How to Choose the Best Home Battery System for Your Needs 

I agree, I've wondered several times if I should have gone Sunsynk, but I think for these systems reliability is more important than price.

Thanks James, glad you found it helpful!

Thank you

Thanks 👍

Hi, glad you found it useful, I also really need to get some solar installed urgently, hate the idea of having all this equipment and still be paying for electricity over the summer. My Octopus Go tariff is up for renewal in April, not looking forward to that, especially when I don't currently have an electric car.

Thanks, glad you enjoyed it.

Sounds great, I need to pull my finger out and get some solar installed before summer.

Glad it was helpful!

Glad you enjoyed it

Thanks, glad you found it useful. I don't think octopus energy care about a home battery or if you have solar, the only bit they need to approve is if you want to feed in some of your solar production and get paid for it. In that case you need to provide them with the DNO approval you'd get from the G99 process and an MCS Certificate. My current plan (which might not work) is to get a small solar installation done on the roof of my garage by an MCS approved installer, my understanding is only one of the installed products needs to be MCS certified, so an MCS installer should be able to install MCS approved panels to an existing inverter / battery system and issue an MCS certificate that will allow feed in to generate cash. I expect the worst case scenario to be they insist on installing a separate inverter which could feed your existing inverter & batteries on the AC side, that could be left as is or "fixed" once you have the certificate.

Thank you

Hi, Thanks, I'm finding it a little annoying but happy to live with it short term until I can move everything to the Multiplus output. If my plans change I might take you up on sharing the node red code, thanks again.

Thanks, glad you found it useful. I've got the opposite problem, should probably use a heater in winter to keep the batteries warm, but so far having everything in a small insulated room is working OK, might need a fan in summer for some extra ventilation. It's always a balancing act, batteries like to be warmer and inverters cooler, about 25c seems to be the sweet spot for both.

Thanks, the Victron units do seem reliable so far and they have a good reputation, they are fairly pricey but reliability is important so worth the extra cost in my opinion.

Thanks, I've already got a video planned that dives deeper into my system, should be coming soon.

@@RodMcBain Awesome, thanks!

Thanks, that's how I have them connected currently, 2 banks of 4, each with a positive on the 1st battery and the negative on the 4th, those then connect onto a Victron Lynx Distributor. I'm still pondering if there is any merit in rotating the batteries like you would car tyres to distribute wear, maybe once a year swap 1 & 4 with 3 & 2 for example.

That's correct and your micro inverters won't work when the grid fails, should still all work OK if you just want to offset your consumption when there is no solar. Glad you found the video useful.

They certainly do look like a good alternative. I think my main concern would be reliability of both the inverter and company. Victron are based in the Netherlands have been around for a long time and their products have a great reputation for reliability. Not saying Sunsynk aren't reliable, they just haven't been around long enough to build up that reputation and trust.

@@RodMcBain I did a considerable amount of internet research on the Sunsynk inverters. They are big in South Africa, where ESCOM the grid supplier has decades of under investment and power outages are frequent. Also farmers in isolated areas have been attacked over land takeovers and use these inverters in an almost war situation. Ask anybody familiar with SA. The same inverter is sold under a different name by a Texas based company selling to "Preppers" for the forthcoming apocalypse! They are also sold under another brand name world wide. The basic difference is that these units are unknown as a low power end of the market. As far as I can see their business makes three phase versions as well as linking individual inverters to scale them up in contrast to some of the brands targeted at the domestic market. The batteries are either BYD or CATL variants both used in cars by major manufacturers. Other branded batteries don't indicate their provenance. The Sunsynk Inverter is China made but so are many others. As for the UK company they are based in Chester and their general manager is based here and fronts the videos not slick buy technical. I've installed mine it's neat tidy with 8kW inverter with four batteries, a meter and isolators that's it! No separate bits, no need for hot water diverter, no need for extras to run generator the only change required to become a UPS is creating an Earth Neutral bond to switch to island mode automatically. There's a video showing how it's done just four connections. No "gateway" box or similar just regular relay switches. I looked at all brands Dutch, German, Austrian, American and the British most of which are made in China. For value this is top spec, the outfield risk is that the USA and China may go to war over Taiwan......bit even then the Preppers will survive.

That's a complicated question, lots of variables and depends on what what you're looking to achieve with the batteries. Personally I want to run solely on off peak electricity in winter, ideally once I have solar I want enough capacity to run 100% on solar for about 8 months of the year. I'd also like to always have enough capacity spare to run the house in a grid down mode for at least a day preferably more. In our case we have the complication of all our heating and hot water being done with the heat pump, combined with an older leaky house, on the coldest days of winter I've seen us burn through 50 - 60 KWh in a day, it's not realistic or required to have that covered by the batteries, sometime you have to compromises when it come to the odd day of exceptionally high usage. A good place to start is to look at your consumption throughout the year and decide how much of that you'd like to come from your batteries. The size of your inverter is also important, no point having more capacity than you can use. Maybe I should make a video that dives into all the factors to consider when deciding on a reasonable battery capacity.

Thanks, that battery bank sounds like a beast.

Hi Fred, I am in Scotland and was told by a local installer that I cannot use lead-acid batteries as SSE will not allow the connection. They do seem much more cost-effective than lithium. I have seen prices around £100 for 140ah.

Micro inverters certainly have their place in a simple grid tied solar system, but they're a lot less appealing if you have storage or want a system that is normally grid tied but will continue to work in island mode when the grid fails. Also who wants to hire scaffolding and remove their panels every time an inverter fails.

It's definitely a decision that required some thought, other than the noise, I had space constraints and I was possibly unreasonably worried about the potential fire risk. Also the heat generated in the garage is not necessarily wasted, I use the garage so having a heat source out there is good thing. Where to place them is going to be something you have to weigh up on a case by case basis, I still think the garage was the right choice for me.

Thanks. I've got the batteries in a small room at the back of my garage which I'm working on insulating, only the door left to do, currently it's -1c outside the garage is 6.2c, the battery room 13.5c and the cell temp is 16c, even when it's been colder outside I've never seen it get cold enough for the BMS to reduce the charge current so I think it's working OK. Next challenge will be keeping the inverters cool in summer!

I'm looking at options. I have insulated the room. I have a electric radiator keeping the temp up but that's not cheap. I was thinking a air conditioner for heating as well as cooling power use for a 12000 btu unit would be from 250w to 1kw costs in the range of £500 to £750 only downside they will not sell for diy. I figured the payback would be about 2 years compared to the electric radiator

We moved about two years ago and have no plans to move any time soon, so portable wasn't high on my list of priorities. But by buying smaller batteries and building stack they're certainly a lot more portable than some of the bigger batteries you can get.

@@RodMcBain yes... over the years I have had loads of lead acid battery systems in motorhomes but I am still researching all this LiFePO4 stuff and i just watched a video posted by "Martin Johnson - Off Grid Living" he has 16 100Ah batteries wired 4 by 4 to get 400Ah at 48V (19.2kWh) in to 2 inverters. with some big victron solar controllers. In my eyes it's perfect. just what I want. and could be built up slowly over time. But it will be nice to see how yours performs once it's hooked up to the house. Do you have a time frame for that ?

@@RodMcBain And... I know you said the fans are loud… but how loud we fitted a combi gas instant hot water, so we took the old hot water tank out, and the ‘airing cupboard’ is quite big. it’s in the centre of the house, an old brick bungalow. It’s about the same size as yours, and is the ideal space for a small system. but I don’t want to put up with the noise. I have seen people swap the fans in the EcoFlow systems for silent running ones. could that be done on a Victron unit, do you know ?

@@IamMotorHomeless Not certain yet, hopefully in the next month or two, I want to wait until the inverters are back on the ENA register and get the final sign off from the DNO. Then it's just dig another trench and connect up the new armoured cables.

@@IamMotorHomeless Funny you should ask, check this out ru-vid.comL5X1Y50z55M One point to note, I believe Victron made a hardware revision last year that was designed to reduce the amount of noise, probably just quieter fans, you will probably end up with one of the newer units. Not sure about replacing the fans, would at a minimum void your warranty.

Hi Stephen, I'm seeing exactly the same behaviour, charging current drops from 144 amps to 128 amps after about 2 hours. To be honest I've noticed that before but it didn't bother me enough to pay much attention. But now that you've pointed it out i'm curious, I don't think it has anything to do with the battery or inverter temp. The Victron page on Pylontech batteries does have this in the FAQ "After charging the battery the charge current often changes between 0A and 25A. This is caused by cell balancing inside the battery. This happens with new batteries and after a deep discharge" If that's what we're seeing it's worded a bit oddly. I notice the min and max cell voltages are constant up to the point where the charge current drops then they fluctuate slightly and gradually increase. I'll let you know if I find a more concrete answer.

@@RodMcBain thanks for the feedback, I definitely think it’s on the Victron side. And now I know it’s not just my setup I’ll make a post on the FB group and Victron forum to see if anyone has a workaround. Will report back if I find out more also.

8 US300Cs and 2 Victron Multiplus 2 48V 5000Va inverters plus all the extra bits like cabinets, cables, fuses etc about £13k, so not cheap, but with such high energy prices the pay back period is much shorter than it used to be.

@@RodMcBain thanks Rod. Any recommendations on where to get the Victron and Pylontechs? Thank you

Thanks! I got the batteries and one inverter from www.itstechnologies.shop, I notice their current stock of US3000Cs are branded "Turbo" which I think are identical but normally sold by a Spanish reseller, might want to look elsewhere for plain Pylontech branded batteries. I got the other inverter from nomadicleisure.co.uk/ as the one from ITS was the last one they had in stock at the time. ITS are cheep and I have no complaints, Nomadic were a bit more expensive but had a discount code available at the time and have good customer service.

@@RodMcBain thanks very much for the links and info.

Wow that sounds like big system. We're also in an old house (1910) with mostly solid walls. We don't have any mains gas here and just managed to get a heat pump installed before the RHI payments stopped. I'm not sure a heat pump would be such an obvious choice if we had gas and no RHI. I'm hoping the heat pump becomes more efficient as we improve the house.

​@@RodMcBain you might want to invest in a phone based thermal camera. Walk around your house inside and out. It'll tell you where to concentrate your money on heat loss. It's also handy to inspect your electrical cable joints for bad connections as they they heat up

@@MichaelPickles It's funny you should suggest that, I've had one for the last week and have a vid coming shortly of what I think of it and some if the issues it's shown up in my house.

I'm going to continue to monitor the situation, to date I've never seen the batteries generate any significant heat, my backup plan is to weld together a new custom rack that will allow for more vertical separation, should be a fun project.

Thanks for the comment and the suggestion. I understand the concept of AC coupling a solar system on the output of a Multiplus and the need for the 1.0 rule, it's a great option to have when you already have solar and an existing inverter. But I'm not sure I understand your suggestion that there's an efficiency gain to be had by purposely adding some solar and an extra inverter on the output over adding all the solar to Victron MPPTs attached directly to the Multiplus? It's very possible I'm missing an important point, I guess there will be some minimal extra losses from the longer wires and DC bus connecting the external MPPT to the Multiplus than you'd get from an all in one inverter. It would be great if you could explain a bit more.

​@@RodMcBain Lots of pros and cons to this, from my limited understanding. One of the pros is adding extra AC capacity for the same price as a couple of Victron MPPTs. You can get (say) an SMA Sunny Boy 4kw with 2x MPPTs for the same price (roughly) as 2 x Victron MPPTs. You would then being able to invert a maximum of your Multiplus's AND the AC coupled inverter, in your case it might be 4.5Kw + 4.5Kw + 4Kw = 13KW max. The downside is if your roof or installation is subject to shading, you might be better off just using the Victron MPPTs, since large string inverters don't handle shading as well. Also depends on how much solar you can cram on your roof. I'm using a mixture of both AC / DC coupled solar, since some of my roof is clear from shading much of time and some is partially shaded at times, and I'll be able to make use of the extra AC capacity.

Thanks, I don't have any experience with V2H, but yes if you have a working solution it would definitely negate the need for a large home battery, depending on your requirements you might still want a smaller battery to cover the occasions when the car is actually being used as a car 😀

Hi, Yes, the DC connections from each inverters are connected to a Lynx Distributor with 70mm cables and fused, the batteries are then all connected to the same DC bus and charge at 140A with 2 inverters.

@@RodMcBain Nice !

Thank for the comment, great idea if you're on a budget, I'm in the UK and I'm sure if I looked I could find someone selling second hand panels. Given the relatively low cost of panels and the costs involved with installation, scaffolding etc I'm not sure I'll go this route, I'd probably rather have newer more efficient panels with a warranty. But going for second hand panels is definitely an option worth considering in some cases.

Thanks for sharing 🧻

Are G99 approvals not fun? Can I do it as an individual or is it a case of using an electrician?

@@imraniqbal4447 They take a long time to get approval. In theory you can DIY the application process, but they’ll want electrical schematics of your system along with datasheets for the inverters you want to connect. You’ll need to prove how any export limitation can be achieved. That’s normally satisfied with a G100 type approval document that comes with the inverter, along with the parameters you intend to configure the inverter with. If they aren’t satisfied with your electrical drawings, they should request clarifications, but be warned that replies are measured in weeks/months rather than minutes or hours. So when you make an application, make sure all the details are comprehensive and correct first time round.

Thanks. I think being accessible for hobbyists was one of their main attractions.

@@anthonydyer3939 great info. Appreciate you taking the time out to respond with detail. Sounds like I’d need to review whether it’s best to diy install or go to someone who knows what they’re doing. Although I’ve tried getting a few Victron quotes for home set up and it’s proving difficult. Suspect it’s a bit of a niche. Thank you

@@imraniqbal4447 Get a professional installer. In order to get money for export, you need the system to be installed by an MCS registered installer, as well as DNO approval. Installer should give you an MCS certificate for the installation. These are required by your electricity supplier before they set you up with an export tariff. However if you go off grid, you aren’t connecting a generator to the DNO network, so the paperwork process is completely eliminated. That said, you’ve got no opportunity for exporting electricity and export revenue is where half of your investment value lies.

GivEnergy have a reasonable reputation, just don't expect a system that can be easily upgraded or that you will have much power available when the grid fails. I'm sure it's a good option for some but not for me.

@@RodMcBain cheers, I've been told the batteries can be extended 🤷‍♂️

@@davidw717 I don't have any personal experience with GivEnergy, I expect you can connect batteries together to give you more storage but can't easily add inverters if you need more kW, but you probably know more than me here.

Thanks, I had thought about that, I might end up going for a 35mm for the grid feed and a 25mm back to the house, Loads like the batteries charging of future car chargers would be in the garage and a 25mm SWA should be more than enough to cover the loads in the house.

Can't help sorry, I've done most of the work myself, the rest was a local electrician who doesn't specialise in storage.

@@RodMcBain no worries. Yeah I think i might end up going down a similar route. Work out what I need then just ask a sparky to wire it all up.

@@lukewoolfson Don't know where you're located but maybe worth checking out @corymac he recently made video where he installed some Victron kit a customer had supplied ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-114XmkpbStI.html

I've never been able to get a definitive answer on this, the Pylontech website doesn't seem to specify the chemistry in their cells and various different websites seem to say different things. My understanding is Pylontech manufacture the cells pouches themselves using their own design and it's probably something slightly non standard. Given the high depth of charge and the advertised lifetime, I'd assume it's LiFePO4 or something very close to it.

Hi, ballpark is £13k, prices for some bits have gone up and some have come down a little. I'm planning to put together a video soon that will breakdown all the costs and If I can gather the required data give an indication of how much I've saved by offsetting my grid consumption.

@@RodMcBain Brilliant. Thanks Rod. 👍🏻😁

I agree, intelligent octopus is definitely worth considering if you have a car or charger that's compatible.

@@RodMcBain the charger is irrelevant, the car and a smart meter do the work. Octopus have made a mistake with listing chargers, they all will be fine apparently. Only one charger, the Ohme charger has actually been fully accredited. Octopus have messed up on this and they keep saying it’s only in Beta so they get away with it.

The new Flux tariff is good I hear. For now we are in the their fan club until we take the leap with batteries and solar. I have zero intention of doing anything that involves home assistant, so unless these systems work with something more home friendly like an EDDI I am out and will be getting something more consumer friendly. (Recommendations welcome)

Don't quote me on this, but I think Pylontech batteries are Lithium Iron Phosphate (LiFePO4). I just went to double check on their website and it doesn't explicitly say they are but most sites list them as LiFePO4 and the >6000 cycles suggests they probably are.

@@RodMcBain yes sounds like it

I'm not running Node Red, I have Hassio running as a virtual machine and Mosquitto running on the host machine. Home assistant talks to Mosquitto using the MQTT integration and Mosquitto has the MQTT server running on the Cerbo GX setup as a bridge. So everything I want from the Cerbo gets mirrored on Mosquitto and is visible to Home Assistant.

I’m located in Scotland and managed to get G99 DNO approval from SP Energy Networks despite the Multiplus-II still being in “awaiting further information” status on the ENA Type Testing register. These inverters were previously compliant and that compliance was revoked for new installs in September 2022 due to additional requirements not being met. Victron have since issued a few firmware updates to address these requirements and it is expected that compliance will be granted soon. Also, regarding the fan and transformer noise you mentioned in the video, Victron revised the Multiplus-II in recent months to significantly reduce noise. Fortunately I have one of the later units with the revisions and although they are far from silent, the noise is perfectly acceptable provided you can house the equipment in a suitably ventilated cupboard or small room. Ours in under our stairs along with the DNO cutout and meter and consumber units and even though it is physically about 4-5m from where my head rests on my pillow at night, the noise is just barely audible, even during the charging cycle which is when they are loudest. This may be partly due to the fact I charge my batteries at 60A rather than 70A because I have a 5 hour Octopus Go Faster tariff between 21:30 and 02:30 hours each day and can easily charge my batteries in that time even at 60A. You can also use rubber washers and pads to isolate most of the humming noise from the transformer.

Sorry for the double post but I can’t seem to edit my above post. I just wanted to say that I should have watched your linked video before posting because you cover the points I made very well there. Nice work. :)

@@craigchamberlain Thanks, I didn't want to add the info in this video as it's UK specific and will hopefully be irrelevant soon. Interesting to hear about the updated hardware revision with reduced noise.

That's kind of hard to express in a comment, I'll try and record a short so you can hear for yourself.

Hopefully this demonstrates how loud they are ru-vid.comL5X1Y50z55M

@@RodMcBain thanks much appreciated. Yeah I can see why you want them in the garage!

It's an investment that will over it's lifetime at least pay for itself, if not save a significant amount of money, but the upfront cost is high.

@@RodMcBain Thanks Pro and have a super day

Even without solar I'm currently saving a fortune, our current average unit rate is around 10p/KWh by charging off peak, I've not done the maths yet but i'd guesstimate it's saved me somewhere between £500 and £1000 over the winter months. I should have solar installed soon, hopefully in time for summer. I think with the timing it's worked out OK doing it this way around.

@@RodMcBain I have a Multiplus-II 48/5000/70-50 and two US5000C batteries and have also saved a fortune in electricity costs over the time I have had them installed. We have a 5 hour Octopus Go tariff at 8.25p off-peak and 40.13p peak and despite me working from home and therefore the house is using power all day, 97% of our energy is at off-peak rate. That’s including charging our BMW i3 EV which we charge in the off-peak window. We also schedule our dishwasher and washing machine and tumble dryer to run in the off-peak window. We will be adding a 6.5 or maybe even an 8kWp DC coupled solar array in the next few weeks and then depending on how often I find the batteries are 100% full during the day and can’t take any more solar power, I might buy another battery. I think a lot depends on which time of year you install your system. A battery is beneficial all year round whereas a solar array is mostly beneficial in the late spring through to early autumn. So for me, installing the batteries first was 100% the correct choice.

I'd definitely be considering Sunsynk if I was buying today, but I think Victron probably still have edge, except on price.

@@RodMcBain agreed. Victron is better in many ways especially with it's modular system, but as a "Swiss army" type of inverter the Sunsynk is great. Great work 👍 keep the videos. Let us know how the pylons tech batteries perform over the upcoming months

I have thought about that, it's a concern but I doubt 3 phase grid will ever be viable here, we're about 200m off the main road, the upgrade would cost a small fortune.

​@@RodMcBain you could always find out for free. Ask your grid operator (not the company you pay) i.e. my one is Northern power Grid. Ask them for a "fuse upgrade" (that exact phrase) say you want say ... 55kW. The should give you a free survey. This will tell you where the cable is and what's available.

You're probably right!