An 88 yr old lady I often help out has an issue with her solar system that charges a formidable bank of 4 Li ion battery units ( recently installed about 6 months ago ) . I know nothing about such systems but understand some of the electricity generated is fed back in to the grid for which she recieves credits against her monthly bill. All has been fine over the summer and autumn but as the days shortened and with the skies often being grey she is finding that the batteries are regularly depleting ,to the point where the protective system kicks in to shut them down and it then requires a manual reset of all 4 batteries before things work again . This can happen more than once a day and to me indicates that the design is barely fit for purpose as who wants to be regularly having to check the status ...surely it should be designed so that the whole process is monitored and automated (so that before the batteries reach shut down the supply is switched ....so that power is then drawn directly from the grid until the batteries recover and charge up to a higher level?
You may say ask the company who installed it ( and it wasn't cheap ) but they have been taken over by another organization who appear to subcontract repairs to various independent engineers. On Xmas eve she managed to get an engineer to visit but he was from London and had been working in Cornwall so called in on his return journey. He seemed knowledgeable enough and at the time I didn't question his suggested fix which was to alter the settings so that the batteries wouldn't self protect until a lower state of charge but now I think about it ..surely all that does is kick the problem down the road a little and they just shut down slightly later than before. He was also the one who gave the instructions for resetting the system if it occured again and it certainly has ..many times hence my post on here . Surely something is not right here as if this were standard there would be a huge number of disgruntled UK customers and someone would have come out with a fix or a box that automated the resetting etc . If anyone has advice or experience in such things it would be much appreciated and I can dig out more info . There was nothing much relating to this in the manual .
One last thing is that I wonder if the system could somehow be adjusted so that the batteries charge at a higher rate and less goes into the grid but I had presumed such a setting would normally be optimal as default?
Please enlighten me !
i had solar panels installed in November with a battery. Mine just charges the battery when there is enough solar power, if not it just sits there waiting. When the sun's out it works fine and the battery charges. Soon as the sun goes down the battery discharges to run the electric. I'm not sure about having to reset anything, doesn't seem right to me. Try talking to some solar installing companies, they might help (wouldn't hold my breath though)
TBH I'm a bit surprised the system just doesn't figure it's own shit out but there you are. Have the panels ever been cleaned? Contamination can have a big impact on performance I understand.
Sounds to my untrained eye it’s a problem with the inverter. Assuming it’s a hybrid inverter and there’s not a separate battery inverter tagged on to a previously installed inverter?
Have a look here, some really good info. Some useful notes regarding compatibility. Essentially you need to balance the battery bank output (4 does seem a hell of a lot for an 88 year old) to the inverter max charge rating (not the same as the solar panel output). If the battery bank is effectively too big, it won’t complete the full charge cycle, then over time batteries will degrade.
https://www.cleanenergyreviews.info/blog/hybrid-solar-selection-guide
Thanks for that link and suggestions ...She has a large property and isn't short of a penny hence the number of power banks I'd imagine.
Contamination can have a big impact on performance I understand.
They get washed every time it rains, so it's not actually a thing TBH.
Might be the panels are optimized for summer with the angle of attack . So they perform better when the sun is highest . One train of thought is that they should be optimised for winter, bigger gain over smaller input as you tend to use more electric in the winter.
I didnt think feed in tarifs were even worth thinking about now. better to power a battery pack or immersion element constantly.
When you say batteries , do you mean car batteries or 48v li -ion ?
One train of thought is that they should be optimised for winter, bigger gain over smaller input as you tend to use more electric in the winter.
Really???
Much less sunlight and far fewer daylight hours makes angling the panels for winter production fairly pointless.
The batteries are huge Li ion packs with various switches/ leds etc all over ..certainly not car batteries ! The issue is more about the inconvenience of having to manually reset the batteries if they go into self protection mode ...regardless of how much the panels are feeding into the system . I accept the more the panels can supply the less likely the batteries are to become depleted but surely ,design wise, there should be a smart system built in that diverts the supply back to the grid before the batteries switch themselves off?
but surely ,design wise, there should be a smart system built in that diverts the supply back to the grid before the batteries switch themselves off?
Many do..... But without knowing what system we has we are pissing in the wind.
Any brand names on the batteries or system at all ?
My solar panels produce much less in winter, maybe 1/6th of summer. You can't capture energy that's not there. It should be expected that the batteries will be depleted to the cut off so they should recharge without intervention, although they won't get full.
The benefit of batteries is that you get paid 4p or 5p per kWh for the power you export, unless you get a special export tariff, and it costs 3 or 4 times that to buy, so saving it and using it makes sense - although the batteries are expensive so the payback time is long.
Feed in Tariff has stopped now. Depending when the panels were installed there might be a small payment. The name is confusing - if you're eligible, you get FiT on everything you generate, whether you feed it in or use it yourself.
Unless she has crazy power demands during the day it may well be worth her while to switch to a time based tarrif and charge up the batteries overnight during the winter and run the house off them during the day. That way they probably won't deplete as much. However it does sound like the system is not configured properly.
Seems like a big system to have had installed so late in life.
Is this lady a genuine hard core eco warrior?
The resetting sounds like a big problem that would defeat the benefits of this system.
As uponthedowns suggests, I’d think about how much electricity I use, how much solar I get, and whether I could switch to a low overnight tariff to charge up cheaply in addition to any solar input, and run my house off of the batteries. Though how long it would take to recoup the capital spend 🤷🏻♂️
