Recommendations for initial charging regimen?

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  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #32
    Re: Recommendations for initial charging regimen?
    Rossman wrote: »
    It's now around 6:30pm, system has been charging since about 11:30am (about seven hours). Charge current is down to 13A and the battery temps are up to 57F. Spot checked a couple cells SG they were around 1.255 or so, which seems not too shabby.

    Think I will let it go another three hours to get to the 10hr mark recommended by Surrette, then shut it all down and let them rest till the morning, and take an official set of readings. Will post back to let you all know how it goes!

    Ho ho ho!
    I think mentioned about the ending amps being around 11 amps when I first started cycling my Surrettes to get a full charge. That now has changed to about 30 amps to reach a full SG charge, but it took about 50+ cycles to reach that point. One other thing you can do is after you let them rest and check the SG level, then start a 30 minute EQ and re-check the pilot cell and see if the SG's have risen from stratification. If the do rise then you can raise the Ending Amps, lower the time some or lower the voltage.

    As I said until the plates are full formed you'll get some funny readings on SG level and capacity and you'll be making some changes. Another thing is that charging from a generator is a tad different from PV for some reason I don't understand, but I can tell from what people say about the way they charge and their batteries react.
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  • Rossman
    Rossman Solar Expert Posts: 178 ✭✭
    #33
    Re: Recommendations for initial charging regimen?
    Blackcherry04 wrote: »
    I think mentioned about the ending amps being around 11 amps when I first started cycling my Surrettes to get a full charge. That now has changed to about 30 amps to reach a full SG charge, but it took about 50+ cycles to reach that point. One other thing you can do is after you let them rest and check the SG level, then start a 30 minute EQ and re-check the pilot cell and see if the SG's have risen from stratification. If the do rise then you can raise the Ending Amps, lower the time some or lower the voltage.

    As I said until the plates are full formed you'll get some funny readings on SG level and capacity and you'll be making some changes. Another thing is that charging from a generator is a tad different from PV for some reason I don't understand, but I can tell from what people say about the way they charge and their batteries react.


    Thanks yeah, it does say in the Surrette docs that it will take 50-60 cycles before things are all settled down. I wish I was charging from my panels but unfortunately that's gonna take a little more time to get done.
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  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #34
    Re: Recommendations for initial charging regimen?

    I assume your going to start cycling them with your house loads. You'll soon learn how much Generator run time you need to keep your overnight free from the generator running ( if thats your scheme ). I usually do a couple hrs in the morning and split that with house loads. I sometimes will do a hour or two in the afternoon to get me through till dinner time. I will start around 6 - 7 ish and charge till bed time ( 11:00 PM ). My wife will cook as soon as I start charging. It's all going to depend on what your charging ability is and how much your loads use from the batteries. You do not have to charge to 100% every charge cycle, 80-85% is ok and then get to 100% once a week or so. If you know what 100% charge is, then you can use voltage as a indicator of how far you should charge to get to 80-85% daily. In your case it's about 55 - 56 volts, that will put you just below gassing level. Then once a week do a full charge and bring your SG's up to full charge.

    Over all my scheme is about 5 hrs generator run time a day with the charging capacity I have. Bulk charging with 20% of C/ not a issue in bulk because there is no heat.
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  • Rossman
    Rossman Solar Expert Posts: 178 ✭✭
    #35
    Re: Recommendations for initial charging regimen?

    Well for right now I'm just going to cycle them with a shop light out of a single wired outlet i have, until I get my electrical rough-in work approved I'm not really supposed to energize any of the rest of the house circuits. But appreciate that info nonetheless, very helpful indeed!
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  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    #36
    Re: Recommendations for initial charging regimen?

    have you got a 1500w space heater?
     
    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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  • Rossman
    Rossman Solar Expert Posts: 178 ✭✭
    #37
    Re: Recommendations for initial charging regimen?

    Yeah I got a small space heater with a couple settings, it draws I think around 900W on low and 1500W on high IIRC.
    I was going to either use that or just fire up three of my four shop lights to get to 1500W.
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  • Rossman
    Rossman Solar Expert Posts: 178 ✭✭
    #38
    Re: Recommendations for initial charging regimen?

    Coming back to give an update. As discussed, I charged the batteries per our agreed approach (~10 hrs), recorded the readings (V & SG per numbered cell), then applied about 1500W of load for a good 8hrs. After that I shut off all loads and set the generator to charge the batteries up again overnight. I forgot to set the XW to do a Float after Absorb, so after the charge cycled finished the system just sat drawing whatever idle power the XW demands until I got out there this morning.

    I was pleased to find all voltages per cell were pretty consistant (average ~2.129V) and the SG's are much closer together now than the first couple readings. The SGs are a bit low, averaging I'd say 1.245 (varying from 1.240 from 1.250), so I have set the system to do an EQ this morning and will stop that in 2hrs and check the SG's again, to see if they are coming up closer to where they should be.

    Any further advice aside from continuing to do a few more loading / charging cycles would be appreciated!

    Thanks again for all the help - I'm feeling a lot better now seeing those SG's tighten up.
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  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    #39
    Re: Recommendations for initial charging regimen?

    Good news. Keep it up and let us know.
     
    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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  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #40
    Re: Recommendations for initial charging regimen?

    Well, you have proved that all cells are functioning and they have a reasonable SG level. A EQ will now bring the SG level up to it's fill strength. I went all last winter doing the same thing, drawing them down and charging them back up and being disappointed in the SG level and doing another EQ and change the voltages again. I'd leave them on float for a couple weeks and check the SG's and they would be back in the 1.230 range, do another draw down and EQ to get them back up. In hind sight all I did was waste a bunch of gas and accomplished nothing. It wasn't till May and I put them into service and could cycle the daily basis did I see the plates form and get the capacity up and SG come up to a normal level on each charge cycle.

    http://forum.solar-electric.com/showthread.php?21330-Commissioning-Day&highlight=Surrette

    http://forum.solar-electric.com/showthread.php?23496-Surrettes-still-trying&highlight=Surrette
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #41
    Re: Recommendations for initial charging regimen?

    You may want to turn the Absorb Voltage up a bit. During solar charging you will not have hours of Absorb time available, so it is important to be able to achieve as close to full SG as possible in the time you do have. This means having to run higher Voltage, perhaps even higher than recommended by the maker.
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  • Rossman
    Rossman Solar Expert Posts: 178 ✭✭
    #42
    Re: Recommendations for initial charging regimen?
    Blackcherry04 wrote: »
    Well, you have proved that all cells are functioning and they have a reasonable SG level. A EQ will now bring the SG level up to it's fill strength. I went all last winter doing the same thing, drawing them down and charging them back up and being disappointed in the SG level and doing another EQ and change the voltages again. I'd leave them on float for a couple weeks and check the SG's and they would be back in the 1.230 range, do another draw down and EQ to get them back up. In hind sight all I did was waste a bunch of gas and accomplished nothing. It wasn't till May and I put them into service and could cycle the daily basis did I see the plates form and get the capacity up and SG come up to a normal level on each charge cycle.

    http://forum.solar-electric.com/showthread.php?21330-Commissioning-Day&highlight=Surrette

    http://forum.solar-electric.com/showthread.php?23496-Surrettes-still-trying&highlight=Surrette


    Thanks BlackCherry, I will keep this in mind. I guess, perfection is not really possible so we will just use it as a good target to shoot for!

    Cariboocoot wrote: »
    You may want to turn the Absorb Voltage up a bit. During solar charging you will not have hours of Absorb time available, so it is important to be able to achieve as close to full SG as possible in the time you do have. This means having to run higher Voltage, perhaps even higher than recommended by the maker.

    Thanks, Cariboocoot! I will only be charging with the generator for the foreseeable future, and normally we just run the generator pretty much 24x7, so I will just leave things as is until I get our arrays hooked up and can figure out whats going on, on that front!

    I guess for now I will just give them a few more charge/discharge cycles with the shop lights and see where I end up, god willing I will pass my electrical rough-in inspection so we can insulate this shell and make moves to getting in there full time to finish up the rest of the work. Getting chilly in the RV!

    Thanks again, merry christmas!
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  • Rossman
    Rossman Solar Expert Posts: 178 ✭✭
    #43
    Re: Recommendations for initial charging regimen?

    Well I still have not gotten my SG's up to where I would like to see them, they still seem to want to hang out around the 1.245 range, which seems decidedly low. This was after the ~2hr EQ @ 2.58V per cell (61.92V), and another charge cycle at the settings previously discussed (57.6V bulk, 58.0V Absorb, with a 480min absorb timer). I started the charge last evening and the generator ran through the night and the system was in Float this morning.

    I think I will try to increase the absorb voltage per Cariboocoot's suggestion and give them another charge cycle. It seems like as with BlackCherry's experiences, these buggers are a bit tough to get up to the target SG. At least glad to know I am not the only one to experience this!
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  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    #44
    Re: Recommendations for initial charging regimen?

    How far is the load cycle taking them down before you recharge? Hrs and size of load?
     
    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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  • Rossman
    Rossman Solar Expert Posts: 178 ✭✭
    #45
    Re: Recommendations for initial charging regimen?

    I try to get them down to 75% using 1500W of shop lights (but they may not even get down that far), that seems about all I can do in a day, and I don't want to leave a load unattended on them at night in case things go terribly wrong somehow. I only have the one 15A outlet wired up right now so that's about all I can draw.

    Should I just draw them down further over two days, then bring them back up?

    EDIT: westbranch every time I see your avatar it reminds me of how my house looks right now!

    EDIT2: interestingly while the SG's have not come up much, the average voltages for the cells is now up at around 2.14 (vs. the 2.12 it was before). I don't know if this matters as much as SG though.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #46
    Re: Recommendations for initial charging regimen?
    Rossman wrote: »
    I try to get them down to 75% using 1500W of shop lights (but they may not even get down that far), that seems about all I can do in a day, and I don't want to leave a load unattended on them at night in case things go terribly wrong somehow. I only have the one 15A outlet wired up right now so that's about all I can draw.

    Should I just draw them down further over two days, then bring them back up?

    You can do this, but 75% SOC should be deep enough to 'exercise' them anyway.

    Big batteries take more time to come up to full capacity. Both initially and afterwards. You're fighting mass! :D
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  • Rossman
    Rossman Solar Expert Posts: 178 ✭✭
    #47
    Re: Recommendations for initial charging regimen?
    Cariboocoot wrote: »
    You can do this, but 75% SOC should be deep enough to 'exercise' them anyway.

    Big batteries take more time to come up to full capacity. Both initially and afterwards. You're fighting mass! :D


    Ok thanks, I won't panic at this point ;)
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  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    #48
    Re: Recommendations for initial charging regimen?

    EDIT: westbranch every time I see your avatar it reminds me of how my house looks right now!

    That pic is deceiving as the left side was sided at that time and we were just starting to do the lake side (front).
    The front is also done now. One side to go come spring..
     
    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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  • Rossman
    Rossman Solar Expert Posts: 178 ✭✭
    #49
    Re: Recommendations for initial charging regimen?
    westbranch wrote: »
    EDIT: westbranch every time I see your avatar it reminds me of how my house looks right now!

    That pic is deceiving as the left side was sided at that time and we were just starting to do the lake side (front).
    The front is also done now. One side to go come spring..


    I got all four sides to go come spring. God willing the Tyvek stays on through the winter.
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  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    #50
    Re: Recommendations for initial charging regimen?

    Hi Mark,

    Agree, that you should probably raise the Vabs, to what Marc, coot recommended initially ... at this point, the you probably Do want to get the SGs into the target range, and higher Absorb voltage should do that while reducing generator run-time, somewhat.

    Good Luck, Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
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  • Rossman
    Rossman Solar Expert Posts: 178 ✭✭
    #51
    Re: Recommendations for initial charging regimen?

    Thanks Vic, I will bump 'er up and see how we get on!
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  • dropkick
    dropkick Registered Users Posts: 23 ✭
    #52
    Good thread... lots of info! On a related question, I have 8 GC2's which will be run as a series of 4 x 2 strings for 24V due to the inverter voltage (I know..). Would it make any sense to connect them as 48V for the first charge/EQ to get things better balanced? I will have the charge capability but wouldn't be able to run a discharge cycle in this config. Or should I just put them in their final config? The interconnects are all identical so I don't expect much variance from that.
    6 250W Renogy panels / Morningstar TriStar MPPT 60 charge controller / 8 Costco CG-2 batteries @ 24V / Samlex PST-1000-24 inverter / Samlex SDC-23 24/12V converter and BG-60 LVD / Midnite Solar boxes, breakers, etc.
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #53
    dropkick wrote: »
    Good thread... lots of info! On a related question, I have 8 GC2's which will be run as a series of 4 x 2 strings for 24V due to the inverter voltage (I know..). Would it make any sense to connect them as 48V for the first charge/EQ to get things better balanced? I will have the charge capability but wouldn't be able to run a discharge cycle in this config. Or should I just put them in their final config? The interconnects are all identical so I don't expect much variance from that.

    The best would be to have a 6 volt charger and charge the batteries one at a time. Next best is to charge them at 12 volts, two at at time. Next best is to charge them at 24 volts, four at a time. Next best is charge all 8 of them at 48 volts.

    The point is that while you are waiting for the slowest cell to be charged, all the other cells are being overcharged. Lets say you have a slow cell in one battery.. If you can charge it at 6 volts, only two cells are being overcharged. If you put that battery in a string of 8 batteries (48 volts), you will overcharge 23 cells.

    If you are willing to go to the bother of re-configuring the batteries temporarily at 48 volts just for an initial charge, why not leave them at 24 volts but disconnect 1 string at a time?

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • dropkick
    dropkick Registered Users Posts: 23 ✭
    #54
    That makes perfect sense... Thanks!!
    6 250W Renogy panels / Morningstar TriStar MPPT 60 charge controller / 8 Costco CG-2 batteries @ 24V / Samlex PST-1000-24 inverter / Samlex SDC-23 24/12V converter and BG-60 LVD / Midnite Solar boxes, breakers, etc.
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