Check out proposed Island system

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  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Check out proposed Island system

    I went back and checked the original calculations. They were based on 450 Amp hours of 12 Volt battery at a 10% peak charge current: 45 Amps @ 24 Volts = 1080 less 77% derating = 1400 Watt array. That should be sufficient for charging on its own without the hydro. If you wanted to depend on that more this array could go smaller. There's no sense in making it larger with that size battery. Having the back-up generator solves the issue of "what if" be providing a third source of charging and/or power just in case. Sounds like the dry spells won't be much of a problem either.

    The dealer's statement "a 30v panel gives you the best value." doesn't really make sense except that the KD235GX I sited is about 30 Vmp and a good value at $1.60 per Watt (at NAWS). You'll no doubt have to pay more there what with extra shipping and profiteering. Er, I mean profit. :p

    Just to be clear, we're looking at about 3.5 kW hours AC per day from that size array (based on 5 hours good sun and typical derating). If the panels do get hot production will go down. But with your hydro running 24/7 you probably won't have any trouble at all.
  • SurfpathSurfpath Solar Expert Posts: 391 ✭✭✭
    Re: Check out proposed Island system
    But with your hydro running 24/7 you probably won't have any trouble at all.

    Just an instinctive aside: I don't know if I will run the Hydro 24/7. It's a gut feeling. Maybe it's from having to stand in the corner from leaving the tap on as a child (or something like that).

    I'm also thinking of the portion of the stream below the source. I may be only using a small share of it, but I don't want to over use if I don't need to.

    Mainly, I dont want to worry about another "system" that has the potential of going wrong when I am not home or asleep.

    I am thinking of just 5 hours at night (6-11pm) while the solar is off. Hopefully I will get somewhere around 2kw/h total per day.

    No doubt this thought will evolve with time.

    OK batteries, I am thinking about the Surrette S600's or another similar 6v battery, such as the Trojan L16RE's (420amp hours). I have read the posts on both of these, and I might be tempted to go for the Trojans, even if they are slightly less amp hours.

    You mention your calculations were "based on 450 Amp hours of 12 Volt battery at a 10% peak charge current: 45 Amps @ 24 Volts = 1080 less 77% derating = 1400 Watt array...about 3.5kwh AC per day (based on good sun)". I'm happy with keeping it at that.

    Last, Does my individual battery size of 6v alter things? I dont think it would but just thought I'd check.
    Outback Flexpower 1 (FM80, VFX3048E-230v, Mate, FlexNetDC) 2,730watts of "Grid-type" PV, 370 AmpHrs Trojan RE-B's, Honda 2000 watt genny, 100% off grid.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Check out proposed Island system

    Larger capacity 6 Volt batteries in series are preferable to smaller capacity 12 Volt batteries in series & parallel:

    Four 420 Amp hour 6 Volts = 420 Amp hours @ 24 Volts
    Four 210 Amp hour 12 Volts = 420 Amp hours @ 24 Volts (if there is such a size)
    The difference? The 12 Volts need two string connected in parallel which introduces the current-sharing problem (although that can usually be handled on two strings). Plus one extra wire & connections to hook them up. The bigger the bank the more problematic parallel connections become.

    Generally a 12 Volt battery won't be more than 130 Amp hours so you'd need three or four parallel strings. Then you've got a lot of extra wires and connections, more cells to check, and bigger problems with current sharing.

    Or I could have just said "the 6 Volt batteries are a good idea." :p
  • nielniel Solar Expert Posts: 10,311 ✭✭✭✭
    Re: Check out proposed Island system

    just to mention there actually is a 12v battery around 210ah and it's the pvx2120l. along that same line there are some with about 255ah at 12v and are the pvx2580l. these are sunxtender agm batteries though.

    you should go with higher ah 6v batteries so that no paralleling of strings are needed, but it's not the end of the world to parallel another string as long as they are kept as electrically identical to each other as possible. ie. same wire gauge and lengths in each string.
  • waynefromnscanadawaynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: Check out proposed Island system
    Surfpath wrote: »
    Just an instinctive aside: I don't know if I will run the Hydro 24/7.

    Mainly, I don't want to worry about another "system" that has the potential of going wrong when I am not home or asleep.

    I am thinking of just 5 hours at night (6-11pm) while the solar is off. Hopefully I will get somewhere around 2kw/h total per day.

    No doubt this thought will evolve with time.

    Well the first year I was always concerned about something going wrong with my hydro, but eventually I began to take it for granted and no longer worry about it. I had actually built an alarm that would sound if the alternator output voltage dropped - - for ANY reason, including vandalism. Now I seldom activate the alarm. I do however, usually shut it down on sunny days to save wear and tear on the bearings etc, and to save lake water in times of drought, restarting it at sundown. So far I've had enough water to run it 24/7 during winter, when shutting it down could result in ice in the pipeline that could break loose and damage the turbine, or it it were to suddenly plug the nozzle, the resulting water hammer could burst the pipeline. As long as the water is moving, it doesn't freeze.
  • SurfpathSurfpath Solar Expert Posts: 391 ✭✭✭
    Re: Check out proposed Island system
    Well the first year I was always concerned about something going wrong with my hydro, but eventually I began to take it for granted and no longer worry about it.

    Wayne,
    Thanks for the reassurance and info. Ariz W & S is a great, active site. The learning curve has been flattened somewhat. Are there any hydro links or hydro specific forums that you or anyone else would recommend for small hydro installation and troubleshooting?
    Thanks,
    -Surfpath..
    Outback Flexpower 1 (FM80, VFX3048E-230v, Mate, FlexNetDC) 2,730watts of "Grid-type" PV, 370 AmpHrs Trojan RE-B's, Honda 2000 watt genny, 100% off grid.
  • stephendvstephendv Solar Expert Posts: 1,571 ✭✭
    Re: Check out proposed Island system

    There's a hydro section on this uk forum: http://www.navitron.org.uk/forum/index.php/board,11.0.html
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