Sunamp container bulging

[Eileen]

We're not at that stage yet, solar being connected next week. Have messaged you separately with some background. Thanks for the tip!

[Jeremy Harris]

I would very much like to see the Sunamp charging algorithm radically overhauled, so that the unit will accept charge whenever there is ANY spare capacity.  Having to wait until the damned thing has discharged 50% before it being able to accept at charge at all is a massive loss of opportunity charging in winter, and significantly reduces our ability to use surplus generation. 

 

I'm not at all happy about this at all, and can only hope that it's looked at with a view to making the charging algorithm  for the electrically charged units far more effective for those of us who wish to charge them from excess PV generation to the maximum extent possible.

[LA3222]

4 minutes ago, JSHarris said:

I would very much like to see the Sunamp charging algorithm radically overhauled, so that the unit will accept charge whenever there is ANY spare capacity.  Having to wait until the damned thing has discharged 50% before it being able to accept at charge at all is a massive loss of opportunity charging in winter, and significantly reduces our ability to use surplus generation. 

 

I'm not at all happy about this at all, and can only hope that it's looked at with a view to making the charging algorithm  for the electrically charged units far more effective for those of us who wish to charge them from excess PV generation to the maximum extent possible.

This is cause for concern.  My house is going to be all electric, with the intention to install as much PV as possible dumping energy directly into SunAmps for both my DHW & Heating.

 

There seems no point having 10Kw of PV on the roof providing power if the bloody SunAmp is not going to accept it.

 

This appears to complicate things and I will have to scrutinise this carefully when the time comes to design the system.

 

Edited December 1, 2018 by LA3222
SIC

[Barney12]

25 minutes ago, JSHarris said:

It's hard to get really good data, which is a pity for those of us who would like to understand/model an installation.  I only discovered yesterday that our Sunamp UniQ eHW 9 was set so that it didn't accept any charge at all until it had discharged down to 90% depleted (10% remaining).  That was only because it was bright and sunny yesterday morning and I happened to go into the services room shortly after we'd run two showers, to find that we were generating loads of excess PV yet the Sunamp wasn't accepting any charge.

 

A quick email to Sunamp discovered the reason for this; our controller was set to not accept charge until the unit was 90% depleted, which is not a great setting in winter, when trying to store every last bit of surplus PV generation.  I've changed the setting so that it now starts accepting charge from 50% depletion, but would far rather have an option to increase that so that the Sunamp will always accept charge if there is any spare storage capacity at all, as that would make a significant difference in winter, when excess PV generation is sporadic.  In effect, we're wasting half of the charge capacity of the unit, which seems a bit bonkers to me.

 

There’s a couple of points here:

 

Firstly the manual is woeful, it’s incomplete (in places) and parts of it are impossible to follow. I emailed them recently to point out the they even had the description of the status LED’s D5 and D6 the wrong way round in the manual!! If they are serious about this being a main stream consumer product they really need to put a bit of work into the manual. It currently comes across as something of an afterthought. 

 

But the second point is the larger one; the lack of meaningful user feedback from the controllers is a massive problem. Even the most basic of devices actually tell you they’re switched on! 

 

As I think is mentioned on this thread there is a new controller with better control and better feedback in development but it has no release date. 

[Barney12]

6 minutes ago, JSHarris said:

I would very much like to see the Sunamp charging algorithm radically overhauled, so that the unit will accept charge whenever there is ANY spare capacity.  Having to wait until the damned thing has discharged 50% before it being able to accept at charge at all is a massive loss of opportunity charging in winter, and significantly reduces our ability to use surplus generation. 

 

I'm not at all happy about this at all, and can only hope that it's looked at with a view to making the charging algorithm  for the electrically charged units far more effective for those of us who wish to charge them from excess PV generation to the maximum extent possible.

 

I completely agree. The Sunamp’s ability to harness excess solar correctly is fundamentally flawed. 

 

Im not a tech expert but I’m not sure the level of control will be achievable with new controller logic alone. The controller gets the charge status from a thin wire which is inserted into a thin copper tube in the middle of the cell. That wire is somewhat “Heath Robinson”; it’s a length of thin 4 core cable with three thermistors soldered along its length; top, middle and bottom (ish) and then encased in some heat shrink tubing. 

[Jeremy Harris]

28 minutes ago, LA3222 said:

This is cause for concern.  My house is going to be all electric, with the intention to install as much PV as possible dumping energy directly into SunAmps for both my DHW & Heating.

 

There seems no point having 10Kw of PV on the roof providing power if the bloody SunAmp is not going to accept it.

 

This appears to complicate things and I will have to scrutinise this carefully when the time comes to design the system.

 

 

It's a major cause for concern, and one I only discovered by accident, although I would have discovered it from the two energy meters I installed last Monday within a week or two.

 

Having the unit sitting nearly half discharged and yet unwilling to accept any excess PV charge is a major flaw, in fact so major that it needs immediate rectification, in my view.  We deliberately opted to "upgrade" to a Sunamp unit with more than double the capacity so that we could better make use of the occasions in winter when excess PV generation is sporadic.  I had thought that we'd be able to keep the Sunamp topped up, so that during days with no excess PV generation we'd be able to use some of the stored heat in our larger than needed Sunamp. 

 

It turns out that this doesn't work at all, and we've already run out of hot water once, before I altered the boost charge timings.  Seeing the unit yesterday morning just sitting there, having just delivered around 4 kWh of hot water, yet not accepting any charge at all from the loads of excess PV we were generating, was bloody annoying to put it mildly.  It's meant we're using significantly more grid power, and wasting a significant amount of PV generation that we should be able to store in the Sunamp.

[Jeremy Harris]

13 minutes ago, Barney12 said:

 

I completely agree. The Sunamp’s ability to harness excess solar correctly is fundamentally flawed. 

 

Im not a tech expert but I’m not sure the level of control will be achievable with new controller logic alone. The controller gets the charge status from a thin wire which is inserted into a thin copper tube in the middle of the cell. That wire is somewhat “Heath Robinson”; it’s a length of thin 4 core cable with three thermistors soldered along its length; top, middle and bottom (ish) and then encased in some heat shrink tubing. 

 

If they don't do it, then I will.  The temperatures that the sensor string uses to trigger events is in the manual (sort of) and I've measured the timing for the cold start system, so it would not be at all hard to make a new controller that both keeps the PCM temperature (both locally and for the whole unit) within limits and yet allows the acceptance of charge whenever there is any spare capacity at all.

 

My inclination would be to increase the number of sensor points, so that mapping the PCM temperature vertically via the sensor tube could be done to a finer degree than the present sensor system allows.  Half a dozen DS18B20s strung together would give a reasonable temperature profile and allow a finer degree of control.  My aim would be to allow excess PV generation charge whenever the upper sensor is indicating a temperature that is below the maximum allowable PCM temperature, say around 65 deg C (that was, I believe, the target temperature that the Sunamp PV used when charging). 

 

I might be inclined to build the PV diverter and boost timer into the same controller, too.  Not at all hard to do for my system, as all the "heavy lifting" in terms of energy measurement is done by the unit that sits outside by the meter cabinet, and which broadcasts energy use data via an 868 MHz data link that any device in the house can link to.  The actual PV diverter I have next to the Sunamp is just a semi-dumb switch, that turns the power on and off based on the data it receives via the radio link.

[Jamie998]

10 minutes ago, JSHarris said:

Having the unit sitting nearly half discharged and yet unwilling to accept any excess PV charge is a major flaw, in fact so major that it needs immediate rectification, in my view. 

I would agree and I will watch this space with interest now.  I am at least a year away from having to make a decision so I would hope that in this time the issue is rectified and sense prevails.  The ability to dump excess PV generation directly into a SunAmp which would then sit there with low SHL was steering my decision making process - now the goalposts have been moved it may no longer be the optimal solution.

 

I'm baffled as to why they would do this - some of their models are geared towards direct connection to PV but if it won't take the charge its bonkers.  

[Nickfromwales]

I had this phone call, literally yesterday, and after an hour of deep conversation, with one of the most helpful guys on their books, I was informed the logic has ( past tense ) been amnended for the options of charge / call for heat to go as high as 20% discharged = calling. There are some clever folk working on and developing the SA units and controls and I have already had a few simple suggestions, that I made, rebuffed. In the light of the responses I got as to why those ‘ideas’ could not be implemented, I now know a decent bit about the product and the huge hurdles that have been jumped to get the product this far. I’m going to afford them some credit for that tbh.  

 

Their aim is to have a reliable, off the shelf item that can go into a domestic dwelling and then require no intervention whatsoever. When I was asked what I was going to do with a SoC ( state of charge ) indicator / display I was a little stuck to reply. It’s not like anyone is going to sit in all day staring at it, what would be the point of that? It’s also impractical to ask an end customer to check in on it daily to see if it needs boosting or not. Not going to happen.

 

Boffins, and folk ( such as myself ) who are curious enough to want to know will naturally be disgruntled at not being afforded this insight, but the product simply isn’t aimed at us at this moment in time. It is something that’s on the cards, possibly for Q4/2018 - Q1/2019, but it’s not a high enough priority is what I’m led to believe. My own perception. I aired my own frustrations re more complex controls / status monitoring etc and was simply told that that is / was not on the immediate list of things to cater for due to ( deemed ) lack of necessity / practically. 

 

Remembering that PCM doesn’t stratify like water does shows the complications of obtaining reliable temperature readings throughout the charged / part charged cell. Also let’s remember that the PCM gets killed by overheating it. As PV is introduced via a 3kW immersion, it’s imperative that that does not get over-energised as it’ll only serve to cook and kill the PCM immediately local to ( surrounding ) the immersion element. 

 

I dont envy SA”s task in achieving the middle ground, but looking at it kW for Kw, it’s still the most efficient way to absorb and store excess electrical energy ( E7 / E10 / PV ). Looking at the alternatives it still seems to rank highest AFAIC. 

 

Some fleas do seem to come with the dog, but hopefully with the newer logic, eg more varied SoC / demand control and some basic indicators, ( personally I’d be happy if each thermistor ( ~33% - ~66% - ~100% ) light an led, would be better than nowt ), it should appease the ‘general public’ accordingly. 

 

I’ll get my tin hat. 

[Jeremy Harris]

I'm not at all fussed about having a SoC indicator, all I MUST have (and this is not at all negotiable) is the ability to charge the unit with excess PV generation whenever there is any spare heat storage capacity available.

 

The present system is ludicrous, and significantly poorer in this regard than the old Sunamp PV we had.  That would always accept excess PV charge if there was any spare capacity in the unit, not refuse to charge when there was still ~50% of the capacity sitting there uncharged.

 

I may just as well have a 4.5 kWh heat store, as that's all I've got, in effect, if the damned thing refuses to charge from excess PV until it's 50% depleted.  If I sound annoyed, it's because I am.  Compared to the Sunamp PV the Sunamp UniQ eHW 9 is only using a fraction of our available excess PV generation, and instead it's costing us money to charge from the grid most of the time.

[PeterW]

14 minutes ago, Nickfromwales said:

When I was asked what I was going to do with a SoC ( state of charge ) indicator / display I was a little stuck to reply. It’s not like anyone is going to sit in all day staring at it, what would be the point of that? It’s also impractical to ask an end customer to check in on it daily to see if it needs boosting or not. Not going to happen.

 

Boffins, and folk ( such as myself ) who are curious enough to want to know will naturally be disgruntled at not being afforded this insight, but the product simply isn’t aimed at us at this moment in time.

 

Hmmm... crap supplier answer, sorry ..!! That’s like Worcester Bosch [other boiler makes are available] saying there is no point outputting the error codes to the LCD as “customers won’t know what they are”... Diagnostics are useful, as are basics such as indicator lights ...! 

 

Sounds like a number of people on here have purchased them (PV models especially) and find they don’t actually do what they say on the tin. 

 

I also find the 3kw immersion thing very “binary” and they should have thought this through better. Units with a series of 1kw immersion’s, each with a controller, would be better as a failure becomes less of a problem as you retain redundancy. 

[Nickfromwales]

1 minute ago, PeterW said:

 

Hmmm... crap supplier answer, sorry ..!! That’s like Worcester Bosch [other boiler makes are available] saying there is no point outputting the error codes to the LCD as “customers won’t know what they are”... Diagnostics are useful, as are basics such as indicator lights ...! 

 

Sounds like a number of people on here have purchased them (PV models especially) and find they don’t actually do what they say on the tin. 

 

I also find the 3kw immersion thing very “binary” and they should have thought this through better. Units with a series of 1kw immersion’s, each with a controller, would be better as a failure becomes less of a problem as you retain redundancy. 

One of my suggestions. Duly repeated  

[Nickfromwales]

I shall update after I get further updates. 

 

[Guest Alphonsox]

Is the changing system in the new designs fundamentally different to that in the original SAPV units ? I have a couple of the originals and assumed they would accept input at any stage of discharge.

[le-cerveau]

2 hours ago, Eileen said:

Thanks - and we clocked your lid from this very useful topic, so will be asking for a new lid on Monday. We're a (hopefully) certified Passivhaus heated by low temp underfloor and have two Dual 4 PCM34s alongside the 12, heated by a low temp Daikin and primarily used for pre-heating the water heading for the 12 which is solar/electric heated, but also for the underfloor subject to some issues being clarified. One thing we were trying to find out, so far unsuccessfully, is whether Sunamp have any similar deployments, but maybe some one here will have a similar set-up.

 

My set up is similar though mine are pre UniQ but dual units.  I have 2 x PCM34 units heated by my ASHP that pre-heat the DHW and the UFH.  Then 2 x PCM58 units for the DHW .

[Jeremy Harris]

3 hours ago, Alphonsox said:

Is the changing system in the new designs fundamentally different to that in the original SAPV units ? I have a couple of the originals and assumed they would accept input at any stage of discharge.

 

Yes, it is fundamentally different, if you use excess PV generation as a source of charge.  The Sunamp PV would accept charge no matter what the state of charge of the heat cells.  All it cared about was keeping the unit hot, as far as I could tell, and it controlled the cell temperature by controlling the water circulation temperature, using a variable speed pump, heating element, flow sensor and water temperature sensors.  If excess PV was available the unit would try and charge, unless the water circuit was above a threshold temperature.

 

The Sunamp UniQ eHW will not accept any charge, from any source, until it is either 50% depleted or 90% depleted (programmable in the controller).  This means that you can have up to 50% of thermal storage capacity available in the heat cell which you are completely unable to utilise from excess PV generation, which is ludicrous, especially in winter, when excess PV generation is sporadic and you want to maximise the utilisation of it whenever it happens.

 

This is far worse than a thermal store or hot water cylinder, and is a very serious disadvantage for those who wish to use these units as heat stores driven largely by excess PV generation.  Unless this is changed I can see that we may well still need to use grid power to heat hot water in summer, as if we were to take bath in the evening the Sunamp may well be out of energy for morning showers, as it may only be just over 50% charged at the end of a sunny day, due to it not having reached the charge acceptance threshold.

 

Right now I'd recommend that no one fit a Sunamp if they intend to charge it primarily from excess PV generation.

[Triassic]

On 18/11/2018 at 09:13, Nickfromwales said:

I think they are due to release a new range of controllers, possibly one that is the pv diverter too. Not much known yet but hopefully that’ll be sooner than later. 

Can you update us on the details once they are known 

[andy]

Hmmm - this doesn't sounds good at all, albeit I'm still in the planning stage and not actually impacted.  Perhaps for safety right now I do go down the mains gas boiler/buffer tank route instead ?

 

A Tesla Powerwall would help here in that the PV would fill that up as required and then the SA would draw from the battery before the mains but that's an expensive option to meet basic functionality.

[Hecateh]

3 hours ago, Nickfromwales said:

When I was asked what I was going to do with a SoC ( state of charge ) indicator / display I was a little stuck to reply. It’s not like anyone is going to sit in all day staring at it, what would be the point of that? It’s also impractical to ask an end customer to check in on it daily to see if it needs boosting or not. Not going to happen.

I'm certainly no boffin but could find a definite use for a state of charge indicator.

 

EG first thing in the morning in winter, today; is forecast to be sunny;  I need to do some washing but am unsure whether to do it now or later in the day. 

Check indicator - 

level very low - leave the washing until later.

level just above half - wash now so that it can utilise the sun to fully recharge.

[Eileen]

We have a battery too - although at the last minute had to switch from Tesla (AC)  to LG (DC) as our power distribution company count an AC battery as micro-generation (3.6kw) alongside the solar (10kw) and the two added together exceeded their absolute limit on microgeneration (10kw). DC doesn't count in that equation as it's considered to be on the solar side. 

 

[Jeremy Harris]

I'm now seriously considering a battery pack.  I think I may start off with a relatively small and cheap Sofar/Pylontech unit, as they seem to be the most cost effective, and then maybe add battery modules to increase the capacity, based on experience.  The nice thing about the Sofar/Pylontech system is that it's modular and "plug and play" so relatively easy to just increase capacity if need be.  The other advantage is that it has a dedicated 3 kW max emergency output, so you can have some power available during power cuts, although that needs a bit of wiring reconfiguration to be really useful.

[Nickfromwales]

2 hours ago, JSHarris said:

I'm now seriously considering a battery pack.  I think I may start off with a relatively small and cheap Sofar/Pylontech unit, as they seem to be the most cost effective, and then maybe add battery modules to increase the capacity, based on experience.  The nice thing about the Sofar/Pylontech system is that it's modular and "plug and play" so relatively easy to just increase capacity if need be.  The other advantage is that it has a dedicated 3 kW max emergency output, so you can have some power available during power cuts, although that needs a bit of wiring reconfiguration to be really useful.

Could we divert that chat into a new thread please, and we can pop a link here to steer folk to it  

[Jeremy Harris]

Might be an idea to tidy this thread and split off the discussion on charging etc into a separate thread, perhaps?

[Nickfromwales]

Most of whats here bears relevance imo, just didn't want to have the useful topic of batteries lost here thats all.

[Ed Davies]

5 hours ago, Nickfromwales said:

Boffins, and folk ( such as myself ) who are curious enough to want to know will naturally be disgruntled at not being afforded this insight, but the product simply isn’t aimed at us at this moment in time.

 

I think their aim's badly off in this respect. Sure, they want to move beyond the early-adopter/beta testers infesting forums such as this but still they're going to be selling for quite a while to people who are willing to do something a bit unusual who will naturally take an interest in the details. Their design should reflect that.