Working Thread for Solar Beginner Post/FAQ



  • BB.BB. Posts: 27,776Super Moderators admin
    Re: Working Thread for Solar Beginner Post/FAQ

    Some threads about Lithium and other rechargeable battery chemistries:

    Pros & Cons of Lithium-ion batteries for solar application

    Charge Controller for LiFePO4 Batteries
    Compare Nickel-Iron Edison Batteries and Chinese Ni-Fe Cells
    New Lithium Ion battery for us?
    Lithium Phosphate Batteries
    Would you consider a Lithium Ion battery?
    Lithium-Ion charging with solarpanel

    As always, you can use Google Search on the forum by using the "" tag to limit searches to our forum:
    • Lithium


    PS: add on 6/22/2014--And leave in the warning that there are many different Li-Ion chemistries out there--And using the wrong charging algorithms/voltages can destroy your battery pack (or worse):
    PNjunction wrote: »
    Wow - no offense, but this is pivotal and I have to use all caps:


    Once again, I'll point out a great REAL-WORLD thread that describes in great detail how to do it with the chemistry we ARE using:

    I can see that this has quickly devolved into a technical p*ssing match between real-world hands on, vs someone who doesn't actually own a bank of his own. Until you have one, all we'll end up doing is throwing links at each other, which does lurkers no good.

    It is for this very reason, that most real-world users try to avoid armchair-engineering squabbles and eventually go silent. Although that might be to the relief of the crowd. :)
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BB.BB. Posts: 27,776Super Moderators admin
    edited January 15 #63
    Re: Working Thread for Solar Beginner Post/FAQ

    We have a fair number or requests about repairing older Xantrex (and others) AC inverters. Here is (or are) some options:
    offgrid me wrote: »
    For anybody that has a problem with an older Trace SW/SW+ or DR-series, contact this guy using his web form on his site:

    He'll get it working again.
    I think this is the one


    PS: As of 10/10/2013:
    Below is a list of companies that can repair the old Trace inverters.

    I suggest Sunpumps.


    -Sunpumps (Rod)

    -Tekris (Brian)

    -RVMD (Steve)

    Old black trace inverters
    Craig Wilburn

    David Lauzon
    Northern Arizona Wind and Sun

    Link to post where you may find updates to list:

    Where to repair old Trace/Xantrex Inverters...

    PPS: 1/5/2013:
    Here are the parts you need, only you know if they are cost effective.

    The problem is buying components is you don't know what the problem is and if one thing went bad what else did it take out. You buy it on a one way trip, if it's doesn't work you eat the cost. I'll take a new one with a warranty and sleep better.

    4/15/2014 (some people that make repairs--PM them for further information--For information only):
    I repair/refurbish SMA Grid tie inverters. I offer a 6 month warranty on all repaired inverters. And i offer a 1 year warranty for a additional $50

    Most repairs cost from $200-$600.


    jclothi wrote: »
    Ray D:
    How did your situation work out, regarding the failed swr 2500? Did you find a repair service?
    If not, I can help you. I am retired but I will help people (only) that are financially squeezed (and screwed by sma!) and simply will be unable to get back on line, otherwise. Why cant they understand that there is good will to be had in providing support? Anyone with your experience may be expected to never buy another sma product, huh!
    jclothi -at-

    Compuhans wrote: »
    I have been repairing various solar inverters for people who had a inverter go bad that is out of warranty, usually they can be restored to where years of life are added to the unit.
    I fix Sunnyboy 1800 2100 2500 3000 4000, Xantrex , Power One Aurora and PV powered ( and likely others if they came across my workbench)
    Only in case of catastrophic burnout do I tell them to throw them out.

    1/15/2018--Dean posted in another thread that he repairs inverters too:
    SolarWizard said
    Contact Dean at for SW & SW+ repair and testing, Oldest Trace repair center in the NW.
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • nielniel Posts: 10,311Solar Expert ✭✭✭✭
    Re: Working Thread for Solar Beginner Post/FAQ

    of course this is not an endorsement or recommendation of anybodies service as naws and ourselves as moderators for naws are not of 1st hand knowledge of anyone and we are not in that aspect of the business as far as i know so this is a disclaimer.
  • BB.BB. Posts: 27,776Super Moderators admin
    Re: Working Thread for Solar Beginner Post/FAQ

    Some early 1960's videos that Verdigo found:
    verdigo wrote: »
    I found these old DOD videos on YouTube . I'm pretty sure I seen these in my Army days, and thought they might be useful for some here. [How AC Generators and Motors Work] [How DC Generators Work]

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BB.BB. Posts: 27,776Super Moderators admin
    Re: Working Thread for Solar Beginner Post/FAQ

    Poster Les Nagy has a thread suggesting various volt meters:

    Which mulitmeter? My opinion for those looking for something reliable

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • PNjunctionPNjunction Posts: 762Solar Expert ✭✭✭
    Re: Working Thread for Solar Beginner Post/FAQ

    LiFePo4 warning for beginners!

    Unless you are extremely astute or have prior experience, I would NOT generally recommend a beginner immediately go with lifepo4 - you have enough going on already with other factors to fill your head.

    The biggest issue in order not to absolutely blow your solar budget right off the bat, is not knowing your power needs FIRST. If you don't, you may end up with a totally inappropriately sized lifepo4 battery, or worse yet, be tempted to buy lower priced CRAP. Please don't do that. I would much rather have a total beginner spend their budget properly on a lead-based system, and then graduate to lifepo4 when / if they are ready.

    It is for this reason that we suggest beginners start with lower-priced, yet still somewhat quality lead-acid batteries as a "learner" bank. I think it would be irresponsible to recommend something like a Rolls-Surrette to an absolute beginner who may not be up to the task of proper maintenance, and likewise, suggest a jump into lifepo4 without having the background in figuring out your power needs, solar insolation, and other hardware infrastructure matching first.

    Up-front costs of lifepo4 are high, and making a mistake here can leave you stranded with a battery with nowhere to go, and possibly nobody who wants to buy one used from you.

    I love lifepo4, but I'm just trying to keep it real.
  • BB.BB. Posts: 27,776Super Moderators admin
    Some more Lead Acid Battery answers from an older 2012 thread:

    "Equalization" is "over charging" a battery (or some cells in a battery) to bring "low specific gravity" cells back up to their maximum SG (hopefully, SG between high and low cell is less than 0.030 or 0.015 s.g.).

    Normally that is done when a battery is already at "full charge" and you are overcharging the fully charged cells to bring up any low cells. Then equalization should end.

    By the way, how often do you need to refill the cells? More or less, ~2 months is "good"... More often, may be over charging. Much less often, may be under charging (although, the Trojan RE batteries have been reported by one or two posters here as using significantly less water than their non-RE Trojans).

    At this point, deep cycling (to ~50% or so State of Charge, as suggested by Vic) to try and knock/converter any sulfation that may be covering the plates is probably your best bet. It may take 10-20 cycles before you see full improvement (if any).

    As Windsun asked, did the batteries sit for months without any charging? That will cause sulfation to form "before its time".

    Where the batteries stored at high temperatures? Typically, every 10C/18F over ~25C/77F causes batteries to age by a factor of 2x (36F over 77F, would be 2*2=4x faster). Also "hot batteries" have faster self discharge.

    I ran across this page on why different types of batteries have different starting s.g. fills... Is pretty interesting:
    Specific Gravity vs Applications
    1.285 Heavily cycled batteries such as for forklifts (traction).
    1.260 Automotive (SLI)
    1.250 UPS – Standby with high momentary discharge current requirement.
    1.215 Geral applications such as power utility and telephone.

    As mentioned earlier, the specific gravity (spgr.) of a fully charged industrial battery, or traction battery, is generally 1.285, depending on the manufacturer and type. Some manufacturers use specific gravities as high as 1.320 in an attempt to gain additional Ah capacity, but at the cost of a shorter cycle life.


    Higher Gravity = vs Lower Gravity =
    More capacity / Less capacity
    Shorter life / Longer life
    Higher momentary discharge rates / Lower momentary discharge rates
    Less adaptable to "floating: operation / More adaptable to "floating" operation
    More standing loss / Less standing loss

    At 77F, the equation that relates S.G. to battery cell voltage is:
    Specific gravity = single-cell open-circuit voltage - 0.845 (example: 2.13v – 0.845 = 1.285)
    Single-cell open circuit voltage = specific gravity + 0.845.

    Or, for your bank:

    Battery "resting voltage" = 6 cells x (1.245+0.845) = 12.54 volts

    So, your resting voltage seems to relate to the S.G. pretty closely (assuming battery bank is around ~77F).

    At this point, it sure sounds like your batteries are sulfated (low S.G.) and, at this time, there are no "accepted" methods to convert hardened (crystallized) Lead Sulfate back to Lead + free sulfur (back to acid).

    Cycling the battery bank (shed material and leave fresh lead exposed) is one solution (by the way, over charging/equalization generates O2 which can corrode the Positive Plate Frame and oxidize the lead (from what little I understand), it is possible to cycle discharge/recharge to drive the Oxygen from the lead plate (but not the frame).

    There are "Desulfators" and people that love them or hate them (a couple such conversations here have resulted in, rare for us, locked/deleted threads). On the positive side, a desufator should not damage a battery bank (that is, otherwise, kept properly charged). On the down side, a poster here has seen a desulfator confuse his Outback MPPT charge controller and dramatically reduce the charge controller's battery charging current.

    And lastly, there are the magic battery additives. Some contain Cadmium (which is a heavy metal that can cause battery recyclers to charge you to dispose of a battery bank)--And has some validity for use with Lead Acid battery chemistry. Epsom Salt variants and even oils -- Which appear to have less validity.

    Not many folks here will tell you to try desulfators/additives... But there are the occasional (apparently) positive results. confused

    Perhaps some others here with much more battery experience/knowledge than I--Can give you some better guidance.


    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BB.BB. Posts: 27,776Super Moderators admin
    This link is a "Generator" link--But it explains pretty much all you need to know about about basic AC power systems, pure sine wave, modified square wave, etc.:

    Thank you Mike for bringing this site up again:
    mike95490 said:
    The lighting & grip website has been revamped, but I found the generator page.  It's basically talking about cheap inverter generators having square and mod sine output, and that even PSW inverter and conventional generators, seeing strangely reactive loads instead of "old style" restive loads, are unable to provide sine waves and the loading distorts the waveform (much as I have experienced with my new small robin/subaru/hatz genset)  it's very interesting and should be required reading. Wave Generators


    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BB.BB. Posts: 27,776Super Moderators admin
    An older thread about why we suggest matching Solar panel Vmp ratings within 5-10% for parallel connections, and Imp to within 5-10% for series connections:

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BB.BB. Posts: 27,776Super Moderators admin
    Here is a nice discussion about how to pick the proper fuse(s) and circuit breaker(s) for your DC power system:

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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