Uhome battery soc

Bobjl

Hi we went online with our solar and Battery storage on Friday We have a  Lux 3,6 hybrid inverter, and two uhome 2400kwh batteries. Until today the weather has been very overcast, and the batteries only got up to around 50% soc, so by the time we went to bed they were down to around 9%. however when I looked on the battery data on the luxpower app, it would appear that the batteries dropped to 7% over Saturday night, and even as low as 1%. At that point they started charging from the grid,  even though I have  charging AC disabled. Not that I mind, a safety feature I guess. But what I cant understand is why the system allowed them to get so low. I have on grid cut off set at 10% soc. I am hoping that this was some sort of start up glitch. we have had sun today so the batteries got a full charge. I emailed my installer, but he didn't make much of it  

Reed_Richards

My battery (4 years old) stops discharging at 10% and it's dropped to 8% overnight.  Something is wrong with your system if it is losing that much more charge overnight.  My battery will charge itself from the mains if the State of Charge drops to 5% but the total electricity used for "safety" recharging is recorded on the generation meter and it's small enough that I know this is a rare event.

cm4ever

Bobjl said:

Hi we went online with our solar and Battery storage on Friday We have a  Lux 3,6 hybrid inverter, and two uhome 2400kwh batteries. Until today the weather has been very overcast, and the batteries only got up to around 50% soc, so by the time we went to bed they were down to around 9%. however when I looked on the battery data on the luxpower app, it would appear that the batteries dropped to 7% over Saturday night, and even as low as 1%. At that point they started charging from the grid,  even though I have  charging AC disabled. Not that I mind, a safety feature I guess. But what I cant understand is why the system allowed them to get so low. I have on grid cut off set at 10% soc. I am hoping that this was some sort of start up glitch. we have had sun today so the batteries got a full charge. I emailed my installer, but he didn't make much of it  

Hi, I have the same system, but just with two extra batteries, some points to note: -

1. The reported soc by the inverter is for want of a better description, it's "best guess" of the combined storage level of your batteries.

2. If the inverter goes a day or two without a certain amount of charge of the batteries, it'll start a 'safety' 300W battery charge cycle to increase the soc, in an effort to help with battery life etc.

3. Your battery storage shouldn't be falling below 10% reported soc if the grid is available, as the inverter should be disabling discharge at that point and going into standby etc.

4. As the soc is a bit of a 'guess' (as it's not necessarily very accurate), you could find often that the inverter stops discharging/supplying power to the house way before a reported 10% if you turn on a high load and the battery storage voltage drops significantly.

Definitely a case for discussing your observed issues with your installer....

I'd be interested in their view point.

Alnat1

I had similar early problems and it turned out to be the communications cable. I don't know correct terms, I'm not very techy, it's the one that clips in to the primary battery with a landline phone type clip. The wiring into the clip had been done badly and was loose. Installers got their electrician back and it was easily sorted.

Also over winter (December cold snap) I noticed my batteries would occasionally discharge to 10% as usual but then go down to 8% over the next few hours. It only happened when it was really cold, normally would stay at 10%. The batteries were on the cold garage floor. I now have them sat on a piece of that hard polystyrene.

Bobjl

Update.  As I said this is a very recent system. I reset the on grid cut off soc on the app to 10% ( although it was showing that anyway) Yesterday we had a days worth of sunshine and the batteries were showing 100% at the time the solar stopped producing. Looking on the app we used battery all night until we went to bed, and they continued to discharge through the night covering the base load. At about 6am this morning at they stopped discharging at 10% and stayed at that soc until the panels started producing. So to my mind they are  now doing what they are supposed to. We have had virtually no solar production today, so I guess the battery will be down very early. That will be the test as to wether my reset did the trick. 

Magnitio

It's possible that the batteries continue to discharge (at a very slow rate) when they reach the minimum in order to power the BMS.

Bobjl

Bobjl said:

Update.  As I said this is a very recent system. I reset the on grid cut off soc on the app to 10% ( although it was showing that anyway) Yesterday we had a days worth of sunshine and the batteries were showing 100% at the time the solar stopped producing. Looking on the app we used battery all night until we went to bed, and they continued to discharge through the night covering the base load. At about 6am this morning at they stopped discharging at 10% and stayed at that soc until the panels started producing. So to my mind they are  now doing what they are supposed to. We have had virtually no solar production today, so I guess the battery will be down very early. That will be the test as to wether my reset did the trick. 

Well in reply to myself, it would appear not. they continued to discharge down to 1% until about 6pm when they started to charge up from the grid. just checked and at just after 8pm they are now at 12% and we are on grid power only. I have sent my installer some screenshots of the monitor, and battery data, to see what he says

Reed_Richards

Completely different inverter but I can set the minimum SOC in software.  Could your software setting be wrong?  

Magnitio

Are you able to see a graph of battery consumption and state of charge e.g.

Bobjl

Reed_Richards said:

Completely different inverter but I can set the minimum SOC in software.  Could your software setting be wrong?  

That's what I am thinking. I woke to an email from my installer this morning. It would seem that they are now taking my concerns more seriously and they have reset the Battery!. At this precise moment it is showing7%. and being charged.  

Bobjl

Magnitio said:

Are you able to see a graph of battery consumption and state of charge e.g.

This was yesterday. interesting things seemed to be working in the early hours, the battery dropped to 10% and stayed there until it got power from the pv, but as you see, at 6pm it plummeted to 1%, and took two hours to charge back up from the grid.