2gcb parallel x 4 =string 1, 2gcb x 4 =string 2, 4 L16s =string 3

assuming equal wire size and distance...
same ah, manufacturer, age, abuse...
interested in imho...
my 48v chinese puresine inverter is popped (x2), internal auto fuses blow upon connection. with no load. first one lasted a day the second two weeks. consolidating systems seems to be my only option, cannot afford another inverter or a good one.system runs large fridge, laptop, and lights. 2fmx 80s @80a should be plenty running a 24v exeltech xp1100 8 years young.how often will i be tearing down strings for individual eq of each batt? ive been getting ten+ out of my flooded banks and live in a cold wet coastal climate @39n
offgrid since 81


  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: 2gcb parallel x 4 =string 1, 2gcb x 4 =string 2, 4 L16s =string 3

    your biggest problem that i can see is that you aren't using the same battery throughout. this can be a problem unless you try to isolate the l16s from the other 2 battery banks. maybe use a heavy duty dc switch like the blue seas type.

    that said it is hard to guess if or when you would need to do an individual eq on your batteries. even identical batteries have differences that can determine how long compared to others that it would even last. some batteries even fail after a month or so and in light of that by comparrison making individual eq needs too unpredictable. best course is to do routine maintenance and observe voltage, sg, wires and connections, etc.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: 2gcb parallel x 4 =string 1, 2gcb x 4 =string 2, 4 L16s =string 3

    Sounds like a smorgasbord of flooded cells. So get a hydrometer and check the specific gravity of each and every one. Keep an eye on it monthly, make sure they're getting fully charged once a week, and EQ as needed. With the mismatched battery strings you can at least isolate one string for corrective charging when necessary. Don't mix the different battery types within a string for sure.

    Are you sure you need all those batteries? The two strings of GC2's would add up to 440 Amp hours @ 24 Volts or up to 5kW hours which is a pretty respectable amount of power. The string of L16's would add about 3.5kW hours and probably more problems than it's worth (uneven current sharing even with proper wiring, charge parameter incompatibility). It does not sound as though your loads are large enough to make it worth the hassle.
  • marineadvectionmarineadvection Registered Users Posts: 7
    Re: 2gcb parallel x 4 =string 1, 2gcb x 4 =string 2, 4 L16s =string 3

    thank you niel, those were pretty much my sentiments in a nutshell. Coot, you also r correct, lots of water matience with cleaning and tightening cabling to boot. i can do with just the 8 gcbs in series of 4 in two parallel strings @24v with the xp1100. ran this for ever, great for anything. problem is my fridge is NOW fullsize and takes 6.5a and starts at like 20ish. must Even in the winter months with low declination and poor weather including 10% pv for two weeks and low batt temps with no rts on either fmx80cc things can work. until another person (gf) is here to add loads. obiously these gcbs are run low even with their 232ah rating the total ah is only 464. so i got an old 36v 79 club car golf cart with 6 batts the same age also two more for drinking h20 assit pump... so over this 24v double string ...combined them to another string of 8 in golfcart, does good now ;) then i found these puresin48v chinese crap inverters for about 150$ but shipping from china was about the same...not worth trying to return? in the process of buildingthe 464ah 48v 16 gcb stringing with the cheapo inverter my old reliable 24v exeltechm xp1100 would be left homeless, except...i happen across 4 lc16s exactly the same age and condition and manufacturer on an system rebuild for a client. they are 464ah too:D i put them in series with the xp1100 and a an fmx80 and hooked my 18.1cf kenmore up. also running the sat for internet and at night a 42"lcd @2.5a and 10w sony bluray. also use a 600w coffee maker from walmart,smallest one i could find 110v.20min a day. figure i can now finally be able to run the fridge on all winter on the 24v sys with the 4 l16s and the 1100 and it will start no matter the weather... use the crap 48v inveter with the 16gcbs in two strings of eight. very very very nice, no more generators this winter im thinking and a working fridge and still healthy even cells with simple strings:D. then the crappy inverter crapped and then the second. now i cant tapp the 16gcbs and everything is now on the 4 l16s and the xp1100.works but wont this winter and the 48v sys with no inverter is not running down the 10-20% a night that batts love. so i turned the cc down a few and still have noticed an increase in h20 consumption:grr i wish i could afford a good 48v inverter. i hate to damage any lead. i feel the need to somehow discharge the 48v banks or combine with the 24v since the exeltech has never overloaded and disconnected i dont really need anything more than the 1100. i just wish it was a 48v or i had 4 more l16s or? i just need another 48v inverter or to fix one of the two bad ones, to keep systems seperate as planned...help...
  • vtmapsvtmaps Solar Expert Posts: 3,738 ✭✭✭✭
    Re: 2gcb parallel x 4 =string 1, 2gcb x 4 =string 2, 4 L16s =string 3

    Wow! I just looked up "Stream of Consciousness" on wikipedia. I think you're pretty good at it. --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: 2gcb parallel x 4 =string 1, 2gcb x 4 =string 2, 4 L16s =string 3

    I have to admit I don't know where we're at with this one now.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: 2gcb parallel x 4 =string 1, 2gcb x 4 =string 2, 4 L16s =string 3

    don't know what to tell you as for if the inverter is bad it needs replaced.

    you don't have to bring batteries down below 80% soc in a single day as it could go 2 days.

    much of what you wrote is a bit confusing and try not to throw it all out there compressed this much. you can also space out your thoughts to make it appear neater such as i've just done here.
  • marineadvectionmarineadvection Registered Users Posts: 7
    Re: 2gcb parallel x 4 =string 1, 2gcb x 4 =string 2, 4 L16s =string 3

    Thanks guys,

    Niel- i actually had a nicely organized explanation typed out twice!! the forum had "expired" by the time i finished editing, both times, lost it all.Hence the compressed, unedited version that was published as a result of having to rethink and explain the last six months three times, before it expired again...

    Wondering now if people really like buying gas or generators? around here it seems they do. I hate it. Winter is coming. I have been been using the honda 1&2k's for about three decades,yes they work but i dont understand anyone using them by choice, evolve. To me it seems like driving a 5 ton to the grocery store. Wondering if people actually live completely off grid or just set up a standalone system on their lawn and run a cord through the window when their gridpower fails?

    Coot-I have never had power and i have always had to do things as simply and efficiently as possible...have owned probably 6 honda eu1000&eu2000 before now, some before the e. hondas are the best, bar none. i just dont wanna play with gas or oil anymore! i have the batts need to use um...

    Standard diurnal marine fog and overcast conditions 12, yes 12, months out of the year. i have 130-160ft trees surrounding me on 4 sides, i log, they grow. my life is relatively low power. I get reallly frustrated when i start up those honda 2k's. i cannot afford the fuel or time, hate the smell, noise, and taste. so im wondering how anyone in this situation ever quits collecting alternative energy, ie; lead, modules, cc's, and inverters? The nearest town to buy food or gas is expensive and far away. Gasoline and food are cheaper in hawaii then here. i have a small farm with about 36 pigs and 25 chickens, i am literate and educated yet generally tired and poor. I live 100% lead dependent and have never had ability (batteries) to store more than 3kw in ah's until now...

    This is why i build multiple or larger systems to prolong cell life? Are their any opinions on which 48v inverter has lowest idle, best value and reliability? NAWS no longer sells the 48v exeltech...i am trying to sell my truck to get a new inverter...or i will combine batts and cc's.This is because i am worried about the 16 gc2's that have not been discharged ever in over two weeks. i cannot use them either. since the truck has not sold i have no money. seems the solution is money. without it i might be rewiring the gc2s as mentioned to be accomidated into the 24v system with the existing reliable inverter and monitoring them daily... thanks for helping
  • BB.BB. Super Moderators, Administrators Posts: 30,490 admin
    Re: 2gcb parallel x 4 =string 1, 2gcb x 4 =string 2, 4 L16s =string 3

    I think I figured out the "time out" issues (at least for me)...

    If I open a thread for a an hour or two, then hit reply, the timer (cookie) is based on the age of the open thread, not on when I hit "reply to post".

    At that point, no matter what you do, the post will not go through because the cookie it too old--Even if you hit "refresh" on the page, it does not refresh the cookie (at least for Firefox).

    If I have a thread open too long (I think), I copy my reply before I hit post... If I get a timeout, I go to the top of the page and hit the "Thread Link" to get a new page (and cookie), scroll to the bottom, then I can post just fine:

    Thread: 2gcb parallel x 4 =string 1, 2gcb x 4 =strinAg 2, 4 L16s =string 3

    Regarding other ExelTech inverters, from NAWS' website:

    We can also order all of the MX series. The XP series are also available in 32, 48, 66, and 108 volt DC input on special order - typically 2-3 weeks. Prices somewhat higher. We can special order any Exeltech product.

    Have you called NAWS and confirmed?

    What is your power usage like? Could you live with a 300 TSW inverter for most of your loads, and 1-2 kWH inverter for a few high power loads (coffee maker, etc.)?

    More or less, the lower power inverters are 12 volt or 24 volts... The higher voltage stuff (48 volt) seem to have higher losses--assuming that they are usually powering larger loads.

    If you have an Energy Star frost free refrigerator--You are pretty much looking at a 1.2-1.5 kW minimum AC inverter. You can still run from a 12 volt battery bank--But it is getting a bit tight (heavy 12 volt DC wiring, etc.).

    With frost free refrigerators, there is a timer that will defrost the fridge/freezer every 12-24 hours. And many of the new/fancy appliances have electronic timers which reset back to zero time (and defrost) if you have the inverter "sleep" when there are no AC loads (compressor pump shut down).

    Now for the interesting thing, there are still refrigerators/freezers that still use the cheap mechanical defrost timers (I found out, because my timer on my new Whirlpool freezer went bad after 5 months--may be a design problem from a few posts I found on the subject--Not sure about the life of the timer--May get the extended warranty because of this).

    Attachment not found.

    You may be able to have an inverter "sleep" with this type of timer (it may defrost once every 24 hours instead of once every 12 hours--may or may not be an issue for your home).

    AC inverters that can "sleep".

    Anyway, back to your loads--I always like to start there first (peak watts, average maximum watts, watts*hour per day, type of loads, etc.).

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: 2gcb parallel x 4 =string 1, 2gcb x 4 =string 2, 4 L16s =string 3

    I might be confused about which thread I'm answering as there are many people in the same situation just now!

    If the problem is dealing with bad charging days adding more battery capacity becomes counter-productive.

    What you want to do is have enough battery capacity to supply your average usage needs @ 25% DOD on any given day. Then the first step is to have enough charging capacity to recharge a a sunny day. If you have a lot of not-so-sunny days you need to be able to supplement or supplant that charging source. Usually the cheapest way to do this is with a generator. If you want to avoid a generator then you are going to have to plan an array capable of delivering full charging on cloudy days.

    The other option of upping the battery capacity until you have several days worth of storage will also require the increase in array size to recharge it once the sun does come out. So you're not much further ahead that way. In fact you can end up needing even more array and having money invested in batteries that do nothing much of the time.

    With a system that's already in place you can take readings about both power usage and available charging and make some calculations as to what will be to your best advantage. For example if you see your array current falls off to 1/2 that of a sunny day then doubling the array size should make up for that.

    Sometimes adding batteries is the right solution, but you can't do that without adding array (or other charge source) unless you already have an abundance. Ultimately you have to get the power you use out of the sun, so to speak, and all the batteries do is shift the time between harvest and use.
  • marineadvectionmarineadvection Registered Users Posts: 7
    Re: 2gcb parallel x 4 =string 1, 2gcb x 4 =string 2, 4 L16s =string 3

    thanks bb for clarifying cookie issue. will definately copy to clipboard more frequently.

    no i have not called naws. they used to list it but now its special order,im sure they can get it for more money like it says, probably be calling um soon...

    was using a 600w tsw on the 48v banks it was fine until it went kapooyah. a 300 tsw would be great. exeltech makes a 250 tsw in 48v but i think a 300 is a ideal. it will be my "recreational" system to power tv and lights, < 3amps 120vac.

    The existing 24v system runs a 18.1cf GE fridge off 4 L16's using the 24v xp1100. Flawless in my opinion. 1920w of monomodules on a fmx80 does well all winter. just want the other loads seperate for bad weather and voltage sag. even though it only probably takes 1.5 kw in summer and <1khw daily in the winter, i dont like to hurt my batts with additional loads... but i would like to use them. i understand the difference between my needs and wants and i consider lights and a 42"lcd borderline but necessary in the winter months with shorter days outside. i will be running these "optional" items off the 48v banks and the 42"tv is 2.5a 120vac and i have a couple cfl's, <50w. fmx80 is currently powering these two 48v strings of gc2's with 12 sharp 235. i have another 8 of the shasrp235 that are waiting for wire that will be going to the fmx80 also. these modules are all roof mounted SE @17 declination angle. so are the 30 sum 60w monocrystine modules that run the fridge. as you can see my modules could use a polemount for better winter gains but i try to compensate with extra modules and low power consumption. seems to work well. who wants to rack 50 modules? in the summer my panels dont light up till about 11am. In the winter the sun hits them at 8 but has shading till 10:30... I never recieve sun after 3:30pm winter or summer ...so its not my loads its my lack of consistant pv or potential energy...

    I need to read up on the fridges and their inside timer stuff, very interested.
    i wish i could get it to run on a little 15a 24v mppt system like everyone else with like 400w or less in modules...might free up some incoming pv for a heater on a timer or something for winter heating...
Sign In or Register to comment.