Navitron Renewable Energy and Sustainability Forum

SOLAR PHOTOVOLTAIC => Solar Photovoltaic Systems => Topic started by: bmouthrob on July 10, 2018, 11:07:53 PM



Title: Growatt SP2000 - battery charging less each day?!
Post by: bmouthrob on July 10, 2018, 11:07:53 PM
I have had my Growatt SP2000 hooked up to the standard 4.8KWh Lithium battery for a couple of months or so. All was going great, until about 5 days ago when it only charged to 95%.
This has point at which the battery will charge no further has been decreasing quite rapidly each day and today it has only charged to 60%; it actually stopped charging around 1pm and there was plenty of solar after this (see attached - you can see that beyond around 1pm it just starts dumping out to the grid on the graph).

(https://s15.postimg.cc/g5fmbx347/growatt.jpg) (https://postimg.cc/image/g5fmbx347/)

Has anyone ever come across anything like this before as I have scoured the 'net and can't find a thing.

Thanks.


Title: Re: Growatt SP2000 - battery charging less each day?!
Post by: RIT on July 10, 2018, 11:19:17 PM
If your supplier can't help it may be best to just call their UK number, I found the following on the net

     UK Subsidiary contact: Service Line: +44 75 8555 9688, Email: UK.sales@ginverter.com


Title: Re: Growatt SP2000 - battery charging less each day?!
Post by: nowty on July 10, 2018, 11:47:07 PM
Have you noticed getting any BMS errors displayed on the controller, especially when it halts charging ?

What does the controller say the battery voltage is at its highest state of charge ?

You might be getting an out of voltage balance error which then later clears itself on discharge. But the offending cell(s) gets more out of balance through each charge cycle.

I had this on consecutive days on one of mine last mid summer when it hit 98% in full sun.


Title: Re: Growatt SP2000 - battery charging less each day?!
Post by: bmouthrob on July 11, 2018, 10:11:57 PM
I've shut it all off now to limit further damage!

I'll put it on for a recharge cycle tomorrow and let you know the results.

Thanks.


Title: Re: Growatt SP2000 - battery charging less each day?!
Post by: linesrg on July 12, 2018, 04:52:19 AM
Good Morning All,

I'm pretty certain that I'm seeing something similar here with my set-up and I was getting BMS errors. Will need to look at it at some point.

Regards

Richard


Title: Re: Growatt SP2000 - battery charging less each day?!
Post by: bmouthrob on July 18, 2018, 04:13:50 PM
Hi,

So when charged to 65% it wouldn't charge anymore the other day and the voltage was 54.7v.

There don't appear to be any errors on the main display. I have tried connecting up the pc application too via serial cable and there doesn't seem to be anywhere there to find any useful debug info.

Am I being dumb or is it just broken?


Title: Re: Growatt SP2000 - battery charging less each day?!
Post by: nowty on July 18, 2018, 07:26:13 PM
Not dumb and probably not broken if there are no BMS errors.

If you are not getting any BMS errors, then the issue may be simply the SOC indicated is a little out.

On a couple of occasions, I have had mine giving erroneous SOC figures but it gets reset at 0% (when empty) and 100% (when full). The actual operation works on cell voltage.

54.7v corresponds to an individual cell voltage of 3.9v which is almost full, circa 85% SOC so I would not worry too much.

You could try fully discharging the battery overnight, followed by a full re-charge. That should reset the SOC to zero and may get closer to 100% on the subsequent full charge.
Then look at the stats of how many kWh's it takes to re-charge, should be around 3.5 to 4kWh.


Title: Re: Growatt SP2000 - battery charging less each day?!
Post by: bmouthrob on July 18, 2018, 10:50:26 PM
Looking today, it seems that it is has been displaying different (equally frustrating) behaviour... It seems to only be storing to battery very internittently - as you can see from the image below, the battery was not full and so nothing should have gone out to the grid (light blue) today. However it just seems to have a mind of it's own!

(https://s15.postimg.cc/4sg58lno7/thumbnail.jpg) (https://postimg.cc/image/4sg58lno7/)

I am using a wireless CT clamp, but I don't think that's the issue as I have now seen it multiple times in an 'operating' state when there is  +900w being exported out to the grid and the battery is no where near full?!

(https://s15.postimg.cc/epr61oapj/thumbnail_1.jpg) (https://postimg.cc/image/epr61oapj/)

Is there anyway to do a 'factory reset' on the battery and SP2000?





Title: Re: Growatt SP2000 - battery charging less each day?!
Post by: nowty on July 19, 2018, 10:11:33 AM
The charging function of the Growatt is a bit erratic, so it can easily be thought not to be working properly. It slowly ramps up its charging, but any disturbance to Solar PV (like clouds) or house loads (fridge starting up,etc) and the charging quits, then slowly ramps up again. Even in full sun it can randomly quit charging for no apparent reason. The graphs you show look odd, but as it was pretty cloudy yesterday, not conclusive to me.

Apart from turning the unit off and on I dont know of a way to perform a factory reset.

You need a good sunny day sitting in front of it to rule out wireless CT or BMS errors.


Title: Re: Growatt SP2000 - battery charging less each day?!
Post by: Tinbum on July 19, 2018, 10:39:26 AM
I had to turn mine off and then back on again- (as if a power cut) as it stopped sending data to the portal. It was communicating OK but sending nothing.

They updated their app the other day but they didnt fix some of the errors that had already been reported in the app reviews!!  ???


Title: Re: Growatt SP2000 - battery charging less each day?!
Post by: bmouthrob on July 22, 2018, 02:24:17 PM

(https://s15.postimg.cc/9rbyzo0d3/Screenshot_20180719-140017.png) (https://postimg.cc/image/9rbyzo0d3/)

Still doing the same thing, I've sat in front of it a few times now but everything *seems* normal to me?

Something I've just noticed however is that the status light is not illuminated at all?! The icons for the state and arrow indicators etc are all there but the status led is neither green nor red. According to the manual this is impossible! Hmmmmm...


Title: Re: Growatt SP2000 - battery charging less each day?!
Post by: nowty on July 23, 2018, 04:07:46 PM
Something I've just noticed however is that the status light is not illuminated at all?! The icons for the state and arrow indicators etc are all there but the status led is neither green nor red. According to the manual this is impossible! Hmmmmm...

It just means its in standby mode, so batteries are either full, there is no load demand or not enough solar power.

I would check the true SOC of the batteries verses what it says on the APP by cross referencing the battery voltage as displayed on the control unit. It could just be that the APP (and maybe the controller) is not displaying the SOC correctly and other than that, all is OK.

Approximate SOC values of the battery voltage are,

100%     57V
80%       54v
40%       50v
0%         47v


Title: Re: Growatt SP2000 - battery charging less each day?!
Post by: bmouthrob on August 07, 2018, 06:40:27 PM
Got to the bottom of it....  exhappy:



There was rogue shadow hitting the panels. Because my strong is only 6 panels, normally running about 160v when the shadow hit (which was very small) the voltage dropped down to ~140v which then fell out of the charging criteria. I'd heard shadowing had a big effect but for a small (approx 60cm2 max) shadow it is massive! Current was barely affected at all (hence there being minimal impact on wattage).

It all became apparent when I realised you can actually pull all this historic data from the app, which is pretty much unusable! Although it seems actually quite functional when you figure it out...