Inverters

[ProAsm]

Personally I feel that during load shedding one needs to change your way of life to benefit the cost of electricity inversion.
For instance during load shedding, we do not use the DVD Home theatre system and just use the on board TV sound.
I also do not play games on my PC during this time.
Do not use the bedroom, study and lounge at the same time, it's one or the other.
In this case you just need 250 watts at any one time, thus a 24 volt Inverter with 2 x 100A/H batteries will give you approx 2.5 hours for a 50% DOD.

 

[cypher912]

RCT ones are very silent

 

[fabzster]

RCT ones are very silent

That is great to know I just picked up a 5kva today with 4x FM100P-X 12v 100Ah Victory batteries

Hope the batteries are ok.... on the spec sheet if they DOD 30% they last 1500 cycles

 

[Sparhawk]

you took advantage of the special

 

[fabzster]

you took advantage of the special

Wahahaaha 100% correct!!!!!

do you know if they are any good?

 

[Sparhawk]

No complaints from my end, sold dozens no issues so far. There are better but lets face it that special was sweet and well worth the dosh!!!

 

[fabzster]

for sure that's why I jumped on it!!!!!!!!!!!!!!

 

[greg_SA]

Nice

Ignoring any losses, those 4 batteries together will give:

4 x 100Ah x 12V = 4800Wh (for the full battery capacity)

So if you only go down to 30% DOD, you have 4800 x 0.3 = 1440Wh. So you can only run your full load for 1440/980 = ~1.5h

But if you go down to 50% DOD, you have 4800 x 0.5 = 2400Wh. So you can only run your full load for 2400/980 = ~2.5h

So I think your setup is fine But try not to draw full load for the whole 2h - the lower the DOD, the better. Powering everything for the full load shedding duration is cutting it a bit fine. Try to limit you consumption if you can (do you need 2 TVs and a PC on together?). As a rule of thumb, never go below 50% DOD. No matter what the manufacturers say.

I'd definitely add the lighting - we run the whole house (LED) at around 200W.

The microwave is also an option - it will draw a heavy peak (around 1000W during operation) but it will be for a short time only. So try to limit its use.

 

[fabzster]

thanks Greg,

Is it not 48V (Or am I just confused?)

So Ideally I should get 4 more batteries and I could also connect my fridge and some lighting(They are already on LED) for approx
3h ish depending on whats on?

Are the losses you talking about due to the inverter efficiency? if so how could I factor that in?

 

[dunkyd]

What on earth do you need a fridge running for ?

 

[greg_SA]

thanks Greg,

Is it not 48V (Or am I just confused?)

So Ideally I should get 4 more batteries and I could also connect my fridge and some lighting(They are already on LED) for approx
3h ish depending on whats on?

Are the losses you talking about due to the inverter efficiency? if so how could I factor that in?

Yes, the inverter is 48V, but when calculating the battery capacity, each battery is 12V 100Ah, and there are four of them.

This is equivalent to one 48V battery with 100Ah capacity.

The inverter will probably be running at about 90% efficiency, so don't worry about that too much. I think the 4 batteries is enough. Get the system installed, see how it works and what your actual DOD looks like, and if you need more battery capacity, add it later.

 

[fabzster]

excellent, advice many thanks

 

[Gnome]

The inverter will probably be running at about 90% efficiency

The inverter is not 90% efficient. Just to be clear that is under ideal circumstances, 25 degrees Celsius with a fully charged battery at ideal load.

Calculate at 85% efficiency for a more accurate number which should be the average efficiency down to about 80% and even lower for really low loads.

 

[greg_SA]

The inverter is not 90% efficient. Just to be clear that is under ideal circumstances, 25 degrees Celsius with a fully charged battery at ideal load.

Calculate at 85% efficiency for a more accurate number which should be the average efficiency down to about 80% and even lower for really low loads.

That's why I said "about".