Absolyte batteries

TnAndyTnAndy Solar Expert Posts: 249 ✭✭
My current system, I have 8 Deka 6v L16 400amp/hr wet cells in two strings of 4 for 24v and about 800amp/hr total bank.

Total panels on system are 18 -- 175w Solarworld for a total of 3.150kw.

Two Flexmax Outback charge controllers

Two GTFX2524 inverters ( master/slave arrangement )

I have a line on getting a couple of sets of brand new Absolyte 24v 1200amp/hr banks ( I think they are 2v individual cells in cases of 3 cells for 6v per "case" the way he described them to me....I haven't seen them yet.....I have to drive 1200 miles to get them.... ) for a REALLY good price + one set that is a year old....all from a cell service company that decided to change specs on batteries before the new sets were even installed....guy I know got these for scrap price and I'm getting them from him.

I'd like to install the two new sets on my grid tie/battery backup system, and another buddy wants the used set.

My question: Is a 2400amp/hr bank beyond what the rest of my system will maintain, grid up......and in a grid down situation for an extended period, ( say 2 weeks....it happens here ), will my 3.15kw panels have any issues with that much bank ?

Is there a "rule of thumb" for the amount of amp/hrs in a bank in relationship to the amount of PV watts ?

Any other advice changing from flooded cell to AGMs .....other than I know the charge controller needs to be re-programed for the different battery type.....

Appreciate any and all advice..




  • mike95490mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Absolyte batteries
    TnAndy wrote: »
    Any other advice changing from flooded cell to AGMs .....other than I know the charge controller needs to be re-programed for the different battery type.....

    Depending on how you reset the charge controller, you may need a voltmeter that has a very good calibration near your desired setpoint.
    AGM does not like any overcharge, you need to nail the right voltage.

    Also, BTS Battery Temperature Sensors, will help keep the charge points dead on.

    Slave the charge controllers, so they work in tandem, and not have one shut down at float hours before the other one does.

    Get the Mfg manual for your batteries. Follow it's advice above all others.
    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
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  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Absolyte batteries

    your pvs added together in a parallel arrangement will be rated at 88a. i don't know what it is your typically are seeing at your place as few see the rated current consistently, but you also have mppt controllers in your favor. the minimum of a 5% charge rate should be present and if the batteries present a 2400ah capacity this would be .05 x 2400ah = 120a. 88a would be 88a/2400ah=3.66%. this could be made to be compoundedly worse if you have loads on during charge times as this detracts from the % of charge reaching the batteries. you might need to upgrade to more pvs or allow some time to allow the batteries to reach full charge. the smaller percentage will represent a longer time to reach a full charge and would be close to 15 full sun hours from 50% dod. if you get 5hrs of full sun per day you need 3 days to do it.
    on a sidenote here, i do hope you know how much weight is involved with batteries of this type and the proper vehicle would be needed to transport such batteries in addition to gas costs and pit stops for sleep and meals.
  • DapdanDapdan Solar Expert Posts: 330 ✭✭
    Re: Absolyte batteries

    Hey andy,

    I would definitely go and get them. Those batteries new would cost about 1500 bucks a cell. I have some that are 10yrs old and they still work and run my entire house even though two of them are low and working below par.

    What i would do is split the bank into two so you would get a pair at 1200 and use a make or break switch to select which bank to charge or discharge. Even if you want to keep one as a spare at 70 deg a full bank would keep for 6 months without charging. I even found some research papers on these exact batteries that showed test results of the same batteries not losing charge after 2yrs. The way I see it if you work between the two or keep one set as a spare you should get at least 15yrs from them easy.

    I have done some experimenting with my Absolyte IIP 100A19 and posted my findings and other research papers I found on them during my experimenting. Just search of post done by me.


    P.S Good luck with the driving
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Absolyte batteries

    dapdan's idea of a switch between the banks of batteries is a good one and i should've thought of it.;)
  • rplarryrplarry Solar Expert Posts: 203 ✭✭
    Re: Absolyte batteries

    One other big advantage, at least it was my experience when Ihad them, is that they are very much more efficient than FLA batteries. Mine were between 97% and 98% efficient compared to when I used wet cells. 1200 miles is a long haul but if the batteries are as advertized then they are the best you can get.
  • TnAndyTnAndy Solar Expert Posts: 249 ✭✭
    Re: Absolyte batteries

    Thanks for all the input, folks. I am going to get them, and will let ya'll know how it turns out...

    My cost on them is so cheap, I simply can't turn it down.....even after cost of trip and all. I have a 3/4 ton Silverado that will hold two sets, and plan to put the third in a trailer behind.....I really think my truck would handle all 3, but don't want to push it.

    Anybody wanna buy a slightly used set of 8-L16 Dekas, less than a year old, only slightly discharged a few times ? You'll need something that can haul 8 x 113lbs each...... :D
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Absolyte batteries

    you might want to hang onto your old ones just long enough to be sure of the absolytes' condition for they may be diminished some on their capacity.
  • TnAndyTnAndy Solar Expert Posts: 249 ✭✭
    Re: Absolyte batteries

    Good point..................
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