Most evenings I'm charging to 100% irrespective of whether I feel I need the full packs the following day (2 x 9.5). As we have ASHP, this will likely become every night as the weather gets colder.
I see mixed advice regarding whether this is a good idea or not with respect to battery longevity. What's everyone else doing please?
Don't see the point in buying stuff if you're not going to use it. My battery goes from 4% to 100% and back almost every day.
Rubikcube I don't agree in general with the first part of your statement.
But in case of a battery that has an unlimited warranty (OP check your small print), there is no reason not to use what is available.
I take the point about unlimited warranty. I was more concerned about degradation over the years and getting to the stage where I need to replace faster than I'd expected. I guess my (possibly unwarranted) concern comes from years of looking after Tesla batteries, although a different battery chemistry. That strategy has worked very well with minimal degradation.
My GE batteries are working harder than the cars, but it would still be good to preserve them as much as possible as long as it doesn't require a lot of faff. For example only charging to 90% where I can get away with it. However, I can't find any definitive guidance as to whether it's worth it or not.
I think the batteries are actually larger than advertised and the usable portion sits in the middle of this.
When you charge to 100% you're not actually getting to 100% of the theoretical capacity, same as 4% not being right at the lower end.
I fully cycle my battery on average more than once per day. The 8.2kWh batteries do have 10 year unlimited cycle warranties.
LordHippos Yes, I saw that and it will definitely help. Any idea what that top end buffer is please? I rarely cycle down much past 10% other than the occasional bottom end self-calibration, but I'm hitting the top end regularly. If that was, say, effectively 90% or so, particularly given the LFP technology, I'd have few/no concerns.
This isn't gospel but for the 8.2 think it was actually around 10. 9.5 should have a similar buffer built in.
LordHippos Excellent thanks. It would be handy to have some guidance from GE on this, but maybe there is and I just haven't found it yet.
Another "concern" I have is charge rate. Batteries prefer gradual charging to help minimise degradation apparently, so where we have time on our overnight tariffs, should we be ramping the charge rate down or just going full tilt? I guess a throttled charge rate could be automated if it was actually beneficial. Maybe I'm overthinking it 🙂
I don't worry too much as the gen 1 inverter is limited to 2.6kW anyway, and it takes 3.5 hours to get from 4% to 100% on the 4 hour Go charge period.
In theory yes charging slower is kinder on the battery, but I don't let it worry me too much.
I've cycled the battery 554 times apparently since my install last September so easily more than once per day.
sponev Another "concern" I have is charge rate. Batteries prefer gradual charging to help minimise degradation apparently,
That's my understanding as well, I've got a 5.2 & a 9.5 so try to charge them at about 1700 watts over my 7 hour economy slot to gets me to an 85% target and seems to keep the inverter temp and the battery temps at sensible levels. That just leaves me with a bit of headroom in case it's a good solar day. and just about scrapes in if it's a poor one.
The one thing I would like is the ability to have a Day-time / Night-time 'Charge Power' setting so that it would automatically change between the low rate at night to a Max rate during the day & vice versa
SilverArt I'm thinking similarly. Even if it saves the battery a little and it's not too onerous, I'd likely adjust to minimise any adverse effects. At the moment 19kwh is keeping us right without peak rate import but I think it will be marginal come colder weather (we have ASHP). So I'm keen to preserve capacity as long as possible.
I think it's still upto date but I did a thing on Givenergy battery capacity here: https://wiki.terravolt.co.uk/docs/givenergy-batteries/
SilverArt The one thing I would like is the ability to have a Day-time / Night-time 'Charge Power' setting so that it would automatically change between the low rate at night to a Max rate during the day & vice versa
Have you actually checked if it was necessary. I had been setting it down to 1kW for overnight charge, and then back up to max for the day, but this morning I forgot to increase it, but it was still charging the battery at 2kW or so. I'm now thinking the charging power limit might only apply to AC charging.
hoggy Really useful thanks. So it does seem that there is decent headroom.
DD Mine's an AC3 and that does as it's told, if I leave it at the 'night-time setting' it exports the excess.
SilverArt I've got a 3rd-gen hybrid, and I'm not even sure if it's discharging down to the charge limit overnight. It didn't seem to the one time that it was above the charge limit I'd set, but usually I need to add power overnight.
DD Here's what I see.
SilverArt On the evening of 27th, I can see from the portal remote-control log that I set charge limit to 40%. But from the power graph on the 28th, the battery was at 66% at midnight, 65% at 12:30pm when timed period began, then my EV started charging at 12:40, but the battery just remained flat at 65% all the way through to 4:30, when it started slowly discharging to the house again. (The second spike is the immersion heater.) Battery didn't run down to 40% as I had expected. (Wanted to make some room for the solar generation the next day.)
But since I'm new to the system, it's entirely possible I screwed something up.
DD That looks as if the EV and the immersion heater are on their own circuit that is being excluded for use by the. battery. A CT clamp in the wrong position/loose/not working, or a setting in the EV control? or something such like? Perhaps start a new topic to attract 3rd Gen Hybrid / EV users? Might also be worth saying which EV box you have.
I'm also charging from 4% to 100% almost everyday. I have 5.2kwh but DOD its 80%. With 8.2kwh and 9.5 they advertise 100% DOD becouse they made bigger battery. Its wired for me buying battery and not use all available capa ity. Its waste of money. This same when I charge from grid. I set max charging power to 1.2kwh piure to efficiency. With that charging rate my inverter sits in about 35 Celsius. But when I crank charging rate to max 2.6 inverter go over 55 and as we know heat its waste as some energy its transfered to heat so basically its waste.
SilverArt No it's nothing like that. EV is just a 3-pin granny charger. The inverter sees the load (in order to record it). Happened again last night, and I didn't charge the car. Battery was 35% at midnight, charge limit was set to 32%. The battery even stopped supplying the base load (around 100W) at 00:30, and resumed at 04:30, so it's not just particular circuits it can't see.
But yes, this belongs in a separate thread...