Mixed battery ages

zozomike Solar Expert Posts: 134 ✭✭✭
I have been reading the forums here and can only say I wish I had joined long ago. Smart folks here.
I have had, for 3 years a stand alone system 6 KY 130s/Outback MX 60 and 4 CR 225 batteries that did fine for the limited uses I had ( just a greenhouse and small tools) A lightning strike took out my Heart Interface 2000 and since I am breaking ground for a house on the property I upgraded to an Outback VFX3524, some 302 surge arrestors ( hard lessons) and wanted to double my storage. I will add more panels to the system when the house is done) Well I am mad at my own ignorance, (and that of the salesman) in adding 5 new CR 225 ( one of my 4 was weak) to the now 24v string.
Now I have learned that was a bad choice, and I should get 3 new batteries to replace the older ones in the string. So I need to figure a use for the older ones. I have a well, ( grundfos SQFlex with 2 Shell 125 panels and CU controller) which feeds 600 g storage, soon to add 3000g storage. Is there any advantage to adding batteries to the well? And if so how does one deal with freezing temps? The well setup BTW is 600' from the point of use.
Any ideas for use for the 3 year old Crowns?

Off grid, all solar, passive and active (winter wood heat supplements) PV DHW.

Array 1-- 12 Sunpower 250, Outback FM 100 3kw

Array 2-- 12 Sunpower 250, Outback FM 100 3kw

Well array 780w, 6 Kyocera 130 w with Grundfos sqflex 11 and cu200 to elevated storage, ( 2- 330 g tanks,) no battery storage at well

10 24 volt Battle Born Lithiums

Outback Flexpower Two, VFXR 3524A 7kw


  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Mixed battery ages
    zozomike wrote: »
    Any ideas for use for the 3 year old Crowns?

    warranty claim ?

    Fully charged batteries don't freeze till really really cold. about -40 or colder. That's easy to look up. Even 50% charged doesn't freeze till -20 ??
    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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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Mixed battery ages

    You might do a WAG calculation. If your older batteries have been lightly used, fully charge, perhaps just add new ones to increase the string and hope for the best. For example, the cost of 3 new batteries would be $X, amortized over the life of the string might be % of $X per per year.

    On the other hand, adding in the old ones to the string might shorten the life of those batteries by some number say $Y. Over the life of the string, you would have a annual cost of % of $Y per year. Question is, in the net/net which is cheaper? $X per year or $Y per year?

    The worst result will be a decrease in life of the new batteries in the string,, the only question is how much?


    I have been running a pair of L-16's and a pair of T-105s in a parallel string in light service for years. These were the remnants of larger strings. They have been holding their own for years, in admittedly light duty.