* NOTES SINCE PUBLICATION * 1. One benefit I failed to mention was that having a near-full battery most of the time really helps in the event of a power outage, which could have any time. 2. If you have an oversized array with a DC-coupled battery and your inverter supports charging of your battery with solar generation above the AC limit, it may be more financially beneficial NOT to charge your battery overnight when it's going to be sunny - instead charging it using a strategy that maximises that feature.

Another great video which really chimes with our situation. We fitted 9kW of solar (6kW peak E/W arrays), EV charger, solar diverter and two powerwalls (27kWh) in March 2020. Back then the aim was to self consume as much solar as possible as the tariffs at the time did not reward export. We exported less than 10% of our solar then but everything has changed with Octopus intelligent Go. We now charge the powerwalls, heat our water, charge cars etc. overnight and export ‘everything’ we generate while running the house on the imported overnight energy in the powerwalls. As of today we have exported over 70% of our generation ytd and expect to be net zero electricity cost for the year including two plug in cars and an ASHP. I don’t expect this tariff to remain unchanged (too good to be true?) but it highlights the advantage of having a flexible system which can adapt to a volatile and rapidly evolving tariff environment.

Good to know I got it right using much simpler modelling spreadsheet, but also good to know your about your model too Gary. I think it’s fabulous that Octopus give a high enough export tariff that it pays you to charge overnight and export in the day. They are actively helping to balance the grid in this way.

For me a fully charged battery means more export and since Octopus upped their export payment to 15p is incredible. Paying 7.5p overnight is a win win. Also it is nice to know we have some cover if there are any power cuts.

Thanks Gary, good video. I'm in Canada and just finished installing my solar system and that's my exact plan. One other benefit with a full battery at night is that you will virtually always be ready with a full, or close to full charge if the grid goes down.

Another fantastic informative video. I regularly forward them on to friends and family who are either considering PV and battery systems or really should.

Another great video, if you have export at double than import it's a no-brainer. Now into spring I'm exporting by 8am. Best move I made was oversizing the array to the inverter.

I have to manually control charge and discharge as, now with decent irradiation I try to deplete my 2 SolarEdge energy banks to allow them to take some charge from ordinarily clipped power. My 10 kWp array can generate 9kW and with a 6kW inverter 3kW would be wasted. It’s tricky but satisfying when you get it right. Very informative video await the next in series

I've been on Flux for a year now, and have been doing this all that time, currently off peak import is 15.175p and day export rate is 15.652p. There will be some efficiency losses, but the cost is so small its not worth worrying about. I charge for exactly the reasons stated, no need to worry about what the weather is doing. I have an 8kW inverter and 29 kWh of batteries, so come 4pm I force discharge to 45% SOC charge, which gains me quite a bit every day - currently exporting at 7kW, DNO approval to 11.68kW as I also have another AC connected inverter.

Very interesting. I will admit i've always set to solar only historically, but this might make me change tact

Hi Gary while I commented earlier this is my current strategy I’ve just discovered why you maybe wouldn’t when guaranteed sun. My inverter will export its maximum kw ( ac ) and charge the battery at the same time if you have solar PV over the rating of your inverter ( not all inverters may do so ) but my 5kw inverter can export 5kw and charge at 5kw simultaneously. I have 7.5kwp so there is a case for charging in the day so I wouldn’t be impacting/reducing any export 👍👍👍👍

Good video. I've got a very complex node red flow controlling my ESS which does a similar thing to what your software does. On intelligent Octopus Go. I look at the next day solar irradiance, battery SOC, and predicted consumption. Then at 23:30 I adjust the charge current for the 6 hours and it works really well. Keeping the charge current as low as possible allow the system to.run at maximum efficiency. It's rare that I have off grid days and find it always charges at night. I'm either running of cheap off peak or free energy from solar. 😊

If using Octopus Intelligent Flux you can generally get the best results by charging to 100% just before the peak period (using your modelling).

Thanks Gary. I always charge the battery overnight. I’m currently on Agile with a small PV/battery system. My last few bills have an average import rate of 12p, so Agile is working well for me. The only thing I might manually do is to inhibit battery discharge during the late morning/afternoon until the 16:00 import peak starts. I do this particularly when the daytime and overnight import rates are similar (like in the last week). However I think I’ll do some calculations to see if the other tariffs are better in the summer. Keep up the great work!

In Ireland we have some tariffs where we can import as low as 5 cents per kwh and export at 25 cents per kwh. Its only a 3 hours off peak window so that creates challenges depending on battery charge rate. I always charge each night regardless of solar forecast. I have an automation in home assistant which runs at midnight. It checks if the battery SOC if above 40% and the solar forecast is above 5kwh the next day and if it is it dumps it for 1 hour which works out about 3.6kwh export. From about March onwards this has been working well for me.. start most days with already having exported 3.6kwh... there were some gotchas - if i had the car plugged in or the eddi solar diverter set to 'on' the export would go into the car (if plugged in) or hot water. I've automation on these which switch them on at 2am and off at 5am.. (my tariff window) I have 13.6 kwh usable battery and 7.1 ish kwp.. seems to be very similar to Tim from Tim and Kats green walk channel.

Another good one Gary. I recently switched to Octopus Intelligent Go I have now changed my charging routine. As you suggested, I now charge my batteries overnight between 11.30pm & 5.30am without exception. I also charge my car & run any appliances overnight that have a delay timer all on the 7.5p/kWh night rate tariff. In addition, between 11.30 & 5.30am I prevent / pause my battery from discharging (GE Portal setting). This prevents the car, or anything else, from draining the battery overnight & ensures I start the next day with the highest possible battery SOC. If the sun is out next day then I'll be exporting to the grid & earning 15p/kWh as early as 7am & for most of the day (ESE array). If there's no sun then I run my house from the 19kWh of stored battery energy plus whatever solar is available throughout the day. I'm already seeing a dramatic reduction in our monthly energy bill by way of generation credits & best of all I don't have to watch the weather any more like a Met Office geek!! 🌧🌞

Definitely my strategy in winter with Intelligent Octopus Go, but in summer I want to limit my DC charge due to an oversized system

Great video. I have just had my export tariff set up so can get payment for export at last. My problem with overnight charging of my battery is that my array peaks at 5kW when the sun shines but my DNO restricts export to 3.6kW. I guess I would only charge the battery overnight when the forecast is cloudy. Maybe even restrict the battery charge rate during the day to lengthen the window when some of the generation was going to battery (when it’s sunny)

Great video. I wonder if the next stage is for the app to calculate the best possible tariff given location, array & battery size etc

Very good Gary. Something I considered a while ago and realised whatever you put into your battery in excess of what you need gets exported and you get paid back at twice the rate on Octopus Intelligent Go for example. However, have you considered what happens when the battery reaches 100%, say two hours into the six hour charge period and then you run for four hours supplying the household load from grid which is possibly significant such as a heat pump? That four hour period is a grid draw and expense that isn't recovered by export. Arguably as soon as the battery reaches 100% it would be better to stop charging and start to consume battery charge. Even better would be to delay the charging so the battery reaches 100% as late as possible making export happen as early as possible. I must admit I've not modeled this yet as I've only just considered it. It's the long six hour off peak on Octopus Intelligent Go as opposed to standard Go, where my battery struggled to reach 100% over most of winter, that's highlighted the issue. I was wondering if it's better to stay on Intelligent Go or switch to Flux over summer as I had presumed was the best thing to do. Flux has a better export rate between 4pm and 7pm but doesn't have as cheap an overnight import and for only half the time. However if you can't charge the battery with the extra cheap hours because it's already full that dead time won't turn into earlier export so perhaps Flux regains the advantage. For the moment I've set my Intelligent Go charge time to three hours whilst I think about it.

We are currently on Flux and about to switch to Intelligent Go next week when our EV arrives. I had been trying to keep some space in the battery and adjusting charging rate to avoid clipping during the day as we have a 5.5kW inverter and 6.5kW of PV, but with the UK weather being what it is, it’s quite different to judge. I think I’m going to revert to the fully charging overnight strategy.

Another clear video, thank you! What I don't see in your modelling is the losses which mean that when you put 10kWh into a battery, you'll get less coming back out. For our installation, the installer estimated the total round-trip loss occasioned by the battery and the two trips through the inverter to charge and discharge as about 10% in total. I've no idea whether I'm seeing that sort of loss or not, but any loss means that paying to put charge into the battery and then selling that electricity back to the grid as soon as the sun comes up is not quite as profitable as just looking at the import and export rates suggest... I'm not suggesting that charging overnight is a bad idea, I'm just noting that whether you charge your battery to 100% on the grid, or on the solar, you'll lose quite a bit of electricity on the round-trip through the battery. Then again, I'm coming to the conclusion that absolutely nothing in this game is quite what it first seems! All the best, Gary...

Gary, great video and analysis. My concern with charging the batteries overnight to full (I am on OIG) is that my 20kW pure drives with a sunny period never deplete, they are cycling between say 70% and 100% is this good for my PuredriveII's? not so sure, does the earned money offset the reduced SOH? any thoughts?

This video really makes a lot of sense. I am on octopus intelligence with my system consisting of 4kw sola 10kw Puredrive batteries a 5kw inverter and an ev, i charge up every night but as he says in the video my batteries are usually 40-60% full by the time it needs charging so i usually don't need much overnight except in the winter when my batteries very occasionally runs low during the day and we use the grid for a hour or two in the late evening. I export a good amount for a small system and it really has cut my electric bill by much more than half even with an ev. I make sure i shift my washing machine and dishwasher to the low night time tariff to get the benefits of 7.5p per kw. And when i get an ashp and water tank i will be doing the same. The information in this video is accurate as i came to similar conclusions months ago while working out if was going to be viable.

Hello Gary Loving your channel. I have one question: Most of the tariffs you mention require an EV to sign up with them. The switch to Intelligent Octopus Go or even Octopus Go require a successful test charge to be eligible......I don't have an EV and probably will not get one. Are there any other tariff options available that you can recommend? Keep up the excellent work.

Hey Gary. Another super interesting topic. Do your calculations account for losses into and out of the battery? In North West, our regular flux export is only 0.05p more than the flux low import. Be interesting if the losses make it pointless to charge. I've been tweaking my home assistant setup and it's gotten pretty good at correctly deciding if to charge or not.

Nice video thank . Only thing for people like me who have restriction on how much we can export , it is not that straightforward . The MPTT's will throttle down if production is too much to match export limit.

Really interesting video again Gary. I was wondering if your utility takes into account oversized hybrid (DC battery coupled) inverters. I have 7.38kW of solar running on a 5kW hybrid inverter. I do use weather compensation to determine how much to charge my batteries overnight moving away from fixed charging in order to maximize the amount of generation. What I had noticed with the fixed charging times was that by about 11am the batteries were full and my solar generation was "clipped" to the 5kW inverting capacity of the inverter. Being that I have a DC coupled battery system, then normally what would happen is any solar generation above 5kw could be put into the battery. I therefore have several options open to me. The first is to use weather compensation to not charge as much or I could also restrict the charging current to the battery over the day (sending any excess generation to the grid for a nice export payout). In either scenario however if my battery is full, even though the solar panels have the capacity to generate more, they'll be clipped to the 5kW once my battery is full. If you don't already factor this in, it would be an interesting case study (and more that happy to share my actual solar generation figures if that helps).

Nice video. One scenario to consider. Dump some or all remaining power at night. For 15p. Then put it back in for 7.5p. Downside is battery wear

Hiya, Agile for me, I have 4 KW panels and 12 KW batteries. I have my lux hybrid inverter set to automatically charge overnight when the 30 min segments are at lowest prices. I always take advantage of the negative pricing plunges and saving sessions. I guess going by your excellent video I have been doing it right from day one, my roof is south facing which really helps my generating. The fly in the ointment with all of this is the standing charges, do you think octopus will better the 15p fixed export this year?

Hi I am with flux and charge the battery every night Usually by 0930 mid April my battery is fully charged (if sun out ) rest of the day export It’s a no brained the export rate and night off peak are virtually the same so with earlier 100% getting max return during the peak sun time

Great video again Gary but, theres no mention of clipping. How does the utility deal with this, if at all?

Charge my Soalr Battery every night (11.30pm-5.30am) + any extra IO Slots (I've got HA Running) and then i export at 15p per kwh, but i buy it at offpeak at 7p.. making me negative £20 per month. I also sometimes force discharge my battery at 15p to then refill it at 7p - but this exclude battery wear etc.

I still can't work out if using Flux to charge my battery overnight is a good idea or not. I don't have an EV so it's either Flux with overnight charging or the normal variable input/fixed output tariffs. I just can't get my head around which is best

Yep I charge regardless with flux. No faffing around and I know I have a full battery most of the time in case I need the emergency power too. It’s a no brainer.

Thanks Gary. Another interesting viewpoint to consider. Many battery systems allow the limiting of the soc from the grid to below 100%. However, not so with solar. So even if I limit my import to recharge, the battery still fills to 100% from solar before export occurs which is a little annoying. Batteries don’t operate well as they approach 100% charge hence we are often told to limit the recharging cycle between 20-80% to aid battery health and stop degradation. What is your view on this and can your modelling accommodate such scenarios?

Great idea. Q: AC coupled inverter - does the AC from panels go 'straight thru' to the grid without converting twice (AC into battery as DC then out as DC into AC) thus saves c6-8% generated power?

Gary, thanks for another interesting video. I am currently in receipt of FIT payments which are based on a notional 50% export. Now I have a battery that's never going to happen 🤣 Do you think Octopus Go / Intelligent Go will support export payment if I am on the FIT scheme? Obviously that would be a nice additional benefit!

My panels will be on a southwest facing roof so will be maxing generation during the peak time of 4pm (to 7pm). So for a forced discharge to grid at peak time (4pm to 7pm) will the 6kW inverter be discharging the 13.5kWh battery at 6kW whilst allowing the 6kW panels to also discharge at the full 6kW?

Is there a way to avoid self consumption of solar during the day, perhaps by steadily discharging the battery during the day, increasing as needed to cover consumption peaks and exporting an excess? This would avoid having the battery sit at 100% most of the time and avoid needlessly recharging the battery during the day, in the event it falls below 100% (as long as it discharges along an acceptable "flight path", so you don't run out while cooking dinner)? I can't seem to find a combination of settings to do this with my GivEnergy battery, but wondered if I could automate via Home Assistant.

Thanks Gary. You have put a lot of hard work into your channel. If battery loses are factored in, then at the current flux rates the profit is only 1.8p/kwh-exported and for the IOG 2.5p/kwh-exported. I have a GE 8.2kwh battery. You will get very interesting results if you ever test the efficiency of your battery. Certainly different to the app readings.

Maths don't lie - good video. How does this model pan out with Agile charging to 100% with a fixed 15p export? Guessing some days will be better/worse than others depending on the varying slot charge price used.

Only thing is my 3.6kw hybrid inverter doesn't clip the solar when it's charging the battery so I can actually generate more if I don't charge the battery. For example if my battery is at 100% the solar is clipped and my max output is 3.6kw. If however it is charging my battery I can see a solar generation of 5.2kw until the battery is full so I limit the maximum charge rate of the battery to stop the battery filling up too quickly. Just another thing to consider 😁

If you're on a wholesale plan like Amber in Australia you get charged for daytime exports so it makes no sense to fill your battery at night and then get "taxed" for exporting in the daytime.

Ref comments about night time content of grid, of total generation Nuclear is 16% biomass 5% wind 29% , day vs off peak demand looks to be around 30% so if wind is generating then off peak grid should be pretty much fossil free , on very calm nights across a large proportion of the wind farm supply base ( unlikely?) there could be a smaller fossil content compared to average 45% gas.

Hi Gary, how do you get export costs of a £300 per day? Surely based on a 10 kW battery calculation would be 10×0.25 if the export rate is 25p ? Great video by the way. Thanks for doing this

I can’t get these tariffs as it’s a business address. We have 8.7kw solar and give energy 13kwh battery. We use about 8000 kWh and produce 5500kwh per year. Usage is Monday to Friday 8-5. I am actually thinking of agile octopus. But charging overnight and a second charge 2-4pm. I’m not sure if the extra cycles will harm the battery? The daytime charge is probably the most important ref the agile oct tariff as fees so high in the evening.if you have any thoughts that would be great and I’ll check out the software also 👍👍

I’m on a FiT tariff- which makes it much harder to know if switching to a measured export will save me money over charging the battery. At the moment I am set up to avoid export whenever possible - but the advent of export tariffs make this much harder to figure out. Any advice?

It's worth noting that you can import and export electricity from different providers. I import from Octopus Energy and export to Scottish Power.

is your flux example accounting for inverter losses of 7-10% ? my calculations are in those specific case its better to let solar charge the battery when guaranteed

Ummm, what about round-trip losses? Does your calculator take those into account for various types of inverter?

I get paid 15p for export. Any time import is below 10p it makes sense to charge the batteries.

I came to the same conclusion as you for Intelligent Go. However it still irks me to export more of my solar, instead using overnight, which is often less clean than the solar. Still, 15p export vs 7.5p import is worth having. I wonder if anybody has tried force exporting their battery every night at 23:30 to see if this also generates 15p income?

Great video Gary. I have solar and 48v FLA battery power.

Even more to be gained if you force export the battery as well 😉

Hi Gary iv commented before re: batteries we were offered a 2nd battery for £1500 when we bought our system but we were already at £12k and basically thought how far do you go? Was disappointed when we saw a buy one get one free a few months later, rang up to see the price now’2k plus vat’ Just had an email offering an additional battery 1- 1485 - pretty much same now VAT been taken off 2-2550 3-3500 they’re only 3.2kw I know it’s more money but I really do like the buy it in the night sell at teatime 😁 what are your thoughts would we get our money back quickly? Once again ‘how far do you go?’ We’re on Octopus flux.

Hello Gary, good job with the videos. I'm on my own experiment currently. I have PV, Powerwall and a ASHP. This week we have been self sufficient from solar with battery. No imports, but very little money making exports. Next week I'll set the TEG to maximise making money, ie, charge overnight and export everything with the Octopus Flux tariff. Hopefully it will force discharge between 4&7 (on top of exports in the day) with enough to get us through to the cheaper period. Luckily we have had decent sunshine this week.

does this take into account the cost of approximately 10p per kwh per cycle on the batteries?

Thanks Gary, you will doubtless get lots of comments about specifics of the modelling scenario. For Intelligent Go, I agree, the overnight import rate is so much better than the export rate that it does make it worthwhile to import overnight. For Go and Flux, I’m not so sure. For Flux in particular by the time ~15% conversion losses are included I think you’re definitely better off not charging overnight, or if you want some contingency against poor solar, only do a partial charge overnight. In fact partial or no charge has the additional advantage of reducing the impact of solar generation clipping as you can trickle feed the battery during the day from solar to avoid generation or export limit clipping occurring. All good fun and a model like this makes it easier for people to understand the trade-off’s

Does your app factor in losses? I.e. My Powerwall losses 10% of the power charging and discharging, I buy 1kw at 9p but it cost 11p by the time I use it.

Thanks ive been asking this question for a long time as i live alone with a Powerwall so i stayed on the standard tariff . But will i still be able to keep my FIT payments on top ?

Another very useful video, thanks. I spent some weeks deliberating what to do and this backs ups my findings. I'm on Flux, with a 5.8kW south facing array and GivEnergy battery and inverter. Was charging to 80%, the risk of pulling in at peak in the evening put me off, so charge to 100% now.

Hi Gary, one point you didn't include in your " better for the environment" argument is that most of the energy from the grid overnight will be generated by burning gas. If this is valid it will get less environmentally beneficial as our (UK) nuclear generating capacity declines as existing power stations are decommissioned and the replacements (on past form) fall further behind predicted commissioning dates. Have I missed anything? Mike

I'm on octopus. My system has 12kwh battery. 5.2kwh of solar. I charge to 50% at night. My heating is electric and my system can run the house if there is a power outage. This week so far (Monday to Friday) I've paid £2 import and been paid £6.22 for export. And it's only been sunny for about 50% of the time. Also for the record the max from my panels coming in I have seen is 4kwh which impressed me a lot. My solar system has meant my energy bills are 25% of what they were. If you can get solar now. I really hope the price keeps going down so others can join in. 🤞

Gary, when you charge a battery overnight you are using gas generated electrcity. Wind and nuclear cannot increase output becaus ethey are alreday at maximum available output and the balancing generation (Gas) will provide the power.

I live in N.Ireland and it's so far in the past with tariffs that I'll probably be dead before they've introduced a smart/intelligent tariff. All export is limited to G98.

I have been doing this following one of your previous videos. This month I have imported £22 and exported £30. I am very happy with that considering it is April. I turn my battery off 12am to 7am. I am normally now exporting by around 8am on a good sunny start to the day. Last year I was on Agile Export which was a mistake. I am now on the 15p export rate and that has made a big difference.

Financially just do a sum of the forfeited feed in tariff vs the time of use off-peak tariff ss experienced - IF you are on "octopus" or some other market exposure plan - just ensure never to export in negative pricing, nor to charge during peak surge prices... (Environmentally - head to the hills and live in a cave...) I have no time of use offpeak (nor an automatically load shedding battery setup), and can ensure some energy whilst charging during the day - even in heavy clouds, half of my daytime charging will still be subsidised by the sun... In my country (Australia) - when assessing real market exposure (Amber Electric), we are often getting negative FIT - real wholesale pricing - during the day and still hit with the grid access charges for offpeak demand - arbitrage does something bt it does need significant investment to make pennies regularly...

Is there a reason you weren't starting at 0% charge and ending at 0% charge? Surely utilising the full SoC during a day is the way to maximise revenue generation and therefore payback period for the solar/battery? Obviously limited by inverter capacity and number of overnight hours at the cheap rate.

Great information and analysis, Gary. I live in BC, Canada - can your solar and modelling utility be configured for CND and BC Hydro rates, etc.? We have time of use rates becoming active, and many of us with solar and batteries are very interested in using a tool like yours. Many thanks!

you could go a step further with IO and force discharge the battery just before 23:30 and then fully charge. This would increase the cycles slightly but you’d gain a little more too much

Thank you Gary! Superb help! According to your data I should really get one more 3.3 KW battery to have 9.9kw total! Which reflects the truth as winter time on our high usage days we run out of juice and we use peak rate electricity.

It's the first time you leave me scratching my head Gary, so I will have to check my own numbers again. Whilst I do add 5 kWh to my SE battery in the Flux Off-Peak period, I don't fill it to full - I leave some remaining 'space' to reduce import costs and to allow room for the solar to top-it-up in the morning (normal day), or in the afternoon (a seriously bad day). For me the maths does not work if I charge from grid to full in the off-peak. The small cost difference between normal hours export and off-peak import are not sufficient to overcome the AC->DC efficiency loss when charging the battery from pure grid power. Indeed, the efficiency lost when filling the last 10 to 20% to achieve a 100% SoC is particularly noticeable; so I only allow that to happen with direct solar DC power. On a sunny day I have more of an issue with what to do with the excess solar. My 8 kW inverter tops-out at 10 kW AC - the house takes around 600W, so the remaining 9.4 kWh is off to the grid. The battery is usually full by this point but in the rare occasion it isn't, I still get 9.4 kWh going off to the grid but now the battery can charge from the otherwise 'clipped' DC as it bypasses the inverter limits. Even in April I have seen 11.4 kWh split between battery charging, house and grid. Not bad for an '8 kWh' inverter! I also don't empty my battery during the peak export period. Indeed, just half an hour (2.5 kWh total) produces noticeable income whilst getting the battery to overnight charging period with circa 20% remaining. I have also added some 'padding' times to allow the battery SoC to settle and, of course, it only gets to 100% once per day. Other than the fixed 5 kWh import and 2.5 kWh export period I am either off-grid or exporting power for the other 22.5 hrs in a day - come rain or shine. I'm still learning though and beating the SolarEdge controls to do exactly what I want is quite an effort!

I've been doing this since SEG increased to 15p/KWh. Charge up my home battery overnight to 100% at 7.5p/kWh. No brainer really...

Thank you Gary, another fantastic video. I am on Octo Intelligent and charge every night simply because you can't really predict PV generation and my ASHP eill kick in anyway early morning to heat the house before we wake up. Do you think it's worth exporting to the grid any remaining energy before the 23.30 off peak starts? Does it shorten the battery life if done every day?

Hi, good application. could you add the ability to import the current agile rates?

Hi Gary, thanks for the videos, always engaging. I've thought about this question a lot. I'm on Flux but tend not to charge overnight in the summer months. In fact I stopped this about 3 weeks ago. I just can't see the benefit of charging in the summer, as you say it depends on the individual set up, but for me I can't get away from the feeling I'm replacing 0% carbon electricity from my roof with emission creating electricity from the grid. As such, the economics may are the same but overnight charging results in a less optimal environmental outcome. Be interested to know if others disagree? Cheers for all the great work, Rob

Makes sense even with Eco7, as Outgoing Octopus fixed export rate is currently 15p/KWh & E7 night rate is 13.31p/KWh inc. vat.

Driving the weakest cell in your battery stack to the BMS charge cut-off point daily ain't doing it's SoH any good. Not much to be gained from going above 3.4 volts. But yes, what you suggest here is what a lot of people have been doing for a while now. I wonder why you didn't show an Agile example ;-)

G'day Gary, great video as usual. I really like your channel, it's tech enough for geeks but straightforward enough for the less tech oriented. My comment is more of a request... I've been reading a bit about Nickel Hydrogen batteries, specifically as a home storage system. You may be familiar with this tech, but in case you're not, here's a short description: * developed by NASA and used in the Mars rover, the international space station, and the Hubble space telescope, along with many other satellites. * good for 30,000 cycles, or 30 years, at a 3 cycle per day rate * large charge and discharge rate. Not sure of % discharge available, but they talk of between 2 and 12 hour discharge available. * not subject to thermal runaway and will not explode or ignite * to date not used in terrestrial applications due to the high cost of platinum cathode, but a few years ago a scientist from Stanford university developed a low cost alternative to platinum. They claim production costs of $100 to $150 per KWh!! That's comparable to Li-Ion batteries * They're being commercialised by EverVenue in the US, and they're about to open a gigafactory in Kentucky. They are focussing on grid scale and commercial applications till now, but their residential products are under development. I would love to see your take on this very promising energy storage alternative to Lithium based batteries. Especially their longevity! Imagine solar panels, micro-invertors and a 30 year battery! You'd be set for life! Cheers, Michael Brisbane, Australia

Thanks Gary. Certainly confirms that what I've been doing is correct although there are some nuances that haven't been mentioned that can improve one's export gain. It's worth draining the battery in the evening once the sun has set as a forced discharge. Also, I prioritise sending excess PV generation to the grid rather than to battery storage. This also increases panel efficiency/yield as the panels generate max wattage for longer.

Anyone got Octopus Go and not got an EV?

I'm on agile and don't have an EV, but do have fixed price export of 15p , so as long as i can charge my batteries overnight for less than 15p, which is pretty much always.. i charge to 100%// also price tends to drop between 1200-1600 before spike, so i make sure i charge then as well.. working well

For me the short term advantage is not worth hammering the batteries for, will just end up needing to replace sooner, particularly if you export the total battery capacity at peak hours every day to arbitrage the rate difference ( some do) . Compared to just using the battery for storing excess solar to use later that day , the daily charge/discharge regime is around 1.8 x higher use of my battery over the year. In my view it's not worth it, I'd need to install more battery capacity to avoid the pain of higher daytime rates during the winter which would take a long time to re-coup and I see a real risk I wouldn't achieve payback before batteries that are fully cycled at least 1x per day need replacing. (More than 1x cycle per day will happen if you charge at night and then get solar later in the day after batteries have supplied the house for 8+ hours already, recharge in the afternoon and then discharge over the evening ) For our use case (home most days) it's better to stay on flat imp./ex. rates, so not charging at night.