Discharge

[Mrjmegson]

Sorry for the gross title, couldn't resist.

So, I'm miffed. My batteries have an individual discharge max power of 2500w, but they are paralleled together as a bank of 3, which I thought meant I would get 3 times the power out of them, but considering my inverter is only 6kw, then obviously that would be the max power output.

But, all I'm getting is 2500w from them, and the rest is coming from the grid.

Can I be cheaky and ask if someone could have a quick scan of the inverter manual and see if you can see which setting I need to change to increase the power I can get from the batteries.

All the settings start on page 27.

Thanks in advance,

Jay

 

[monkey5]

I'm not 100% sure but think the discharge rate is down to the inverter rather than the battery's. Unless there isn't much charge available In the battery.
Someone will know soon I'd have thought.

 

[Mrjmegson]

The inverter charges and discharges at 80A, 4.8kw, so way above what it's giving me.

I've asked the provider, but they just skirt around my question. I've set the settings I think are right, but I'm obviously wrong.

 

[poni]

do you know your set points?

 

[Mrjmegson]

Hey poni.

I don't even know what a "set point" is.

 

[poni]

All the settings

this

 

[johnb2713]

What figures are in these two settings? in fact all of the settings in that section ?

 

[Mrjmegson]

IsoChk OFF
GfciChk OFF
EarthChk OFF
V.max 262.2
V.maxT 1.06s
V.min 184.0v
V.minT 2.56s
F.max 52.00Hz
F.maxT 0.56s
F.min 47.50Hz
F.minT 20.06s
ISO.min 50K
T.com 60s
T.Reconn 20s
RSDEN OFF

Did them all, just in case they are relevant.

Thanks for looking for me John, you know I'm a moron.

 

[johnb2713]

I cant see any issues with the settings.

When you say 'the rest is coming from the grid', what is the total load i.e. 2500w is from the inverter, how much more is coming from the grid and how are you measuring that?

What happens if you reduce the load does both the inverter output and the grid import reduce or does the inverter stay at 2500w and just the grid import reduce?

 

[Mrjmegson]

Oh that's a shame, I was really hoping you were going to say there was a glaring issue with the settings.

So as an example, if we have the TV on, with all the things connected too it, and the fact it's 11 years old, the draw is typically over 400w, so then if you add in a few other bits, lights chargers etc, and then put our 3kw kettle on, the inverter will show the battery discharging at roughly 2500w, and the grid providing 1000w. As soon as the kettle, or other large load stops, the inverter will show the grid at zero, (it often bounces around, a few watts plus or minus) and the battery discharging at what ever the load is, so 4 to 500w again.

Ive now complicated things further, as I got the rear panels on today, so started up the rear inverter and batteries, and initially it seemed like they saw each other as the grid, and started charging each others batteries. I've since linked them together and set one as slave and one as master, and they have stopped fighting each other (I think).

The wife forced me to spend time with the family this aft, so haven't had chance to look at anything since I got you those stats.

As always John, thank you so much for trying to help me, I think you know it's massively appreciated.

 

[johnb2713]

So the inverter is reaching a barrier at 2500w, that's it's upper limit? If you switched another load while the kettle was going as the above scenario is the inverter still at 2500w?

 

[johnb2713]

How about the values in here?

 

[Mrjmegson]

So I've been doing a bit of research and that lead me to change the IDChgMax and IChgMax to 80A, (the max the inverter can put out), about half hour ago.

I haven't tested it yet, but will when we next need a brew.

I also changed the charge power to 4096w, but noticed the inverter that I put on line today, so hadn't messed with, was already set at 4500w, so set them both to that. The inverters ask you to chose the battery brand, and has my batteries in its list, so I assume that's the intended wattage.

Fingers crossed this works.

The manual is crap isn't it?

 

[johnb2713]

So I've been doing a bit of research and that lead me to change the IDChgMax and IChgMax to 80A, (the max the inverter can put out), about half hour ago.

What was the previous IDVhgMax value?

 

[Mrjmegson]

50A.

So I've just made a brew and looked at the values while the kettle was on, and it's partly good news.

The values jump about all over the place, and then the display cycles round different value sets, so it's really hard to get an accurate value, but the battery was discharging at around 3000w, going slightly above and below all the time, but, it was still pulling from the grid.

So the batteries are 51.2v, and the inverter can charge/discharge at 80A, so that means I should be able to get a 4Kw peak from them doesn't it? Especially as the particular bank I was looking at was the bank of 5 batteries.

 

[Mrjmegson]

Sorry, I'm wrong, the IDChgMax was set at 60A default.

 

[johnb2713]

Sorry, I'm wrong, the IDChgMax was set at 60A default.

So that would give approx 3kW.

 

[Mrjmegson]

The original 60A, yeh that's what I'd make it, but it never went over 2.5kW.

I'm going to try and find a time that me and the supplier can be on a call together and get them to walk me through the settings.

I set what I think is the export settings, to zero last night, but the app often shows something going back to the grid. I suppose it's trying to balance it, but that's just a total waste of my stored energy, as obviously the cost of the electric is considerably more than I get back for exporting, so I'd rather it not try to balance.

 

[johnb2713]

The original 60A, yeh that's what I'd make it, but it never went over 2.5kW.

Theres some room for losses and inaccuarcy here, what was the DC voltage at the inverter under these conditions?

I'm going to try and find a time that me and the supplier can be on a call together and get them to walk me through the settings.

Thats a good move, it will be interesting to hear what they say / find.

I set what I think is the export settings, to zero last night, but the app often shows something going back to the grid. I suppose it's trying to balance it, but that's just a total waste of my stored energy, as obviously the cost of the electric is considerably more than I get back for exporting, so I'd rather it not try to balance.

You will never get it to zero especially with zero export set. They always hover around zero but due to the digital nature of inverters each change is a step. It's possible that at one point to have 5w of import and when it adjusts it's voltage the next step gives it 10w of export. It may not have a step where it can hit zero. By setting export to zero, the inverter will always stay on the side of import so cant average out the export and import (well thats how the Growatt logic seems to work).

 

[Mrjmegson]

John,

I just got my message quote and no reply, was there meant to be a reply?