24v Lithium resting voltage

On the pv side the voltages tends to be higher so you can get away with thinner
No idea what the rated amps is for a 4mm i would take a guess around 35amps



And 6mm 45-47ish

On the battery side the thinnest cable to start with i would say is 25mm for the 100amps we tend to use

On very short runs

When it goes longer thicker it has to be

And the 8kw inverters guys can just
Forget that a 25mm cable even exists period
 
I cant recall what the mecer comes paired with

Would have to go dig out the cables to check
I think it is 2x 6mm ie 12mm
For the 60 amps it can pull from the battery

Assume an electrical engineer had to be involved with making that decision
 
The problem with cable thickness and electricians is they want to know the length how is it cooled , ie in the air in conduit , in other covering is it clipped to the wall is it armoured , is under ground

And what is the run length

Before they will give you an amp per cable

And quite rightly so if he has to sign the coc

And all we normal folk want is a rule of thumb

So rule of thumb run every cable 50mm /jk
 
wingnut771 said:
@soulie, we are getting 0.4V drop between battery and inverter with no load, what do you suggest?
Click to expand...
Buy a new multimeter until you find one with calibration that matches the inverter

I would measure at the poles of inverter and battery

If they match i would set inverter till i have the required voltage on terminal

Heck even if they don't match i would do the same

Dont go to sea with 2 chronometers go with 1 or 3

Set the inverter to 29.2 ie 3.65v per cell that 0.4 problem becomes irrelevant
 
Last edited:
leon.davibe said:
Buy a new multimeter until you find one with calibration that matches the inverter

I would measure at the poles of inverter and battery

If they match i would set inverter till i have the required voltage on terminal

Heck even if they don't match i would do the same

Dont go to sea with 2 chronometers go with 1 or 3

Set the inverter to 29.2 ie 3.65v per cell that 0.4 problem becomes irrelevant
Click to expand...
Maybe do that first before getting a new multimeter. If multimeter reads the same as display at inverter end, what now?
 
ie if it gets to cv stage you don't exceed the 3.65v cell max

And you get it fully charged on cc not on cv which gets reduced to almost nothing
 
wingnut771 said:
Maybe do that first before getting a new multimeter. If multimeter reads the same as display at inverter end, what now?
Click to expand...
Then it's easy one of the 2 is wrong

If batteries don't charged full
ie don't get the caoacity expected
I would assume inverter is wrong and set the 3.65v max ie 29.2v

If you get the capacity you expect most likely multimeter is wrong do nothing
 
leon.davibe said:
ie if it gets to cv stage you don't exceed the 3.65v cell max

And you get it fully charged on cc not on cv which gets reduced to almost nothing
Click to expand...
Can we stop using cell voltages, it's really hard work for everybody.

What about the voltage drop? That cable does look pretty thick.
 
Yea the first part isn't needed to measure the poles on inverter just a joke as a lead in
 
leon.davibe said:
Then it's easy one of the 2 is wrong

If batteries don't charged full
ie don't get the caoacity expected
I would assume inverter is wrong and set the 3.65v max ie 29.2v

If you get the capacity you expect most likely multimeter is wrong do nothing
Click to expand...
If the multimeter is reading the same as the inverter on inverter side, and same multimeter is reading 0.4V more on battery terminals, how can anything .

Never mind, I've lost interest. This is becoming like pulling teeth.
 
wingnut771 said:
Can we stop using cell voltages, it's really hard work for everybody.

What about the voltage drop? That cable does look pretty thick.
Click to expand...
Hence why i say measure on the poles to see if there really is a voltage drop

Or if it is just calibration
Also put the multimeter on the closest setting that battery voltage is still in the margin

Ie if your multimeter has a 200 and a 500v setting set it on the lowest one that is still higher than the bat voltage

Often we are lazy and just leave it on the max but accuracy suffers
 
My opinion is always if you struggle to get it full

Go the max ie 29.2v
the charging really slows down if there isn't a nice voltage differential

Sure if you always get it full
You can choose a slightly lower voltage to take it easier on battery until you hit the sweet spot where you get it full just in time for next loadshedding

I full ball mine lately since i discovered the inverter efficiency is lower at lower amps

ie i pay more to get a battery full if i cahrge slower
 
To be honest this feels like I have opened a can of worms. Thanks to everyone that had input, I am gonna get a sparky to assist me and I will post his findings once done.
 
Measure on each side of the fuses

Have heard they run. Hotter than Breakers ie resistance
 
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