Load Shedding - whats needed to keep watching

elf_lord_ZC5

elf_lord_ZC5

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Getting rather pee'ed of with load shedding, disrupting my after work evening relaxation.

What am I going to need UPS or similar to keep my 55 inch TV, Mi-Box, router, and a background light bulb running for 3 hours, no, make that 4-5 hours to build in a wee bit of Murphy proofing. Besides I have an aversion to running batteries till they are dead, would rather have around a 3rd capacity left, after around 3 hours of use.

Thanks
 
Don't you need an inverter for extended periods (hours)?
 
elf_lord_ZC5 said:
Getting rather pee'ed of with load shedding, disrupting my after work evening relaxation.

What am I going to need UPS or similar to keep my 55 inch TV, Mi-Box, router, and a background light bulb running for 3 hours, no, make that 4-5 hours to build in a wee bit of Murphy proofing. Besides I have an aversion to running batteries till they are dead, would rather have around a 3rd capacity left, after around 3 hours of use.

Thanks
Click to expand...

Budget portable solution for modified sine Inverter/UPS

12V
https://www.geewiz.co.za/long-run-u...t-720w.html?search_query=Inverter+&results=83

Or
12V
https://www.geewiz.co.za/long-run-u...5ah-battery-8-hour-battery-life-kit-720w.html

Or
24V
https://www.geewiz.co.za/long-run-u...ah-battery-8-hour-battery-life-kit-1440w.html

You can get a watt meter or simlar to check how much power your stuff uses, although I don't think it will be much:
https://www.geewiz.co.za/gadgets/43...usage.html?search_query=watt+meter&results=27


If you want to spend more you can look at Pure Sine Inverter systems etc.
 
RedViking said:
Budget portable solution for modified sine Inverter/UPS

12V
https://www.geewiz.co.za/long-run-u...t-720w.html?search_query=Inverter+&results=83

Or
12V
https://www.geewiz.co.za/long-run-u...5ah-battery-8-hour-battery-life-kit-720w.html

Or
24V
https://www.geewiz.co.za/long-run-u...ah-battery-8-hour-battery-life-kit-1440w.html

You can get a watt meter or simlar to check how much power your stuff uses, although I don't think it will be much:
https://www.geewiz.co.za/gadgets/43...usage.html?search_query=watt+meter&results=27


If you want to spend more you can look at Pure Sine Inverter systems etc.
Click to expand...
Prices have steadily gone up. Just last week the 24v was 7000.
 
Lupus said:
Prices have steadily gone up. Just last week the 24v was 7000.
Click to expand...

Yap. Demand and Supply. Big increase from last year! This excludes the *R800 shipping fee. Once Eskom stabalised again they will have to bring prices down again if too much stock. Maybe. Don't think the companies can currently keep up with demand?
 
RedViking said:
Yap. Demand and Supply. Big increase from last year! This excludes the *R800 shipping fee. Once Eskom stabalised again they will have to bring prices down again if too much stock. Maybe. Don't think the companies can currently keep up with demand?
Click to expand...
For R800 I would drive and get it. Only 20km away :)
 
You will only be pulling less than 200w. The systems mentioned above are 750w so they will run you stuff comfortably. You would need at least 2 x 105Ah batteries.
 
Number of Batteries x volts x AH ratings ÷ watts drawn

I.e. 2 x 12v x 105ah / 750w = 3.36hrs
 
TV, media player, router and light will be less than 300w = 8.5hrs, but you don't want to run non lithium batteries below 50% dod (depth of discharge). So you are looking at 4.25 hours.

DOD is important to the life of the battery. running your batteries till they have 20% left and you get maybe 80 cycles (1 cycle per % used), to 50% and you get 300 cycles (6 cycles per % used), to 80% and it's about 1200 cycles (15 cycles per % used). it's exponential.

The deeper you run your batteries down, the longer they take to charge. The shorter the interval between load sheds, the more likely your batteries never get fully charged, the less they will last.
 
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elf_lord_ZC5 said:
Getting rather pee'ed of with load shedding, disrupting my after work evening relaxation.

What am I going to need UPS or similar to keep my 55 inch TV, Mi-Box, router, and a background light bulb running for 3 hours, no, make that 4-5 hours to build in a wee bit of Murphy proofing. Besides I have an aversion to running batteries till they are dead, would rather have around a 3rd capacity left, after around 3 hours of use.

Thanks
Click to expand...
TV 200w, mibox 10w, router 20w, energy saver or led bulb 15w

So even with 300w and 1 battery 1000w inverter and 1 battery you'll be running 8 hours
 
42" tv + media player + Creative 5.1 sound system (yes 2000 called and wants it's speakers back)+ wifi router + router + 5Ghz AP = working load of around 200w with startup spike of 250-275w *think it's the power supply for the speakers). The load on the inverter is more important than the size of the inverter. Assuming you are not running on the edge of max load.
 
I have the ellies unit

Plasma tv. Energy hungry run in power saving mode during load shedding
Mi box
Dvr
Fibre cpe and router
Tplink cpe
Led light
Xbox
Yamaha avr with 5.1
Sub gets turned off during load shedding

Comfortably runs through load shedding. Bought 2 and half years ago

Would recommend the mecer inverters rather though

Snd even better a pure sine wave if money permits
 
I also forgot to add efficiency into the mix. Work on 85%. This is how much power you get out of the system versus what you put in. It takes power to keep the batteries at float level (while you are not using them) and you lose some power through heat generated when converting ac to dc and back to ac.

2 x 12 volt 105Ah
300w inverter
Batteries to 50% dod
85% efficiency
2 x 12 x 105 / 300 / 2 x 0.85 = 3:35
If you want 5 hours then multiply your batteries by 1.2 = 2.4 batteries
So 3 batteries will give you 5:20 hours.
 
shearder said:
Number of Batteries x volts x AH ratings ÷ watts drawn

I.e. 2 x 12v x 105ah / 750w = 3.36hrs
Click to expand...

Technically accurate - though you are not factoring in that running these batteries to depletion is not recommended.

Also - something to note - include the actual draw of the Inverter in your calculations - as it will also be using battery power when loadshedding kicks in. Some inverters, as is the nature of these things, draw more than others and that's why speccing the inverter as well is key
 
@MEIOT Some inverters come close to 1:1.02 efficient. These are generally larger inverters (2% of 5000w is 100w), as opposed to smaller inverters (15% of 300w just 45w). I did add to @shearder calculation factoring in dod and efficiency. See post #14.
 
MEIOT said:
Technically accurate - though you are not factoring in that running these batteries to depletion is not recommended.

Also - something to note - include the actual draw of the Inverter in your calculations - as it will also be using battery power when loadshedding kicks in. Some inverters, as is the nature of these things, draw more than others and that's why speccing the inverter as well is key
Click to expand...
Yes you're right I didnt add that
and one never thinks of the inverter itself drawing power.
 
(12 x 100 x 0.85 ) / ( 140 x 2 ) = 3.64

Is that 4 hours and 4 minutes? ( what unit is the above, if 3 is hours ? )
 
That DoD number, confuses me

For lithium I want to pull 80% of the battery leaving 20% left in the battery, do I then use 5 in the formula?

In the formula what does 5 represent ( 20% used or 20% left ? )

@Dairyfarmer / @Geoff.D / @RedViking
 
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