SunAmp : Snog, Marry, Avoid?

[scottishjohn]

5 hours ago, Pete said:

All Hail Jeremy!!

Jeremy is spot on with his views on this unit  and I applaud him for being so dogged  chasing them about the problems 

we are being told continually to save energy and be more efficient with its usage  

the ability to use ALL of the excess PV is an imperative  towards this goal  ,

especially as now there is no FIT tarfiff  worth having to make people go down the PV way  
5 -7 years to pay back was one thing now it is much longer ,then some  people are just not going to take it up .

[ToughButterCup]

In fairness, and in pursuit of a balanced discussion, I would like to point out that Jeremy's opinion is not the only one. 

 

[Onoff]

2 minutes ago, recoveringacademic said:

In fairness, and in pursuit of a balanced discussion, I would like to point out that Jeremy's opinion is not the only one. 

 

 

Yeah, but it's probably the only correct one! 

[ToughButterCup]

30 minutes ago, Onoff said:

[...] it's probably [...]

 

My concern is to keep the thread (in truth, all threads ) balanced and factual. And in that respect, expert opinion is highly valued. But danger exists - especially on line - where there is little or no challenge to perceived  technical expertise. 

 

Currently, we only have direct evidence of one problem install  and, as written, second hand reports of others: hearsay. And we have direct reports of many problem free installs.

We have to be seen to be objective, fair, and balanced   in our treatment of what for many members (and non members)  could be an expensive purchase decision.  

[Jeremy Harris]

First off, I'm not an expert, by any stretch of the imagination. 

 

Secondly, @Barney12's problems are well documented here, as are those experienced by @Eileen, so there are at least three members here who've experienced some problems/issues with their Sunamps. I think that @readiescards may also have had a unit replaced by Sunamp.  I think we may have around half a dozen or so members that have the newer model Sunamps, so it would seem that perhaps 50% of them, maybe more, have experienced some problems.

[ProDave]

3 hours ago, scottishjohn said:

especially as now there is no FIT tarfiff  worth having to make people go down the PV way  
5 -7 years to pay back was one thing now it is much longer ,then some  people are just not going to take it up .

I think PV, as in a paid for installed system, is dead just now except for someone who wants it for eco reasons.

 

I am hoping my DIY system will be paid for in energy saving in about 5 years, but it was hard work getting the kit cheap enough to achieve that even with DIY install.

[scottishjohn]

19 hours ago, recoveringacademic said:

In fairness, and in pursuit of a balanced discussion, I would like to point out that Jeremy's opinion is not the only one. 

 

His numerous explanations of the system and how it is not doing what the first units did has convinced me ,

and that@s not easy !!

He has not convinced  meto go PV +sunamp though .LOL

,that there is a problem with later units and needs to be addressed  is obvious and he seems to have used  sound experimentation to find this out

as to how good the units  are in reality in either old or new form  could be open to a biased opinion of those that have spent the cash

,but the problem I believe is real 

If I want to heat  from  the sun ,then I will be staying with solar thermal for that ,as i have done for last 20 years 

Edited March 21, 2019 by scottishjohn

[NSS]

Never mind a Sunamp (or Tesla Powerwall for that matter), just stick a Renault Zoe in you plant room (or garage) - https://www.autocar.co.uk/car-news/industry/renault-scheme-transforms-evs-energy-storage-units

[ProDave]

 

1 hour ago, scottishjohn said:

If I want to heat  from  the sun ,then I will be staying with solar thermal for that ,as i have done for last 20 years 

But what is your solar thermal feeding into?  Presumably a hot water tank of some sort?

 

So if you have a hot water tank, don't rule out solar PV.  It's a more versatile source of energy as it can help to power your house and reduce your electricty bills as well as heat some water.  Just because you might have chosen not to have a Sun Amp is no reason to rule out solar PV

[ProDave]

2 minutes ago, NSS said:

Never mind a Sunamp (or Tesla Powerwall for that matter), just stick a Renault Zoe in you plant room (or garage) - https://www.autocar.co.uk/car-news/industry/renault-scheme-transforms-evs-energy-storage-units

Is that really a good use of the batteries in an EV?

 

Not long back in one of the discussions on EV's I raised battery life as a concern.  A well reasoned argument suggested with a typical range of 200 miles and batteries being good for 1000 charge / discharge cycles, a battery life of 200K miles was a reasonable expectation.

 

But that is blown out of the water if your car is going to sit there charging and discharging while going nowhere.  I would want to be paid handsomely for that to compensate for the lower battery life I would get as a result of that.

[Jeremy Harris]

9 minutes ago, ProDave said:

Is that really a good use of the batteries in an EV?

 

Not long back in one of the discussions on EV's I raised battery life as a concern.  A well reasoned argument suggested with a typical range of 200 miles and batteries being good for 1000 charge / discharge cycles, a battery life of 200K miles was a reasonable expectation.

 

But that is blown out of the water if your car is going to sit there charging and discharging while going nowhere.  I would want to be paid handsomely for that to compensate for the lower battery life I would get as a result of that.

 

 

It's my primary concern about the whole idea of V2G.  It keeps getting promoted, but the impact of cycle life on a vehicle battery used as a domestic energy store is going to be pretty high.  I typically charge my car about once every week or two, so over a year it might, possibly, get around 50 cycles (allowing for multiple charges on longer trips).  Using it as a home storage battery, with PV and off-peak charging, would probably increase that to around 500 cycles a year or more.

 

The requirements for vehicle and home storage batteries seem markedly different, in that cycle life isn't really at all significant for a vehicle battery, but having a high peak charge and discharge capability is.  A home storage battery doesn't need a high charge or discharge capability, as it'll probably never charge or discharge at over a fraction of 1C, but it does need a useful cycle life that's at least 4000 cycles or so. 

 

[Barney12]

20 hours ago, JSHarris said:

First off, I'm not an expert, by any stretch of the imagination. 

 

Secondly, @Barney12's problems are well documented here, as are those experienced by @Eileen, so there are at least three members here who've experienced some problems/issues with their Sunamps. I think that @readiescards may also have had a unit replaced by Sunamp.  I think we may have around half a dozen or so members that have the newer model Sunamps, so it would seem that perhaps 50% of them, maybe more, have experienced some problems.

 

Agreed. Further, I can confirm that my own testing (and fault finding) matches  @JSHarris findings in terms of how the system operates.

Of course that operation could be deemed as not a 'fault' or 'problem' but at the very least is at odds with their own marketing materials and specification.

 

[ProDave]

Do EV's have a log or readout of how many charge / discharge cycles they have done?

 

Or in the future if buying a used EV should you be asking "Has it been used for V2G charging?"

[Jeremy Harris]

10 minutes ago, ProDave said:

Do EV's have a log or readout of how many charge / discharge cycles they have done?

 

Or in the future if buying a used EV should you be asking "Has it been used for V2G charging?"

 

In general yes, it's pretty easy to plug a OBD connector in and then use some readily available software to look at the battery health in detail.  Most EVs have some form of open source software available that can read data via the OBD port and give a health report.  Some manufacturers include a battery health display in the car, Nissan I believe do this with the Leaf, but it's not as capable as using LeafSpy and a laptop.

[Ed Davies]

New study: V2G may not degrade EV battery life – it might actually extend it

[Jeremy Harris]

6 minutes ago, Ed Davies said:

New study: V2G may not degrade EV battery life – it might actually extend it

 

Interesting, but it assumed that vehicle would be driven for between 21% and 38% of their maximum range every day, which is pretty unrealistic.  For someone with a newer EV, like a Hyundai Kona or Kia eNiro, or even a Tesla or Jaguar iPace, that battery capacity usage equates to around 45 to 90 miles per day.  I doubt that many people drive that far every day.  My mileage is probably around 1/3 of that.

[NSS]

15 minutes ago, Ed Davies said:

New study: V2G may not degrade EV battery life – it might actually extend it

If I read and understand that correctly, it's a bit like phone batteries in that they tend to last longer if near fully discharged before recharging they last longer.

[LA3222]

This thread seems to veering off from the main issue now? 

[scottishjohn]

5 hours ago, ProDave said:

Is that really a good use of the batteries in an EV?

 

Not long back in one of the discussions on EV's I raised battery life as a concern.  A well reasoned argument suggested with a typical range of 200 miles and batteries being good for 1000 charge / discharge cycles, a battery life of 200K miles was a reasonable expectation.

 

But that is blown out of the water if your car is going to sit there charging and discharging while going nowhere.  I would want to be paid handsomely for that to compensate for the lower battery life I would get as a result of that.

I know of no car maker that warranties the EV components for 200k 

6years or 60 k is most i have seen --that whilst not saying how long they will last tells you how long the maker expects them to be definately trouble free

and last time i asked a new battery pack for one car was 6k--thats a shit load of fuel -and all test i have seen say fast charging shortens battery life-

I will hold my judgement on Ev cars for sometime yet 

[Nick1c]

Back to reliably charging sunamps.....

would one or two solar thermal panels do the job using the water based variety - the temperature requirement of the pcm means that ashp's (mostly) don't work at a good cop, but those sorts of temperatures could fairly easily be hit by a st unit & boosted if necessary by an electrical element. 

Or it it too expensive. 

[Onoff]

6 hours ago, Nick1c said:

Back to reliably charging sunamps.....

would one or two solar thermal panels do the job using the water based variety - the temperature requirement of the pcm means that ashp's (mostly) don't work at a good cop, but those sorts of temperatures could fairly easily be hit by a st unit & boosted if necessary by an electrical element. 

Or it it too expensive. 

 

My experience of ST panels here is that could perhaps get too hot to feed some pcms and that you could cook them without some sort of temperature limiting and heat dump.

[ProDave]

2 hours ago, Onoff said:

 

My experience of ST panels here is that could perhaps get too hot to feed some pcms and that you could cook them without some sort of temperature limiting and heat dump.

I don't think even near boiling water would cook the PCM

 

The fluid in a ST panel starts circulating when the temperature at the panel exceeds the temperature in the tank. So it would not normally be massively hotter than the tank.

 

Do the Sun Amp's have a spare "user"  thermostat pocket?  If not that pretty well rules out using them with ST

[Jeremy Harris]

The PCM breaks down at around 125° C I believe, so an ST system pressurised to 1.3 bar above atmospheric would be enough to raise the boiling point to the critical temperature for the PCM.  From what I've seen, it's not that hard to get ST systems to this sort of temperature when they stagnate.

[scottishjohn]

3 hours ago, Onoff said:

 

My experience of ST panels here is that could perhaps get too hot to feed some pcms and that you could cook them without some sort of temperature limiting and heat dump.

thats part of your solar controllers job

you set max tank temp  and also max panel temp --the temp of water leaving the panel .

it turns off if too high or you can divert to to a heat dump -like an old radiator somewhere   --I like that system better as you do not get high stagnation temps in the panel which will damage panel over time if a regular occurrence.

It is unlikely if you have matched panel size with storage tank-- that was my mistake on old system 

300litre tank and 2x20 evac tubes--good day you got boiling tank by lunch time even though it the same tank had an UFH coil in it

add to that the system was supplied with a PLASTIC  air separator --which when temp sensor went faulty  some years on it melted

then panel temp got that high that it melted foam insulation from the copper pipes .

partially my fault trying to get max from it so did not have high temp cut offs set ,but  who would spec a solar thermal with anything plastic in it !!

but it shows how much heat  you can get if tank is not big enough for panels you have

one 20-30 evac tube panel is plenty for a 300 litre dhw tank 

better to have too much and dump it ,than be struggling on a winters day for heat 

 

[Barney12]

13 hours ago, LA3222 said:

This thread seems to veering off from the main issue now? 

 

Agreed!