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LED lights?
- Thread starter w1z4rd
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I told him enough for 3-4 hours. I have no idea, will see when the unit is completed on monday.
The_Traveller
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This is being built by a friend of mine. Only reason there is a delay is because someone in town bought up all the batteries and invertors. So we are waiting for stock to arrive :/ Im paying the guy R500 a month over a year for what is being builtWill let you know how testing goes
R6k for the year ... And you need 4 hours backup time which means you need 240 amps for 1440kw.
That's not a bad price for rental but since it's a modified sine wave unit, don't be surprised to see your equipment go faulty within that 12 months.
Why would my equipment go faulty?
The_Traveller
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On an [-]icrock[/-]ipad with 1% power left so please google 'dangers of modified sine wave inverters' and you will get a lot of info.
Not saying damage is a guarantee .
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HavocXphere
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4 hours? You're insane bro. Eyeballing those numbers I'd say 30 mins max and that is being optimistic.
On the plus side...you seem to be off on the other side too...PC, TV & DSTV is not going to get you to 1300W unless you've got at least 2 heavy spec PCs under full load simultaneously. (For reference a high spec PC idling goes for ~100W so we're literally talking high spec under full load here to reach 1300)
Messugga
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Based on what numbers are you calculating the 30min uptime under the stated load?
The_Traveller
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He can get 4 hours of backup time but only with 240 amps of battery power. That's why I said paying R6k for the year ain't that bad considering the system will cost much more than R6k to build.
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tRoN
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Not a bad price that for a 1400w inverter/charger.
But it's not a pure sine wave? Won't that be bad for the electronics?
The_Ogre
Honorary Master
Fear mongering.
Unless you're trying to drive anything with an AC motor, you should be fine.
I searched for a pure sine wave thingy. Apparently only a very few amount of computer UPS`s have them. Only the really expensive models. So basically 90% of the computer UPS`s out there have a modified sine wave. Seems good enough for them, should be okay for my needs.
The_Traveller
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Its not badly priced if it is 1. Deep Cycle 2. Gel
I would ask for the spec sheet of the battery to see DOD etc.
Also consider that 200ah needs a very good charger no less than 20A , otherwise slow charging a battery can affect life span.
How do come to that conclusion without knowing the batteries involved?
All I know about the batteries is they are being produced at a local battery factory (as in a factory in East London) that makes the batteries for Daimler-Chrysler (mercedes). That is the hold up at the moment. I have been told they will be completed today.
I calculated every watt required. To be on the safe side I worked under the assumption that everything was at peak load:
Device Watts
Dell Monitor 264
Dell Monitor 264
PC Box 500 (my computer has a good high end gfx card. Two IDE hard disks, Two SATA hard disks, a SSD drive and DVD writer)
Large Mecer Monitor 240 (this is attached to the DSTV)
Router 12
DSTV 30
Total 1310
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richjdavies
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Some of those numbers feel a bit high. Not for the TOTAL kVA needed - could possibly be right, but for the on-going usage -- i.e. monitors are more likely 30-90W I'd imagine in normal usage - although they might spike at 260W as they turn on. Same goes for the PC - may have a 500W PSU, but probably doesn't use all of that most of the time. CPU, disks etc. will all spin down when not being thrashed.
May be worth getting a quick effergy energy monitor or something just to check your usage over an hour or two before buying batteries for that amount of usage.
PS: https://www.energystar.gov/index.cfm?c=most_efficient.me_comp_monitor_20_to_23_inches
Are all around 22 kwh/year at 4 hours per day usage. That makes them around 15W?!
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itareanlnotani
Executive Member
It has ide... - seriously, how old is that thing?
Probably has a floppy or stiffy drive too if its that vintage!
Lead Acid you only get about 30% usable vs wattage.
So guesstimate 3x your hourly usage in watts for each hour you want to be able to run sans grid.
V x A = W
So if you need 1000W / hr, you actually need 3000W of Lead Acid.
12v x ? = 3000W = 3000/12 = 250.
So at least 1 x 250Ah battery per hour per KW.
Probably has a floppy or stiffy drive too if its that vintage!
Lead Acid you only get about 30% usable vs wattage.
So guesstimate 3x your hourly usage in watts for each hour you want to be able to run sans grid.
V x A = W
So if you need 1000W / hr, you actually need 3000W of Lead Acid.
12v x ? = 3000W = 3000/12 = 250.
So at least 1 x 250Ah battery per hour per KW.
Aah well, I installed it today. I worked all my math on peak usage so as to be sure not to under cater for my power needs. So this is my beast. I call it a beast because it fsking heavy. Requires two people to move it around.
SilverNodashi
Expert Member
Aah well, I installed it today. I worked all my math on peak usage so as to be sure not to under cater for my power needs. So this is my beast. I call it a beast because it fsking heavy. Requires two people to move it around.
Many places sell those units and you can get batteries for it everyone. Diamel batteries are not needed.
Run it for 4 hours and see if it copes. Then see how long it takes to re-charge, probably about 3 to 4 days.
The case is from an older unit (unrelated, we just needed a case to put the batteries in), batteries and inverter were put in an old case. So dont judge it by its case. Its got 2x 103ah batteries in it. Batteries are from First national Battery and produced here in East London. Inverter is from Mustek or something like that. Cant remember. Charging should take around 24 hours (if I empty the batteries).
A guy at work got a smaller unit. With one battery. And he says it lasts 6-8 hours with his PC on it. I think I now have the batteries to carry my equipment for the 2 hours downtime load shedding will give me. The reason I wanted 4 hours is so I dont run the batteries too low to mess up how long they last.
I am going to charge it for a day or two then test on Sunday to see how long it lasts.
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