Batteries will not achieve desired SG

slavco
slavco Registered Users Posts: 7 ✭✭
Hi All,

Looking for some guidance/help with my batteries not holding enough charge. 

My current setup is;
8x 6v Surrette S-550 batteries (428ah) connected in series & parallel - they are about 6 months old
24v / 4000w Samlex inverter/charger
Outback 80amp CC
4 x 370w Hanwah q cell panels connected in series / parallel 
5500w backup generator
All wiring is done with 4/0 connectors and the interconnects between batteries are the same length. The + / - load and cc connections are done on the opposite strings (+ on one string and - on the other string).  

I know that I'm a bit low on the panels in terms of power requirements and plan to add 2 more of the same panels in the spring.
This is in an off-grid cabin which is usually not used during the week, allowing the CC plenty of time during the week to charge up the batteries. When checking the logs on the CC I can see that it gets to the Float stage of charging and on a good day the panels will generate between 6-7KWh.  I feel that with having almost 860ah capacity, the system should last a day without dropping below 50% soc, and this just doesn't happen.  Our power usage is generally low to moderate, with a few LED lights, some TV (LCD) and phone chargers. The largest drain would come from out well water pump (it pulls about 1100w), but it only runs 2-3 times per day 15 minutes at a time to fill up the pressure tanks. So at most that's 45mins per day. 

I have checked the batteries with a hydrometer on numerous occasions when the batteries are in float mode and I never get to 1.250. At best I get to 1.225. 
I have tried disconnecting one string and charging just one string at a time and equalizing it but this does not seem to help much. 
I also checked the individual battery voltage with a multimeter and they're all very close - 6.55 to 6.57.

So I'm not sure where to go from here and how I can get the SG up to 1.250-1.275 range. Should I change up my wiring between the batteries to something more optimal?

Any help, suggestions would be greatly appreciated.


 

Comments

  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    There will be setting(s) on the controller for how it goes from absorb to float, generally a timer and/or "end amps".  You may want to try increasing the absorb timer (eg if set at 2hrs, increase to 3).

    There will also be an absorb voltage setting, which you should check to ensure it's up to Surrette spec (which are fairly high IIRC).

    If the batteries get cool/cold, make sure there's a remote temp sensor attached to the batteries, and the controller is set up to use it.

    When did you check the battery voltages (eg in float with no large loads)?  How long and at what voltage was your EQ?  Are the batteries using any water? 

    My guess is the problem lies somewhere in the charge settings, but a clamp-on DC amp meter and an infrared temp meter can be helpful diagnosing wiring issues.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • jonr
    jonr Solar Expert Posts: 1,386 ✭✭✭✭
    edited October 2019 #3
    If you gave it a proper equalization, then the SG you got immediately after that is probably all you are going to get.  Some of the sulphate is no longer available.  But with proper charging you can do better on the next set of batteries.

    Alternatively, you could add more acid to bring up the fully charged SG.  No idea if this is a good idea.

    I am available for custom hardware/firmware development

  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    What are the  charging voltages or absorption time, having such a small PV capacity in contrast to battery capacity may be resulting in undercharging, especially as the days become shorter, assuming northern hemisphere.
    Is temperature compensation being used and if so what are the settings. What is the equalization voltage, has the SG been normal in the past and were the batteries given an equalization commissioning charge before use.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
  • WaterWheel
    WaterWheel Registered Users Posts: 375 ✭✭✭
    edited October 2019 #5
    Having dealt with a similar (although not as severe) problem with my 1st set of batteries (Crown batteries) In my case my controller was ending absorb too early.      According to Rolls you want the charge controller to hold the batteries in absorb for 30 minutes to an hour after your absorb amps drops to 2%.     (About 4.5 amps for your battery bank).           My Conext controller wasn't able to do this (hold absorb for a while after end amps setting was reached) so the Rolls tech support had me set my battery bank size (in the controller) to about 60% of the actual battery bank size for a few weeks to help get the batteries back up (This made my ending amps lower keeping the batteries in absorb a little longer after the absorb end amp setting of 2% had been reached.).       After a few weeks I then raised the battery bank size (controller setting) up to about 70% of the actual battery bank size so the controller held the batteries in Absorb for about 45 minutes after the batteries had charged to a 2% amp draw.

    Rolls had a video specifically for Conext controllers  that the Rolls tech sent me a link to but I can no longer find the video.       I realize that you've got a Midnight controller but it sounds like you've got a similar problem to what I had.

    I'd suggest bumping your absorb voltage .2v.     And lower your ending absorb end amps by 40% for a few weeks to see if that helps.

    Conext XW6848 with PDP, SCP, 80/600 controller, 60/150 controller and Conext battery monitor

    21 SW280 panels on Schletter ground mount

    48v Rolls 6CS 27P

  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    You need to increase your ABSORB times, and possibly raise the Absorb voltage.
    Also, try running the genset & it's charger for an hour or two in the morning, to bulk the batteries up and see if the solar can finish them.

    Sadly, you have repeated the mistakes of the 70's, with massive battery banks, that never got fully charged and sulfation just ate away at capacity.   So you have to take steps to de-sulfate the batteries, if it's even still possible at this point.
    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 ,

  • Ralph Day
    Ralph Day Solar Expert Posts: 1,019 ✭✭✭✭
    I have the same batteries, but not the same problem.  One string so 428AH to charge.  2.1kw pv, grid available.

    The equation from Steve at Surrette:  (.42 x AH)/maxAmps available = hours to fully charge.

    Mine:  (.42 x 428) / 30 = 5.9 hours.

    My experience...equation is accurate.  It took a while to appreciate it.  No end amps used, just time.  Absorb voltage 60vdc, Absorb timer set for 6 hours when cycling.  When on HBX (loads carried overnight to voltage setpoint below float) absorb for 2 hours or trip the Midnitesolar 250 to float if absorb is not needed.

    With your low PV available you'll need to run your generator a lot to get to acceptable SG readings.  Maybe just one string at a time?

    Ralph
  • jonr
    jonr Solar Expert Posts: 1,386 ✭✭✭✭
    edited October 2019 #8
    > equation from Steve at Surrette:  (.42 x AH)/maxAmps available = hours to fully charge

    Note that the formula isn't for hours to fully charge.   It's "hours needed in absorb to fully charge".    Say the battery was discharged to 50% SOC.   Ralph needs about 5 hours to get to 80% and then 5.9 more hours after that for absorb.   But not clear to me that the formula is useful in a case where the intention is to charge over several days.  Ie slavco shouldn't set absorb time to 14+ hours.

    I am available for custom hardware/firmware development

  • slavco
    slavco Registered Users Posts: 7 ✭✭
    Thank you for all the replies! I will need to check what the absorb timer is set to this weekend. As for the voltages, I set them based on the Surrette manual: Bulk 30.0v , Absorb 30.0v and Float at 27.9v. When I equalized the batteries, I had them at 31.5v.  They were bubbling a bit but nothing over the top, and in general they don't seem to be using a lot of water, I only had to top them off once in 5 months since I bought them.

    I did not do an EQ charge from when they were brand new, wasn't aware that it was something that needed to be done?

    I will be at the cabin for a few days this coming week and will try to run just the one string and see what happens, as someone accurately guessed, I am in the northern hemisphere (southern Ontario to be exact) so the hours of full sun are getting pretty slim. I will bulk them with the gen in the morning and see where the sunshine takes me from there. 
  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    If possible, it would also help if you can monitor current going into the bank, especially during the absorb stage.  With newish batteries, it shouldn't stop absorb until current tapers to ~8a.  Hopefully you'll get a nice sunny day.

    Do you have temperature sensors and compensation set up?
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • slavco
    slavco Registered Users Posts: 7 ✭✭
    Estragon said:
    If possible, it would also help if you can monitor current going into the bank, especially during the absorb stage.  With newish batteries, it shouldn't stop absorb until current tapers to ~8a.  Hopefully you'll get a nice sunny day.

    Do you have temperature sensors and compensation set up?

    My multimeter doesn't do DC current unfortunately, will need to invest in a new one. I do have temp sensors attached to the batteries, one from the CC and the other from the inverter/charger.

  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    Can you read output current on the charge controller?  If loads are kept minimal, that might give you some idea of what the batteries are taking.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • slavco
    slavco Registered Users Posts: 7 ✭✭
    Estragon said:
    Can you read output current on the charge controller?  If loads are kept minimal, that might give you some idea of what the batteries are taking.

    Sure. I'll check the history log on it this weekend, going by memory I did see it it go over 40amps at times when the sun was strong.

  • 706jim
    706jim Solar Expert Posts: 514 ✭✭✭✭
    I had a similar problem with my 8 L16 bank. Used Trojans's recommended float of 26.4 and bulk mid way between recommended 28.2 and 29.6 (I think). SG was always in the red. On the advice of others her I increased bulk to 29.8 and float to 27.6 and SG now comes up to about 1.25. Due to panel placement my system usually charges about 25-30 amps but when all 17 panels are getting sun I'll see nearly 60 amps. In your case, I would stay with your 30 and 27.9 voltages but increase absorption time. My ancient controller is set to an unchangeable 2 hours at bulk voltage and the system now seems to work just fine.
    Island cottage solar system with 2500 watts of panels, 1kw facing southeast 1.3kw facing southwest 170watt ancient Arco's facing south. All panels in parallel for a 24 volt system. Trace DR1524 MSW inverter, Outback Flexmax 80 MPPT charge controller 8 Trojan L16's. Insignia 11.5 cubic foot electric fridge. My 30th year.
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    water every 5 months indicates undercharged batteries to me.
    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 ,

  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Batteries in series should always be very close to matching voltages (charging, discharging, resting, etc.). When you have a big difference between two (or more batteries) in a series string--You need to figure out why they are so different.

    With flooded cell batteries, you can check the specific gravity of each cell... More or less, the resting voltage of a cell is proportional to the SG (a battery with high terminal voltages should have high SG in all cells).

    If you find a cell that is very high or very low SG--Then you may have a bad cell.

    EQ charging is the controlled over charging of a battery. The "high" EQ charging voltage (usually something around 15.0 to 16.0 volts) forces current through the "full battery" (FLA batteries, the high cells/battery will just gas) while charging the low cell(s)/batteries. You should see something like 5% minimum rate of charge (200 AH battery bank * 5% = 10 Amps EQ current).

    You check the cells every 30 minutes, and when the all the cells stop rising in SG--You now have the battery at 100% State of Charge. If the low cells have still not reached full charge, and the batteries are getting hot (happens with EQ), you do not want to exceed the battery maximum temperature--Shut down charging if near max temp and start charging again the next day.

    Some batteries types/models do require some very vigorous charging current and a relatively high charging voltage (and if batteries are cold, a temperature compensated charge controller will increase the charging voltage setpoint).

    A  DC Current Clamp DMM is really nice for confirming charging current, and if you have parallel battery strings, will allow you to confirm that they are sharing current properly. A couple of meter links for you to start your search:

    https://www.amazon.com/gp/product/B019CY4FB4 ($100 meter)
    https://www.amazon.com/gp/product/B07546L9RT ($50 meter)

    Note there are AC only current clamp meters, and AC+DC current clamp meters--Both types are fine meters--But for our needs, we usually need the DC Current Clamp function.

    As Mike says, it sounds like the batteries are being under charged... A higher charging voltage setpoint and/or longer absorb times (typically something like 2-6 hours, 2 hours for light cycling, 4-6 hours for heavy cycling).

    As always, make sure the plates are at least covered by electrolyte before charging... But don't fill the cell up until the batteries are fully charged and warm--Filling a cold battery to the split ring runs a good chance of electrolyte spilling out of the top of the cells as the battery fills with gas and warms up.

    Even with the higher charging voltage and longer absorb times, it may take weeks of cycling (and several EQ cycles) for "weak SG" cells to come up and stabilize.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    What I'm thinking is the array is too small to provide enough current to reach a fully charged state, especially during the absorption stage which may itself never be satisfied either by being terminated prematurely, or by diminishing solar input after the peak harvest period. This is a classical mistake, everything seems fine at the beginning but the undercharging manifests over time often rearing it's head when things become obvious, such as diminishing capacity.

    The need to force the charging regime is important to recover what appears to be lost capacity, this should be performed at equalization voltage without interruption by cycling, the only time to terminate is if the battery temperature approaches 50°C.

    Additionally, get a second opinion with another hydrometer, preferably a quality glass type and increase the array by a minimum of 100% or better yet 200%  due to geographicl location. 

    Just my thoughts and opinions.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
  • jonr
    jonr Solar Expert Posts: 1,386 ✭✭✭✭
    IMO, a system designed for a couple days of use and then "catch-up" charging over several subsequent days is fundamentally different than the typical use (full charge daily) that many recommendations are based on.  I expect that end-amps (make sure there is no load) will work better than a timer by ensuring that a full absorb cycle is eventually completed and then backing off and not giving much absorb time when the batteries are not in use.    IMO, a small charging system can, with the right algorithm,  properly charge a large battery bank over several days. 

    It would be useful to pull one of the batteries and do a load test on it.   Eg, fully charge it, draw a steady 20A for 5 hours, rest, measure voltage to determine SOC.

    I am available for custom hardware/firmware development

  • slavco
    slavco Registered Users Posts: 7 ✭✭
    Thanks everyone for the wealth of knowledge and suggestions you have shared. I will use this information and do some experimenting over the next few weeks and let you guys know how things panned out.

    Side question on the number of panels I should have.. As I mentioned, I currently have 4 370w panels for 1480 watts total. I was thinking of adding 2 more panels but I fear my current CC (Outback FlexMax 80) will get overloaded as I believe there is a 2000w limit when running 24v.  I do have another, older CC (Solar Boost 3048) 30amp and was thinking of connecting the 2 extra panels to it separately - do you see any issues in doing so? 


  • Photowhit
    Photowhit Solar Expert Posts: 6,002 ✭✭✭✭✭
    slavco said:
    Side question on the number of panels I should have.. As I mentioned, I currently have 4 370w panels for 1480 watts total. 
    So you currently have a 24 volt 856amp hour battery bank.   Rolls  suggests a 10-20% charge rate, most  flooded batteries use 13-15% as an upper end, I think the 20% is a bit surprising for me. (I looked it up a few months ago and was surprised by the 20%)

    As a group with weekend use, I think 5%  would be a minimum. So you should be able to deliver 428 amps to the battery bank.

    You currently have 1480watts, of 370 Q-cell panels,  under normal Operating  conditions  they will  produce;


    https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=2ahUKEwi9pOa-k7PlAhUN5awKHaVXBJ4QFjAAegQIABAC&url=https://www.q-cells.com/dam/jcr:65757b64-455f-4079-8c78-051f8c9c4e34/Hanwha_Q_CELLS_Data_sheet_QPEAK_L-G4.2_360-370_2017-10_Rev02_NA.pdf&usg=AOvVaw0TX0hCFRNcogmLHv9gFZj4

    About  273  watts so  through an MPPT  type controller you can deliver  4x273=1092watts  <> 1092÷24=45.5 amps so you are in the ball park. For daily use double that size array.  The FM80 can be 'over paneled' up  to take advantage of the difference between Normal conditions and labeled wattage cost effectively.
    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.
  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    There are normally no big issues having multiple different controllers on a bank.  Both my banks have small separate arrays and controllers as well as the larger main pv systems.  The small ones are mounted vertically and are just to ensure winter floating when/if the main arrays get snow covered in winter when I'm not there to clear them.

    That said, I agree with photowhit that the fm80 should be okay with the extra pv.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • jonr
    jonr Solar Expert Posts: 1,386 ✭✭✭✭
    edited October 2019 #22
    IMO, when Outback specifies a limit of 2000W of panels for their controller, that means under any conditions (not just typical/normal conditions).  So I wouldn't put more than five 370W panels on it.      Two charge controllers on the same batteries will interfere with some charging algorithms (like ending absorb based on amps).

    A small charging system may not produce enough power to properly destratify your batteries.  You can do that with the generator when you are there.

    I am available for custom hardware/firmware development

  • softdown
    softdown Solar Expert Posts: 3,812 ✭✭✭✭
    Are you disconnecting all the batteries for awhile prior to checking voltage? The exceptional proximity 6.55 - 6.57 suggest that they may be "borrowing voltage" from adjacent batteries.  I doubt many do that which represents a flaw in checking voltage.

    OP never said there were any problems other than low measured S.G. As one who has possibly bought a few hundred saltwater S.G. meters over the past 26 years I have seen how likely it is to get a S.G. meter that is off. A strong possibility.

    I would also look for a weak battery in the array. Does OP check the S.G. in every cell? All it takes is one bad cell to effect the whole battery array.

    OP has indicated very light usage of his system. No mention of an electric fridge? Motion activated lights with lots of animal activity? This system should be fine unless there is a drawer of heavy current. Unplug as much as realistic when not there. Some electronics have heavy standby current usage so that they "turn on" very quickly. We can thank an electrically uneducated populace for that phenom. 

    My FM80 has a default absorb time of 1 hour - a horrific idea. Try going into Advanced Setting and change that to 4 hours. It may not be possible unless you are in Advanced Setting - then it is extremely easy. 

    Are all the connections clean? 

    Voltage of 6.55 indicates healthy batteries unless that is the voltage at peak charge. The batteries have to be disconnected for a couple hours after peak charge for voltage readings to render any degree of true functionality. 

    Seems like the well pump could be disconnected when not there? 

    What kind of conditions are the batteries kept in? Cold? Hot? Outdoors? 
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • jonr
    jonr Solar Expert Posts: 1,386 ✭✭✭✭
    edited October 2019 #24
    > My FM80 has a default absorb time of 1 hour - a horrific idea. Try going into Advanced Setting and change that to 4 hours

    Does this mean that the batteries will then receive 4 hours/day of absorb even when they haven't seen any use?  If so, that's unnecessary wear.   Ending absorb with amps resolves this.

    +1 on letting the batteries rest (I'd say 6 hours) before using their voltage for determining anything.  6.55V would be a crazy high reading for an at-rest battery.   Your open circuit rested voltage should be about equal to 3 x (SG + 0.84).

    I am available for custom hardware/firmware development

  • softdown
    softdown Solar Expert Posts: 3,812 ✭✭✭✭
    jonr said:
    > My FM80 has a default absorb time of 1 hour - a horrific idea. Try going into Advanced Setting and change that to 4 hours

    Does this mean that the batteries will then receive 4 hours/day of absorb even when they haven't seen any use?  If so, that's unnecessary wear.   Ending absorb with amps resolves this.

    +1 on letting the batteries rest (I'd say 6 hours) before using their voltage for anything.  6.55V would be a crazy high reading for an at-rest battery.

    Good point. 

    Been thinking about mentioning the newly carried Duracell battery charger at Co**co. Little 4 amp charger and it seems to be a little miracle box. Takes a  l - o - n - g  time but achieves much better resting voltage levels than others. 
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • jonr
    jonr Solar Expert Posts: 1,386 ✭✭✭✭
    edited October 2019 #26
    > Little 4 amp charger

    But does it have enough power to destratify or equalize?    Some people say you need >= 5% for this - if so, this charger shouldn't be used for more than an 80AH battery.   Rolls says: 

    "The recommended charge current is 10%-20% of the AH capacity of the battery bank ... lower current ... will ... increase the potential for sulfation build-up."

    Not clear what their reasoning is (inadequate mixing or just too much time to charge?), but maybe a 4 amp charger shouldn't be used for more than a 40AH battery.

    I am available for custom hardware/firmware development

  • softdown
    softdown Solar Expert Posts: 3,812 ✭✭✭✭
    jonr said:
    > Little 4 amp charger

    But does it have enough power to destratify or equalize?    Some people say you need >= 5% for this - if so, this charger shouldn't be used for more than an 80AH battery.
    Sometimes people should consider putting down their tech manuals for a second. It took a 270 Ah from 12,7 to 13 with five days of daylight charging. I'm not saying that it equalizes, I am saying that it delivers a better charge than my dozen other chargers. For $45, I don't expect equalization. 

    "shouldn't be used for more than an 80AH battery"   Seems like it got a better job done than I expected. 

    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • jonr
    jonr Solar Expert Posts: 1,386 ✭✭✭✭
    I agree - occasional use is one thing.  As the only charger used is where problems could occur.

    I am available for custom hardware/firmware development

  • softdown
    softdown Solar Expert Posts: 3,812 ✭✭✭✭
    edited October 2019 #29
    Then again, I have made some mistakes in the past. 



    j/k - thats not me. Seriously. It is not me. 
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • slavco
    slavco Registered Users Posts: 7 ✭✭
    Hey All!

    So just a quick update. I did check my Outback CC and it was set to the default 1hr absorb time, I have changed this to 3hrs now. I also ran the generator quite a bit over the past few visits and ran it to fully charge batteries + eq each time. This has definitely helped. I'll continue with this routine each time we go up there through the winter (which won't be that much). Also, I now know that 2 extra panels will be the first thing to add to my to-do list as soon as spring comes.  :)