Home Battery System Exposed: Discover the Real Cost & Essential Components! 

Sounds great, thanks for sharing, I bet a 4.5kw array performs well in Kenya.

Only time will tell. It's hard to put a figure on these things in years as it depends so much on how the batteries are used. The PylonTechs claim 6,000 cycles or >15 years. I had been working on the assumption that they will last 10 years, any longer is a bonus.

@@RodMcBain I wonder if those Australian results are more prone to degradation through the effect of their hot climate (no problem in Scotland).

@@fredflintstone1428 I'd expect so, a study like this is good at showing the differences between manufactures batteries under the same conditions, but there are too many variables to draw real world conclusions about how long a battery will last. In Scotland you have the opposite problem, the batteries like to be about 25°C so you struggle to keep them warm enough in the winter months, but on the flip side that will de-rate their charge / discharge capacity but will probably prolong their life.

Hi Chris, thanks for the comment, I grew up in Aberdeen so know first hand how cold it gets in winter 😀. I've not had to resort to wrapping my batteries to keep them warm, the small room they're in with the inverters seems to be enough to keep the winter temps up to reasonable levels. I'm hoping some added ventilation will be enough to get through the hotter summer days without needing to re-rack the batteries. I did run some 50mm Twin Walled Cable Duct for network cables when I put the 10mm SWA cable in. I had thought about putting in a larger duct for the new cables but might follow your lead on the drain pipe, thanks.

That's probably why SSEN are calling it a fee for the witness test 😠 might still be worth a call to see if I can get it back, especially when the witness test was supposed to take 2 weeks, but has taken over 2 months.

Hi Alan... I posted my G99 line diagram on the Victron Community pages... if that helps you

Hi Alan, You can find a PDF and XML file for my site / system schematic here rodmcbain.com/downloads/g99/ I created it with app.diagrams.net/ you should be able to open the XML file there if you wanted to alter it for your system, hope that's of some help.

Still no solar 😭 SSEN it have been a real pain, it's taken months to get a witness test for the final commissioning doc to be sent off, I wanted to have all that sorted before moving onto solar. What company did you use to install your MP2s? It was probably a good call getting someone in to install, just makes everything simpler. I still think I should be able to get an MCS cert if I have a MCS installer fit some panels and MPPT, but not certain.

Thanks. I went into this with the same idea, it's great that they save money and will probably pay for themselves, but it was as much for the peace of mind.

Thanks, I'm planning my solar install now, will probably end up getting it done just in time for winter 🥶. I'm not sure installing the battery first was as nuts as it first seems, even without solar I'm saving loads on my electricity bill using off peak electricity. I'll definitely be making more videos about how I'm using home assistant, working on a video now about switching the heat pump integration to use modbus.

I have no doubt that's true, I suspect I'd also struggle to find someone to install exactly the kit I wanted in the way I wanted. On the flip side and something I didn't mention in the video, there is a lot of work goes into designing the system and arranging everything required for G99 sign off by the DNO etc. I did this because I wanted to and enjoyed it, if I factored in the cost of my time the price would be much higher.

I think I'm going to end up doing a mix of things, my garage is south facing but with some tree shading earlier in the day, my initial plan is to get a small MCS certified install done on the garage where the batteries and inverts are, that way I'll have the cert to export if I want to. One side of the roof on the house is south east facing so gets good sun all morning and early afternoon, the tiles are also in bad condition and need replacing, so will probably get in roof solar. Then I'll ground mount some more, will probably also need planning, I think it's 9m² you're allowed but with a 3m max width & height so not very big and I'd probably want them within 5 meters of my boundary fence. Good luck with your planning permission.

It's not heated, but it is small and well insulated, last winter the heat generated by the inverters seemed to be enough to keep the room warm enough. I had setup a heater but ended up not using it.

@@RodMcBain I’m waiting to see if the inverter does the same for me but think I’ll run it in the box for two winters and see how much the internal temperature of the garage gets too. Mines in a garage so not the best to insulate single wall brick

Those are all important questions to ask. In our case with a heat pump our winter consumption is much higher, this specific system copes OK most days but on colder days we do run out of stored off peak energy in the evening. I'm working on a video now that will detail the savings made over the first 6 months of running the system.

@@RodMcBain Thank you for your response. I will check the video once it’s published. Fingers crossed.

Backup power is certainly one of the use cases I have and if it was the only use case you're almost certainly right about a generator being a much cheaper option. My main use case was initially to save on electricity costs by charging the batteries on cheap off peak electricity and consuming from the batteries during the peak period, this saves me money every day and reduces the pay back period significantly, once I add solar into the mix it becomes a no brainier. A hybrid system with a smaller battery and a generator is probably a great option that could give you the best of both worlds without the cost of a battery that lasts 3 days.

@@RodMcBain Please, do not take this as an attack, but solar is not always the best investment. If you live somewhere with very high electricity prices, like Sothern California residences served my Sempra, then a battery system is indeed a wise investment. For many people though, where the electricity is far less epensive, most people that put in solar have probably made a financial mistake doing so. In those cases, they would have probably done better to invest in electric utility stocks. I had a quotes to do solar at my house that averaged out to about $36K (not counting interest if I were to take a loan.) Now at the time, I would have gotten about a 25% rebate or something, and that would have made the investment maybe $27K. For $27K, I could have bought 330 shares of Duke Energy, which was trading at about $80 a share. Today the Duke stock would be worth $29.7K but along the way, I would have collected $5000 in dividends. Now, had I used that money to buy a S&P 500 mutual fund, it would be worth about $45K today. What this means is that a lot of people would probably be much better served buying stocks than spending money on solar. In the long run, it is a far better investment.

@@RodMcBain Also this. If people buy because they want to be green, the flaw in that is that if you invest in a utility company that is expanding their renewable power, they can create 4 times the renewable generation with that money than the homeowner can because of of the enormous benefits of scale. I had some wind power stock that skyrocket because the more people invested, the more wind power they could generate. I would say that I am have a sizable investment in eclectic utilities (I own about $45K of electic utility stocks and continue to add more because eletricity is the future) and what I would say to people that are looking are looking to install very expensive solar systems is that they should have a financial advisor go through the numbers first. Now again, if you live in a SEMPRA (and I own some SEMPRA) area and pay $.45 a kilowatt for electicity in the afternoon, then solar might make more sense, but if you live somewhere that your peak rate is about $.15 per KW, solar is almost for sure not worth the investment, especially if you are paying cash.

@@shenmisheshou7002 It's certainly true that if you're only interested in solar as a financial investment, there are almost certainly better options. I'm in the UK and currently on a reasonably "cheap" tariff, but our peak rate is still about $.40 / kWh. In my case adding a large solar array will cost about $10k so makes sense for me as something I want for many reasons but will also pay for itself over time.

I think maybe I said that in jest rather than as a challenge 😀 Sounds like a great system you have there. I don't know how you managed to buy all that for 15k Euro, what brand of batteries and inverters do you have? I could certainly have achieved the same headline spec for less money but I'm not sure it would necessarily be "better". Using Sunsunk inverters for example would have been much cheaper but probably not better.

@@RodMcBain I DIY'ed my battery packs with prismatic cells; gives you more control over the build and saves quite a bit of money. I've documented most of what I did - search for my blog "Up North and Off Grid" if you're interested.

1700 Wp panels, 5kVA inverter, 10x100Ah batteries... total under 800 €.

Hi Craig, I'm really happy with the quality of the Samson SRK,s, they are really sturdy high quality racks. I think having the screw holes threaded into the rack itself adds to the strength, I'd be a little wary of a rack that requires the little square push in brackets. The Samson racks were the only ones I found that were actually rated to handle the weight of the batteries. My only complaint is entirely my fault, I've not left enough room for cooling, probably should have also gone for the 16 instead of the 12. On the plus side that did mean I didn't really have to deal with supporting the batteries at the back, they are only about 1mm apart and I placed some washers in the gap to ensure they were not stressing the battery case or the front of the rack. I think in an ideal world you could purchase short 19" rack shelves and fit them in the back of the case to support the rear of each battery, but at about £20 each I'd probably still go down the route of some kind of spacers along the back or make up my own brackets to screw into he rear of the case. If I was I only installing 3 or 4 batteries I'd possibly consider the Pylonteck brackets www.itstechnologies.shop/products/2-x-brackets-pylontech-us5000 not as smart looking but more compact.

@@RodMcBain Thanks for taking time to respond in detail - very much appreciated. I'll do a bit more searching and see if I can find somewhere which has the Samson SRK16 in stock. It does look like a tidy rack and seems to be good value. I agree that shelves are a bit pricey so would probably do something bespoke to support the rear of each unit. Unfortunately I don't think the Pylontech brackets are suitable because the operation manual says they are limited to 3 units in a stack. These modules are 40Kg each so a stack of 4 would be applying 120Kg to the bottom one. I know the modules are sturdy and I can see them taking 80Kg but 120Kg is quite a step up. I might not go beyond 3 modules but I want to keep the option open to go to 4 modules if it makes economic sense. As a bit of background, we installed batteries (US5000 x 2 + Multiplus-II 48/5000/70-50 x 1) before solar PV to take advantage of our Octopus Go Faster tariff (8.25p/kWh / 40.13p/kWh) and because we were in the process of refurbishing the roof on our garage which needed to be completed before we could install our PV panels. The batteries alone were great and kept our average cost per kWh around 9p. Most days we could charge the batteries, and our EV (BMW i3), during the off peak period (21:30 - 02-30) and run on that energy until the next off-peak period. But a few times a week we'd run out of battery energy during the day and would then be paying 40p/kWh for a few hours. Our self-installed solar PV (Trina Vertex S 425w x 16 + Victron MPPT 250/60 x 2) was operational just a couple of weeks ago and is a 6.8kWp array on a south facing, North Ayrshire, 15 degree roof. We're still figuring a few things out such as solar forecasting, but in general it's working really well! We've generated 203kWh in the last 13 days and it has been very mixed weather to say the least! On days when we have excess energy we dump that energy into the EV by allowing the batteries to discharge to 25% SOC during the off-peak period. But, there have been a few days where solar generation has been very limited and we've then struggled to maintain the house never mind the EV. So this is why I think a 3rd battery would help, and possibly a 4th in the future. As I'm sure you're aware, it's a difficult equation to calculate the cost-benefit of battery storage, especially when combined with solar PV. But I think that equation becomes simpler when we have some days when our batteries are full by 11:30am and other consecutive days when we are struggling to maintain 14% charge. Clearly we need more capacity to smooth out the bumps but the question is how much more. Thanks again.

@@craigchamberlain I think the US3000Cs can be stacked 4 high with the brackets, but with the added weight it makes sense the US5000s can only do 3. Sounds like you've got a great setup, the ability to incrementally add batteries is a big advantage of rack style batteries like the Pylontechs.

That is a concern, they do come with an extended 10 year warranty, but I have little doubt they will attempt to weasel out of honouring that wherever possible. I guess I look at all the possible battery options like a bit of a spectrum, with powerwall type solutions at one end and home made packs with recycled 18650 cells at the other end. There are lots of options in between, each with their own pros and cons. I think the various 48v rack mount solutions sit somewhere in the middle, probably a good compromise, but at the end of the day it's personal choice around how you want to balance the pros / cons.

@@RodMcBain Even if they honor the warranty, the next concern would be possible long waiting period for a replacement rack unit. Then you have the heavy weight of these as well in terms of shipping. As for 18650 cells, DO NOT install these within 50' of a residential structure. When they ignite, they are impossible to extinguish.

@@basspig That's true but at least you only loose a fraction of your capacity and the rest of your system continues working. I just mentioned 18650 cells as an extreme end of the spectrum, not seriously suggesting anyone use them.

@@RodMcBain I use three banks of prismatic cells and three BMSs for redundancy. If a cell goes bad, I just replace the cell--socket wrench, two nuts and done. 18650 if you have your power in a concrete pillbox.

Sounds like a great system you have there, I'd not really considered building my own packs. When I first planned this system I was considering installing it in the house so wanted something compact and tidy, probably worth considering for the future given how much cheaper they are.

Those Genmax Tri-Fuel generators do look interesting, can't see them available in the UK and although interesting they are not really comparable to a home battery system. At some point I might want my system to be able to survive off grid all year round and that would require a generator in winter so thank you for introducing me to the Genmax.

Thanks for the tip, if I'd done some more research I think I'd have gone for another Lynx Power In instead of the Distributor, apparently they can easily be modified to accommodate fuses, bust since I've got the Distributor it probably makes sense to try and get the LEDs working. Other than the problems with the MP2s loosing their ENA certification I've had no problem with the G99 process, my DNO was slow but helpful and the guy who did the witness testing was happy with everything. Well done noticing my omission on the earth rods, I could claim I did that on purpose to see if anyone was paying attention, but I only realised I'd forgotten to mention them after the video was up 😀. I have 2 x 2.4m earth rods about 8 meters apart and connected back with 16mm cable, don't recall off the top of my head but the reading was very low as well so more than adequate. Adding all the bits up that was about another £192. I think it's an advantage to doing this yourself, a spark might bang in a single rod and get a reading under 150ohms and think that's good enough.

@@RodMcBain yeah there is benefits to doing it yourself. And yes get those LEDs working as it will show up if one has blow the board actually has some smarts to it or rather logic and will give different LED eliminations well worth doing we paid for it already 😂 I looked at modifying the power in and couldn’t be asked doing it all and I wanted LED’s looks good when it goes through the start up process 😂

Thanks, glad you liked it. I think if I was starting again I'd probably still go Victron but might not use the Pylontechs, nothing against them but like you said there are a lot of options so it would be worth investigating alternatives. The US5000's are going to be better value, just keep in mind their weight, both for handling during installation and for where and how you mount them. I don't think there's much in it cost wise between a Multiplus 2 GX and Multiplus 2 and a separate Cerbox GX, the Cerbo has more connection opportunities and if your considering going parallel your multiplus 2s should be identical model number and you don't want 2 GX devices, so the Cerbo GX is again probably the better option.

Yes, I had an electrician move my consumer unit, he installed the meter at the same time, but I did everything else.

@@RodMcBain Cheers. :)

I think a lot of electricians would like you to believe that's true, as this is installed on an existing circuit there is no building control notification needed and on top of that my electrician has checked my work and is happy everything compiles with BS7671.

@@RodMcBain Cheers. I’ve always been told that a qualified electrician has to do any work these days. I was interested in how you dealt with that. :)

​@@SirHackaL0t. after watching Rods videos I was going to do it myself too... but in the end I got my local Victron installers, mainly because I wanted the MCS certificate to export to the grid. You don't need the MCS certificate to get the solar "smart export guarantee" rate (6.4p/kWh), but I found that if you want to get the higher rates (21.4p/kWh and up to 34.36p/kWh in my area), you seem to need a MCS certificate. It pushed the cost of my build up a little, but I should make that back... I hope

Sounds like that was a really bad experience. I thought the Battle born LifePO4 batteries were just dumb cells that you needed to add your own BMS functionality to, I'm curious how you're going to get much more DIY than that? Build a pack out of 18650 cells?

I think that's very possible, but as production capacity ramps up demand is also rising rapidly, not sure prices will come down as fast as we'd all like.

@@RodMcBain Lots of variables we can't calculate like war, but lots of improvements on the battery efficiency and cost just around the corner. Better batteries being built out of lower cost material at lower prices will happen. Just hope Edison doesn't own my house before we get there.

Certainly cheaper and let's say different rather than inferior 😀. I don't think there's anything wrong with building your own pack of cells, it's cheaper but comes with some added complexity. Has advantages as well, like the ability to easily replace a bad cell or replace the BMS. Victron kit is also certainly not cheap but is also very good. It's really hard to judge if it's worth the cost. I agree offsetting to the cheep periods is good, but I think I'm still getting solar, the idea that I can essentially be off grid most of the year is appealing, it's also hard to know what's going to happen to electricity prices going forward. Sounds like you've built a great system for a very good price.

@@RodMcBain thanks, yours is nicer looking! btw, I'm in ROI, have an EV tariff for €0.07/kwh, there is no solar that can be worth having if all my needs are at that price per kwh, if that tariff stays where it is, a big IF

You certainly can have more capacity for less, I still think there are pros and cons to consider when building your own packs, but it's certainly something I'll consider in the future given the much less they cost.

I think I'd consider building my own packs out of raw cells, but recycling a BEV pack is probably a step to far for me.

Yes, I must be crazy or made of money and I'm not made of money 😁