Does anyone know if it's possible to get the battery display in the beta portal to show the current charge in kWh instead of %? It'd be a lot easier to do the mental arithmetic of "how long will the battery last..." without having to first do "what's the current charge".
I don’t think so, but I agree! Maybe put in a feature request? Bear in mind it wouldn’t be hugely accurate, though.
I think a while back i suggested some sort of logic that would give a rough approximation of "how many hours left at current consumption level" - It would be nice to add that kind of thing at the same time, even if it's just done in the browser rather than their servers having to specifically calc it.
I did similar via API which also took into account Solcast aswell BUT all this is going to die in a few months as the APIs it relies on are getting canned. I'm not sure I have the energy to go through that all again!
BarbaraG Given the update frequency on the portal accurate would be pretty pointless anyway wouldn't it. My thinking is that the battery management software must already be running a conversion from the battery cell voltage and amp-hour data to generate a percentage, so changing that logic to output the actual calculated value should be fairly simple.
hoggy Doing it in-browser should be fairly simple - they'd need to add something on the database side to the account details that would show your total battery capacity (or per battery would be better) and then the actual display could be entirely user-side. Something as simple as the current status card flashing between % and actual value in the same way as, for example, grid usage flicks between import and export values.
For any of this to be useful the starting figure for the battery's SOC needs to be accurate. It is not the most reliable piece of information and drifts from the truth over time by an unknown (at least to the customer) amount. Today my battery's SOC climbed to 84% then instantaneously dropped to 0% then climbed to 43% then instantaneously jumped to 100%. Heaven knows what the real figures were at any given time!
I hope this is addressed before next winter otherwise setting a "charge to" percentage is just going to be pot luck on what the subsequent energy available from the battery is. I can foresee the situation where the battery runs out in middle of peak tariff because it stopped charging in cheap tariff when it thought it had reached the requested "charge to" percentage but actually had not. Having a reliable SOC figure is a fundamental prerequisite for a customer to be able control their battery system.
EV manufacturers must have found a way around this as you don't hear of cars displaying "40 miles of range left" and then stopping abruptly because the battery is flat.
Woodstock Yes that is a good point.
Have they not got to the bottom of that yet? I'm lost as to why only certain people have this issue, mines been in since 2020 and (as far as i know) has gone through every firmware.
It religiously reports the correct SOC without all this oddness stopping at a %'age it shouldn't, bouncing around and so on.
Must be quite frustrating really.
hoggy I am starting to think that maybe this has something to do with how the batteries are used. My battery can go for days or weeks without the SOC showing discharge down to the 4% reserve. During this time the reported SOC seems to get further from the true value until there comes a time when the battery really is empty while still reporting a considerably higher SOC %age figure. At this point the reported SOC plunges to 0% and an auto AC recharge kicks in to bring the battery up to a reported SOC of 4%. I wonder if people who frequently take their batteries down to the reserve %age (the majority?) are getting the SOC figure realigned each time and so don't suffer from this weird behaviour.
Woodstock Just to chip in here. My battery drops down to 4% reserve almost everyday and I have to say I haven't seen any SOC oddities, even at my 5s update resolution via GivTCP.
That said I have had the odd occasion where it jumps from 80% to 100%, but this is due to one or more battery cells hitting the limit.
Woodstock As with others here I'm generally not seeing the same problem. I definitely did have it over winter and I suspect that it was connected to the battery being charged significantly for the first time since installation (which was last October). The issue occurred on pretty much the first day we managed to charge it over about 20% by solar. Since then it has been pretty reliable so I suspect that routine charging up to high or full capacity, followed by a discharge down to 4% (my minimum buffer) is keeping the BMS properly calibrated.
As you say EV manufacturers must have sorted this though I suspect that in that setting the BMS for the vehicle is being far more aggressive monitoring the cell states and thus can be more confident of the value - something I imagine a household battery simply doesn't have or need most of the time.
MRich What you and Britkat have reported makes me jealous! From my perspective the only reported SOC figure that can be relied upon is 0%! (When my SOC reaches 100% the battery can continue charging for anything up to 15 minutes). It is as if the system uses a way of determining full and empty that does not involve the SOC figure. The problem is that operation of the system between full and empty does!
@Woodstock The top 1% definitely is definitely bigger than the bottom 1%! If my battery is charged to 100% overnight, it will cover the background house load for at least 2 hours without dropping from 100%. Guess it's just the way it's all based around the internal battery voltages.