Battery 200w min response

[Mrjmegson]

Hey guys,

Not sure if anyone will be able to answer this, but I've got an issue with how my batteries work.

My supplier, Afore, say my batteries won't respond to loads of less than 200w, which sounds fine in theory, but in practice, that's a huge amount of things, so much so that we are still importing 3kw (a third of our usage) from the grid, despite having very full batteries.

1. Is this normal?
2. Can this be reduced?
3. If so, what settings should I be looking for on the inverter?

Cheers,

Jay

 

[binky]

Hey guys,

Not sure if anyone will be able to answer this, but I've got an issue with how my batteries work.

My supplier, Afore, say my batteries won't respond to loads of less than 200w, which sounds fine in theory, but in practice, that's a huge amount of things, so much so that we are still importing 3kw (a third of our usage) from the grid, despite having very full batteries.

1. Is this normal?
2. Can this be reduced?
3. If so, what settings should I be looking for on the inverter?

Cheers,

Jay

Annoying as hell isn't it. Unfortunately there's not a lot you can do as it's down to the algorithms and CT clamp accuracy. If you have a read through various battery posts on here it's a problem discussed in detail several times over.

 

[johnb2713]

Hey guys,

Not sure if anyone will be able to answer this, but I've got an issue with how my batteries work.

My supplier, Afore, say my batteries won't respond to loads of less than 200w, which sounds fine in theory, but in practice, that's a huge amount of things, so much so that we are still importing 3kw (a third of our usage) from the grid, despite having very full batteries.

1. Is this normal?
2. Can this be reduced?
3. If so, what settings should I be looking for on the inverter?

Cheers,

Jay

Neither inverters on my system (Growatt and Victron) behave like that. Have you got it set for zero export by any chane? My Growatt when export is set to zero is always importing a small amount less than 100w, but if a small amount of export is allowed it hovers either side of zero. Are you using a CT clamp or a power meter? CT clamps dont perform well at zero current but are responsive, power meters are good around zero but dont react as fast.

 

[Mrjmegson]

Hi guys, thanks for the replies.

Binky, I'll have a read through some posts then. Cheers.

John, the export is set to zero as you say, so I might try allowing a little and see what happens.

Also I am using CT clamps, but do have a din rail meter which I intend to fit when I get a minute, as they are considerably more accurate.

I'm tempted to run it all off EPG mode and turn the grid off, then I assume they will take all the load.

Jay

 

[johnb2713]

Hi guys, thanks for the replies.

Binky, I'll have a read through some posts then. Cheers.

John, the export is set to zero as you say, so I might try allowing a little and see what happens.

If export is set to zero it will hover on the import side, I would set it to 1 kw or so and then see what happens.

Also I am using CT clamps, but do have a din rail meter which I intend to fit when I get a minute, as they are considerably more accurate.

Yes they are better from an accuracy point of view bet dont respond as fast to load changes so you end up with more import and export as loads vary.

I'm tempted to run it all off EPG mode and turn the grid off, then I assume they will take all the load.

Jay

That would do it, remember you need to connect up to the EPG output though and isolate the incoming mains.

 

[Mrjmegson]

Hi John,

Cheers for your detailed reply.

Interesting about the DIN meter, I would have expected the opposite. You've put me off of using it now.

I'm definitely thinking that EPG is the way to go, and then just turn the grid back on during Dec and January when my solar doesn't cope.

 

[johnb2713]

Hi John,

Cheers for your detailed reply.

Interesting about the DIN meter, I would have expected the opposite. You've put me off of using it now.

The power meter has to convert the measurements into digital form and then transmit it to the inverter which then has to process the information. The CT is an analogue signal there literally at the speed of light. The CT has to be quicker both in theory and born out in practice. The downside with a CT is that the closer you get to zero, the lower the voltage is coming out and the noise induced on the wiring becomes significant. The signal to noise ratio gets worse as the current reduces.

I'm definitely thinking that EPG is the way to go, and then just turn the grid back on during Dec and January when my solar doesn't cope.

Seems a lot of trouble considering our climate.

 

[Mrjmegson]

Thanks for explaining the CT Vs meter, that's really interesting.

I'm not 100% sure what you're referring to as a lot of trouble, switching to EPG mode and isolating the grid? If so, then all that requires is me throwing the master switch in my consumer unit, so seconds, and the inverter will (apparently) seamlessly switch modes. And considering I'll only have to do that once a year for two months, I'm good with that.

How is your battery build going?

 

[johnb2713]

Thanks for explaining the CT Vs meter, that's really interesting.

Hope you find it useful.

I'm not 100% sure what you're referring to as a lot of trouble, switching to EPG mode and isolating the grid? If so, then all that requires is me throwing the master switch in my consumer unit, so seconds, and the inverter will (apparently) seamlessly switch modes. And considering I'll only have to do that once a year for two months, I'm good with that.

If your inverter(s) are connected grid tied you will have use a separate output on the inverter to supply your load.

How is your battery build going?

All up and running since 24th December, no problem at all. Peak unit use now less than one per day!

 

[Mrjmegson]

Less than 1kw a day from the grid? Well done you, that's a fantastic build. How much solar do you have?

The inverter has two outputs, I'll just wire the EPG to spare MCBs, and turn them on and the others off when I flip the switch on the CU.

 

[johnb2713]

Less than 1kw a day from the grid? Well done you, that's a fantastic build. How much solar do you have?

Thats at peak rate, I still use off peak for charging the batteries etc. That said, the last two days I've run without grid power at all. 6.7kW solar array, not massive, room for more!

The inverter has two outputs, I'll just wire the EPG to spare MCBs, and turn them on and the others off when I flip the switch on the CU.

That has huge potential for disaster, be VERY careful, it probably contravenes a lot of regulations too which I’m sure others may educate us both on.

 

[michael8554]

Hi Jay
"3kw (a third of our usage) "
So about 9kW usage?
Be aware that the maximum EPG output from the inverter may be way less than that.
Eg my "5kW" Inverter only has a 3kW EPS output.

 

[Mrjmegson]

That's still really good peak usage though, if everyone could do that.

I'm pissed that I don't have more batteries, as over the last two weeks my batteries have been full by lunch time and the system has shut the solar side down, so I've just been watching wasted solar. Incredibly annoying. Need to get your favourite tank installed (Mixergi, lol), I've got it sat at work in a box, had it since Nov, but not done anything with it yet.

Michael, thanks for the heads up mate, that's a very important consideration. However, I don't know if this is unusual, but my inverters are identical on both sides.

John, your probably right about contravening regs, so I'll just swap the plugs over one a year, it's a 2 min job.

Jay

 

[Mrjmegson]

Also Michael, sorry, I used the wrong terminology, I should have said 3kwh of usage from the grid, we average 10kwh a day. So the inverter power output obviously wouldn't be relevant at these levels if I'd not missed the "h" off the end. My fault, sorry, but your point is excellent.