Is it worth the risk to buy used batteries?

Hi. I'm building a system primarily for backup. I'm on the grid, but have been acquiring used parts to build a system. I've bought a panel setup with two SW5548's, disconnects, and have an Outback MX60 charge controller, and approx 1600 watts of panels at this time.

The gentleman who I'm getting the 5548's has a set of batteries also. 12 6v L16's, 18 months old. I've surfed and found prices for new ones about $320 each (shipping extra, which would be significant). So a new set would be at least $4500-$5000. In your real world experience, is it worth the risk of 1/2 price? I know the solar setup was at a cabin, so I have some hesitation about maintenance. ????

Comments

  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Is it worth the risk to buy used batteries?

    welcome,
    buying used is always a tough call. if you know the batteries to be good then, sure, buy them when the price is inline with a used set of batteries of a certain age and capacity. it is sometimes a good idea to shell out less money on a system starter set of batteries so if any mistakes are made that destroys the batteries or reduces the capacity of the batteries that you then won't be out as much cash. when not knowing the battery condition for sure it is a risk and it is a further risk if you don't know the guy selling them or if it is a, by parcel, sight unseen deal.
  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: Is it worth the risk to buy used batteries?

    I would definitely want to know their complete history. Proof that they're only 18 months old and why is he wanting rid of them etc. Just sounds fishy that if the batteries are as he says, he'd want to sell them. His explanation should be interesting.
    My L-16's are about 10 years old and look like new / could easily be presented as 18 months old.
    And: "the setup WAS at a cabin" - - so how long have the supposed 18 month old batteries been sitting around and possibly sulfating since they were taken from the cabin?
    Just call me suspicious :) .
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Is it worth the risk to buy used batteries?

    Just my opinion but ... used batteries are difficult to test to say the least. Fortunately with flooded types you can check the specific gravity on each cell and see if they're up to par and equal across all cells. You still won't know how they've been treated and if the plates have been stressed/exposed and are ready to drop dead tomorrow.

    Also, those SW inverters may be in much the same state. They haven't been made for a while now and getting repairs/parts is nearly impossible these days.

    So ask yourself "How much do I need this system?" and weigh that need against the price. If you really have to depend on it, don't buy used stuff. If you can live without the power should it go down and the price is within your budget, then maybe.

    On the whole I'm not keen on used equipment because it's so easy for it to appear to be good yet have little actual life left in it. Especially batteries.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Is it worth the risk to buy used batteries?

    Also, check on the Xantrex (Trace?) SW series inverter chargers. While most people have found them to be good units, they are fairly old by now and (I think) no longer have parts or service available... So, if something goes wrong, there is a good chance you will have to replace them with new (or other used) equipment.

    Pretty much, any electronics over 10 years old can be very difficult to get parts for (so much change in components like processors, memory, surface mount components, power electronics, custom power devices) and the new cheaper/better/faster inverters/charge controllers/etc. are cheaper than attempting repairs on the old stuff which may not last very long after the repairs anyway.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • jeffkruse
    jeffkruse Solar Expert Posts: 205 ✭✭✭
    Re: Is it worth the risk to buy used batteries?

    1/2 the price, no. What is the scrap value? 50$ each? I would pay $100 - $125 each at most.
  • ggunn
    ggunn Solar Expert Posts: 1,973 ✭✭✭
    Re: Is it worth the risk to buy used batteries?

    Look up "pig in a poke" and you will find a picture of a used battery. You have no way of knowing what you would be getting in terms of capacity and lifetime. At 5-10% of selling price it might be worth the risk, and buy lots so you'll have a reserve to pull from as they fail.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Is it worth the risk to buy used batteries?

    Also, check and see what you will "make" or what it will "cost" you to get rid of the old batteries... Some telecom lead acid batteries have cadmium in them which can make it very expensive for you to get rid of them (you are stuck with "toxic waste").

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • RCinFLA
    RCinFLA Solar Expert Posts: 1,484 ✭✭✭✭
    Re: Is it worth the risk to buy used batteries?

    Remember movie 'Forrest Gump'.
    Used battery is like a box of chocolates.

    After you buy the used batteries hopefully another quote won't apply.
    "Stupid is as stupid does"
  • tallgirl
    tallgirl Solar Expert Posts: 413 ✭✭
    Re: Is it worth the risk to buy used batteries?

    In addition to checking the specific gravity for each cell, check the color of the electrolyte. Then get a clamp-on battery load testing (they often look like a metal box with two jumper cable ends and a switch) and make sure they'll hold a load.

    If the electrolyte is reasonably clear to very light gray (some small amount of particulates), the specific gravity is uniform, =and= the batteries will hold loads, have at it.
  • techntrek
    techntrek Solar Expert Posts: 1,372 ✭✭✭
    Re: Is it worth the risk to buy used batteries?

    I agree on the load test. I would take voltage measurements at several locations, then load them up with those inverters (might as well test the inverters too), to at least 10% of their max discharge rate. Keep measuring the voltage to see how it holds up over 10-15 minutes.
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is