This is for those with Batteries outside. Are you looking to set a slow charge overnight, to keep the batteries above freezing? As if charging or discharging they will keep themselves warm. But left Idle will chill down, if they go below 0C they wont charge.
I have set an automation, that if any battery pack reports under 5C, to set a force charge for 1Hr.
This will warm them up, then they will discharge again.
Process repeats
I have been concerned that my battery would drop below 0 since I had it installed july 2021. But I don't recall seeing it lower than 7 or 8c.
THALL
Mine went below 5 last night. The automation triggered. But didnt charge at 3kw. It charged at 1.6kw. Despite saying 3000w in the portal
Seems that in low temperatures the charge rate is reduced.
I have a single AC3 charging a 9.5 and 8.2. My charge is 2130 til 0230 so it is very hard to get a full 100% charge for me in 5 hours.
Last night, 0230 charged ended sucking 2859 watts. Battery temp was 15C, that temp dropped to 11c around 8am. This morning’s air temp when I left my home was 3c.
I will be very interested in how the system performs over the next few nights. Day temps here are no higher than 2c from tomorrow, -3 -4 maybe -5 for me as I am more rural. My system is kind of covered, like a wheel bin shed so a roof and slatted panels all round so extremely well ventilated but the gaps are small enough no one can get their hand through to tamper with the system (it is on the front of my house!)
TheDragon (GivEnergy) I've been checking the temperature recently for the reasons you state. the lowest I saw a couple of weeks ago was 9°C. The battery is sheltered in the shed next to the house but it will get cold in there so last week I loosely placed a few old sheets over the battery and since then, the temperature fluctuations have been less severe along with the drop when idle. As for the charge rate, I have left at maximum as when the battery is empty, it will take almost all the four hours to fill and that's what I need given the poor generation of late.
On saying that, today is a glorious day! ☀️
TheDragon (GivEnergy)
Hi
Can you tell me how to set an automation please to do what you did based on battery temperature.
Regards
Steve
Forgot to update this, lowest temp battery last night (air temp -1.5c) battery got to 7c for about an hour. Tonigh is forecast to drop to -4 so I will check it again. But performance seems fine, most likely because I ahve a single AC3 charing 2 batteries. Still added 70% total charge.
THALL Reviewing my AC3 history it has never dropped below 7°C and there's quite a number of periods where that 7°C is maintined flat line for several hours. It's almost as if something is looking after it.
cluelesscris Interesting. Mine dropped down to 5C, but I have had the covers off for the last few days, due to lots of firmware tests. Ive put the covers back on, to see if that helps
cluelesscris I've got a 9.5 battery and last night it went down to 2°C. It is located outside, protected from rain but otherwise exposed (which keep it cool in the summer). It has warmed up to 10°C today and I'm going to put some insulation around it tonight to try to stop it getting too cold - not sure I want it to freeze! No sign of any clever internal heating happening.
ajcrewe
If they get under 0C, you shouldn't charge them. Discharge is fine down to -20C. Charging under 0C is not good at all for them. The BMS may even prevent it, I wouldn't like to test that. I'd rarther add a bit of charge here and there to warm them. Hence I was experimenting with the Automation and the lowest Im comfortable with 5C
TheDragon (GivEnergy)
Hi
Can you please explain how to automate a charge based on battery cell temperature
Regards
Steve
SteveCook
If you have HomeAssistant and GivTCP.
Here is my code to achieve this
alias: Force Charge for 60min If any battery below 5C
description: Check if any battery drops below 5C - Force charge for 60 Mins
trigger:
TheDragon (GivEnergy)
Thanks
I have neither of these so have a bit of research and learning to do!
Regards
Steve
Revisiting this thread as winter temperatures kick in and I have an external AIO.
I hit a battery temp low of 5.8*C earlier in the week. I think because we were away so the underfloor heating of the room on the otherside of the external wall was off (and temp hadn’t fallen low enough indoors to trigger frost protection).
Currently I have octopus go so fast charge at 6kw starting at 00:30, finishing 02:30 if totally empty. Should I instead charge the AIO at a slower rate so charging all the way to 0430 rather than stopping at circa 02:30 and so being idle for longer? Or should I fast charge to get more heat into the batteries?
Would appreciate others thoughts on this!
26Left
Nice thread revival!
But I hit an obstacle immediately - GivTCP doesn't seem to expose the AIO battery temperature to HA. For me, at least, no battery temperature sensor. Seems like a very odd oversight, and possibly to do with the fact that the dev has yet to engage with the AIO battery structure.
There is an MQTT entity published called raw/invertor/temp_battery so this looks like a way forward for now.
PianSom AIO isn't fully supported yet for battery data (you can't see what your 96 cells are doing either like you can with the older LV batteries) Author doesn't have an AIO AFAIK, so probably not as far up the todo list!
PianSom ha, thanks. I’m yet to fall down the HA / GivTCP bespoke automation rabbit hole, so stick and rudder flying for me right now.
Here’s the response curve for a 3kW charge rate from overnight. Appears to exhibit the same +6*C temp lift from charging up at half the rate, so looks like a good idea for me to keep it this way and so keep the AIO warmer for longer / later into the small hours.
26Left You won't be able to fast charge at 5C due to the increased cell resistance at lower temperatures. I'm assuming the designers of the battery knew that much at least and built it into the battery firmware.
Charging at 0C or below will cause plating of metallic lithium on the anode during a charge which leads to a permanent degradation in performance and safety - cells with plating on the anode are MUCH more likely to fail and once a cell has plating on the anode its not repairable.
Vestas fingers crossed the firmware has the right logic in that case given all the challenges to date with the SOC drops etc. - especially given the stated operating range. Here’s hoping that I can self manage to keep it above 5*C and so not find this bug/feature…
26Left That temperature range is misleading to say the least!
You can certainly discharge lithium-ion batteries below 0C (in theory down to -20C) but the cells in ALL GivEnergy products do not support charging below 0C.
They've simply copied the operating range from all of their other inverters - none of which contain batteries 🙂
26Left
The next week here has forecast temperature not going above 5 degrees in the day and down to -3 degrees some nights. So a good time to work out how insulated those batteries are.
PianSom Given that GivEnergy support outside installations, you'd think they'd have insulated the battery cells better - like a Powerwall for example. A friend in Ballater (70 snow days a year or so, temps regularly below -10C) has a Powerwall outside and has no issues at all, works like it does in summer.
Some possible thoughts, as mentioned above, charge the battery slowly so it charges throughout the entire off peak period
If you have to, discharge the battery for the grid to warm the battery up, then start charging (they can discharge at lower temperatures than charge).
If you have an export tariff, even better, get paid for that export. Otherwise maybe try to use that discharge in the house.
Plus put some insulation around the battery, but remember to remove it before it gets warmer out again! Don't insulate the inverter.
Also the install guides state the kit should be covered, so if you haven't already got a canopy or something similar, get one installed. Remember to leave the clearances around the units as specified in the install guides.
Had my install a couple of weeks ago. I have my AIO in a brick built outhouse a couple of metres from the house. I've yet to go on a Smart tariff as I am looking at the options. Slightly but not completely tongue in cheek, has anyone considered an electric blanket? Fleecy, low wattage, stick it on a smart plug so you can control it remotely?
Tenkaykev In theory you should have less problems with an AIO as the inverter (with associated heat) is in the same box, should help a bit.
If I had one of the GivEnergy batteries outside I think initially I'd just get some heavy-duty velcro tape and use that to secure some 25/50/100mm* PIR insulation boards to the case. They're easy to cut (stanley knife), lightweight, easy to remove and once you're happy with the results then you can build a more permanent "cover" if you want.
*depends where you are, I'd probably use 25 or 50mm in East Mids
I’ve been doing that for some time. I set my 8.2kwh battery over my Octopus period 23:30-05:30 at 1100kw and it gets it too 100% by 05:00 if the start SOC is at 5%: which it usually is. Battery temp has never dropped below 15c since I did it and it’s on an outside wall.
2 years ago, on 2 separate nights, it failed to charge because it was too cold. So I’ve enclosed it in a wall cupboard & insulated it with Kingspan.
Posted this strategy sometime ago on FB.
Anecdotal evidence time. AIO user.
At my location, for the last three days the ambient temperature as measured by a weather station has been in he range -5C to +5C, with the air temperature being above 0C for approx only 8 hours out of the 72 hours. MY AIO is outside, attached to the wall of my house, under over-hanging eaves but otherwise exposed to this chilly East Anglian weather. My standard usage pattern at this time of year is to fully charge and use mains power in the Octopus Go period of 00:30-04:30, then run down the battery to flat or close to flat, with flat often happening in the late evening. Solar charging has been strong for the Winter during this period - there has usually been a midday full top up. In addition, I manually topped up before and discharged during an Octopus Saving Session.
Over that 3 day period the battery temperature has been in the range 9.3C-22.6C, with the low points typically being just before the charging starts at 00:30. Relatively slow solar charging (3-4kW) only gives rise to a modest increase in battery temperature (a couple of degrees), but fast mains charging (6kW) gives a 10+C rise.
So there doesn't seem to be anything to worry about right now, as the combination of insulation and constant use seems to be keeping things at a pretty stable level. It'll be interesting to see how it behaves if we get an extremely cold and dark snap this winter. But I'm not rushing out to get the PIR just yet.
26Left Hope the next firmware can be more consistent in giving me all the battery capacity back, within 24hrs if it isnt depleted topping back up puts me at around 10kwh before it discharges completely. On 24301 ive had consecutive 0.0 drops when its discharged, it doesn't seem to want to stop at 4% for me, ill find out later if it happens again.