Power outages - What is the bare essentials? RSM 250

Discussion in 'Power cuts' started by Bendor, 10 Dec 2012.

  1. Bendor

    Bendor

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    I have a new RSM 250 that's busy with it's cycle and I'm trying to get everything ready for it's first inmates.

    I have bought a 6.5 kVa generator that provides 27.5 Amps which I will have connected to the house by a qualified electrician. This is supposed to support the whole house and tank with large appliances and lights off (geyser, stove, microwave).

    Inverter backup: I got a bit of a shock. a 1000W pure sine wave inverter that connects to 12V batteries, automatic start, charges batteries when power is on for R3087. Add to that deep cycle 102 ah batteries at R1600 each totals a minimum of around R4700.

    I would like to only get 1 battery which means I have to run as little as possible in my tank. So what is the minimum I must run?

    The return on the left side of the tank which also goes through any media and the largest macro sponge filter is a 2400lt/hr Sicce pump at 40 Amps.

    Is it ok to run no lights, no chiller (PMB can get quite hot), no heater, no ATO and no other pumps?
     
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  3. Bendor

    Bendor Thread Starter

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    My maths might not be to bad but my electricity really sucks!

    Inverter running off 12V deep cycle 102 ah battery.

    40W pump: 40W at 12V = 3.34 Amps which allows for 30 hrs standby on this battery???

    or

    40W at 240V = 0.17 Amps whick allows for 600 hrs?

    or

    0.3 Amps according to spec sheet by Sicce allows for 340 hrs?

    All of the above seem to good to be true.
     
  4. RiaanP

    RiaanP Moderator

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    a battery driven airpump.

    well, you asked for the bare essential. That's it.
     
  5. Express Reef

    Express Reef

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    Will say put the return pump on only
     
  6. carlosdeandrade

    carlosdeandrade

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  7. Bendor

    Bendor Thread Starter

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    I suppose I did :)

    But it has to be part of the system that is running already as I would be away and the inverter would kick in automatically when the power shuts down.
     
    Last edited: 10 Dec 2012
  8. mariusmeyer

    mariusmeyer

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    Your first calculation is the closest. Although it will be less hours than that since you need to take the efficiency of the inverter into account. But it should not drop to less than say 25hours
     
  9. Bendor

    Bendor Thread Starter

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    Like the youngens say: "That is awesome!" :yeahdude:

    Thanks

    (If my tank doesn't overheat or underfreeze from ambient temps.
     
  10. mariusmeyer

    mariusmeyer

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    You can get 102AH batteries from current automation in DBN for around R1100. Which inverter was that quote for?
     
  11. Bendor

    Bendor Thread Starter

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    From ACDC. 1000W, automatic start, charges battery, pure sine wave.
     
  12. Bendor

    Bendor Thread Starter

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    Also got a quote from Battery Power in Umbilo road for R990 for a 105 ah battery. @WarrenElvis put me onto them.
     
    Last edited by a moderator: 26 Nov 2015
  13. chikaboo

    chikaboo

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    BTW .... The pricing you got on pure sine wave and batteries sre a bargain. ... I would also say main return pump ... If temp start to drop too low use blankets around the tank .... Temp too high .. Use 2 litre frozen bottles floating in water and not to forget ... Battery air pump although this can be compensated by picking water up and dropping back into tank yo aerate it
     
  14. Wes

    Wes

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    I've found that all you need is a power head at the correct height in the DT once the power goes off, your water level in DT drops, if the powerhead is at the correct height it should be just below the water level to allow it to suck a little air in on occassion by starting a vortex swirl, hence you keep the flow going as well as sufficient air being mixed with the water, and trust me the shlurping noise is enough to wake you up if nothing else does. on the plus side as well, powerhead/blower pumps are around 12W, so you're safe for a lon g time... just some personal experience.
     
    Last edited: 10 Dec 2012
  15. Bendor

    Bendor Thread Starter

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    That's good to hear about the pricing. If I get the battery for R990 then I'll come away at about R4000. I'm starting to doubt if I needed the genie if the inverter can run a 40W pump for 20+ hours. Won't tell my wife that though. :whistling:
     
  16. Bendor

    Bendor Thread Starter

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    Thanks everyone. Seems like main return only by majority vote. That also means I only need one battery.
     
    Last edited: 10 Dec 2012
  17. Bendor

    Bendor Thread Starter

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    Size of inverter

    If I only run the 40W pump which is rated at 0.3 Amps.
    Can I get a 150W inverter with a peak power rating of 300W? To me that appears to be enough but the force is not strong with my electricity.

    So according to @mariusmeyer battery life is 40W divided by 12V (for the 12V battery) equalling 3.34 Amps and therefore 20 to 25hrs on a 102 ah battery. (102 divided by 3.34 = 30 hours minus running costs to efficiency)

    But

    The pump is rated for 0.3 amps which means the 150W inverter running at 0.6 amps should be able to power it easily.

    I can up the scale to a 300W (peak 600W) inverter running at 1.5 Amps if the above is totally inadequate.

    I know this is really only interesting to me at this very moment but any input would be appreciated.:peroni::peroni::peroni:

    @mariusmeyer
    @RiaanP
    @chikaboo
    @WarrenElvis
     
    Last edited by a moderator: 26 Nov 2015
  18. mariusmeyer

    mariusmeyer

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    The only issue with smaller inverters are that they tend not to come with built in chargers or transfer switch. But if you can find one that does then there is no reason to go bigger. I would go for a 600W but thats my personal preference.
     
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  19. Bendor

    Bendor Thread Starter

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    That's a good point. Thanks mariusmeyer.
     
  20. Bendor

    Bendor Thread Starter

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    Bugger. The smallest inverter from acdc with charging is 600w.
     
  21. WarrenElvis

    WarrenElvis

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    Just remember although the calculation is correct this is based on discharging the battery completely. It is normally recommended to use up to 80% of the battery capacity in order to prolong the life of the battery. Also depends on the battery as you can buy cheaper but not great quality best to check with the supplier.
    An 80% efficient inverter will use 40 / 0.8 = 50W to produce 40W. So the power required from the battery is 50W.

    The electrical formula for power is:
    Power = Amps X Voltage
    So Amps = Power / Voltage

    A 12 volt battery will use 50W / 12 = 4,167 amps to produce 50 watts.
    A deep cycle battery has a capacity of 102 Ah. Remember that one should not aim to discharge the battery more than 80%. So would say there is only +/-81,6Ah available. So that battery would supply 4,167 amps for 81,6 / 4,167 = 19,58 hrs. So for the length of time you want maybe best for you to get 2 batteries just to be on the safe side.
    I have on one occasion completely discharged my battery not on purpose as it was early hours of the morning and did not realize the plug circuit the tank was on was down, but i try not too, and as far as inverter, stick with the 600w as being you minimum but should have a built in charger.
    Hope you come right mate
     
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