Maintaining solar pv battery life

sewingqueen

I have recently had solar panels fitted and a give energy battery. Due to the time of year the battery is not charging to its full capacity and what charge I do gain is quickly used in the evenings. Is it bad for the battery if it does not charge fully? The factory setting is to stop discharging at 4%. Is there any advice you can give to maintain the batteries life?

Exiled_Tyke

My Solax is set to stop discharging at 10%. I think the best advice is to go with the battery settings.  At this time of year as it's not fully charging you aren't actually losing anything by going to a greater degree of discharge. 

If  you can get a time of use tariff you may be able to charge up fully overnight at low cost which is worth doing. 

My initial installation was at the end of November and for the first few months really thought I'd wasted my money. Nothing much will happen with it now with the long nights and terrible weather.  Come March you'll really enjoy the benefits. 

Screwdriva

sewingqueen said:

I have recently had solar panels fitted and a give energy battery. Due to the time of year the battery is not charging to its full capacity and what charge I do gain is quickly used in the evenings. Is it bad for the battery if it does not charge fully? The factory setting is to stop discharging at 4%. Is there any advice you can give to maintain the batteries life?

What tariff are you on? If you can charge upto 50% on an cheaper night tariff, Solar PV may make sense as a top up mechanism for the next 2-3 months?

sewingqueen

Thanks for the replies, I'm on a one 1 rate tariff that is fixed for 2 years. Fixed in at Aug 21 prices so considerably cheaper than any new tariffs on the market. Moving to 2 rate is something I will consider for next winter.

EcoScruples

I'm not sure what other batteries have in place but my Huawei has an optimiser built in so it tops up the batteries to different levels when they're low.
Sometimes it's 200w sometimes it's 2kw.
Most of Nov they stayed at 0% (although I doubt this is actually empty) so if they run this way and guarantee them for 10 years I'd imagine your batteries will be fine.

ispookie666

@sewingqueen
Batteries have an efficiency of 95% and I suspect the round trip is around 85%, maybe you can charge to 15% to keep the batteries charged just enough?  But I would strongly suggest to charge it to 100% at least once every week or the other week.  

Givenergy batteries are notorious for not sticking to the set lower limit of 4%!  Mine often go down to 0% even though the set % is 4.  I'm pretty confident my batteries are taking a beating.   I charge for 6 hours using the E7 tariff.  

At least on paper they have mentioned unlimited cycles and 10MW throughput 10 year warranty(but will not trust a word they say)

Waywardmike

My Growatt is hardly charging from the sun at all at the moment, in fact there's only been one day in the last 7 where's it's charged much at all and it only got to 24%.

At 10% it stops supplying the house.  When it drops to 9% (leakage?), It charges back up to 12% (at around 200w), then discharges to the house again till it hits 10% and stops again.  It's currently doing this about twice a day.  I'm assuming this is to prolong battery life as it stops it discharging fully.

Reed_Richards

I can adjust the minimum charge level of my battery.  In the summer this is set to 10% but at the moment I have it set to 25%.  This is mainly because the battery slowly "leaks" charge and we have too many dark days at this time of year.  

Rheumatoid

Reed_Richards said:

I can adjust the minimum charge level of my battery.  In the summer this is set to 10% but at the moment I have it set to 25%.  This is mainly because the battery slowly "leaks" charge and we have too many dark days at this time of year.  

I have mine set to 15% but also to force a charge when they reach 10%. do you not have a force charge setting? Seems a shame not to utilise 10 just in case.

sewingqueen

@ispookie666

Found this article from give energy which explains that when your app says the battery is at 4% its actually more like 15% because of a reserve you can't see

https://kb.givenergy.cloud/article.php?id=10