Losing stored power from solar battery

[brianrob14]

I have recently had a 4.8kw solar system, with 5kw Puredrive battery storage, installed at my property by a professional company (promoted by the Scottish Government). I have been monitoring the system very closely during recent weeks and have been baffled by what appears to be a battery 'discharge' which drops the battery power overnight by around 40%. The app which came with the package even calls this 'discharge', so it is nothing to do with 'self use' or 'power to grid'. This 'discharge' seems simply to be power draining from the battery, which is more noticeable overnight when there is virtually no usage.
I have tried communicating with the installer about this problem but I'm getting very little help from them and they haven't been at all forthcoming with any useful information.
I am not an electrician and I'm completely ignorant of such matters, but I have read about Charge Controllers and Blocking Diodes which can prevent such leakage. Will these components be fitted to my system 'as standard', in which case I presume that my system must be faulty? Are some systems installed without charge controllers and blocking diodes?
I can't believe that these solar power/battery systems are designed to lose 40% of their power overnight, so surely something must be wrong somewhere?

Any advice would be appreciated (please keep it simple) !!!

many thanks,

Brian

 

[ProDave]

Take a meter reading (your main electricity meter) before you go to bed and then again first thing in the morning. That will tell you how much if any electricity you have imported over night.

 

[Barx]

I would think it is just usage in keeping the house ticking over. My house for example ticks over just under 300w when everyone is in bed and no extra gadgets on. 300w x lets say 8 hours (probably more like 10 at moments as nights are starting to draw in) = 2400wh or 2.4 kWh. If you have a 5 kWh battery probably, thats about what you are reporting...

 

[brianrob14]

Many thanks to you both for your comments. We have done an 'overnight' calculation on power usage and concluded that the battery power we were 'losing' was considerably more than what the fridge, freezer and TV box were using. When the battery was at 100% yesterday evening I shut down the inverter and battery, and even isolated the main battery power cables. When I fired it up this morning the battery was at 50%.
Even with my ignorance of most matters electrical, that seems to confirm to me that there is a battery problem !!

 

[johnb2713]

Many thanks to you both for your comments. We have done an 'overnight' calculation on power usage and concluded that the battery power we were 'losing' was considerably more than what the fridge, freezer and TV box were using. When the battery was at 100% yesterday evening I shut down the inverter and battery, and even isolated the main battery power cables. When I fired it up this morning the battery was at 50%.
Even with my ignorance of most matters electrical, that seems to confirm to me that there is a battery problem !!

I would agree with you, battery or BMS problem. How old is the system? if it's not very old, get back onto the supplier/installer, that definitely isnt right.

 

[Murdoch]

Are you importing over night from the grid?

Are you cooking your dinner using the batteries?

Overnight to me means from sunset to dawn

 

[binky]

Many thanks to you both for your comments. We have done an 'overnight' calculation on power usage and concluded that the battery power we were 'losing' was considerably more than what the fridge, freezer and TV box were using. When the battery was at 100% yesterday evening I shut down the inverter and battery, and even isolated the main battery power cables. When I fired it up this morning the battery was at 50%.
Even with my ignorance of most matters electrical, that seems to confirm to me that there is a battery problem !!

Certainly sounds like there's a problem. If you get no joy with the installer I would have a chat with Puredrive technical helpline. It might be something simple like having been left in the 'wrong mode', you generally get 4 work modes for the battery, it should be set on self consumption - or words to that effect.

 

[johnb2713]

Certainly sounds like there's a problem. If you get no joy with the installer I would have a chat with Puredrive technical helpline. It might be something simple like having been left in the 'wrong mode', you generally get 4 work modes for the battery, it should be set on self consumption - or words to that effect.

How can it be ‘left in the wrong mode’ when with the battery isolated it still loses 60% overnight? I don’t see how that’s possible?

 

[binky]

How can it be ‘left in the wrong mode’ when with the battery isolated it still loses 60% overnight? I don’t see how that’s possible?

nor do I, but it's always worth checking the simple stuff first

 

[brianrob14]

Thanks again for your replies.

Just to explain, this is a brand new system installed professionally, but once the installation is in the company is only interested in their next job, and I'm having dreadful trouble getting support from them (a familiar tale I'm sure). Yesterday however I finally made contact with the installing electrician, who is now trying to help me.

As 'customers' who know absolutely nothing about how this technology works, we were given absolutely no instruction or even basic guidance on how the system operates or how to interpret the info. on the app. The people in the office don't want to know; the customer service is appalling.

What is clear from speaking to the electrician yesterday however is that not even he knows fully how to set up the SOLIS inverter. I'm spending hours on youtube trying to learn myself how to set up these Inverters, but even amongst the 'experts' there are conflicting ways to set them up.

It is becoming apparent that when I disconnected the battery the night before, the battery reset the state of charge estimate to a default level of 50% until the charge controller re-learns the state of the battery. That must have happened to me and I just assumed that the battery had 'lost' 50% of its power overnight whilst disconnected.

I'm learning as we go along and hopefully (now that I have got the spark's phone no.) we can make some progress and get to the bottom of what I still think appears to be some sort of battery drain,

thanks again,

 

[johnb2713]

Jeez that sounds bad, good luck in getting it sorted, please do let us know the outcome.

J

 

[binky]

the Solis technical helpline is very good, if you can get through as they are currently very busy.

Now I have fitted a few Solis units and there's 2 common mistakes, not setting the right battery, it has options for Pylontech, lead acid and many others. If it's on the wrong setting it won;t work properly.

The other common mistake is work mode, there's 4 to choose from, you want 'self consumption mode'

 

[brianrob14]

Thank you for your comments. When the unit was commissioned on July 1st the battery name was entered by the engineer as 'Puredrive'. It worked fine until I got a 'Batt Name' alarm a couple of days ago. I tried re-entering 'Puredrive', but it wouldn't accept it. Upon consulting Solis I was told to enter the name 'LG-Chem-LV'. I did that, and it has been okay since !
I have tried looking for a 'work mode' heading, but my unit doesn't appear to have a heading of that name,
thanks,
Brian

 

[binky]

look under 'storage mode select'

 

[brianrob14]

Yes, I found it, but on my unit it's called 'self use'. It's set to 'ON',
thanks,

 

[binky]

Yes, I found it, but on my unit it's called 'self use'. It's set to 'ON',
thanks,

I forget the terms used, it's been a while since I fitted a battery.

 

[brianrob14]

Hello all,
I'm just picking up on this thread again, and thanks to all who have responded so far.
I'm still putting pressure on the installing company to address my issue of 'apparent' battery power loss, but the installing engineer is off sick at the moment (probably stress) so things have currently stalled for a few days. He did make a brief visit here last week however and I was relieved when he did concede that there does seem to be a problem.
In the meantime, I have been closely monitoring my power usage and I bought one of those devices which you can plug into an appliance to check what that appliance is using. Having now gone round the whole house, I reckon that our total daily usage is between 4.5 and 5 kw per day. I know that that will rise sharply as we go into autumn and winter. Could I ask, does that level of daily power usage (in summer) for a standard 3 bedroom semi-detached seem reasonable?
I mentioned before about blocking diodes and charge controllers. My system comprises JA 390 watt Solar Panels (JAM60S20-390/MR), Solis hybrid Inverter (RHI-3.6K-48ES) and 5kw Puredrive battery (PureStorage II DC). Does anyone happen to know if these components have either blocking diodes or charge controllers installed as standard? This question has come about following my viewing of the link below, which I found most interesting:-

https://solargearguide.com/do-solar-panels-drain-at-night-weve-got-the-answer
I have been asking the installing company this question but (surprise, surprise) I have as yet had no answer,

many thanks,

Brian

 

[royb]

Like you I am new to solar systems.
Howerver too have the same issue that you have, loss of battery power overnight. I have assumed this was simply exporting energy from the battery to the grid overnight - and so you should be credited for it.
However I fail to see what the benefit would be in the long run.

Royb

 

[brianrob14]

We have learned so much since our system was installed, but still we have so many unanswered questions (and with very little help or guidance from the installing company).
A few weeks ago, we purchased one of these 'plug in' units which allow you to monitor the power used on any individual appliance, so we have been going round the house checking what our usage is.
We were away on holiday last week, and this gave us an opportunity to monitor our usage when the house was empty (we can view our house statistics on the phone app. which came with the solar power system). The results were, to some extent, quite surprising ! Like many properties, we have the usual fridge, freezer, TV boxes, Internet Hub, house alarm system, security camera, etc., all of which require to be on constantly, and all of which draw power constantly. We knew that the fridge and freezer together draw about 1kW in 24 hrs, but we were staggered to find out that the TV box and Internet hub in our front room uses approx. 1.5kW in 24 hrs. So there is 2.5kW straight away, before you add on all the other bits and pieces. All in all we found that our house is using about 3.5kW per day, even when we are not there !
Our battery storage is 5kW and we have been finding that the battery power drops overnight by approx. 40%, which is disappointing, but hardly surprising when you acknowledge that there is still considerable usage in most households, even when the lights are off and the occupants are in bed!
If you, like us, think that you are 'losing' power from the battery overnight it would certainly be worth you doing what we did and monitor, very closely, your power usage on all your appliances. You may be surprised by the results!

Brian