Discover EVL16A-A batteries?

rrroae
rrroae Solar Expert Posts: 46 ✭✭
Anyone ever use these or hear of them? 390 AmpH at 6 volt AGM batteries.


http://www.discover-energy.com/files/datasheets/EVL16A-A.pdf


I can get 4 from a local dealer for $2100 which includes taxes and shipping to my home. Will run 4 in series for 24 volt system. My other choice is 4 Sun Xtender PVX-2120L AGM 212 amp 12 volt batteries that would cost around $1800+ shipping and I would run the 2 in series parallel.

Comments

  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Discover EVL16A-A batteries?

    they sound like an interesting and good battery, but you may have the better deal powerwise with the sunxtenders. i was trying to weigh in on the warranty for the discover batteries and you almost need to be an attorney to figure it out. i think it's too much smoke and mirrors to cover their butts with.
    http://www.discover-energy.com/files/shared/Discover_warranty_updated_nov_2008.pdf
    i'd go with the known sunxtender, but i'm prejudiced because i have one.:roll:
  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    Re: Discover EVL16A-A batteries?

    Having a single string saves easily the 300 dollar difference, its expensive in connectors, wiring and over current protection, so while the 1800 looks like less, go add up what it costs to have two instead of a single string of battery's. I would select the single sting.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,433 admin
    Re: Discover EVL16A-A batteries?

    Just from a price view...

    I really like single strings.

    They are easier to diagnose (just put a DMM across each connection point/cell/cable/etc. when the system is under heavy load (or charging)--an you can immediately find any weak cell/connection.

    Also, when you add up the extra hardware (fuse/breaker, cable, holder/box) to manage a 100-200 amps--the extra costs to protect paralleled strings starts to add up. Each parallel string should have its own fuse/breaker -- as well as a breaker/fuse/switch for the paralleled bank (if needed).

    Note; I have seen many more installations (the few that I have seen/paid attention to) without a fuse per parallel string vs those that have fuse/breaker per string. And, probably 98% of the people/installation will never have a problem (how often has a breaker tripped in your home because of a short/appliance failure?).

    However, with the kinds of currents/energy available from these big lead acid storage batteries and banks of same--I would suggest that you treat these with even more respect with respect to your utility feeds. The amount of current/energy available from a dead short is astounding (from the little I have seen). And the chances that hydrogen gas explosion, spraying of sulfuric acid, and possible electrical fires--I would humbly suggest that this not one area to save money on (get cheaper batteries, few batteries, etc. if you need to conserve).

    One string, you only need one fuse/breaker for the entire bank.

    I can understand a desire for two parallel strings for a remote area (can isolate a string/cell if bad--but still run the home from the "good" string)... Many times, the installation with twice (or more) as many parts will fail twice (or more) as often--sort of the downfall of redundancy.

    Also, with redundancy, 1/2 the work is trying to reliably crate a "fool proof" method/configuration to identify when one of the redundant elements fail.

    Say you have two parallel 12 volt batteries, sealed AGM's, with no access to the internal cell bus bars (can measure single cell voltage/status). If you have one open cell--it is very difficult to notice that the cell is open unless you notice that the bank voltage falls more with equal discharge...

    The only way to isolate a week/failed cell is to use a DC clamp meter (or I use a DMM set on mVolt scale) and under load see how much current flows to each battery (or with DMM, measure the voltage drop on two identical cables between the two "strings"--if one has "higher" voltage drop than the other, then one string is taking/supplying more current than the other--and you need to investigate why--could be a corroded cable causing high voltage drop too).

    And, as you add more parallel strings (3, 4, 8, etc.)--the ability to "see" the performance drop of an individual string is more and more difficult (2 strings, one fails, 1/2 the capacity--8 stings, one fails, 12.5% capacity lost; very difficult to "see").

    Is the "Discover" battery the same quality/performance as the other brand? I don't know.

    Is it worth $300 more to have one string? My guess is by the time you add the extra hardware for a second parallel strings--the cost differences ($45 for a fuse+holder; $280 for a breaker+box; $10-$20 for extra jumper cable; per string) will be much less. And the reliability (of equal quality batteries) will probably be better--and easier to diagnose and address failures quickly.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • rrroae
    rrroae Solar Expert Posts: 46 ✭✭
    Re: Discover EVL16A-A batteries?

    Decided to go with the Sunextenders. Known batteries and I know NAWS stands behind what they sell.


    Hopefully I'll be ready to place my order for my system upgrade tomorrow.


    Wanted to thank all the good people here who so selflessly give their time and expert advice.