Battery Storage recommendations

[Thorfun]

Hi all,

for our self-build we are looking to put in at least a 4kWp solar PV array (maybe more if I the DNO will let me and it's not too expensive) and I would like battery storage as well to act as a battery backup for power cuts, blips and outages.

I am aware of the arguments about it not stacking up financially but I'm not so fussed about that as I can't put a price on the fuzzy warm feeling inside that I don't have to use bought in electricity, at least not at full price.

I have a Tesla as well just for completeness of my electric requirements.

 

so, financial arguments aside, has anyone had any good experiences with battery storage?

 

just to add that I was at the Build It Live show in Kent on Sunday and was talking to a guy from Solar Watt (who I'd never heard of). he was very vocal on the fact that BMW are their parent company and how their system is a DC system which increases efficiency as there's no conversion from the panels to the batteries. downside is that they don't work as a battery backup and can't charge them from the grid. so, they're pretty much out of the equation! but I was wondering if anyone had heard of them? I couldn't find any mention of them at all on here.

 

Most of the other threads on battery storage on here are pretty old so I thought I'd start this as a way for people to recommend or give updated experiences on the whole battery storage topic.

thanks in advance.

 

[SteamyTea]

To run a PV/Battery system during a power cut you need to isolate from the grid.  This saves linesmen getting a surprise.

There are islanding system that can do this, but they tend to start getting expensive.

[ProDave]

Personal question:  do you go out to work, or work from home / retired?

 

If the latter then with an EV to charge, I an near certain you will use all that you can generate from a 4kWp solar PV system so there will be none going to "waste" to charge the batteries.

 

So the question boils down to providing some form of backup for when you get power cuts.  How likely is that? Are you in some remote location prone to overhead lines coming down? 

 

It is very laudable wanting to be environmentally friendly but sometimes you have to be pragmatic and just buy a petrol or diesel generator for the power cuts.  for the few times it will be used, pollution is insignificant.

[Delicatedave]

I'm interested in this too, did some nieve research and spoke to some companies but it all get  tangled in gimmicks and they can't seem to understand saving money is not the be all and end all for some people.

The are some system that use econ 7 as backup to charge the batteries others are not compatable.

Edited February 11, 2020 by Delicatedave

[DamonHD]

FWIW, here is my little survey of grid-tied storage and what I went with, also not for saving money, and also not able to keep us up if the grid goes down.  (The grid has only been down for 2x30m in ~15Y here!):

 

http://www.earth.org.uk/electricity-storage-whole-household-2018.html

 

http://www.earth.org.uk/Enphase-AC-Battery-REVIEW.html

 

Rgds

 

Damon

[Jeremy Harris]

I've been looking at various battery storage solutions for a few years.  None are perfect, and some are a bit bizarre in the way they work.  Until recently, getting backup power from a battery system wasn't that easy, but there are a few systems around that offer a separate, always on, supply via the battery.  This can be connected to a separate circuit in the house to power essentials that are needed in the event of a power cut.  Tesla offer a changeover relay option with their latest Gateway, too, but of all the battery system the Tesla Powerwall seems the least flexible.  Users have little control over the way that the Powerwall works, so it will charge and discharge according to what its systems believe to be appropriate, rather than what the user actually wants.  Sometimes this is OK, sometimes it results in the system charging from peak rate electricity.  A good example was this weekend, where Powerwalls went into "Storm Mode" automatically, and fully charged from the grid, on the assumption that there would be power cuts.  I suspect that those not in an affected area, who had to pay for peak rate electricity used to charge their Powerwall because of this behaviour may not have been best pleased.

 

Of all the other systems available, it looks as if the Pylontech batteries may well be the best overall value, plus they use a battery chemistry that is well suited to the high cycle life required for home battery storage.  When it comes to inverter/charger units, then there are several that are compatible with the Pylontech batteries, and the choice really comes down to the peak power needed, price plus how much control you would like to have over the system.  For example, SMA make a pretty good inverter/charger, but it suffers a bit from the same sort of behaviour as the Powerwall.  The Sofar and GroWatt inverter/chargers are more flexible, but the most flexible seems to be the Lux Power range.  These seem to be more easily programmed to do exactly what the user wants, rather than what the manufacturer expects the user to want. 

 

For me, having control of when the unit charges and discharges is key; the very last thing I want is a system that charges because some bit of remote code in another country has signalled the thing to charge because it believes that's the best option.  I want to be sure that the battery only ever charges when there is an excess of PV generation, and then, as a secondary charge source, during the E7 off peak period.

[ProDave]

3 minutes ago, Jeremy Harris said:

For me, having control of when the unit charges and discharges is key; the very last thing I want is a system that charges because some bit of remote code in another country has signalled the thing to charge because it believes that's the best option.  I want to be sure that the battery only ever charges when there is an excess of PV generation, and then, as a secondary charge source, during the E7 off peak period.

My thoughts entirely. Which is why when I eventually install some form of storage, it will be home made with my own controlller that I can program myself (probably an arduino or a Pi)

[Jeremy Harris]

The Lux Power AC systems look very controllable, and are top of my list at the moment: Lux-Power-Hybrid-Inverter-Datasheet.pdf

[Thorfun]

35 minutes ago, SteamyTea said:

To run a PV/Battery system during a power cut you need to isolate from the grid.  This saves linesmen getting a surprise.

There are islanding system that can do this, but they tend to start getting expensive.

 

I would've thought that any system that connects to and can be charged from the grid would do this, no? if not then surely the grid companies would be complaining. ?

15 minutes ago, ProDave said:

Personal question:  do you go out to work, or work from home / retired?

 

If the latter then with an EV to charge, I an near certain you will use all that you can generate from a 4kWp solar PV system so there will be none going to "waste" to charge the batteries.

 

So the question boils down to providing some form of backup for when you get power cuts.  How likely is that? Are you in some remote location prone to overhead lines coming down? 

 

It is very laudable wanting to be environmentally friendly but sometimes you have to be pragmatic and just buy a petrol or diesel generator for the power cuts.  for the few times it will be used, pollution is insignificant.

 

I work from home 4 days a week at the moment and my wife also works from home occasionally making personalised cuddly toys and the like.

I don't think we get a lot of power cuts but seem a little prone to power trips/blips. and that means that my computers/NAS and other devices with hdd storage take a battering when that happens and unceremoniously shutdown. this could lead to hardware failure. the new build will have whole house automation so this will only get more important after we build. I could by a UPS big enough to power the IT equipment and allow them to shutdown nicely in case of a power trip but they tend to be pretty expensive in themselves!

 

7 minutes ago, DamonHD said:

FWIW, here is my little survey of grid-tied storage and what I went with, also not for saving money, and also not able to keep us up if the grid goes down.  (The grid has only been down for 2x30m in ~15Y here!):

 

http://www.earth.org.uk/electricity-storage-whole-household-2018.html

 

http://www.earth.org.uk/Enphase-AC-Battery-REVIEW.html

 

Rgds

 

Damon

 

Thanks. will take a look.

 

6 minutes ago, Jeremy Harris said:

...

For me, having control of when the unit charges and discharges is key; the very last thing I want is a system that charges because some bit of remote code in another country has signalled the thing to charge because it believes that's the best option.  I want to be sure that the battery only ever charges when there is an excess of PV generation, and then, as a secondary charge source, during the E7 off peak period.

 

thanks for the info. some good names for me to research there. interesting about what you say about the Powerwall and that is definitely the Tesla way (as we both know with the software updates on our cars!). they're very much a release it and see what happens type software company. doesn't mean I don't love my car though. ?

[SteamyTea]

1 minute ago, Thorfun said:

I would've thought that any system that connects to and can be charged from the grid would do this, no?

They disconnect, but don't island.  Islanding is totally isolation from the grid.

[Jeremy Harris]

1 minute ago, Thorfun said:

 

 interesting about what you say about the Powerwall and that is definitely the Tesla way (as we both know with the software updates on our cars!). they're very much a release it and see what happens type software company. doesn't mean I don't love my car though. ?

 

My view of Tesla is that their work model seems to be "release an update and let our customers find what's broken". . .

 

A lot of Powerwall owners didn't even know that Tesla had rolled out the Storm Mode update here in the UK, and only found out over the past few days when their Powerwalls opted to 100% charge, irrespective of the power source, in readiness for a power outage.  If I had one and it had done this I'd not be a happy customer at all.  I want control so that I can decide when and from what source the system charges, so, for example, if we are going to be away I want to turn off off-peak charging, but still allow excess PV generation charging, and I definitely do not want the unit to decide to charge from the grid because some algorithm has predicted that bad weather is on its way.

 

 

[Jeremy Harris]

3 minutes ago, SteamyTea said:

They disconnect, but don't island.  Islanding is totally isolation from the grid.

 

The Lux Power AC units disconnect from the mains in about 10ms and island the maintained supply circuit in the event of a power cut.

[Thorfun]

thanks guys. great information so far. keep it coming. ?

[SteamyTea]

41 minutes ago, Jeremy Harris said:

Lux Power AC units

Is that the one that Wind & Sun sell?

If it is a very similar price, and reliable, then worth having.

Though I am a SMA fan.

[Jeremy Harris]

54 minutes ago, SteamyTea said:

Is that the one that Wind & Sun sell?

If it is a very similar price, and reliable, then worth having.

Though I am a SMA fan.

 

 

I don't think so.  The snag with the SMA Sunny Island is that it apparently has similar behaviour to the Powerwall, in that it can seemingly charge from the grid even when it's not supposed to.

[SteamyTea]

9 minutes ago, Jeremy Harris said:

SMA Sunny Island

Seem to remember that can be changed if you have the installer password. There were loads of this he you could do once given access to the 'proper ' software.

One common was to up the voltage a bit to stop them cutting out. Very illegal, but done a lot is rural areas. I never did it, all my time was taken up with setting the country code to GB. Something sparkies failed to do, no matter how many times I told them.

 

[joth]

On 11/02/2020 at 14:58, Jeremy Harris said:

 

The Lux Power AC units disconnect from the mains in about 10ms and island the maintained supply circuit in the event of a power cut.

 

The Luxpower units look very interesting alternative, they even have a hybrid inverter that could take our 8kW array as direct input, although we'd loose out on 3kw of generation when the batteries are full as it only has a 5kw inverter. On balance I think I'll keep the batteries AC coupled just to keep the systems independent. Although the cost savings are substantial; at £950 their hybrid inverter charger is less than the solaredge PV inverter on its own. And having a single app for monitoring both is systems would be convenient

 

 

Speaking of which, the one potential downside of the Luxpower is it almost certainly has a bunch of built in "phone home" code connecting to a server in Shenzhen I have no control over, for firmware updates and for their monitoring &control app service, which makes me a little uneasy. Not sure what local interface it supports for control, e.g. if it is blocked it off from public internet access. 

 

 

 

[tonyshouse]

Re battery storage generally-  we need to reduce our overall energy demand as a nation, battery storage increases this as it is inherently inefficient 

[SteamyTea]

57 minutes ago, tonyshouse said:

Re battery storage generally

While I agree in principle with reduction.

With batteries the overall efficiencies losses may be less that the equivalent losses in bulk generation.

It could be that loosing 20% on the battery round robin is still better that running a CCGT at 80% of design capacity.

At the end of the day it is all about carbon dioxide reduction, not energy reduction.  That message sometimes get lost in the white heat of technology.

[ProDave]

But with the new regime of no FIT payments, battery storage, when it get a bit cheaper will be a way to use 100% of your PV generation.  It is more about what's good for an individual, than what's good for the grid as a whole.  Grid scale storage, or any form, is someone elses problem.

[MortarThePoint]

Lead Acid batteries are about to be in massive demand as people wander out to their cars and find the batteries are stuffed. RAC has had a special offer of free replacements which I think they will regret.

 

A friend got a text message from their car dealer to say their car needed charging. Makes you wonder how much they know these days.

[Thorfun]

Hi all. I'd like to revive this thread as I'm back on the battery storage research trail again after our M&E consultants no longer offer it and have refunded my deposit for a Tesla Powerwall 2 and left me to my own devices to source another.

 

I got a quote from a local certified PW2 installer and the price has increased by £2k in the 18 months since I was last quoted and so I cannot afford a PW2. I have been looking at other options.

 

I have a 10.5kWp array with Solaredge optimisers on each panel (28 x 375W) with a Solaredge single phase HD Wave 10kW inverter. I want the battery storage to be able to power the house in case of a power cut. As I already have an inverter the Hybrid systems don't work for me unless I eBay my inverter and even then they tend to be 5kW inverters max. so, from what I can see, my options are as follows:

 

1. Tesla Powerwall 2 - £703/kWh - too expensive so not actually an option

2. Sofar ME3000SP with Pylontech batteries - £375/kWh - (https://midsummerwholesale.co.uk/buy/sofar-storage/sofar-me3000sp-us3000-type-c-kits)

3. Sofar ME3000SP with Sofar battery pack - £405/kWh (https://midsummerwholesale.co.uk/buy/sofar-storage/sofar-me3000sp-gtx5000-kits) (https://www.sofarsolar.com/product-detail/566/GTX5000) 

3. Lux ACS 3600 with Pylontech batteries - £617/kWh (online price here https://www.thesolarpeople.co.uk/shop/lux-power-battery-storage/ I think includes installation so figures might be wrong and further investigation that requires actually speaking to people will be done) 

4. Sonnen Battery 10 with Sonnen protect - I'm awaiting a quote from a Sonnen installer. I could only find the hybrid version to buy online (but I have to admit I didn't look that hard!)

 

all the other battery storage options are either Hybrid or don't have EPS functionality.

 

have I pretty much got it all covered? if so, the Sofar with Pylontech is definitely looking like a very good option although I'm a little put off by Midsummer's comment "Wifi commissioning is vastly easier on the Android app over iOS. Only use iOS if no Android device is available." as we're an Apple household and don't have any Android devices.

 

any comments or suggestions please?

 

oh and before it starts I'm not interested in payback periods etc I'm just looking for a cost effective way of storage for our excess solar PV! 😉 

[Ferdinand]

The Apple device I would use - since I can't stand iPhones - would be a low end iPad.

[Thorfun]

1 minute ago, Ferdinand said:

The Apple device I would use - since I can't stand iPhones - would be a low end iPad.

I'm the other way around, can't stand Android phones. 😛 

[Thorfun]

just remembered that for the Sofar ME3000SP Midsummer mentions this:

 

"

Emergency backup power:

The ME3000SP is able to provide backup power of up to 3kW via its EPS circuits. To use this feature you'll need an additional contactor chint to change the power supply from the mains to the batteries in the event of a grid failure. The ME3000SPs backup power is designed to power critical circuits and is not suitable for whole house backup due to the power limitations.

"

but from what I can tell the Lux doesn't have that limitation and switches to EPS in 10ms.