Wet Cell Batteries

BEFUDDLED
BEFUDDLED Registered Users Posts: 8
New to the forum, but hopefully I will not break any rules here!

My question is very simple. I purchased 18 6V 420amp batteries for our system. We received them in mid-August, 2013. My work does not allow me much time to do fun things like construction and installation of a solar system, but I wanted to get the system, including batteries on hand for the fall construction season. Unfortunately, our fall was not only wet and cold, out of character for our area, but other issues prevented me from installing the system. In fact, it has not been installed as of yet. I was told that it would be okay for them to sit for 90 days. I got to mid-November and saw that installation may not happen any time soon, so I put a 48V 25amp charger on each string of 8 batteries. Before I started, I identified 6 of the 16 that were showing signs of going bad. I charged each string and was told to do it again monthly. After two months of this charging, those 6, plus one more, showed either one or two bad cells in each battery. The original 6 were replaced under warranty, but not without a lot of people going to bat for me. I will not name the battery manufacturer, but the distributor in our area and the people I bought from have gone above and beyond the call of duty.

The string of 8 original batteries seem to be doing well and respond well to the monthly charging. The other string, now with 6 new batteries and 2 of the original batteries, one of which now shows a bad cell, fully charges per the charger indicator, but clearly, the battery with the bad cell will not charge above 4.39 volts. I read all of this stuff about all or none with batteries. Replace them all or none. Now for the question, should I replace

A) the one bad one,
B) both of the original batteries, so that the second string would be all new batteries of the same type, model, etc., or
C) replace the original 10, so that all 16 are new and of the same type, model, etc.

A second question would be based on what I read, these deep cycle batteries are designed to cycle, should I connect the batteries to the charge controller and inverter in my garage and connect the AC 48V DC charger to the charge controller rather than panels at this time, to charge the batteries, then put loads like freezers or window air conditioners on the inverter to drain power thereby artificially creating the charge-discharge cycle?

Many thanks to those that respond with your good knowledge and advice.

Comments

  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Wet Cell Batteries

    Welcome to the forum.

    Well you are trying to do the right thing. Batteries do not like to sit. They probably should have been charged when first bought to make sure they were all up to snuff to begin with.

    Since the system still has not been installed I would replace any and all that aren't up to the level of the new ones. It is best to start out with all batteries showing the same SG in all cells.

    Also there is charging and then there is charging. What sort of charger do you have? If it is an Iota with the IQ4 plug-in module be sure and let it run an EQ cycle from time to time. If these are by any chance Surrette or Trojan batteries you may need to adjust the charging Voltage up as well. Both of those prefer higher than typical Absorb Voltage.

    As for cycling them, it is true that they do not reach full capacity until they've been cycled a few times. It will not hurt to 'try them out' but it won't improve their resistance to sulphation, stratification, or self-discharge. You still have to charge and check regularly.
  • BEFUDDLED
    BEFUDDLED Registered Users Posts: 8
    Re: Wet Cell Batteries

    Thank you for your thoughts. At present l think l am going to replace the 2 so that l will have 8 new batteries in one string and 8 older ones in the second string. My plan was to have a 48 volt 840 amp battery bank and l can not afford to replace 10, but can replace 2 now. I will try to save them over the next few months until the installation is complete. Then if things are not right, l will go for 16 New of the best that are available at that time.

    I am using a Schumacher 48volt 25 amp that was provided by the company that l bought everything from. I will look into the purchase of an lots charger, but l do not think that they have a model with as many amps as l will need to get the job done. We'll see.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Wet Cell Batteries

    Well 25 Amps to an 840 Amp hour battery bank isn't much either; about 3% charge rate. Under the circumstances I wouldn't try to charge all at once from that but do half at a time. Even that is a bit light at 6%.

    You are right that Iota only goes to 15 Amps @ 48 Volts. 25 Amps @ 48 Volts is 1200 Watts; a pretty full load for an electrical outlet. Do you know if your charger is 3-stage?
  • BEFUDDLED
    BEFUDDLED Registered Users Posts: 8
    Re: Wet Cell Batteries

    According to the manual, the charger has a charge mode, a maintain mode and a desulfation mode, so I guess that means 3-stage. I have reviewed the literature on Iota's website and they discuss connecting their chargers in parallel or series if you want to up the voltage or amperage. I read somewhere where the charge should be about 17% of the battery bank's capacity. If I only do one string at a time, 17% of 420 amp/hours is 71.4 amps, so it would take at least 4, maybe 5 of the things. I do not have a power outlet in the area that could handle that. It seems to me if they are basically fully charged, one, or two should be able to top them off and maintain them. I might be able to run an extension cord to give the second outlet. I don't know. This all sounded like it would be something that was doable, but now, having gotten the cart before the horse, the batteries are in jeapordy, at best. Seems to me that the seller of solar stuff, should know that these things can not sit and when I bought them saying they would be installed within 90 days, certainly before year end (mid-August), they would have insisted on me buying the batteries later, or dry at the time, or suggested that I would have to have a charger and adequate AC power for the charger to keep the batteries in good condition. They don't acknowledge that, but they did provide the Schumacher charger which the battery distributor supposedly said would be what should be used. Some of the Iota chargers have more amps at lesser voltages, such as 12V and 55amps and break this down into 8 groups of 2, or a 24V and 40amps and break this down into 4 groups of 4. None of it sounds like a good solution. The quandary continues, but again, thanks for your thoughts.
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Wet Cell Batteries

    You said you already had the Inverter / Charger in your garage, put a pigtail cord with a plug for Input on it and use it to charge them. The Inverter output does not have to be hooked up or can be shut off on the remote. I have several Inverters set up like that I use to charge banks with different voltage requirements. You can set the allowable AAC input and the Charger DC amp output. You may have to start out low, once you get them charged it won't take much current.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Wet Cell Batteries

    A 17% charge rate is more than is needed. That's probably the upper limit for the batteries. 10% is usually enough, especially with no loads being drawn.

    As Blackcherry said, if you've got the inverter-charger there wire it up temporarily to act as a battery charger only. The chargers built in to these are capable of much more current than stand-alone units and can be programmed with the correct charging profile for the batteries (Voltage set points, current limits, Absorb time, etc).
  • BEFUDDLED
    BEFUDDLED Registered Users Posts: 8
    Re: Wet Cell Batteries

    Thanks, I had no idea!
  • BEFUDDLED
    BEFUDDLED Registered Users Posts: 8
    Re: Wet Cell Batteries

    No kidding, looks like you and Blackcherry may have solved my problem temporarily anyway. I bought one of those package deals and it never occurred to me that this could be done. Is this something that an owners manual would spell out? (Magnum MNEMS4448PAE & MidNite CL150)
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Wet Cell Batteries

    Owner's manuals tend to lean toward how to use things. Installation manuals lean towards how to put them in. Neither talks about how to keep batteries from going bad until you can get everything up and running. They sort of assume you'll get everything you need all at once and put it in right away.

    Life doesn't always work that way. I spent a couple of months charging mine "the hard way" while waiting for a single piece which had been misdirected by the shipper. :p
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Wet Cell Batteries

    Please call a electrician if this is something you do not understand. The Inverter manual shows the schematic on how to wire it for 120 V or 240 V input , If your going to plug it into a regular socket you'd want 120V. Since you have the Midnight panel that you can go around. remember one wrong wire and you'v bought the farm. All you want is a cord with a plug so you can plug it into the wall. The best is to buy a short ( 6 ft ) # 12 ga extension cord and cut the female end off and use it for input. The DC is up to you, I use a set of 1/0 jumper cables with lugs on one end. You don't need that big, # 4 ga would be ok.

    Wiring the Inverter AC Input (from the main panel)
    3. a. For a 120/240VAC input: From the main panel’s dedicated dual-pole circuit breaker, connect
    the hot 1 wire (black) to the “AC HOT 1 IN” terminal and the hot 2 wire (red) to the “AC HOT 2
    IN” terminal.
    b. For a 120VAC input: From the main panel’s dedicated single-pole circuit breaker, connect the hot
    wire (black) to the “AC HOT 1 IN” or AC HOT 2 IN” terminal, but NOT both or damage may occur.
    4. Connect the neutral (white) wire from the main panel’s neutral bus bar to one of the “AC NEUTRAL”
    terminals (both “AC NEUTRAL” terminals are common to each other).
    5. Connect the safety ground (green) wire from the main panel’s ground bus bar to one of the
    “AC GROUND” terminals.

    http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CEQQFjAA&url=http%3A%2F%2Fwww.magnumenergy.com%2FLiterature%2FManuals%2FInverters%2F64-0032%2520Rev%2520A%2520(MS-PAE%2520Series).pdf&ei=wcUPU5tmpojKAcCIgfAH&usg=AFQjCNGmWU2nPuTlvxUNiUlRWzAToJyeUQ&bvm=bv.61965928,d.aWc&cad=rja
  • BEFUDDLED
    BEFUDDLED Registered Users Posts: 8
    Re: Wet Cell Batteries

    Absolutely cool! Thanks, l believe l understand the wiring you described. It is just a shock as l thought the only role of an inverter was to get from AC to DC..... l had thought briefly about the possibility of connecting a charger to the charge controller sort of like connecting a generator. Many thanks to the both of you!