Choosing home storage batteries - GivEnergy vs. SolarEdge

hi everyone it's Tim here again and sat in front of the world's most boring video background uh but don't worry this uh is only temporary we're going to be putting up some much more interesting diagrams shortly but the reason I'm sat in front of this um very boring garage wall is that this is where we're going to be storing or installing our storage battery system uh and I'm going to be explaining in this video uh the options that we've been considering um for what we're going to get installed and why that particular Arrangement might be beneficial to us but there's several options to consider because not all of them have everything that we want so it's a case of um weighing up the pros and the columns and so what I'm going to do in this video is explain the different pros and cons for the the three different systems I'm going to explain to you and hopefully by the end of the video you'll you'll understand the sorts of things that it's worth thinking about when you're planning your own home storage battery system and what the relative benefits and drawbacks might be of those different systems I've tried to prepare the diagrams and the information as best as I can based on my uh not first-hand knowledge of this sort of thing and it's I'm not an expert by any means I've learned a lot from the um the various sources on the internet that I can find but I may have misinterpreted some of the information so if you know better please let me know in the comments um and uh some of the numbers that I'm going to show you might be slightly wrong and so if you have first-hand knowledge or know any better than me then please let me know if you've spot any mistakes and that will help me out um improve my understanding and help me make the better decisions which I'll be very grateful for if you can help me out as well but I think I've got most of the numbers more or less correct so let's let's work on the assumption that I've I've done I've done a good job researching this and we'll see we'll see where we end up at the end of the video uh so uh we've had uh conversations with a solar panel and Battery um storage installer for several months so we're effectively nearing the top of their list for for getting the system installed um so what we're planning on getting is a 7.1 kilowatt system which will be split um East and West half and half so roughly three and a half kilowatts on on the East and three and a half kilowatts on the west and that will be coupled with um a battery storage system at the moment that will be a give energy 9.5 kilowatt hour battery however since the conversations we had initially with them with our installer I in my um in my genius decided that actually why don't we get two nine and a half kilowatt batteries because that will help us cover our heating as well as our um normal electrical usage during the day uh and that slightly changed the conversation now you may be thinking well okay why are you trying to cover your eating using battery storage so here's my uh justification for that if I can charge up um roughly let's say 20 kilo hours of battery during um the off-peak octopus go four hour period I can effectively run the heating and the Electrical uh rest the rest of the electrical needs of our house using just off-peak electricity and which at the moment I'm paying um seven and a half Pence a kilowatt hour so that makes it all of a sudden significantly cheaper than using gas to eat your home because um when you're using gas you're you're burning it at something like 80 or 90 efficient when you're using an electrical heating system based on a heat pump for example which is what we're aiming to do that is roughly 400 efficient which means that you get four times as much heat as the amount of energy that you put in through to your heat pump so last winter using our gas boiler we were using something in the region of 60 kilowatt hours per day in the coldest months uh for a heat pump to do the equivalent amount of heating you'd only need about 15 one five kilowatt hours of electrical energy so we use roughly five kilo hours of electricity per day just in our general usage add that on to the uh 15 kilo hours of energy that we need for heating and that gives you roughly 20 kilowatts so two nine Market or hour Active Energy batteries would almost exactly meet that requirement if there's a little bit solder as well then that will help make up any of the difference so that was my justification for um for using uh two batteries instead of one uh whether that's cost effective is a different question uh it I'm not going to explain my calculations because um uh it's a little bit tedious and not really appropriate for this particular video um but on from the back of the envelope calculation I I deduced that it was roughly break even based on the current prices uh to get the second battery to uh to allow us to to run our heating using an overnight uh cheap rate electricity uh I might be slightly wrong but that's the ballpark figure and I think it's I think it just about makes sense and of course it um if you use open white electricity that's greener than daytime electricity anyway so there's that benefit which is actually something that's um that's quite important to us as well so anyway Let's uh let's move on to the actual options that we're considering for these um these home storage batteries and uh and explain what the relative pros and cons are of those different systems but with that um Preamble uh in mind as you as you see what these systems look like so when we first spoke to our um our solar panel and battery storage installers they proposed an AC couple to give Energy System using a solar Edge inverter with optimizers on the solar panels which would then obviously convert the DC from the solar panels into AC that would then be then then be coupled to the give energy AC inverter which would then convert the AC back into DC for storage in the batteries right so this is your classic AC coupled battery storage system and this is the sort of thing that you'd typically get if you've already had an existing solar panel system and then you retrofitted batteries to that system which is this is usually what you would end up with um so that's great um I was quite happy with that however the give energy AC inverter runs at three kilowatts which means that the maximum rate that we could charge those batteries would be three kilowatts I think it might be a little bit lower than that I've heard talk of 2.6 I might be wrong but um I'm working on the assumption that I'm overnight I'll be able to charge the batteries at three kilos now here's the problem uh three kilowatts multiplied by the four hours of cheap Moscato overnight um tariff is only 12 kilowatt hours now that would be insufficient to completely fill up those two nine and a half kilo hour give energy batteries so that's that's a slight problem uh which then leads me on to the second option that our installer suggested which was a DC coupled solar Edge uh battery storage system where we keep the the solar Edge inverter as before but this time we instead of the give energy nine and a half kilowatt hour batteries we replace those with the solar Edge energy Banks which are 10 kilowatt hours but I believe uh they can only provide 9.7 kilo hours or something like that so let's assume uh 9.7 to 10 kilowatt hours for those batteries so roughly equivalent to the um the give energy ones uh and um that would then still allow you to um couple to the optimizers on the solar panels but um you then have a five kilowatt charge rate which is great because multiplied by the four kilowatt and the four hours of cheap overnight rate gives you 20 kilow hours of potential charge that you can uh you can fill up your batteries in that four hour period overnight and that's great that would be everything that we would need the full 20 kilowatt hours or slightly less given that it's a 9.7 kilowatt hours per per battery that you can use so that's that was an interesting um option um but then I thought well hang on a minute can you do uh power cut um backup with that system and it seems that might not be necessarily possible uh certainly with the HD wave inverters that um that our installer was suggesting uh I believe it's possible now please correct me if I'm wrong because I don't know for sure it's very difficult to get a solid answer to this but I believe you can couple the energy Bank solar Edge batteries to their storage inverter which does allow you to have a battery backup system but again very hard for me to get a solid answer on that so I'm working on the Assumption at the moment that we won't we wouldn't be able to get um battery back up in the in the case of a power cut with that option too so then that got me thinking well okay if we've got if we're considering a DC coupled system uh using solar Edge batteries how about we go back to considering give NG but this time using their five kilowatt hybrid inverter connected to the the two sides of the and the solar panels because the hybrid inverter has two stream inputs so that would then get us the the battery um backup for for power Cuts back again which would be great um but it means that we wouldn't be able to use um optimizers for the the solar panels uh so that may or may not be an advantage because um from what I can tell optimizers only make a difference if there's um shading on your solar panels now from what from what I can tell with our situation we get very little shading almost basically none during the the vast majority of the day we get a little bit in the morning from a tree uh in the East and a little bit in the evening from a tree in the west but for the vast majority of the rest of the time there's no shading at all and I think in that situation actually don't really gain much benefit from having optimizers so that's something to consider and I'll explain a little bit more in a minute but um the advantage again of the of this DC coupled give Energy System is that again from what I can tell from the data sheets please correct me if I'm wrong I think that the give energy 9.5 kilowatt hour batteries can charge at a maximum rate of 4.72 kilowatts uh which would give us 19 kilowatt hours of potential charge over that four hour block during um the cheap overnight rate from octopus go which again would be more or less completely covering our needs for both Heating and the rest of our electrical needs during the coldest months of the winter so bearing in mind those three options let's bring up a table summarizing all of the pros and cons that I believe um uh are representative of these particular systems so this um this table here shows what I consider a a pro a benefit in blue and a con or a downside in Orange so from for the AC coupled I give an energy system that we described first the main benefits that I can see is well it usually optimizers for the um solar Edge system which would be good and the main advantage for AC coupled systems is that you get much better data for all of the various different energy flows um because you can put CT clamps around all of the AC cables basically which means apps like um like my energy for example who provides the the zappy and Yeti we're also intending to get those installed by the way so I probably should have mentioned that before um but that would make um monitoring those much easier and easier to manage um so that but that's probably the main benefit of the AC coupled system um and the other thing that I really like about the give energy batteries in particular is that they have the um this uh lithium ion phosphate battery chemistry which I think is um is a better option for uh for home storage because um it's fully recyclable at the end of life which is not the case for the solar Edge um batteries which are the lithium nickel manganese Cobalt chemistry which is the same sort of um chemistry you get in in electric vehicles typically and that is not currently 100 recyclable at the end of life now I'm assuming clever people are working on this and hopefully we'll find a solution for this within the next few years but let's assume that that's that it's not going to be the case that they're fully recyclable so I would much prefer the lithium-ion phosphate and Battery chemistry and it's much much safer for a um for for a home situation it's much less likely to catch fire for example I know it's a very very unlikely thing to happen um they're all very safe nowadays but uh even so still a nice bit of peace of mind if you've got a battery that's uh impossible to catch on fire basically in your house um so those are the main benefits of of the AC coupled system but the main downside is as I explained I think I can only charge and discharge a battery at three kilowatts which means I can only only charge up the batteries to 12 kilowatt hours overnight which is insufficient to cover our needs for heating and electrical usage so that might be a deal breaker option two for the solar Edge DC coupled system again you can still use the optimizers because it's um it's a solar energy inverter coupled with um with the solar panels uh but because it's DC coupled it means it's much harder to monitor the data flow of the energy that's flowing around your cables which makes it much more difficult to manage the zappy and Yeti for example uh I believe there are ways around that um but I think it's a little bit fiddlier than than the AC coupled system if you've got experience of a DC coupled system with a zapian and Eddie please let me know in the comments I'll be really interested to hear how you get on with that and because it might be that I'm worrying about nothing um but the main disadvantage I think from option two the solar Edge system is that it doesn't have a power backup option I don't know how true that is uh if we can connect it to a connect the batteries to a storage inverter instead maybe that's that's possible that we could get that battery um power cut back up back again but again I don't know for sure I can't find that information in any sort of right away on the internet so if you've got experience with this please let me know I'll be very interested to hear the main advantage of the solar Edge DC coupled system is that it can charge and discharge at five kilohertz which is great because in four hours you can charge up 20 kilo hours no problem and that would completely cover our needs for both Heating and electrical usage so that would be the most ideal uh situation from that perspective however I think that the solarage DC coupled system was probably the most expensive of the three because the batteries are I think they're quite a bit pricier than the the equivalent give energy batteries um so yeah that might be that might be an issue so that leads me on to the pros and pros and cons of option three which is the DC coupled give Energy System the one downside that I can see is that we couldn't then use optimizers on the solar panels because it's not coupled to a solar Edge inverter it goes straight into the sun panel will go straight into the give energy hybrid inverter uh because we're back to the give energy batteries now we're back to the lithium ion phosphate battery chemistry which I like and we've got the battery um backup in the case of a power cut which I really like as well because we're we're slightly um more rural here than uh than most people probably so we we have had a couple of power Cuts in the last year one of which lasted for more than more than a day so it would be really nice to have that backup option if possible um I know they're very rare but even so it would be it would be nice to have the option uh and I think from what I can tell and again please correct me if I'm wrong the uh hybrid inverter would couple to the um the give energy batteries with a maximum charge and discharge rate of something in the region 4.7 kilowatts from what I can tell uh I get I got that number from multiplying the maximum charge current of I think it was 80 amps by multiplying by the 59 volts maximum voltage for the give energy 9.5 kilowatt hour um batteries from the data sheet that I could get online now if I'm misinterpreting that I'm getting that wrong um then it might be lower than that but working on the assumption that that we can charge and discharge the batteries at 4.7 kilowatts for four hours um uh overnight octopus go uh off peak period that would allow us to charge up 19 kilowatt hours of those batteries which is essentially the 100 capacity and that would very nearly cover our needs I think for the uh for the winter both Heating and electrical usage so that would be great and the other main advantage of option three is that I think that would probably be the cheapest option because it's only using one inverter again and the batteries are a lot cheaper um well slightly cheaper but then also we don't have the um the optimizers which obviously has a cost involved as well so I think that might be the cheapest option I haven't actually done the sums uh 100 um and I do need to talk to my installers about about this option so they can probably give me a better quote but I'm I'm working on the Assumption that's probably the cheapest option at this stage so let's talk briefly about the um uh the lack of optimizers I think because we don't have much shading it's it we it might be only a marginal benefit to have optimizers uh in our situation if at all and I've from what I've found out and by reading around on the internet it might actually be uh detrimental to have optimizers in a situation where you don't have any shading at all so because we don't have very much shading or basically no shading during the vast majority of the day it might not actually be a benefit to us to have optimizers at all so maybe that is something that's um that's a non-issue maybe I don't need to worry about that so it's looking to me at the moment like option three is probably the best option for us but if any of you have experience of anything even remotely resembling any any of these three options I'd be super interested to hear uh your personal experience of those systems and if you've got any advice or additional pros and cons that I haven't considered I would really really really um be very grateful if you could uh could let me know what I'm missing uh any numbers that I've misinterpreted in this video that you've spotted and shouting at the screen saying you know you've got this completely wrong I would you know I don't have a first-hand experience with this I'm only going off of what I can find on the internet and talking to my installer um and um I it would be much better to actually have than a first-hand knowledge of this stuff and if if you can explain that to me then that would be brilliant uh so on that note I'll probably leave it there for this video it's gone far too long already uh I am I'm intending to follow this video up um I'm gonna get cat involved fine issues uh I've been promising that she's going to be in one of these videos sooner or later and she's she's going to help me out in the next video uh where we're going to go around the house and we're going to turn things on and off and see what what uh what items in our house draw the most power and that will hopefully tell us what we would be able to run from just the battery system if there was no solo for example so that's going to be that's going to be an interesting experiment and so hopefully that will come within the next couple of weeks and I'm sure you're as interested as I am in finding out what sort of things that we can run during a power cut tour um or when there's uh when there's no solar so yeah join us for that in the next week or two hopefully um and uh for now I'll say goodbye and hope you have a good day thanks for watching

Channel: Tim & Kat's Green Walk

Views: 24,499

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Id: HYjUfPGM1lk

Length: 19min 36sec (1176 seconds)

Published: Sun Oct 02 2022