Excessive Charging Current

jcheil
jcheil Solar Expert Posts: 722 ✭✭✭
in Advanced Solar Electric Technical Forum #1
Hopefully someone can clarify something for me.

I have the Mate3 option "Global Charger Output Control" set to YES and a Value of 110A.
I did this because I have a 2-string (740ah total) battery bank and 110A was about 15%, the max charge rate I heard you should charge at.
I have the ability to produce more than that in perfect summer conditions just with the solar but in the winter, it would never get up that high.

However, I am running my generator this AM, in addition to the Solar and I noticed that I am producing a total of 150+ amps of charging current according to the inverter/charge controller shunts. Now I know some of that is being consumed by my running loads, so I was figuring that the Mate3 would still only allow/restrict 110A to go "into the batteries". But it seems like more is going into the batteries than 110a.

So I put a clamp meter on each of the wires going to each string and I am reading about 75amps going to each bank. Now each bank is 370ah so to me that is too much current going into it?? Am I reading/measuring this right? Is it 75a going to each bank or is it 75a being split between the 2 banks? To clarify again, I read 75a on the pos or neg wire going to EACH string, if I clamp to the single wire coming from the inverter to the battery bus (where it splits to the two banks), I read 150a.

Jay
Off-Grid in Central Florida since 2005, Full-Time since June 2014 | 12 X Sovello 205w panels, 9 X ToPoint 220w panels, 36x ToPoint 225w panels (12,525 watts total) | Custom built single-axis ground mounts | Complete FP2 Outback System: 3 x FM80, 2 x VFX3648, X240 Transformer, FLEXnet-DC, Mate-3, Hub-10, FW500 AC/DC | 24 x Trojan L16RE-B Batteries 1110ah @ 48v | Honda EU7000is Generator and a pile of "other" Generators | Home-Made PVC solar hot water collector | Custom data logging software http://www.somewhatcrookedcamp.com/monitormate.html
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Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,658 admin
    #2
    Re: Excessive Charging Current

    I don't know about programming the Mate3... Does it support current shunt on the battery so you can measure the total current into the battery? I thought the system may need the Flexmate (or whatever they call it) system to support the battery shunt.

    Charging the battery--You can go upwards of 20-25%, especially if the batteries are below ~80-85% state of charge. As the battery SOC rises, then they start gassing and generating more internal heat.

    Watch the battery temperature and gassing. As long as they don't get too warm or gassing too much (to high of charging voltage), you should be OK. Especially as the charging current starts tapering off >~80% SOC. By the time the batteries are >~90% SOC, you should be in the ~2.5 to 5% maximum charging current range (and the batteries will start to warm more quickly).

    Some of the folks (EV Car people as I recall) will pump crazy amounts of current into well discharged Lead Acid batteries.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    #3
    Re: Excessive Charging Current
    BB. wrote: »
    I don't know about programming the Mate3... Does it support current shunt on the battery so you can measure the total current into the battery? I thought the system may need the Flexmate (or whatever they call it) system to support the battery shunt.

    Charging the battery--You can go upwards of 20-25%, especially if the batteries are below ~80-85% state of charge. As the battery SOC rises, then they start gassing and generating more internal heat.

    Watch the battery temperature and gassing. As long as they don't get too warm or gassing too much (to high of charging voltage), you should be OK. Especially as the charging current starts tapering off >~80% SOC. By the time the batteries are >~90% SOC, you should be in the ~2.5 to 5% maximum charging current range (and the batteries will start to warm more quickly).

    Some of the folks (EV Car people as I recall) will pump crazy amounts of current into well discharged Lead Acid batteries.

    -Bill

    Yes I do have the FNDC with the shunts. And I did compare and match the shunt readings to my clamp-on readings. And they are right on.
    I spoke to Outback support this AM and they are concerned about it. They state that it SHOULD be working but tend to agree it appears at this point it is not.
    They asked me to send logs to temp, but ironically even though the mate3 is set to create logs, it has not been.

    I determined via support the other day that with the new Mate3 firmware (3.5 I believe) that the Mate3 graphs no longer work. They state it is because of the OpticsRE and that someday they may fix the internal graphs.

    I have a feeling they are going to discover that the reason the graphs are not working is because the data logging is not working as I just discovered :)

    In any event, I did notice that after about 1.5hrs the current dropped off quite a bit, as expected (See my online graphs). I do have the temp sensor installed and it does appear to be temp correcting the voltages when needed so I GUESS I would not have to worry about any kind of thermal runaway condition. I was just concerned about 25% going into them for that short period of time. I tend to go down to 65-70% SOC every night now anyways. Last night it got down to 52% because I foolishly left on 2 of the mini-splits set to 78 degrees in heat mode all night :( But if 25%+ is OK, then I guess I can live with it (until outback fixes the bug - if it is a bug).
    Off-Grid in Central Florida since 2005, Full-Time since June 2014 | 12 X Sovello 205w panels, 9 X ToPoint 220w panels, 36x ToPoint 225w panels (12,525 watts total) | Custom built single-axis ground mounts | Complete FP2 Outback System: 3 x FM80, 2 x VFX3648, X240 Transformer, FLEXnet-DC, Mate-3, Hub-10, FW500 AC/DC | 24 x Trojan L16RE-B Batteries 1110ah @ 48v | Honda EU7000is Generator and a pile of "other" Generators | Home-Made PVC solar hot water collector | Custom data logging software http://www.somewhatcrookedcamp.com/monitormate.html
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,658 admin
    #4
    Re: Excessive Charging Current

    If the battery temperatures stay relativity cool during high charging currents... I would not worry too much--Other than getting the configuration/firmware working correctly.

    Also keep an eye on cabling and connections... You would not be the first one to melt the lead terminals under heavy/sustained currents.

    -Bill "Trust but verify" B.
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,658 admin
    #5
    Re: Excessive Charging Current

    Related: Boy--I am so close to spending $200...

    Seek UW-AAA Thermal Imaging Camera USB Connector (Android and IOS versions)

    http://thermal.com/what_is_thermal_desktop.html

    Don't "need one"... But would be fun (yea, I am an Engineer, why do you ask?).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Blitz
    Blitz Solar Expert Posts: 33 ✭
    #6
    Re: Excessive Charging Current

    I like it.

    Always wanted FLIR, but its thousands of dollars.

    this is affordable.
    many many uses...

    Thanks for the link.

    well worth visiting the site and observing the various uses they photographed.

    Insulation and security...

    gotta have one now.

    ( and I'm NOT an engineer : ) )
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #7
    Re: Excessive Charging Current

    I use a hand held IR thermometer "gun" to check battery terminals and breakers. it's pretty good, don't know if I can get the FLIR past the $ gatekeeper.

    I have heard of taking out the IR filter from a CCD camera and voila - you now have an IR camera for nighttime use.
    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 ,

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  • BB.
    BB. Super Moderators, Administrators Posts: 33,658 admin
    #8
    Re: Excessive Charging Current
    mike95490 wrote: »
    I have heard of taking out the IR filter from a CCD camera and voila - you now have an IR camera for nighttime use.

    That will not work... The CCD only works on near infrared--Not the long wave IR that is related to the temperature of objects.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    #9
    Re: Excessive Charging Current
    BB. wrote: »
    That will not work... The CCD only works on near infrared--Not the long wave IR that is related to the temperature of objects.

    -Bill

    I may buy one just to help me with my night hunting of the damn armadillos that are over-running my place :)
    Off-Grid in Central Florida since 2005, Full-Time since June 2014 | 12 X Sovello 205w panels, 9 X ToPoint 220w panels, 36x ToPoint 225w panels (12,525 watts total) | Custom built single-axis ground mounts | Complete FP2 Outback System: 3 x FM80, 2 x VFX3648, X240 Transformer, FLEXnet-DC, Mate-3, Hub-10, FW500 AC/DC | 24 x Trojan L16RE-B Batteries 1110ah @ 48v | Honda EU7000is Generator and a pile of "other" Generators | Home-Made PVC solar hot water collector | Custom data logging software http://www.somewhatcrookedcamp.com/monitormate.html
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