SunAmp : Snog, Marry, Avoid?

[ProDave]

18 minutes ago, joth said:

 

To be fair, this is "how much battery storage can I get for £13,000?" which if very different to  "how could I usefully spend the £3000 I save by not going with a sunamp?".

 

To the latter, I think 2x PylonTech US2000B plus an inverter and installation might be possible around £6-700/kWh? (And easy to add more storage in future as prices drop).

 

 

 

So 4kWh battery storage for £3k

 

Lets assume an ideal world of unlimited spare solar pv otherwise going to waste.  So your batteries let you capture and use 4kWh per day or about 50p per day.  So about £182 per year.

 

That will take 16 years to recoup the £3K outlay.  What state will the batteries be in by then?

 

The real payback will be way longer because there will be plenty of days when there simply is not enough surplus solar pv to fully charge the batteries or not enough evening demand to fully discharge them.

 

So once more, the economies of battery storage are not there yet.

[NSS]

45 minutes ago, Dan F said:

 

2 x Powerall2 @ £480/kWh.  If you get just one it's a bit more (given gateway is one-time expense) @ £560/kWh.

 

Ah, not quite what I thought you were suggesting. 

[SteamyTea]

1 hour ago, ProDave said:

What state will the batteries be in by then?

If EV batteries are used as a guide, probably still useful.

And inverters seem to be lasting better than most people assumed.

 

Hard to come by independent data though.

[joth]

1 hour ago, ProDave said:

So your batteries let you capture and use 4kWh per day or about 50p per day. 

And even less if you have an export tariff, in which case you'd want to use the market spread - difference between average "buy" and "sell" prices.  So about 10p/kWh

On the other hand, the point here was batteries allow a system design where ASHP will maximize its contribution to DHW needs from the PV, rather than using the immersion, so allowing the COP of 3+ to come into effect, which does provide a little more economic up-side.

Still, at this point anyone installing it is doing so for more than pure economic value alone. (Be it environmental, or the benefit of grid failure backup -  which itself maybe an economic justification in these days of home working)

 

[NSS]

17 minutes ago, joth said:

On the other hand, the point here was batteries allow a system design where ASHP will maximize its contribution to DHW needs from the PV, rather than using the immersion, so allowing the COP of 3+ to come into effect, which does provide a little more economic up-side.

Still, at this point anyone installing it is doing so for more than pure economic value alone. (Be it environmental, or the benefit of grid failure backup -  which itself maybe an economic justification in these days of home working)

 

 

Nail on head. Sure, cost is a big consideration (and running the ASHP overnight is definitely of potential benefit in that respect), but the environment and at least a degree of grid backup are also important factors to us. We'll definitely add battery storage at some point, it's just a case of waiting for the cost to drop to a level we can live with.

[scottishjohn]

surely the true test of costings is 

can you go off grid as cheap as your cost to have a connection on a new house .my connection is going to be 30k

and istill don,t see cost of PV and storage can compete with that in my life time 

only way that could happen is if electricity costs went crazy

[NSS]

3 minutes ago, scottishjohn said:

surely the true test of costings is 

can you go off grid as cheap as your cost to have a connection on a new house .my connection is going to be 30k

and istill don,t see cost of PV and storage can compete with that in my life time 

only way that could happen is if electricity costs went crazy

 

But I guess you'd need a lot of storage (and generation) capacity to go off-grid in anything approaching a typical household with all the appliances, gadgets, heating and lighting requirements. All I'm looking for is sufficient storage to power the ASHP for a few hours overnight and/or the MVHR, dishwasher and washing machine, and to provide power for the fridge, freezer, a couple of led lights and (if required) a nebuliser in the event of a power outage.

[SteamyTea]

11 hours ago, NSS said:

and at least a degree of grid backup are also important factors to us.

That starts to get expensive as a 4 or 6 kW 'islanding' inverter is not cheap.

10 hours ago, scottishjohn said:

surely the true test of costings is 

can you go off grid as cheap as your cost to have a connection on a new house .my connection is going to be 30k

and istill don,t see cost of PV and storage can compete with that in my life time 

You would use a combination of a generator well as PV, Wind, nanoHydro and storage in that case.

[NSS]

1 hour ago, SteamyTea said:

That starts to get expensive as a 4 or 6 kW 'islanding' inverter is not cheap.

 

Apparently my SolarEdge inverter can fairly simply be converted to a StorEdge inverter that will (with LG Chem batteries) enable backup.

[SteamyTea]

25 minutes ago, NSS said:

SolarEdge inverter can fairly simply be converted to a StorEdge inverter

How much.

I can't see any reason why all inverters are not capable of being islanding ones, except for the bean counters stopping it.

 

Just looked at the price of pure off grid inverters and they are a lot cheaper than grid ones. This is understandable as they do not need a safety certificate i.e G99.

So may be cheaper to have a mix of inverters and a large change over switch.

Could a pure sine wave inverter trick a grid inverter to boot up?

Edited June 30, 2020 by SteamyTea

[NSS]

1 hour ago, SteamyTea said:

How much.

I can't see any reason why all inverters are not capable of being islanding ones, except for the bean counters stopping it.

 

Just looked at the price of pure off grid inverters and they are a lot cheaper than grid ones. This is understandable as they do not need a safety certificate i.e G99.

So may be cheaper to have a mix of inverters and a large change over switch.

Could a pure sine wave inverter trick a grid inverter to boot up?

 

No idea yet. I haven't gone as far as getting a quote as can't have anyone round before the end of July (at least).

[SteamyTea]

3 minutes ago, NSS said:

No idea yet. I haven't gone as far as getting a quote as can't have anyone round before the end of July (at least).

Construction has never been on lockdown, just lazy suppliers not wanting to work as they can get paid by the government.

Wish my boss was that sensible.

[joe90]

14 hours ago, scottishjohn said:

surely the true test of costings is 

can you go off grid as cheap as your cost to have a connection on a new house .my connection is going to be 30k

and istill don,t see cost of PV and storage can compete with that in my life time 

only way that could happen is if electricity costs went crazy

have you established flow rate of the water you have on site to consider hydro?

 

i remember Dick Strawbridge building a water wheel to generate power fir lights, luckily he found a 60:1 gearbox but the losses with so many cogs was high, i surmised a chain drive of 60:1 would be a lot more efficient, but didn’t find a plot with water ?

[SteamyTea]

4 minutes ago, joe90 said:

i remember Dick Strawbridge building a water wheel to generate power fir lights, luckily he found a 60:1 gearbox but the losses with so many cogs was high, i surmised a chain drive of 60:1 would be a lot more efficient, but didn’t find a plot with water

Direct drive and let the electronics deal with the rest.

 

I seem to remember that the peripheral speed of the turbine needs to be half the jet velocity for a Pelton wheel.

Edited June 30, 2020 by SteamyTea

[NSS]

17 minutes ago, SteamyTea said:

Construction has never been on lockdown, just lazy suppliers not wanting to work as they can get paid by the government.

Wish my boss was that sensible.

 

Not the issue. We simply can't have anyone here because of shielding. 

[dpmiller]

2 hours ago, SteamyTea said:

How much.

I can't see any reason why all inverters are not capable of being islanding ones, except for the bean counters stopping it.

 

Just looked at the price of pure off grid inverters and they are a lot cheaper than grid ones. This is understandable as they do not need a safety certificate i.e G99.

So may be cheaper to have a mix of inverters and a large change over switch.

Could a pure sine wave inverter trick a grid inverter to boot up?

 

But as inverters are current sources, trying to drive into what is basically an open circuit and minimal load would likely have the voltage swinging wildly. The mains supply isn't just for frequency control...

[SteamyTea]

54 minutes ago, dpmiller said:

3 hours ago, SteamyTea said:

Could a pure sine wave inverter trick a grid inverter to boot up?

 

But as inverters are current sources, trying to drive into what is basically an open circuit and minimal load would likely have the voltage swinging wildly. The mains supply isn't just for frequency control...

Why I was wondering if it could be tricked.  It may need a reasonable resistance load onto it, say 1 kW, to give the impression there is some grid impedance.

Was just a thought.

Edited June 30, 2020 by SteamyTea

[scottishjohn]

11 hours ago, SteamyTea said:

You would use a combination of a generator well as PV, Wind, nanoHydro and storage in that case.

Ihave the space and water to do all that --but it just is not viable -even if i lived for another 30 years 

this is my pointoff grid is not a technical problem --cost is 

[scottishjohn]

7 hours ago, joe90 said:

have you established flow rate of the water you have on site to consider hydro?

all depends on how much of the site  is good for 5kw  according to hydrologists quick cal on how much land drains into it 

I could raise the level of the pond by 10m if idammed it up some more ,so out put go up some more 

the water that used to supply the house iam rebuilding -would only be good for hydro if i put turbine at bottom of quarry -350ft below

and then its variable flow could mean forn 2-5kw 

but it all costs loads of money to do and Iwil look at it gain ,but think iwill just suck it up and pay for a supply 

for who ever buys the quarry --then that could very well be a viable option 

wind turbine -- thibk planning would be the problem theregetting very hard to put them up now 

the farm above bought a fairly big one a few years ago -cost 600k --he gets 175k a year from it ,so he tells me --not sure what he will get when his contract runs out --he has had his outlay back already 

[scottishjohn]

pv on the jetty --30acres --could be good --but again its the outlay 

3oacres =3mw  so i am told

-but with the pitful FIT you need to find customers to sell it to at 10p a unit -then its a real winner--again 

I had companies willing to do that if there were users close at hand -then they pay me rental --about 25k a year and they build it 

I,m too old for all that sort of messing about 

Edited June 30, 2020 by scottishjohn

[Triassic]

7 hours ago, NSS said:

 

Not the issue. We simply can't have anyone here because of shielding. 

I’ve worked on my self build throughout lockdown in a three builder bubble. Very cosy!

[SteamyTea]

Just now, Triassic said:

I’ve worked on my self build throughout lockdown in a three builder bubble. Very cosy!

Have we not been warned about this sort of talk, wives and daughters read this.

[Triassic]

37 minutes ago, scottishjohn said:

Ihave the space and water to do all that --but it just is not viable -even if i lived for another 30 years 

this is my pointoff grid is not a technical problem --cost is 

I assume you’ve read Paul Canelli’s blog, he has self installed hydro, wind turbine and PV, his house is way off grid. Well worth the read.

 

https://lifeattheendoftheroad.wordpress.com/category/hydro/

[DamonHD]

On 29/06/2020 at 19:09, Dan F said:

 

Batteries only? That sounds like an awful lot!  I have a quote for <£500/kWh AC-coupled incl labour.

 

Everything.

 

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

 

Rgds

 

Damon

[Russdl]

Dragging this thread kicking and screaming back up to date and on topic.
 

We love our Sunamp and are definitely in the ‘marry’ camp though I suspect what follows will make most readers think we are nuts. 
 

We had the Sunamp on site for 10 months before it was finally commissioned and when it was finally commissioned there was a click, a couple of lights in the control unit and that was it, 30 mins later it was producing hot water. That first full charge was all we gave it for a week or two (we weren’t living there) and it was only towards the end of the second week that it became obvious that the water temperature was dropping. We hadn’t used it for much, washing up and the like, but I was quite surprised at how long it was able to produce hot water for. I’ve never treated a UVC in the same way so no idea if that would continue to produce hot water for the best part of two weeks after initially getting up to temperature. Would it?

 

All was well for a month or so charging up every time the sun came out, and if the sun couldn’t be bothered to shine then we didn’t charge it.
 

Then it stopped working. 

 

In the control box the LED’s were telling us that there was a ‘temperature sensor fault’. The only reset button was not the issue. A call to Sunamp and their technical department got back to me quickly. The problem was diagnosed as a failure of the 4 core temperature sensor that slides down a thin tube in the centre of the PCM. They sent an electrician out to confirm that, and then sent him back to refit a new one so everything is back up and running and hunky dory at the moment. 
 

If that fails again, or any other part does, then I’m sure my good lady will insist on a divorce, from the Sunamp to start with I guess, because when that was down there was no hot water, apart from the Quooker. 
 

Actually the Quooker was great, I could still do the washing up because you can get it to dispense boiling water and cold at the same time so even without the Sunamps help it is a perfect mixer tap. But probably a bit of a stretch to have a bath that way!

 

Has anyone else experienced a failure of the temperature sensor?

 

Is it likely that it was faulty and a few charges killed it? 
 

Could our ‘charge every fortnight if we felt like it’ policy have killed it?
 

Any other ideas as to why that bit of wire and gubbins would have failed?

 

One other thing (if anyone has got this far) when it was first commissioned the LED’s never showed ‘cold start active’. When the replacement temperature sensor was fitted there was still no ‘cold start active’ indication from the LED’s but on starting after the replacement temperature sensor was fitted the cracking from the PCM as it started to melt was louder than I’d heard before. Much louder.