Help! MCT II 4000 batteries and more

katbastard
katbastard Registered Users Posts: 9 ✭
in Off Grid Solar & Battery Systems #1
So here is the short version of the story, I live in slab city, ca. I have been self teaching my self solar for about a year now. I run 5 panels that total out to 273 watts, and have 3 r.v. deep cycle batteries that total 365 amp/h 12 volts.
sooo, my friend died and i am the care taker of his place, i was the only one in the group of friend who could stay at his place, being it is in slab city also. and the only one of his friend that knew anything about solar... this is his system

48v-C&D MCT II 4000 2v x24-2.5kw Solar-Kubota 5 Kw Diesel Generator-
outback flexmax 80 fm80-150vdc x2-Outback FX3048T 3000W 48V Inverter/Charger x2

I have been reading and learning everything there is to know, been on the phone with the C&D rep here in cali. and doing a pretty good job, i think.

So here is what happened, right after my friend died there was some other guy here taking care of the place, well he ran the batteries down to the ground, they where down for about a month before i got here and started playing with them. the float setting was off and all kinds of other small thing in the programming in the charge controllers to prevent the batteries from being charged from the solar. so since i have been here i have programmed the cc right, and trying to get the system healthy again. The issue i am dealing with now is that one cell was lower (1.99v) when the other 23 where at 2.13, that is after all night with little draw on them. Also some of the batteries have sulfates on the plates. anyway the C&D rep told me i need to equalize the batteries. and that should fix all my issues. so the past 100 hours i have been doing that had it set for 57.6 volts, for 24 hours, then 60volts for the last 72. but the amps where holding steady at 16.6amps, so i just now reset the volts to 57.6 and the amps dropped way down to around 4 or 5 amps, so now i am letting it finish up on that voltage. but the main thing i am worried about right now, before i have test each cell again at least, is the sulfates are still there on the plates. i was really hoping to see them come off.

Also what should i expect to see in volts, when this system fully charged?
is there any advice on anything that i have talked about here? about the sulfates and the overall care i am taking of the system.

thank you for reading this.
kat bastard
· Share on Twitter

Comments

  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #2
    Re: Help! MCT II 4000 batteries and more

    it's a real shame that all it took was one idiot to screw up some very nice cells. i'm guessing the low cell is possibly bad with the other cells compromised in their capacity due to the sulfation. usually none of us would have need to see a battery bank get an eq charge for such a long period and i'm sure c&d knows that was a last ditch effort. btw, did they recommend that you check the specific gravity of the cells and tell you what to look for in them?

    is it your buddy's intention that you get to keep this system? if so maybe c&d has a cell that is used or in similar condition to the rest of your bank to replace the cell that's low in voltage (a new cell would be dragged down to the level of the other cells and may not be worth the costs), but i think the capacity needs to be evaluated on the remaining cells first to see if it is worth adding another cell to the system or scrap them all altogether. they know their batteries best and can advise you on them as to what is the best course of action.
    · Share on Twitter
  • katbastard
    katbastard Registered Users Posts: 9 ✭
    #3
    Re: Help! MCT II 4000 batteries and more

    The C&D guy has been real awesome, he thinks that the system can be saved the way it, said that this EQ don't work then we could try to get that cell up to voltage by singling it out. i am a n00b for sure, but he knows the situation i am in over here and does not think its that bad over all.

    here is a few links to what we are doing over here, the first link is off of my website, [strong language/content warning. -Bill B.]
    http://squattheplanet.com/threads/east-jesus-post-apocalyptic-life-in-a-pre-apocalyptic-world.10228/

    The next link is from Kcet a public t.v. station out of L.A.
    http://www.kcet.org/updaily/socal_focus/commentary/east-jesus-desert-art-project-in-peril.html
    · Share on Twitter
  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #4
    Re: Help! MCT II 4000 batteries and more

    Here is some interesting information on recovering capacity on AGM type cells:

    Low rest voltage on GNB absolyte IIP cells
    Sulfated Lifeline Concorde AGM Batteries

    Good Luck!

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
    · Share on Twitter
  • katbastard
    katbastard Registered Users Posts: 9 ✭
    #5
    Re: Help! MCT II 4000 batteries and more

    Bad news, all batteries are at 2.17, but that one battery is testing at 1.87... unhappy. Hoping we can get up the money to find one used maybe.
    · Share on Twitter
  • Jenn Nelson
    Jenn Nelson Registered Users Posts: 2
    #6
    Re: Help! MCT II 4000 batteries and more

    Hey folks. I'm hoping some of you who were on this thread before are still here.

    Kat is no longer with us at East Jesus, and I'm one curator removed from his tenure here. I'm the current curator-in-training, and I'm slowly taking over some of the administrative duties in this transition. Salvaging our battery bank is now my project.

    The situation with our array, sadly, is roughly where it was when Kat posted and has degraded from there. I'm following some of your advice; getting in contact with C&D, investigating replacing the damaged cell, etc. etc.

    If you've got a line on a used one, let me know!
    · Share on Twitter
  • bill von novak
    bill von novak Solar Expert Posts: 891 ✭✭✭✭
    #7
    Re: Help! MCT II 4000 batteries and more
    Jenn Nelson wrote: »
    The situation with our array, sadly, is roughly where it was when Kat posted and has degraded from there. I'm following some of your advice; getting in contact with C&D, investigating replacing the damaged cell, etc. etc!

    Replacing one bad cell will not likely help much. Sounds like that battery set has been hammered so badly that it's almost gone. The MCT II line is designed for telecom standby, not renewable applications (i.e. cyclic) use and thus won't have the life of better cells even if they weren't abused. In fact the manual does not recommend more than one significant discharge a MONTH.

    All of which means you will probably need new batteries. The ones you have will likely keep getting worse, and at some point you are going to see voltage reversals across cells, at which point your capacity will rapidly drop to zero.

    (Sorry, I figure that's not the news you wanted to hear, but you generally can't undo the abuse.)
    · Share on Twitter
  • Jenn Nelson
    Jenn Nelson Registered Users Posts: 2
    #8
    Re: Help! MCT II 4000 batteries and more

    I kinda figured. I read that too. I know we're running on fumes. I'm looking at our replacement options.

    We've got 23 of them- We should get 4000 amp hours in our current configuration.

    We're getting 150.

    On a good day.

    That's 7.5% of their capacity. I know failure is immanent. Recommendations for replacement would be appreciated.
    · Share on Twitter

Categories