Hello,
Does anyone know how many cycles Givenergy batteries are meant to last. I tried to find this info in my doc and online, but I could not find anything. Mine pack has about 700 cycles at the moment, but am considering if this does make economic sense to force discharge batteries at specific times. Max number of expected cycles would help with that calculation.
What size? 8.2s and 9.5s are unlimited cycles. Smaller sizes have limitations.
WhiteGablesBR6 It depends is the answer 🙂
Depends on temperature, charge/discharge rates and depth of discharge.
The cells used in the 9.5kWh battery are rated for 5000 cycles @ 25C; 3500 cycles @ 35C; 2500 cycles @ 45C. That's at a maximum charge/discharge rate of 0.5C.
I'm at 1,306 on mine no problem. Averaging 1.114334470989761 cycles a day if being picky!
Thanks that helps a lot. I have 5 batteries each of 2.6kW. They are about 2 years old, so not the latest technology.
If this depends then, let me state the question differently. I started using automation this month (Predbat - really good software https://springfall2008.github.io/batpred/), but what it does it effectively discharges battery to 4% everyday even when there is some spare capacity as it optimises costs for me and discharges it when rates are high. I am on Octopus Inteligent, so at night and sometimes during the day I get smart slots for 7p so predbat is charing battery fully at those times automatically.
I never discharged my batteries forcefully before and this strategy is new to me. I started wondering if this is actually economically logical, if this kills my batteries quicker maybe it actually does not make sense to discharge battery fully even when I am making some small profit. Hence my questions.
WhiteGablesBR6 Quite a few questions there, I'll give you my point of view.
As you said, Predbat will do a cost optimisation and will charge and discharge your batteries to give you the lowest electricity consumption bill. Depending on your tariff that could involve regular full charge and discharge cycles.
You can turn that off if you want, simply set the Predbat mode to Charging rather than Charging and Discharging and it will only charge the battery and let the house demand discharge the battery.
Or you can set input_number.predbat_battery_metric to provide a "value" in pence for the cost of charging and discharging your battery. https://springfall2008.github.io/batpred/customisation/#battery-loss-options - this enables you to model the effective cost lifespan of the battery and will only charge or discharge if its financially worthwhile.
On the "does it kill the batteries more quickly". GivEnergy CEO has stated that the batteries do not degrade with use and you can use them as you wish without concern about impacting their longevity. The video was I think on the GivEnergy news page about 4 months ago.
Having said that the warranty on the earlier batteries did have a limited number of cycles which roughly equates (from memory) to about 1.5 full charge and discharge cycles a day.
I personally take the view that I've spent a bunch of money on the batteries and I want to get value from them so I'll use them as much as I can do rather than having them sit idle in the garage and not get as much as I can from my investment. Maybe some point in the future the batteries will stop working and I'll have to look at replacing them, but that's a future problem, battery prices are coming down all the time.
TIL that GivEnergy published a new warranty summary last week that says
- The Customer shall:
a. not exceed the Maximum Consumption Usage;
where
“Maximum Consumption Usage”
i) Unlimited cycles when used for self consumption of renewable generation or
energy charged from the grid; orii) When controlled by a 3rd party or used for grid trading, a fair use allowance of
10MWh/1kWh stored capacity applies.
Grid trading refers to the system being used to offer services to the grid whether or
not for financial gain.
or as notified by the Supplier to the Customer from time to time.
Is this new?
In any case, my AIO has a capacity of 13.58kWh, so on the assumption that Predbat actions mean 100% of my exports count as "used for grid trading" then 130.58MWh at my current export price of 15p/kWh would make me approx £20k. Since the replacement cost of an AIO is less than £10k this limit looks irrelevant.
PianSom
Good luck with trying to retrospectively change the terms and conditions of a contract that's already in force!
Zakalwe Especially when they forced GivBack (Axle Energy) down our throats 😉
How do you check how many cycles the AIO has done?
Vestas
Strangely enough, I was never actually given the terms of the AIO warranty when it was installed (a week or two after the 12y warranty introduction) .
And, in spite of the summary saying "The customer’s formal, legal warranty documentation is found in their individual online account", it isn't!
I don't seem to have many lower limbs to stand on. 🙂
gbleeds How do you check how many cycles the AIO has done?
You can check with GivTCP if you have Home Assistant, or the Android app https://play.google.com/store/apps/details?id=uk.rubikcube.invertermonitor&hl=en_US
geoffreycoan There isn't an entity for it in my GivTCP
gbleeds Hmm, maybe this is an AIO thing?
On my gen 1 hybrid the entity is sensor.givtcp<battery serial number>battery_cycles
I looked on the givtcp github and there's an issue for adding battery voltage and temperature for the AIO (and a workaround to create them manually) but nothing about the battery cycles that I could see
https://github.com/britkat1980/giv_tcp/issues/161
Maybe someone else with an AIO can advise, or it be raised as a new feature request (assuming it is in the MQTT data)
The AIO BMS is completely different so most of the juicy battery stuff remains out of reach of GivTCP. Had my post not been deleted you can see them being put together on a factory tour!
You may or may not get 4x cycle readings given there is 4 packs or just a single combined one, it's all a mystery....
geoffreycoan
Nope, Britkat's GivTCP does not report battery cycles as yet.
IIRC it's on his to-do list to do the work needed on AIO batteries. We get no info at all on individual cells, for example.
This is a little bit strage. Givenergy cooperates for example with Octopus, this is the only system that Octopus Flux Inteligent supports at the moment. So why would they on one hand cooperate with Energy supplier to do forced discharges to grind and on other hand stand that in the warranty?
"Intelligent Octopus Flux is currently only compatible with GivEnergy batteries. Got a different battery? Tell us which one and we'll let you know when..."
Doesn't 10MWh/kWh correspond to 10000 (full-depth) cycles? You'd be working the battery pretty hard to exceed this (and it does seem like quite a good life's work for a lithium battery).
Currently GivTCP only works with an AIO if you set num_batteries = 0. Hence no battery info is available. My app also does not give detailed battery info for an AIO.
However I think I know how to get the information (using an android device). Is anyone with an AIO sufficiently interested to volunteer to test this out?
BTW in the warranty summary the key clause is
- The Supplier guarantees that each GivEnergy Product will retain 70% of its
useable capacity for the Warranty Period.
For the AIO 13.5kWh x 70% = 9.45kWh
(And 9.45kWh is about 60% of 15.96kWh - the actual battery size)
PianSom
OK so hence my original question. Does it really make that much sense to discharge battery forcefully? If you get to this point quicker ? Those bateries are not that cheap actually and prices are not guaranteed to fall in the future with all those geopolitical frictions....
Not sure, what do you guys think ?
WhiteGablesBR6
What is the point in buying the battery and then not using it to it's potential? What exactly are you saving it for...that one magic day when we will all be paid millions to use it?
Or is the intention to just use a fraction of it's abilities to preserve a hypothetical lifespan? If that's the case then why not just save money at the outset and buy a smaller battery?
I am of the firm opinion that the only reason why people think this is the insidious propaganda that the FF industry has been pumping out for years that lithium batteries, particularly those powering BEVs, will only last a couple of years, will combust on the last day of the warranty period and end up being dumped in the sea.
In relation to car batteries, the vast majority of the data seems to show that these batteries are remarkably resilient and last far longer than the expectations.
WhiteGablesBR6 Does it really make that much sense to discharge battery forcefully? If you get to this point quicker ?
I think this question puts your finger right on it. Who knows? No-one!
It would be great to do a proper calculation to determine the cost of running a battery through a full cycle in terms of reduction in capacity and so increase in equivalent replacement capital cost. Sadly, as far as I can work out there is simply no proper data available, and there likely won't be for years. And also no crystal ball to tell us whether geopolitics will make its replacement dirt cheap or like hens teeth. So any pricing model you care to build is likely to have VERY wide uncertainties in its outputs, so much so as to make it practically useless.
So - like @Zakalwe - I adhere to the "bird in the hand" philosophy. I bought the battery to use it. I don't abuse it - it's always run within published spec, and I will endeavour to keep it warm in a cold winter etc. But it's there to be used. And the sooner I can make my investment back on hit, the better. At the moment I am getting about 1/3 off the cost of my overnight charge by doing the import/export shuffle with Predbat. And still keeping well within the warranty limits. This will be reducing my payback period considerably, for as long as this pricing system lasts.
But your battery, your decision what to do with it!
There is a school of thought that if you can get a decent tariff, and do your washing and tumble drying at night and charge your EV at night (if you have one), then a battery isn't really necessary! With say a 9.5kw battery installed and commissioned for say £4500 lasting 15 years, it's costing you £300 a year. Plus of course conversion losses of 20% over the 15 years which will vary by individual battery usage.
If you have a decent size solar array, your exports from March to October will likely cover your home use, and yours exports in the summer may well give you enough to cover the winter months import, depending on usage.
As with all things, everyone will have different usage and system sizing, and there is no one size fits all, and of course there's always the convenience of a battery and maybe EPS too.
Personally, I enjoy having the convenience of the battery, and having had my system, including an A2A heat pump for heating, 16 months now, I know that my electric exports with a battery, covered all my energy costs last year (including gas charges, electric import charges, gas and electric standing charges), and I finished up with around £125 profit.
I'm happy with that, and the whole system, 5kw inverter, 9.5kw battery and 5.46 array, including the A2A peat pump was £12,200 and should pay for itself in 6.5 years.
WhiteGablesBR6 Those bateries are not that cheap actually and prices are not guaranteed to fall in the future
Another thought on this, specifically the quote above. I agree, the batteries are not cheap at all. This makes the case to use them to the full even more compelling. Otherwise all you are doing is buying an expensive thing and trying to make it last longer so it still owes you money in 10 years.
Far better to work it hard, maximise your return so the break-even point is as soon as possible. Then you are into profit as early as possible.
Alternatively, nurse-maid it and when it does finally die it will probably not have earned it's keep.
TimHutchings Tim you make a good point. I too like the convenience of having the battery and being able to avoid peak rate electricity charges, but is it actually financially worthwhile …. ?
Model’s I’ve done for adding an extra battery to my setup give a payback of anywhere between 5 and 22 years depending on which scenarios and combination of scenarios I adopt (e.g. save solar for peak rate Flux discharge, overnight charge to avoid day-rate import, etc). 22 years is not good a good investment!
So having got the battery storage I’ve got I’m going to work it and like @Zakalwe get the best return from it I can do.
Maybe if starting afresh I wouldn’t get battery storage as the payback is not good enough and just get the solar panels as they are far simpler and less likely to have issues over the next 20 years.
OK that all makes sense. We also have a2a heat pump and the assumption initially was that we shift expensive electricity and charge battery at night to run heat pump later during the day, so the overall cost comes down. This year winter is extremely warm and I noticed the heat pump does not run that much . As a results we very often end up with about 30-40% of battery left, which I suppose can be dumped into grid. I like, however the idea of having a storage of cheap electricity to run heat pump and do not want batteries to die too quickly. As you all say every one is different and has different preferences.
Overall with more data we all hopefully will make more informed decisions in the future.
Thanks.
WhiteGablesBR6 just in case you weren't aware, when dumping battery to grid, it doesn't have to be at max power. It will honour the max discharge power, and discharging gently (say 1kW) won't elevate temperatures to the same extent, and may be gentler on the battery.
Anyone with an AIO considered getting their installer back in say 18 months to swap the 4 x batteries round (1,2,3,4 to 4,3,2,1) ?
Would this make any difference?
Is one of the 4 batteries the primary and swapping it may make the AIO think there has been new batteries installed?
Sorry just my imagination wandering 😜
TimHutchings To be in profit at the end of the year is very impressive. What tariff are you on?
anthonypar I was on The Octopus standard flexible tariff from Nov '22 with a fixed 15p kw export till April, then Flux from early April till October, and finally Cosy which I'm still on with a fixed 15p kw export. I will be moving back to Flux in March when it brightens up a bit and the days lengthen.
I did export loads last year and made over £770 exporting in the end, as Flux rates were very good. Not sure it will be as lucrative this year, but that covered all my standing charges, gas for hot water and imported electric energy costs over the darker months of Jan, Feb, Nov and Dec.
@anthonypar I’m also hoping to be net-neutral as well this year. I only went onto Flux export in August last year and then Agile from October for the winter, but from mid August to end December 2023 I received £333 in export income and another £55 so far this year.
In the summer once the heat pump is off I should get enough from the solar panels into the battery to run the house for the day and export the excess on Flux
TimHutchings we also hope to be net neutral this year with £800 worth of Flux export offsetting the winter import and tiny amount of gas usage. We run two A2A heat pumps which means we now only drop on to gas heating for a few hours on the very coldest days. We use Flux and IO depending on season. A large PV array and 19kwh of batteries is essential for making this work, so whilst our power bills are now effectively zero, we did make a substantial investment to get there. We also cover EV charging in the equation although not substantial these days. Hopefully Flux rates remain worthwhile again come late March!
Rubikcube I have an AIO installed two months ago. I installed your app 10 mins ago and like what I see. Drop me a line. :-)
(I'm not seeing a way to send private messages on this board. Is that correct, i.e. everything is public?)
SunnyWithAChanceOfPV Yes, everything on this forum is public. If you have a question, posting it here helps both you and others to find the answers.
I hope you find the app useful.
Rubikcube thanks for telling me about it. im just checking it out now. I could never get HA & GivTCP to work and had resorted to my own python scripts for cloud control
When you guys talk about the temperature of the battery; I see 2 figures for temps. One seems to be external and one internal. The external might read 15c but when charging or discharging at the full 2.6kw the internal temp can jump to 35c.Whichh temp is the one to keep an eye on for battery longevity?
I sort of hoped the internal temps might add some heat into the garage. I understand the internal battery temps shouldnt go over 45c or the battery can vent to gas. But can i ignore the external temps no.? I doubt it will ever go above 32c in my insulated garage.
Marren2016 The battery temp in the app/portal is the BMS board temperature, which isn't helpful at all really.
For a Gen2 9.5kWh battery there are 4 battery pack temperature figures (16 cells, 4 in a pack, 4 packs & each has a sensor) which are the ones to look at. You can only do this using GivTCP/HA or @Rubikcube 's app, they aren't visible on the GE app or portal.
Found one of the apps and got some data from it. 
What do the numbers mean?
Marren2016 That's not what you want, tap the battery bar at the bottom and it should show voltage, capacity and temps.