady (measurement errors I guess) for the last 6 hours, so I had to wait for 6 hours to be 100% convinced it wasn't increasing any more. At the end it was right at the spec. If I were you I would be doing it for as long as it takes for SG to stabilize (given that the batteries do not overheat). I was doing three pilot cells averaging the numbers and adjusting for temperature every hour. IMHO, if it is not rising any more, 1.275 is close enough.
  • zozomikezozomike Solar Expert Posts: 87 ✭✭✭
    Re: Battery emergency

    You guys are the best. Actually makes a guy off in the mountains where no qualified service people seem to want to go- feel not quite so alone. I am now looking for some info for temp adjustment that you might have used, but yet to find. Certainly not on the GB site. I feel very confident that I have not been overheating. So I will continue to charge till I am sure I have no more increase. Never mind I am also building a house, trying to make a living and ....

    Off grid, all solar, passive and active ( winter wood heat supplements) solar DHW, no backup.

    Array 1 1980w,   12 Solarworld 165 w panels - Outback Flex max 80

    Array 2 1590 w, 6 Solarworld 265 w panels - Outback flex max 60

    Well array 600w, 6 Kyocera 130 w  with Grundfos sqflex11 and cu200 to elevated  storage, ( 2- 330 g tanks,) no battery storage at well

    GB industrial 510 AH battery 24 V

    Outback VFX 3525 inverter,


  • BB.BB. Super Moderators, Administrators Posts: 29,523 admin
    Re: Battery emergency

    The basic temperature factor is -5mVolts per C per Cell...

    -0.005 * (5C batt temperature - 25C Standard) * 24 cells (for 48 volt battery bank) = +2.4 volt offset for 5C battery bank

    I.e., a 58 volt at 25C room temperature would need a + 2.4 volt offset or 60.4 volts at 5 degree C.

    Problem is many 48 volt AC inverters have a cutoff voltage of ~60-62 volts, so many times, you have to set a "hard limit" for maximum temperature so your AC inverter does not shut off in very cold weather with "high battery charging voltage" set point...

    So I understand, as a guy who sees 50F-80F for most days of the year here and runs a Grid Tied system (no batteries). I will leave it to the folks that are off grid in extreme environments to confirm or "fix" my post.

    -Bill :roll:
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • vtmapsvtmaps Solar Expert Posts: 3,738 ✭✭✭✭
    Re: Battery emergency
    BB. wrote: »
    The basic temperature factor is -5mVolts per C per Cell...

    No argument there Bill, but I think you changed the subject.... we had been discussing temperature compensation of SG readings.

    zozomike, Bill is referring to the temperature compensation of the voltage that you charge your batteries at. We had been discussing that the SG reading you get with a hydrometer also needs to be temperature compensated. Both are important.

    You should buy one of these: http://www.solar-electric.com/rts.html for your inverter and another one for your controller. Then you will have automatic temperature compensation of your charging voltage.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • BB.BB. Super Moderators, Administrators Posts: 29,523 admin
    Re: Battery emergency

    Sorry--You are correct vtMaps.

    From Trojan Battery Company, some handy temperature rules of thumbs:
    How does temperature affect the performance of my batteries?
    At higher temperatures (above 77oF) battery capacity generally increases, usually at the cost of battery life. Higher temperatures also increase the self-discharge characteristic. Colder temperatures (below 77oF) will lower battery capacity and prolong battery life. Cooler temperatures will slow self-discharge. Therefore, operating batteries at temperatures at or slightly below 77oF will optimize both performance and life.

    How do I determine my battery capacity when it is colder/hotter?
    Battery capacity is basically a linear relationship. A good rule of thumb is that for every 15oF above 77oF, capacity is increased by 10% and for every 15oF below 77oF, capacity is reduced by 10%.

    How do I account for temperature when taking my gravity readings?
    Temperature will affect specific gravity readings. As temperature increases, the electrolyte solution expands and as temperature decreases the electrolyte solution contracts. As a result, it is a good practice to temperature correct specific gravity readings. Here are the relationships Trojan recommends using:
    For every ten degrees above 80oF add 3 points to the hydrometer reading.

    Example: @ 90oF the hydrometer reads: 1.250 The actual reading: 1.250 + .003 = 1.253
    For every ten degrees below 80oF subtract 3 points from the hydrometer reading.

    Example: @ 70oF the hydrometer reads: 1.250 The actual reading: 1.250 - .003 = 1.247

    How do I account for temperature when taking my voltage readings?
    Temperature will affect voltage readings. As temperature increases, voltage decreases. Conversely, as temperature decreases, voltage increases. Here are the relationships Trojan recommends using:
    For every 10 degrees below 80oF, add .028 volt per cell to the charger voltage setting.

    Example: A 12 volt battery @ 70oF. The recommended charging voltage (@ 80oF) is 14.60 volts. The adjusted charging voltage is 14.60 +(6 cells * .028vpc) = 14.77 volts.

    For every 10 degrees above 80oF, subtract .028 volt per cell to the charger voltage setting.

    Example: A 12 volt battery @ 90oF. The recommended charging voltage (@ 80oF) is 14.60 volts. The adjusted charging voltage is 14.60 -(6 cells * .028vpc) = 14.43 volts.

    Is there a maximum temperature for charging my batteries?
    When charging lead acid batteries, the temperature should not exceed 120oF. At this point the battery should be taken off charge and allowed to cool before resuming the charge process.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • zozomikezozomike Solar Expert Posts: 87 ✭✭✭
    Re: Battery emergency

    OK, I am ordering the two RTS, just checked batt temp with a thermometer, may not be adequate but it was 82f mid day with the generator running and the solar adding as well in bulk. Controller says 1.290 kw incoming. Of course then the afternoon clouds rolled in and I am incoming .200 kw. Two degrees above 80 does not seem it will matter much for compensation reasons if the thermometer reading I have is accurate.
    Questions;
    when I ordered the Mate, ( not yet received) I did not order the Hub, if I have RTS on the controller I guess I need that also?
    When I receive the Mate I will use it to program the inverter for the higher charging values ( including equalizing) mentioned by Northguy?

    Off grid, all solar, passive and active ( winter wood heat supplements) solar DHW, no backup.

    Array 1 1980w,   12 Solarworld 165 w panels - Outback Flex max 80

    Array 2 1590 w, 6 Solarworld 265 w panels - Outback flex max 60

    Well array 600w, 6 Kyocera 130 w  with Grundfos sqflex11 and cu200 to elevated  storage, ( 2- 330 g tanks,) no battery storage at well

    GB industrial 510 AH battery 24 V

    Outback VFX 3525 inverter,


  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Battery emergency
    zozomike wrote: »
    OK, I am ordering the two RTS, just checked batt temp with a thermometer, may not be adequate but it was 82f mid day with the generator running and the solar adding as well in bulk. Controller says 1.290 kw incoming. Of course then the afternoon clouds rolled in and I am incoming .200 kw. Two degrees above 80 does not seem it will matter much for compensation reasons if the thermometer reading I have is accurate.
    Questions;
    when I ordered the Mate, ( not yet received) I did not order the Hub, if I have RTS on the controller I guess I need that also?
    When I receive the Mate I will use it to program the inverter for the higher charging values ( including equalizing) mentioned by Northguy?

    If you want the Outback controller and inverter to "talk" to each other you need the hub. Otherwise you will need an RTS each, or you can ignore it for the inverter as that will only be charging when the the solar doesn't work and you'll really only be running up through Bulk for it under operating conditions. Yes, it's complicated.

    First thing you do with the MATE is find out what the FX charge parameters are at now. Then adjust to suit. You may need higher Absorb Voltage and/or longer time. You may also have to change the parameters again once you do get those batteries up in order to keep them up. On the whole you try not to use the inverter for charging.
  • vtmapsvtmaps Solar Expert Posts: 3,738 ✭✭✭✭
    Re: Battery emergency
    or you can ignore it for the inverter as that will only be charging when the the solar doesn't work and you'll really only be running up through Bulk for it under operating conditions.

    If the batteries are cold, your FX inverter will never get all the way through bulk without RTS. If the batteries are hot you will overshoot your absorb voltage without RTS.
    If you want the Outback controller and inverter to "talk" to each other you need the hub.

    Cariboocoot, the MX controller is from before my time... does it communicate through the hub like the FM controller? In any case, I agree that he doesn't need a hub. It's a lot cheaper to by two RTS than to buy one RTS and a hub (with a hub the FM controller and the FX inverter can share an RTS)

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Battery emergency
    vtmaps wrote: »
    If the batteries are cold, your FX inverter will never get all the way through bulk without RTS. If the batteries are hot you will overshoot your absorb voltage without RTS.

    Not really a problem when using the gen for supplemental charging. Applying current will warm the batteries up nicely before Absorb Voltage is reached, and you would not be running through a full Absorb cycle so there's little chance of over-heating them. Definitely not recommend for a full charging cycle in any temp, especially not with EQ (which isn't temp compensated so by then you could have seriously hot batteries).


    Cariboocoot, the MX controller is from before my time... does it communicate through the hub like the FM controller? In any case, I agree that he doesn't need a hub. It's a lot cheaper to by two RTS than to buy one RTS and a hub (with a hub the FM controller and the FX inverter can share an RTS)

    --vtMaps

    Yes; the MX can connect to the HUB and share data with the FX. The MATE can do limited programming adjustments to the MX. I do not bother because the MX is the primary charge source and I only Bulk with the gen "as needed". That was how I intended the system to be used, and it works well.
  • Blackcherry04Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Battery emergency

    One thing you have to remember with a RTS is that it doesn't only effect Voltage it will also effect the amperage output of your charging source. When I have used it, I'v seen it drop as much as 50 amps off the charging source. Now that may not seem like a lot, but it is if your buying fuel or it short changes your charging time. Generally unless you have a worthless set of batteries you don't have to worry about them overheating in the first place and seasonal changes are not that hard to make.
  • zozomikezozomike Solar Expert Posts: 87 ✭✭✭
    Re: Battery emergency

    Hmmm, That would be bad. Maybe I will let the dust settle on this before I order the RTS. I think I need more panels for sure. The Mate just showed up so Ive got plenty to do installing and programming right now anyway. Thanks again!

    Off grid, all solar, passive and active ( winter wood heat supplements) solar DHW, no backup.

    Array 1 1980w,   12 Solarworld 165 w panels - Outback Flex max 80

    Array 2 1590 w, 6 Solarworld 265 w panels - Outback flex max 60

    Well array 600w, 6 Kyocera 130 w  with Grundfos sqflex11 and cu200 to elevated  storage, ( 2- 330 g tanks,) no battery storage at well

    GB industrial 510 AH battery 24 V

    Outback VFX 3525 inverter,


  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Battery emergency

    Outback's RTS should have no effect on current per se; it merely alters the "read" Voltage raising or lowering it in respect to temperature so that it meets the right parameter at charge point. If there is any decrease in current it is because the current is not needed for the corrected Voltage reading.

    Can't say about other companies' units. I know some of them do not utilize this ability properly or well (altering parameters instead if read Voltage for one thing).
  • Blackcherry04Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Battery emergency
    Outback's RTS should have no effect on current per se; it merely alters the "read" Voltage raising or lowering it in respect to temperature so that it meets the right parameter at charge point. If there is any decrease in current it is because the current is not needed for the corrected Voltage reading.

    Can't say about other companies' units. I know some of them do not utilize this ability properly or well (altering parameters instead if read Voltage for one thing).
    Does that Voltage know what loads you have ?? Does the Voltage know the true SOC of the Battery ??
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Battery emergency
    Does that Voltage know what loads you have ?? Does the Voltage know the true SOC of the Battery ??

    Is there any way that it could? No.

    I just explained how it works.
  • Blackcherry04Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Battery emergency
    Is there any way that it could? No.

    I just explained how it works.
    I know how it " Works or doesn't work. Just unplug one and see what happens. It reacts to the Over Voltage when it charges, cut the voltage back, you cut the current back. The batteries will limit what they accept. Voltage as you have said many times is not a indication of SOC. You can have 2 charging sources and remove one at the absorb set point, what happens, the voltage takes a nose dive.
  • NorthGuyNorthGuy Solar Expert Posts: 1,925 ✭✭
    Re: Battery emergency

    I think some controllers may decrease (or completely cut off) the chagring current based on the information form RTS (either temperature or its rate of change) to prevent battery overheating. However, most controllers will do this only if the battery is really overheating.
  • Blackcherry04Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Battery emergency
    NorthGuy wrote: »
    I think some controllers may decrease (or completely cut off) the chagring current based on the information form RTS (either temperature or its rate of change) to prevent battery overheating. However, most controllers will do this only if the battery is really overheating.
    I'd suspect that this poster with a Fork Lift battery is going to find out like everyone with a tall case battery that he's going to need every thing he can get to keep the battery charged. Maybe it's just my equipment, I'v just had no luck with them, if you could charge a battery in a vacuum where you had no outside forces to over come, they might work. My case is I'll be charging at 123 AMPS and I plug it in and it drops to 86 AMPS. I checked to see what it reacted to, it was the temperature of the cables, the battery was 20 degrees cooler at the plate level.
  • zozomikezozomike Solar Expert Posts: 87 ✭✭✭
    Re: Battery emergency

    Got the mate installed, connected to the VFX only, to my surprise its status only reads in 100 watt increments. Configured like the charge controller as follows;
    Charge limit default 18aac default
    Absorb setpoint 29.6 vdc 4 hours
    float setpoint 27.2 vdc 1 hr default
    refloat 25 vdc default
    EQ 32 vdc 3 hours.
    I did not tinker with some of the defaults, but will be pleased if I am corrected here.

    Got one RTS, with no instructions-gonna hook it to the VFX for generator charging as my array will never overheat this batt, is that correct? Where is the best place to attach the sensor?
    Thanks again

    Off grid, all solar, passive and active ( winter wood heat supplements) solar DHW, no backup.

    Array 1 1980w,   12 Solarworld 165 w panels - Outback Flex max 80

    Array 2 1590 w, 6 Solarworld 265 w panels - Outback flex max 60

    Well array 600w, 6 Kyocera 130 w  with Grundfos sqflex11 and cu200 to elevated  storage, ( 2- 330 g tanks,) no battery storage at well

    GB industrial 510 AH battery 24 V

    Outback VFX 3525 inverter,


  • Blackcherry04Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Battery emergency

    With a Fork lift battery it's a real dilemma on where to install it. If your battery is located somewhere that the ambient temperature swings it's going to be effected by it. You have a steel case and outside it won't do what a RTS is supposed to do. I guess you could place it on top of a kind of center jar and put a piece of foam insulation over it. The whole idea is to give you the battery temperature as you charge, not 4 hours afterwards.

    Your settings are a starting point, you'll know from you SG's where you need to go.
  • vtmapsvtmaps Solar Expert Posts: 3,738 ✭✭✭✭
    Re: Battery emergency
    Your settings are a starting point, you'll know from you SG's where you need to go.

    That cannot be emphasized enough. You want to minimize your absorb time and voltage as much as you can while keeping your SG where it should be.

    I would lower the float voltage to 26.4 volts and increase the float time to several hours. The main purpose of float is to allow your controller to pick up the loads without discharging the battery.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • Blackcherry04Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Battery emergency

    All the float settings are probably moot unless he has a Grid connection. The float setting and re-float is only active if you choose " Gird " as the Input, although you can use either. With a PTO generator sounds like a Tractor is involved, one would assume that he'll be using Bulk and maybe some absorb a lot with the inverter.

    By the way, if you choose " Gen " all the timers set to 24 hrs automatically except for the Absorb Timer.
  • zozomikezozomike Solar Expert Posts: 87 ✭✭✭
    Re: Battery emergency

    Thank you, the battery has a plastic case, not steel. I guess I will just stick the RTS it to the side where it won't get dribbled on an where I could actually insulate it if needed. No grid tie here. I will make the float adjustments.

    Off grid, all solar, passive and active ( winter wood heat supplements) solar DHW, no backup.

    Array 1 1980w,   12 Solarworld 165 w panels - Outback Flex max 80

    Array 2 1590 w, 6 Solarworld 265 w panels - Outback flex max 60

    Well array 600w, 6 Kyocera 130 w  with Grundfos sqflex11 and cu200 to elevated  storage, ( 2- 330 g tanks,) no battery storage at well

    GB industrial 510 AH battery 24 V

    Outback VFX 3525 inverter,


  • vtmapsvtmaps Solar Expert Posts: 3,738 ✭✭✭✭
    Re: Battery emergency
    zozomike wrote: »
    I will just stick the RTS it to the side where it won't get dribbled on and where I could actually insulate it if needed.

    Don't stick it too near the top... The top inch or two of your battery is filled with air, not electrolyte. The insulation is a very good idea.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • zozomikezozomike Solar Expert Posts: 87 ✭✭✭
    Re: Battery emergency

    Well I mispoke in my last post, the case is steel, I meant to say the top is open plastic cells. I guess I already screwed up though cause I took off one of the connecting bar covers and stuck it with the pressure sensitive backing to the lead, thinking that the connecting bar would be in direct contact with the plates, then deformed the cover a bit and snapped it back on. Would that not give me more of an accurate reading than the steel side of the case??

    Off grid, all solar, passive and active ( winter wood heat supplements) solar DHW, no backup.

    Array 1 1980w,   12 Solarworld 165 w panels - Outback Flex max 80

    Array 2 1590 w, 6 Solarworld 265 w panels - Outback flex max 60

    Well array 600w, 6 Kyocera 130 w  with Grundfos sqflex11 and cu200 to elevated  storage, ( 2- 330 g tanks,) no battery storage at well

    GB industrial 510 AH battery 24 V

    Outback VFX 3525 inverter,


  • Blackcherry04Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Battery emergency

    I have never seen a plastic outer case, most are steel, But what do I know. The problem with the connecting straps is that they will heat up from high current, I think I said that before, put your hand on the cables when you have the charger running. Getting a false reading costs you valuable AMP's because it will lower the voltage and that lowers the output. Think of how a Voltage limiting charger works.
  • zozomikezozomike Solar Expert Posts: 87 ✭✭✭
    Re: Battery emergency

    And it already confuses me, because the Mate Status/FX/Batt temp screen reads 118-- not in degree c/f, what the heck is that value? the manual states the value reflects the battery temp, but obviously it is not the temperature as we can use it. How do you guys check battery temperature if not with that reading? I need a college degree in this stuff...

    Off grid, all solar, passive and active ( winter wood heat supplements) solar DHW, no backup.

    Array 1 1980w,   12 Solarworld 165 w panels - Outback Flex max 80

    Array 2 1590 w, 6 Solarworld 265 w panels - Outback flex max 60

    Well array 600w, 6 Kyocera 130 w  with Grundfos sqflex11 and cu200 to elevated  storage, ( 2- 330 g tanks,) no battery storage at well

    GB industrial 510 AH battery 24 V

    Outback VFX 3525 inverter,


  • westbranchwestbranch Solar Expert Posts: 5,142 ✭✭✭✭
    Re: Battery emergency

    buy a cheap laser temp reader, or a cheap old style thermometer(wall type) and use one to 'calibrate the other. Alternatively an Indoor/Outdoor thermometer with sensor on a wire... all cheap quick checks against the RTS reading.
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
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