Using more grid than expected

[AlexGoldie]

Hi all,

New to the forum and solar energy. Really liking the system so far but I've noticed something strange and I'm not sure if this is typical.

We got the solar panels installed last week and finally got the battery in place yesterday. Last night, after the sun went down, I noticed we were using about 600w per hour, the battery was fully charged (well to 81% which I think is what the installer set the batter to charge to). We were only taking 125w from the battery and then 475w from the grid. Is that right? It seems that the battery is only ever providing 125w of power. Also, right now we're making 375w from the panels and drawing 22w from the grid, while the battery is sitting there fully charged.

I thought the way it was supposed to work would be, take from solar, then battery and then only grid when the other two aren't providing enough. Like I said, I'm new to all this so could be way off and it's working the way it should be.

The system we're running is:
10x V-TAC 410W Half mono solar panels
1x Solis rhi 5kw hybrid single phase inverter
1x Pylontech us5000 5kw battery

Hope someone can help and sorry if these questions are silly / obvious.

Thanks
Alex

 

[SeaGal]

Welcome! There are no silly questions.. you just get silly answers sometimes

I have a Solis RHI too and that behaviour is not correct.

At night, the Solis should supply the house load from the battery, up to the limit of the inverter or battery. One US5000 should provide up to 50A at 48V, so I'd expect you'd get up to 2400W from the battery after sun-down, until the battery reaches its minimum SOC, that is.

How are you measuring those values? Is that is what is showing on the RHI's front screen? If so, can you post a screenshot?

 

[SeaGal]

Further thoughts... though not directly related to your original question...

1) To get the most from your battery then, if £££ is not a limiting factor, you'd do better with two battery packs. That would give a maximum power (when there is no solar) of 4800W, which is about the limit you'll get from the inverter anyway. Plus two battery will likely get you though the winter evenings, if not night, depending on your typical usage.

2) You mention you are drawing 22W from the grid right now - that's OK/expected - the Solis will be measuring grid usage every second and trying to balance the import/export to zero, but as things switch on and off and grid voltages fluctuate, combined with the inaccuracy of the measuring CT clamp, there will always be some import and export - I personally wouldn't be concerned with anything less than 50W either way.

 

[AlexGoldie]

Thanks for the quick response. I'm seeing the figures through the SolisCloud app (but the screen on the invertor matches up).
Screen shot taking a couple of minutes ago.

Yep, the plan is to get a second battery in the near future, we just don't have the cash right now. We're going to go with the same type of battery daisy chained.

ah ok, that's good to know. thanks.

 

[rpdom]

Further to what @SeaGal said, are you using the App or SolisCloud website to get those values? (I see from your reply that you do). The current usage values shown on there are snapshots taken every five minutes and often show odd values that in reality only last a second or so. It's the cumulative figures that are more useful and the graphs showing use over a day.

 

[SeaGal]

@rpdom Agree re the snapshot on the cloud view, but if @AlexGoldie 's Solis screen is showing the same as the picture above then something is wrong. The Solis screen updates every second, so I'd expect the 116W to be coming from the battery, rather than the grid.

Can you send a pic from the screen as well please @AlexGoldie ?

I'm not familiar with the Pylontech battery, but it looks like its not discharging as it should.

 

[SeaGal]

@rpdom As you know, I don't use the Solis cloud... but just wondering whether the fact that the battery symbol is showing as grey is significant?

 

[AlexGoldie]

pic attached

 

[SeaGal]

Thanks - gosh it must be dull and rainy in Scotland today as you're only getting 140W from 4.1kW of panels

But, seriously, looks like a similar issue to this thread that I contributed to ...

PylonTech batteries apparently in protect mode. Will not discharge without reset

Hi i have a Solis 3.6KW system with two PylonTech 3000C batteries. The system has been generating Alarm_BMS messages, apparently due to excessive charging voltage from Solis, now reduced. However now have a more worrying problem, the batteries charge normally in the morning, however when they...

diysolarforum.com

or this one, but the person never got back with an outcome (I hate it when that happens)...

Solis hybrid inverter pylontech battery not charging/discharging

We recently installed a 10kwh solis hybrid inverter with around 21 panels. This all works great but we just got our pylontech 5kwh batterij today but it just doesnt seem to work. We connected the positive and negative leads to the hybrid inverter and the can rj45 cable to the battery and the...

diysolarforum.com

You could check the info page showing BMS data to see if there is anything obvious and try rebooting the Pylontechs

Otherwise, get your installers back to fix it.

 

[timselectric]

I would also ask your installer, why they set it up to only charge to 81%.
Your cells are never going to see any balancing.

 

[rpdom]

@rpdom As you know, I don't use the Solis cloud... but just wondering whether the fact that the battery symbol is showing as grey is significant?

@SeaGal the circles go grey when idle. 0W in or out. For the batteries that can happen when the panels are generating just enough to cover the load, but not enough to charge the batteries as well.

I agree the OP should go back to their installer. Limiting the battery charge like that seems a strange thing to do and it does sound like there is something else wrong there.

 

[AlexGoldie]

thanks for all the responses guys. I've got back in touch with the installer (not heard back yet). I'll update this thread when I hear back.

Thanks again

 

[AlexGoldie]

So, still not heard back, but the installer left the advanced settings password at the default. I don't know what any of this means. But do these setting look right? It's set to "Self use" mode.

 

[rpdom]

You've got a discharge time of 14 hours set. That discharges your battery to the grid! Set it to 00:00 - 00:00 to stop it doing that.

Do you get cheap power from 22:00 to 06:00? If so, that's fine as you're filling your batteries from the grid at those times.

I have heard (not tired it myself), that having a charge time that crosses midnight can confuse the inverter as it clashes with all the times set 00:00 to 00:00. You would think that it would ignore those times, but I've heard that it doesn't. Advice is to change all the others to something like 06:00 to 06:00 and they won't clash with the other times.

The charts on the App and Website are useful for seeing what has been going on with your inverter overnight.

 

[SeaGal]

You've got a discharge time of 14 hours set. That discharges your battery to the grid! Set it to 00:00 - 00:00 to stop it doing that.

Yes, those time are set... BUT, optimal income is set to STOP, so they won't actually be used to force any charge or discharge.

All looks fine on the settings to me - what does the info page about the battery show? (it's one of the 4 info pages, reachable by pressing ok/enter from the main screen).

 

[AlexGoldie]

So it turns out when the electrician was setting it up he did it all wrong. The boss came out to check it today and fixed things. All sorted now.

Thanks all

 

[nc73]

I would also ask your installer, why they set it up to only charge to 81%.
Your cells are never going to see any balancing.

Probably thinks it's an EV

 

[SeaGal]

So it turns out when the electrician was setting it up he did it all wrong. The boss came out to check it today and fixed things. All sorted now.

Thanks all

Good you got it sorted - if you can post what exactly had been done wrong, that will help others in the future who have similar issues and find this thread through a search - TIA