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Author Topic: Water Filtration and pumping  (Read 7818 times)
heatherhopper
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« Reply #30 on: February 24, 2016, 10:27:20 AM »

Apologies if I didn't express the bank configuration precisely enough.
Paul is correct - Four 6v 576ah Rolls 6CS Batteries in series forming a 567ah bank @ 24v.

Quote
24v x 576ah would be 13.824 kWh
That is right but perhaps it would be more accurate to add "approx 6-7kWh useable" at the end.

I do not operate the bank below 50% as a rule - anything less is flirting with voltage dips below 24v. The Inverter will call for generator support if voltage registers at about 23.4 for a defined period (I cant' recall the exact numbers) regardless of actual SOC or generator trigger auto start settings. I prefer manual intervention before this point which means I am sometimes running the generator at night simply in anticipation of a possible low voltage situation in the morning triggered mostly by the water pump.

Batteries are in good condition before anyone asks the obvious!
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Off grid AC coupled, 6kW Proven, 2.8kW PV, SMA SI/SB/WB Inverters, 4x576ah Rolls batteries @ 24v, 25kW Biomass Boiler, Wood Stoves, Spring/Well water. Sorry planet - I did try.
Justme
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« Reply #31 on: February 24, 2016, 09:13:25 PM »

Apologies if I didn't express the bank configuration precisely enough.
Paul is correct - Four 6v 576ah Rolls 6CS Batteries in series forming a 567ah bank @ 24v.

Quote
24v x 576ah would be 13.824 kWh
That is right but perhaps it would be more accurate to add "approx 6-7kWh useable" at the end.

I do not operate the bank below 50% as a rule - anything less is flirting with voltage dips below 24v. The Inverter will call for generator support if voltage registers at about 23.4 for a defined period (I cant' recall the exact numbers) regardless of actual SOC or generator trigger auto start settings. I prefer manual intervention before this point which means I am sometimes running the generator at night simply in anticipation of a possible low voltage situation in the morning triggered mostly by the water pump.

Batteries are in good condition before anyone asks the obvious!


I do know the usable amount, been living off grid for over 6 years.

So your bank is not small as you mentioned.

The voltage under a large load going below 24 is not an issue.

Unless the voltage is dropping lots with a small load which is an indication of a duff battery.

I doubt even a heavy water user/family could use 0.5kWh of energy pumping water internally each day.

Why run genny at night in anticipation of needing it in the morning?
If its needed then run it at the time its needed.
Direct use is always best.

I can auto start my genny via:-

Soc
wattage being used
voltage instant
voltage for X time period

I only use Soc & wattage. The others are set but it would be rare for them to be triggered.

In winter I use 60% soc & a lower wattage. In summer 50% & a high wattage.

The reason being that in winter the cold slows the reaction so less is available & as the solar make less to nothing there is no point not using the power direct from the genny with no conversion losses, hoping that the solar will replace it the next day.

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Navitron solar thermal system
30 x 58mm panel 259L TS
1200watts solar 120vdc
FX80 Solar controller
Victron 12v 3000w 120a
6kva genny
6 x 2v cells 1550amp/h 5C
24 x 2v cells 700amp/h 5C
Total bank 4350 amp/h 5C
camillitech
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« Reply #32 on: February 24, 2016, 11:50:54 PM »






I do know the usable amount, been living off grid for over 6 years.




Methinks you've been living 'off grid' much longer than that Justme, you joined here in 2008 and you weren't a novice then  Grin How time flies when you're having fun hey.
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http://lifeattheendoftheroad.wordpress.com/

'Off grid' since 1985,  Proven 2.5kW, Proven 6kW direct heating, SI6.OH, 800ah Rolls, 4.75kW PV ,4xTS45, Lister HR2 12kW, , Powerspout pelton, Stream Engine turgo, 60 x Navitron toobs and a 1500lt store. Outback VFX3048 and 950ah forklifts for backup,
heatherhopper
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« Reply #33 on: February 25, 2016, 11:58:37 PM »

Quote
I do know the usable amount, been living off grid for over 6 years.
Sorry Justme - I wasn't questioning your knowledge, just trying to confirm my own.

Quote
So your bank is not small as you mentioned.
Depends on what criteria you are judging by. I consider it to be on the small size for it's intended purpose and way less than the often recommended several tonnes.


Quote
The voltage under a large load going below 24 is not an issue.
Refreshing to hear an experienced voice make a such a statement and I agree - to a point. Doesn't fit with much of the waffle you do hear about maintaining battery voltage though. How low and for how long is I suppose the critical bit. I would be very happy to hear more about this but any changes to low voltage trips need to match all circumstances - this is after all battery preservation territory. Can't think how this setting is accessed on the SI either.

Quote
Unless the voltage is dropping lots with a small load which is an indication of a duff battery.
No sign of this and as I said Battery is in good condition (standard checks done periodically).

Quote
Why run genny at night in anticipation of needing it in the morning?
If its needed then run it at the time its needed.
Direct use is always best.
Sort of disagree here. Direct use is certainly best which is why I usually run at night (perhaps evening would be a better description as this is exclusively somewhere between 19:00 and 22:00). This is the highest usage period and with no Solar (outside summer months). Knowingly allowing the battery to run down and the generator to auto start when the other half is brushing her teeth and flushing the loo in the morning does not make sense to me. Particularly since Solar generation is just about to wake up and is then likely to have to be diverted. Also have potential wind addition to factor in - there are no operating regimes that can match a simple weather forecast for deciding best time to run the generator.

Quote
I can auto start my genny via:-

Soc
wattage being used
voltage instant
voltage for X time period

I only use Soc & wattage. The others are set but it would be rare for them to be triggered.

In winter I use 60% soc & a lower wattage. In summer 50% & a high wattage.

The reason being that in winter the cold slows the reaction so less is available & as the solar make less to nothing there is no point not using the power direct from the genny with no conversion losses, hoping that the solar will replace it the next day.
Yup have all the same potential triggers and it is the Voltage for x time which is the issue - but only with respect to the s*****g water pump. SOC is the main operator. Wattage being used is almost never a trigger - if we are drawing from the battery no high loads are ever started - except, of course, the water pump. I used to operate different summer and winter regimes but have got lazy and rarely remember to make the change. With the Turbine the difference in summer and winter and day and night is not really so clear cut anyway although I am very conscious of the lower battery performance due to temperature.

Have rather strayed from the original topic here. Since we only run the generator 20-30 times a year in total it just irritates me that probably a third of those are prompted by water pump voltage dips and I was looking for a convenient solution other than having the generator on when not needed for any other reason.
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Off grid AC coupled, 6kW Proven, 2.8kW PV, SMA SI/SB/WB Inverters, 4x576ah Rolls batteries @ 24v, 25kW Biomass Boiler, Wood Stoves, Spring/Well water. Sorry planet - I did try.
Justme
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« Reply #34 on: February 26, 2016, 07:05:40 PM »

Bank size relative to load is the yard stick I was using.

Re voltage under load the problem with any setting is that it cant really distinguish between a low V due to a high load or a low v due to a flat bat.

Most inverters have cut off setting of around 10.5v with a sensibly sized system it should not ever see that voltage even under full load.

So I would not worry if I saw 11v if I was pulling 3kW (well not a normal bank, on mine I might as its big enough to hold its voltage better than that), however if I saw 12v with little or no load then I would be concerned.

Is your pump capacitor start?

You can get soft start controllers that you can add that would reduce the start up current.

If evenings are your peak usage then that is the time to run the genny.

With just 30 runs per year I would not worry to much. In winter we have multiple runs per day.

Using a 24v pump will draw the same current from the battery still possibly triggering the genny run.

Try altering the settings just enough to stop the problem.

Oh I also forgot the time clock that wont allow our genny to start during unsocial hours.

What about fitting a header tank so you can pump a full tank in one go?
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Navitron solar thermal system
30 x 58mm panel 259L TS
1200watts solar 120vdc
FX80 Solar controller
Victron 12v 3000w 120a
6kva genny
6 x 2v cells 1550amp/h 5C
24 x 2v cells 700amp/h 5C
Total bank 4350 amp/h 5C
Justme
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« Reply #35 on: February 26, 2016, 07:07:29 PM »


I do know the usable amount, been living off grid for over 6 years.


Methinks you've been living 'off grid' much longer than that Justme, you joined here in 2008 and you weren't a novice then  Grin How time flies when you're having fun hey.


Oh er lol.

I think I stopped counting at 6.

Been in the current place for that long & spent a while in a caravan first whilst building it.
Logged

Navitron solar thermal system
30 x 58mm panel 259L TS
1200watts solar 120vdc
FX80 Solar controller
Victron 12v 3000w 120a
6kva genny
6 x 2v cells 1550amp/h 5C
24 x 2v cells 700amp/h 5C
Total bank 4350 amp/h 5C
heatherhopper
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« Reply #36 on: March 02, 2016, 10:41:01 AM »

Thanks Justme - couple of things to think about.
Pump start up current is not the problem - it is running current for excess time.
I could restrict Generator start times but this might get a little over-complicated in practice.
I could re-instate house tanks but then lose pressure delivery at the outlets and the system was designed to keep everything except pipework in the outbuildings.
Fiddling with the settings is easiest and least intrusive so I will start there.
Meantime still browsing for a second pump.
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Off grid AC coupled, 6kW Proven, 2.8kW PV, SMA SI/SB/WB Inverters, 4x576ah Rolls batteries @ 24v, 25kW Biomass Boiler, Wood Stoves, Spring/Well water. Sorry planet - I did try.
martin W
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what do you mean my snoring is too loud!


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« Reply #37 on: March 04, 2016, 10:33:10 PM »

Thinking sideways here...

I'm not sure how much water storage you have now as typing this on a tablet and its a pita to look back through the posts....

But

Can you store enough water in your vessels to cover evening usage, and manually/timer run the water pump to top pressure / storage up during daylight? Would this help battery volts?

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Solar Water Heating since 17th March 2009, 2.94kW PV since Dec 2011
Chicken Owner - Self sufficient in chicken c*@p, boy watch those tomatoes grow. Allotment owner since August 2011
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rogeriko
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« Reply #38 on: March 05, 2016, 03:16:48 PM »

Try using an old central heating pump. they are only 30/50 watts but will pump 2 tons an hour. Dont expect high pressure but you probably dont need it. I used to have a 250 watt pump in my house and it was plenty to lift water from the tank under the house and up 2 floors. The pump is probably using 600w just to spin and only 100w to move water, grossly overspecd. A central heating pump will definately give you more pressure than just a tank in the attic, they are just under 1 bar  thats equivalent to having your header tank 3 floors up!!
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heatherhopper
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« Reply #39 on: March 06, 2016, 11:13:11 AM »

martin W - I have sufficient storage for many days but the delivery system is pressurised so all pumping is after storage. I took the decision to go for a pressurised system perhaps against "best practice" for an off-grid set-up but it has advantages and works fine apart from this one very small anomaly. I do have the option of reverting to a gravity flow, vented system but would be prefer not to for many reasons.

rogeriko - I assume you mean a separate pressure switch controlled pump (current pump pressure control is integral)? This is certainly an option and I do have a suitable spare. Just not sure I want to go back to low pressure and I would need a back-up high pressure pump for maintenance of the Boiler system anyway. I might look at messing around with this in parallel for a while.

Attached is the battery data for a typical instance of the "problem". This follows several days of zero wind and typical February PV (insufficient sustained output to raise the bank voltage to bulk charge settings). I would normally have run the generator the night before for about an hour just to prevent this generator morning start but deliberately didn't on this occasion. Note that the times are one hour out as I don't always remember to adjust from summer time!

Also evident in this data is the fridge/freezer and freezer operation. I have never really looked at this and would be interested if anyone knows if it is typical of such appliance power draw, both are A rated at best I think.


* Pump effect 24 Feb .pdf (35.79 KB - downloaded 76 times.)
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Off grid AC coupled, 6kW Proven, 2.8kW PV, SMA SI/SB/WB Inverters, 4x576ah Rolls batteries @ 24v, 25kW Biomass Boiler, Wood Stoves, Spring/Well water. Sorry planet - I did try.
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