Generator or Inverter for residential use?

saflyfish

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Ive been looking at the two options.The quietest genny you can get for the power i need is the honda eu65is inverter gen at R60k.Its a 6.5kva unit with 5500W.Im in a complex so cant have a noisy gen.
Ive phoned a few inverter supply companies and they reckon about R40k for a similar inverter unit with batteries.
I need to run the following:
1 x 12000 btu split unit aircon,non inverter (new ac)
10 x overhead energy saving bulbs at 14w each,not led
2 laptops and chargers
Fibre line,fibre router so we can work on laptops and have internet
2 x 32" full hd led tvs and two dstv decoders

Price aside when we run into stages 3 to 8 the gap between sheds can be as short as 2 hrs.I believe the batteries take 6-8 hrs to fully charge.
So im undecided as both have advantages and disadvantages.
Any advice,suggestions greatly appreciated.
 

Segg

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Ive been looking at the two options.The quietest genny you can get for the power i need is the honda eu65is inverter gen at R60k.Its a 6.5kva unit with 5500W.Im in a complex so cant have a noisy gen.
Ive phoned a few inverter supply companies and they reckon about R40k for a similar inverter unit with batteries.
I need to run the following:
1 x 12000 btu split unit aircon,non inverter (new ac)
10 x overhead energy saving bulbs at 14w each,not led
2 laptops and chargers
Fibre line,fibre router so we can work on laptops and have internet
2 x 32" full hd led tvs and two dstv decoders

Price aside when we run into stages 3 to 8 the gap between sheds can be as short as 2 hrs.I believe the batteries take 6-8 hrs to fully charge.
So im undecided as both have advantages and disadvantages.
Any advice,suggestions greatly appreciated.
Definitely the inverter - the chances of us getting into stage 6 or 8 long term is low
The inverter will automatically switch over and avoid your devices going off and on all the time
 

CataclysmZA

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An inverter with a solar charger is a good idea. Later down the line you can add solar panels that are meant to charge the batteries during the day, and that gets you a fairly reliable setup for load shedding.

The most cost in the build will be batteries, especially if you don't go with bog-standard lead acid units.

Edit: To get the most out of your system, stick to 24V or 48V builds, and avoid putting batteries in parallel. Series only.
 
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Papa Smurf

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generators need servicing and can stop working at any given point, its a petrol/diesel motor
my opinion is go solar and add each year as you have funds
 

thechamp

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Ive been looking at the two options.The quietest genny you can get for the power i need is the honda eu65is inverter gen at R60k.Its a 6.5kva unit with 5500W.Im in a complex so cant have a noisy gen.
Ive phoned a few inverter supply companies and they reckon about R40k for a similar inverter unit with batteries.
I need to run the following:
1 x 12000 btu split unit aircon,non inverter (new ac)
10 x overhead energy saving bulbs at 14w each,not led
2 laptops and chargers
Fibre line,fibre router so we can work on laptops and have internet
2 x 32" full hd led tvs and two dstv decoders

Price aside when we run into stages 3 to 8 the gap between sheds can be as short as 2 hrs.I believe the batteries take 6-8 hrs to fully charge.
So im undecided as both have advantages and disadvantages.
Any advice,suggestions greatly appreciated.
Go the inverter plus battery route, it is the future, a generator needs fuel to run and maintenance.

It is going to cost you more than R40k though, a 6.5kva is between R20k to R25k, leaving you with only R15k for a battery, which is obviously not enough for a decent battery capacity.
 

Steamy Tom

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The inverter without a doubt. And I agree you don't need the air on, ecspecially as you say for 2hr bouts
 

Tun@

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Once load shedding finishes i'm charged back up to 100% in 2 hours.
Using a 3000 VA inverter + 3 x Pylontech US3000 batts (daily avrge usage 30kw/h/day here)
Gennie you got to go start it & get power back up ------- inverter/batts = what load shedding.
 

saflyfish

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Jul 2, 2013
Messages
341
Hey guys thanks really appreciate all your advice and feedback
Just some more questions:
The previous post mentioned that batteries can be charged back to full in 2 hrs from flat.I was under the impression they took 6-8 hrs to fully charge back up.
Secondly the batteries need to be re charged from mains...does this use a lot of electricity?
 

SwaarMetaal

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Jul 20, 2012
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If you will permit saflyfish, I would like to ask, which suppliers / shops are recommended for inverter, battery and all related item purchases?
 

Paul_S

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Hey guys thanks really appreciate all your advice and feedback
Just some more questions:
The previous post mentioned that batteries can be charged back to full in 2 hrs from flat.I was under the impression they took 6-8 hrs to fully charge back up.
Secondly the batteries need to be re charged from mains...does this use a lot of electricity?
The previous poster uses Pylontech batteries which are either lithium-ion or LiFePO4 based batteries.
Lithium based batteries can typically be charged and discharged at much higher currents than lead acid batteries without damaging them.

If you have a 105Ah lead acid battery and you charge it at C/4 (26.5A) then it would take more than four hours to charge (the charge curve is not linear). 6 hours would be reasonable for lead acid.
If you have a 105Ah lithium based battery that can be charged at C/2 (52.5A) then you can charge it well above 85% capacity within two hours.

Yes, it does cost to charge the batteries from mains and there are charging losses in the charger and battery.
I'm not sure what those losses are but I'd imagine 30% would be a fair figure to work from.
To charge a 105Ah 12V battery from mains it would require 1.6kWh of electricity from the mains (assuming a 30% loss).
 
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Steamy Tom

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The previous poster uses Pylontech batteries which are either lithium-ion or LiFePO4 based batteries.
Lithium based batteries can typically be charged and discharged at much higher currents than lead acid batteries without damaging them.

If you have a 105Ah lead acid battery and you charge it at C/4 (26.5A) then it would take more than four hours to charge (the charge curve is not linear). 6 hours would be reasonable for lead acid.
If you have a 105Ah lithium based battery that can be charged at C/2 (52.5A) then you can charge it well above 85% capacity within two hours.

Yes, it does cost to charge the batteries from mains and there are charging losses in the charger and battery.
I'm not sure what those losses are but I'd imagine 30% would be a fair figure to work from.
To charge a 105Ah 12V battery from mains it would require 1.6kWh of electricity from the mains (assuming a 30% loss).
you would not discharge LA to 100%, so even at c/4 it would only take ~2 hours.
 

Steamy Tom

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Once load shedding finishes i'm charged back up to 100% in 2 hours.
Using a 3000 VA inverter + 3 x Pylontech US3000 batts (daily avrge usage 30kw/h/day here)
Gennie you got to go start it & get power back up ------- inverter/batts = what load shedding.
so much backup on that system O_O, how are you pulling so much through the system on average, that is like running 4 pool pumps continuously for 10 hours every day
 

catman37

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An inverter with a solar charger is a good idea. Later down the line you can add solar panels that are meant to charge the batteries during the day, and that gets you a fairly reliable setup for load shedding.

The most cost in the build will be batteries, especially if you don't go with bog-standard lead acid units.

Edit: To get the most out of your system, stick to 24V or 48V builds, and avoid putting batteries in parallel. Series only.
Why should you avoid putting batteries in Parallel?
 

thechamp

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Why should you avoid putting batteries in Parallel?
I am afraid that's a very ill-informed opinion. I wonder how big solar plants like in big shopping malls go about it if they can put batteries in parallel.
 

newby_investor

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Batteries in parallel can do interesting things if one of them goes wonky. For most household use you'll be fine with two or more in parallel. Once you scale up to commercial-size things, you'll want probably some kind of per-battery fuse, and a battery management (levelling) system. Lithium batteries typically have a BMS built in, lead acid you can get away with not having one but your batteries will likely not last as long.
 

thechamp

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Batteries in parallel can do interesting things if one of them goes wonky. For most household use you'll be fine with two or more in parallel. Once you scale up to commercial-size things, you'll want probably some kind of per-battery fuse, and a battery management (levelling) system. Lithium batteries typically have a BMS built in, lead acid you can get away with not having one but your batteries will likely not last as long.
Interesting things can also happen if one battery in a 48V series connected system goes wonky, so it's not really about parallel or series connection, it's about proper battery management and system protection.
 

Gaz{M}

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OP, you don't need lithium batteries for your use case. The aircon will blow you budget by R20k, so do you really really need it? Just run it full blast at 16C when you have power. Use a pedestal fan on the inverter during load shedding.

Besides the aircon, the loads are small, probably < 400Watts total.

Just get a Pure Sine wave 2kVA inverter (around R6000).
Get enough batteries to last 6 hours at 400W (2400Wh @ 50% discharge is 4.8Kwh /12V = 400ah)

So 2 x 200Ah batteries or 4 x 100Ah batteries should be fine.

They won't recharge fully in 2 hours, but they have 6 hours reserve, so you should be fine over 2 loadsheds.
 

newby_investor

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Interesting things can also happen if one battery in a 48V series connected system goes wonky, so it's not really about parallel or series connection, it's about proper battery management and system protection.
Yeah this is also true, but the failure mode in parallel (can be) more dangerous, if the bad cell starts draining current from the others in parallel very quickly, it can cause things to get hot.*

A failed series battery will drop your voltages and may cause your system to go wonky / not be able to provide power, but it won't likely be a fire risk. At least not as far as I'm aware.

*Lead batteries are however less prone to this than lithium, AFAIK.
 
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