I think I messed up my system

Options
Hi all, very helpful forum.

Ok, I've had my system for about a year now and am having some problems. Specs of my system are as follows -
8 US 2200 batteries wired in series parallel for a 12 volt 880 amphour bank
3 120 watt Kyocera panels
Dr 1512 inverter
trace Tm500 monitor
solar boost 2000E
Trace 40 charge controller
Honda 5500 watt generator

I'll start out by stating the obvious, which is I am technologically challenged. That being said, my problem is in the past couple months I've noticed that when my generator was being used to charge my battery bank, it has melted a good portion of the plastic off my inverter's positive connection. I had the inverter set at bulk charge. Now my battery bank only producing about half its normal run time(amphours). Not sure if it matters but the 1st 6 months, my batteries were charged exclusively off my generator and I have only equilized my batteries twice(Iknow, I know).

Did I fry my batteries? If so, would I be a good candidate for gel batteries which are less maintainance?

I've been largely ignoring my solar problem because I didn't want to deal with it and was to embarrased to admit how little I actually knew about my system but have little choice now except to humbly ask what I have done wrong.

Comments

  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Options
    Re: I think I messed up my system

    it could be that, but it's hard to say. if you relyed on solar to bring the batteries up that could be part of the cause as your solar will deliver at a rate under 2.4%. batteries can't be allowed to be undercharged for long periods of time as sulphation sets in. we recommend a minimum charge rate of 5%. we also don't know if you had allowed your batteries to be discharged below 50%. doing this takes away from battery life. it could also be a bad wire or connection. it is hard to say and i fear if these batteries are fried that going to more batteries will result in the same dissastrous results if the causes aren't rectified. gels are a bit more expensive and picky in their charging than standard lead acids.
  • crewzer
    crewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    Options
    Re: I think I messed up my system
    ...I've noticed that when my generator was being used to charge my battery bank, it has melted a good portion of the plastic off my inverter's positive connection.

    This sounds (smells?) like a loose, dirty, and/or corroded connection at the terminal, or perhaps even inside the inverter. What you've got is a high resistance point that's heating up as current flows through it, and there's an associated voltage drop across this point. This may well be why your batteries aren't being fully recharged: The charging voltage at the battery terminals could be too low. This problem needs to be corrected right away.

    HTH,
    Jim / crewzer
  • System2
    System2 Posts: 6,290 admin
    Options
    Re: I think I messed up my system

    I'll try cleaning and tightenening that connection. Thanks for the help as I've gone over everything but this never occured to me.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,479 admin
    Options
    Re: I think I messed up my system

    Get a digital volt meter that can read three decimal places (xxx mVolts)... And measure each connection point and note the results (either while under load or during high charging currents)... (you need stable current flow, the larger the better, to get voltage drops across your various connection points during your measurements).

    Do this throughout your DC distribution/battery/charger/inverter system... Any connection that reads high, you should double check each accessible point (say end to end is 35 mV drop at 20 amps--then measure post to terminal, terminal to cable, cable end to cable end, cable end to terminal, terminal to post, etc.--you should find many of the connection points are in the x mV range, and you may fine one point in the xx mV range--i.e., dirty or loose terminal bolt, corroded cable, etc.).

    As always, remove any jewelry, watches, metal belt buckles, etc., wear safety glasses, and use insulated tools when working on your battery bus system when energized.

    Any place that feels warmer than any other identical place (or shows signs, like melted plastic) is a sure warning signal that something is not right

    And to be clear, "frying the batteries" would probably be indicated by having to add a bunch of water every few weeks or month--and could be caused by too high of charge voltage settings, improper setup of the charger (asorb, bulk, float, equalize voltage/current settings), or if you are in a warm climate and don't have a working battery temperature probe connected to the battery charger(s) (batteries need lower charge voltages as the temperature increases).

    What may have happened is that you undercharged the batteries... Either because you over discharged and did not immediately recharge (less than 24 hours???), and/or poor electrical connections, and/or because of not compensating the charge voltages by battery temperature, and/or simply not running the generator long enough, and/or not having enough solar energy (panels/clear weather or other issue) to simply fill up the batteries--all possibly leading to early sulfate formations (sulfates form when a battery is discharged and the longer/thicker the sulfates, the less likely they are converted back to lead/lead oxide during battery recharging--hence the recommendations for not discharging a storage battery bank much below 50% capacity and recharging a depleted bank within 24 hours--or less--of a deep discharge cycle) of the batteries and early life failures (or at least reduced capacities).

    I am not the battery expert here--but, roughly those are the reasons why you may be having storage/capacity issues.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Options
    Re: I think I messed up my system
    rrroae wrote:

    3 120 watt Kyocera panels

    What are your loads ? You can generate about 300W on a good day, for a few hours, but if you are pulling more out of the batteries - they will discharge too low. Try running the generator for recharging about an hour before your panels get lit by the sun, that should do the bulk charge, and and the sun will top them off for a few more hours if you are lucky. You have a lot of batteries, but not much PV
    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 ,

  • System2
    System2 Posts: 6,290 admin
    Options
    Re: I think I messed up my system

    Bill, thanks for the advice on the batteries. Anyone recommend a good voltmeter?

    Mike, my loads are very minimal. My wife uses a laptop to work from home. Roughly 5 amps/hr. Maybe another 2 hrs of tv at night on a 14 television for another 5 amps/hr.

    Thats about it except for an occasional 8 watt fluorescent light here and there. I'll admit we're pretty lucky with our setup.
    Gravity spring and 2 natural gas wells make electricity almost unnecessary for us. If not for my wife needing a laptop for work, we could really do without but I'm not ready to make that big of a leap yet.

    I can't tell all of you how appreciative we are with the advice. Maybe there is hope with me and solar.
  • System2
    System2 Posts: 6,290 admin
    Options
    Re: I think I messed up my system

    I sense some new life with my solar. After cleaning all the connections and really tightening things up, I turned my generator on for 1 1/2 hrs. The reading on my TM500 went from its usual 11.8 to 12.6 after I shut the generator off. Big improvement.
    Next my wife turned on the dryer for about 3 minutes just to see if it would work and it did. First time in 3 months without using the generator. One odd thing with my TM500 is it has been showing 100% no matter what charge we're at. Reset it numerous times with no change. It's obviously incorrect as I watch the amps go from 58 down to 44 when charging with the generator. 44 should be my amps for an 880 amp/hr battery bank right? Real happy with everyone's advice so far, just wish I wouldn't have been so stubborn to have waited so long to ask for help.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,479 admin
    Options
    Re: I think I messed up my system

    I would just find a cheap reasonably priced meter that reads millivolts... Fluke is probably the number 1 brand of meter if you wish to buy one for life.

    I am still using the cheap meter I purchased for college some 25 years ago. Isn't pretty, but it works fine.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • crewzer
    crewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    Options
    Re: I think I messed up my system

    :-) 8-)
  • BB.
    BB. Super Moderators, Administrators Posts: 33,479 admin
    Options
    Re: I think I messed up my system

    You may also wish to read Wind-Sun's battery FAQ--has a lot of information:

    http://www.windsun.com/Batteries/Battery_FAQ.htm

    Also, you should monitor the battery voltage/current and watch for bubble formation (hydrogen gas) in your batteries... As the voltage rises during charging, you will know your batteries are pretty much fully charged when they reach the appropriate voltage (per temperature chart), specific gravity, and when the batteries start bubbling well. The charger should also start cutting back on charge current at this point.

    Your bank, running 44 amps will take approximately 10 hours (at 44 amps) to recharge if 50% discharged.

    And, because you have so few solar panels, they probably are not helping to charge the batteries much--but just, more or less, helping to keep them charged and not really making up for any major usage/loads.

    Here is the recommendations from US Battery for charging their batteries (voltage, current). Once you fully recharge the set, you can monitor your usage and better estimate how long to run the generator to fully recharge the bank (best running the generator in morning, and let the solar charger finish the last bit of charging during the day).

    http://www.usbattery.com/pages/usbspecs.htm

    According to US Battery you can safely charge up to 88 amp rate (C/10 charge rate).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • crewzer
    crewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    Options
    Re: I think I messed up my system
    Your bank, running 44 amps will take approximately 10 hours (at 44 amps) to recharge if 50% discharged.

    It'll probably be at least 13 hours... :cry:

    The coulombic efficiency (Ah out / Ah in) of flooded-cell batteries like the US2200 is 90% or less. If the battery bank is 50% discharged, it'll take ~489 Ah to replace the 440 Ah used. So, figure on about 11 hours of constant current (bulk) charging to get the batteries up to ~90% SOC, and then a minimum of two more hours of constant voltage (absorption) charging to get them close to full.

    Considering that past problems with charging the batteries, they're probably due for an equalization charge. This should be done after the absorption cycle is complete, and, in this case, should run for perhaps two hours.

    While I generally defer to manufacturer's instructions, I'm not a big fan of US Battery's absorption stage charging recommendation of 2.583 V per cell for two- to four hours (15.5 V for a 12 V battery :-o ). This value is much higher than that suggested by major flooded-cell battery manufacturers such as Trojan and Rolls / Surrette. It's possible that US Battery uses a different plate chemistry, but I've not seen this explained anywhere.

    My specific concern is the amount of electrolyte water that will be lost to outgassing via electrolysis and the resulting maintenance requirement to regularly check and refill the cell with distilled water. Trojan Battery's maintenance guideline, for example, may be a gentler solution for your GC2 size batteries, which are roughly the equivalent of Trojan's vaunted T-105's.

    See: http://www.trojanbattery.com/Tech-Support/BatteryMaintenance.aspx
    and: http://www.rollsbattery.com/Bulletins/605.htm

    Either way, maintaining 24 battery cells on a regular basis will not be fun, and make sure you follow all safety precautions. Also the batteries need to be ventilated, especially during absorption and equalization stages. See here for more info and a solution: http://www.solarseller.com/battery_box_power_vent_by_zephyr_industries.htm

    HTH,
    Jim / crewzer
  • System2
    System2 Posts: 6,290 admin
    Options
    Re: I think I messed up my system

    The coulombic efficiency (Ah out / Ah in) of flooded-cell batteries like the US2200 is 90% or less. If the battery bank is 50% discharged, it'll take ~489 Ah to replace the 440 Ah used. So, figure on about 11 hours of constant current (bulk) charging to get the batteries up to ~90% SOC, and then a minimum of two more hours of constant voltage (absorption) charging to get them close to full.

    Considering that past problems with charging the batteries, they're probably due for an equalization charge. This should be done after the absorption cycle is complete, and, in this case, should run for perhaps two hours.

    Crewzer, this the info I really needed. Apparently I was mistaking the burnt plastic at my inverter's positive terminal as overcharging, when in fact it was due to dirty/untight connections as you pointed out previously. I've been charging my batteries for 6 hrs so far and now see that my batteries have been in a constant state of undercharge. It didn't help that my Tm500 registers a 100% charge when it is in fact only 65-90% full. I have it set at 14.4 volts, 44 amps and 880 amp/hrs, so somethimg must be wrong with my meter. Either way, I'll rely on my inverter state of charging(bulk/absorption) and wait until I hear the batteries bubbling as Bill explained before I know the batteries are full and proceed to the equalization process.

    What I find interesting is that in a few posts here, I have learned more about my system than the countless hrs I've spent trying to decipher my manuals. For this I am truly grateful to all who would take the time and try to help us and by doing it in a way we could understand.

    Thanks and much appreciated
    Rex
  • crewzer
    crewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    Options
    Re: I think I messed up my system

    :-) 8-)