Loadshedding affordable battery setup?

Park@82 said:
@wingnut771 I am still a bit confused about the implications of this.

Does this mean that if you draw 600w for 1 hour it would have used 1000W from the battery?

Can we take the power factor and multiply it with the Wh of the battery to get to the capacity that you can get from it?

So when looking at their trolley with this inverter: https://www.geewiz.co.za/long-run-u...life-kit-600w-with-lithium-battery-640wh.html

and you take the power factor of .6 x 640Wh = 384Wh. (not sure if it works this way)

Why does Geewiz then claim that you can get 3 hours of use with a 150W load? (450Wh)
Click to expand...
No this only applies to certain devices,ie like induction motors for example

dumb resistive devices will pull at PF1

ie the inverter efficiency is just another aspect and not related to PF more related to heat losses during step up

I suppose they do reduced claim so that they have to deal with less queries

ie under promise over deliver = less complaints
 
leon.davibe said:
No this only applies to certain devices,ie like induction motors for example

dumb resistive devices will pull at PF1

ie the inverter efficiency is just another aspect and not related to PF more related to heat losses during step up

I suppose they do reduced claim so that they have to deal with less queries

ie under promise over deliver = less complaints
Click to expand...
What’s the difference between a 3kVA/3kW inverter and a 3kVA/2.4kW inverter?
 
leon.davibe said:
Read with a clamp meter what you pull from battery at the same time to see the difference

At lower PF there should be a difference ie lower on battery side if i understand it correctly
Click to expand...
I don’t have a clamp meter yet.
 
OK, with just my PC and wifi running I get a PF of 0.75 (0.6A@229V=137.4W)
Watts being reported is around 103W.

If I add the oscillating fan, PF increases to 0.81 (0.7A@229V=160W) . Watts being reported 130W.

So it looks like we need to take the Wh and divide by the PF to factor in those losses when sizing your battery. Regarding inverter efficiency, lets just go with 0.8. I will be able to confirm in more detail when I have a way of measuring the battery current, but lets just go with the inverter manual which says 80ish% efficient, then again, this will be inverter specific, so imho, 80% is a good thumbsuck average to use.
 
wingnut771 said:
What’s the difference between a 3kVA/3kW inverter and a 3kVA/2.4kW inverter?
Click to expand...

Imo

The one will be able to carry max
2.4kw constant load if the power factor isn't perfect ie 3kva

The other will be able to carry 3kw constant load irrespective of the PF
 
I am curious if the 2400w model is loaded with 2500w load at pf 1

Will it trip overload
 
leon.davibe said:
Imo

The one will be able to carry max
2.4kw constant load if the power factor isn't perfect ie 3kva

The other will be able to carry 3kw constant load irrespective of the PF
Click to expand...
I think the 2.4kW is pulling 3kVA from the battery same as the 3kW one.
 
I'm now charging the 100Ah LFP with a shitty chinese-special charger, killawatt is reading 0.55 PF.
 
Last edited:
And if what i read is accurate or at least accurately understood

You will essentially pay eskom 1.8 times what you put into the battery

If a decent charger can do pf1 then the cost will very soon be earned back

Obviously just throwing around thumbsucking here
 
The kilawatt will say how much kw you used in the end

And you can compare to what the battery should take

Would be nice to see if this idea is correct
 
1677331307290.png
The stupid thing charges to 16V, automatic my ass. I couldn't leave it unattended with my LA battery, now with the LFP, the battery disconnects at 14.6V.
Still charging: 13.1V 0.55PF
 
leon.davibe said:
The kilawatt will say how much kw you used in the end

And you can compare to what the battery should take

Would be nice to see if this idea is correct
Click to expand...
I'm expecting that to be close as an LFP battery is 95ish% efficient.

I just used 1.8 times of leccy to do it.
 
wingnut771 said:
I'm expecting that to be close as an LFP battery is 95ish% efficient.

I just used 1.8 times of leccy to do it.
Click to expand...
Does the w /amps pulled drop on this float voltage

From what i understand it will taper off to almost no amps

Does the killawatt show amps or only watts
 
leon.davibe said:
Does the w /amps pulled drop on this float voltage

From what i understand it will taper off to almost no amps

Does the killawatt show amps or only watts
Click to expand...
It's like you don't even read what is said.

Where do you get "on this float voltage" from?
 
But then again a cheap charger so can't hope for much

I can't see PF as mine is connected via db

And the prepaid meter unfortunately doesn't seem to have a code to get powerfactor

Though i know the meter can measure it

All i can get is watts i am pulling on prepaid meter
And can use the amps the inverters say it is pushing into the battery

If i set my inverter to charge 10a deducting my idle load i pull about 912w and charge 800w battery calculated so that would mean 0.87

I set it at 30 but it was going at 29a on that i charged at 1461w and pulling 1570w so that is 0.93

Then i set it at 60 it pushed 64a
Charging 3276w and pulling 3444 so that is 0.95

Now this is reliant on prepaid meter and inverter measurements who knows how accurate the inverter is
 
wingnut771 said:
It's like you don't even read what is said.

Where do you get "on this float voltage" from?
Click to expand...
You said after the battery was full the bms cut charge and the charger went to 13.1 or something can't recall what you said

ie no load was flowing into battery thanks to bms bms

But the charger was in a float type stage , so was curious if it was still wasting power ie if some people set and forget it

ie how much power does it waste in that state
 
leon.davibe said:
You said after the vattery was full the bms cut charge and the charger went to 13.1 or something can't recall what you said

ie no load was flowing into battery thanks to bms bms

But the charger was in a float type stage , so was curious if it was still wasting power ie if some people set and forget it

ie how much power does it waste in that state
Click to expand...
No, I said this charger puts out 16V. The last time (first time after receiving battery) I charged it (a few days ago) the battery cut off at 14.6V (16.3V reading on V display).

Its busy charging now since 12pm after my 2 hour 10am-12pm session and is on 13.1V at the moment. So it's been charging for 4 hours now. It will get to 14.6V and then I hear the tone of the charger fan change when the battery cuts out. I then turn the plug off and disconnect the charger. The battery settles down to 13.8V.
 
You must log in or register to reply here.
Back
Top
Sign up to the MyBroadband newsletter
X