Generator or Inverter for residential use?

Gaz{M} said:
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.
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Yip aircon is for my server room has to run
 
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Gaz{M} said:
Then you are forced to get a 3kVA pure sinewave inverter and at least a 2.4kWh lithium battery.

R40k to 50k minimum.
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Yea its a lot of cash.What is the approx charge time from empty to full on these batteries?
 
saflyfish said:
Yip aircon is for my server room has to run
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Gaz{M} said:
Then you are forced to get a 3kVA pure sinewave inverter and at least a 2.4kWh lithium battery.

R40k to 50k minimum.
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saflyfish said:
Yea its a lot of cash.What is the approx charge time from empty to full on these batteries?
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I'm not an electrician but a couple of points you would need to do some homework on.

1)The lithium batts have a max discharge/load rating & i doubt you'll get away with just one with the start up of the aircon...so i'm thinking maybe 2 needed for that reason?.

2) 3kva inverter - also there, will that handle the startup of the aircon or maybe you need to be looking at 5kva units rather?

I don't know but you'd need to suss it out with someone to get the full correct picture.

Was some 2.4kwh pylontech's about for R13k each not so long ago, the 3.5kwh's are more closer to R20k each.
Those batts pack away into like a server box pretty nice + are supposedly good for 10 years versus lead acid/gel that in theory will need replacement come 5 year area. Do your own research there i'm just mentioning it , not quoting it as fact but its worth putting in the picture when considering cost.
 
CataclysmZA said:
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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i was always told to not do series as the battery bank is limited to the weakest battery.
 
I’m an inverter fan but NO for you if you going to run an aircon.

Get in touch with bundupower and check for a gennie with them.
 
if you want aircon i would go for a combination of both genny and inverter/batteries, at least you won't have to spec the batteries so big, genny can charge batteries if they get too low.
 
saflyfish said:
Yea its a lot of cash.What is the approx charge time from empty to full on these batteries?
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You can work it out based on your inverter. (no of kwh in batteries) / (charging wattage of inverter) = (no of hours to charge).

Batteries have limits as to how much charging current they can accept but with such a big one it shouldn't be an issue.
 
wingnut771 said:
i was always told to not do series as the battery bank is limited to the weakest battery.
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It depends, you can't exactly avoid doing series when you have to connect a 48V system. It's not always one or the other, it is mostly a combination of both.
 
saflyfish said:
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.
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A better place to ask is here: https://powerforum.co.za/

Plenty of people actually using one or the other or the two combined.
 
wingnut771 said:
i was always told to not do series as the battery bank is limited to the weakest battery.
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If you're connecting batteries in series, you usually aren't attaching weaker batteries to the existing pack. You can have, say, a 12V 50Ah battery connected to another 12V 100Ah, but your 50Ah battery may drain beyond what's reasonable.

catman37 said:
Why should you avoid putting batteries in Parallel?
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You have to think about the load on batteries differently than if you were to do series. At 12V, one 100Ah battery realistically only has 50Ah available before the depth of discharge is too low. At 24V with two 100Ah batteries, you have 100Ah of actual capacity. At 48V, you have 200Ah of actual capacity. In parallel, two 12V batteries at 100Ah will give you 100 of usable capacity, and it will charge quicker. But if you want to use 100Ah for anything useful, at 12V the current may be too low.

Say now you want to charge the battery bank, and here you run into a problem. In a series system, you can charge all the batteries at the same time even if their voltages are different. If one battery is at 11.0V, and another at 10.5V, this isn't too much of a problem. Charging times for a series system are longer because you have to raise the voltage of all the batteries to nominal levels, and batteries in series have a higher resistance so you need to account for that as well.

If you have a parallel system, you can't have too much of a variance in charge levels between batteries, because otherwise you run the risk of damaging both batteries (extra heat levels, shorting, wires burning out, etc). The batteries will attempt to equalise their charge, and in a bank with a faulty battery that will lead to fire hazards. You can install additional fuses to protect against over-current situations (one per battery and another one for the system), but you need to keep a much closer watch for failures.
 
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saflyfish said:
Yip aircon is for my server room has to run
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What is keeping the servers running then? Must be a lot so gear if you getting heat that makes you worry about the heat. But then again the days of ice cold server rooms are long gone.
 
Sorry i shouldve been clearer and said computer room.I run laptops and routers,switches etc but since me and my team are in there basically 24/7 we cannot not have aircon for the 2 hr loadshedding outages.I stay in Durban and the room gets to 38 degrees with humidity so the aircon is non negotiable.
 
ok, so servers don't need cooling, people need cooling.
 
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