Solar PV Hints, Tips & Troubleshooting

unkel

slave1 wrote: »

I like seeing the US off-grids setups on YT, they are awesome, do what they want and noone to tell them otherwise

Any particular ones? I like David Poz, not quite sure if he is off grid or not though. But he has a lot of batteries

slave1

unkel wrote: »

Any particular ones? I like David Poz, not quite sure if he is off grid or not though. But he has a lot of batteries

I recommend these two, you'll be taken from woodland to house including PV tinkering, now their journey is almost over there's a large number of videos...I like their raw videoing and hands on.
Best to watch from the very first video on and in order

https://www.youtube.com/channel/UCX49PVlb4bpvee5mZe1LIyA

mp3guy

slave1 wrote: »

I recommend these two, you'll be taken from woodland to house including PV tinkering, now their journey is almost over there's a large number of videos...I like their raw videoing and hands on.
Best to watch from the very first video on and in order

https://www.youtube.com/channel/UCX49PVlb4bpvee5mZe1LIyA

Wow those videos are insufferable. Long winded self indulgence. Just give me the numbers.

slave1

mp3guy wrote: »

Wow those videos are insufferable. Long winded self indulgence. Just give me the numbers.

This covers just the PV element for you but I prefer the raw bits over extended period of time, where you see them make mistakes and realise they could do things different so just go at it in real time

https://www.youtube.com/watch?v=436kcVOaEGk&ab_channel=WildWonderfulOff-Grid

irishchris

This would be my favourite one of the off-grid Americans
https://youtube.com/channel/UC-l69It3hxAY3tkBH_utLNQ

tails_naf

Hi all,
I have an eddi and use it to first heat my hot water tank and then my under floor heating buffer tank. I don't need the UFH tank to be heated in thr summer months, but I just found out that the eddi has no way of disabling the 2nd output unless I unwire it. Does anyone else have a similar issue, or an idea for how to not have the eddi run the 2nd output?

If I can disable this, I would instead like to turn on other loads when I have excess energy in summer. Any tips for how that can be achieved, do I need something else monitoring the export and trip a relay?

Evd-Burner

tails_naf wrote: »

Hi all,
I have an eddi and use it to first heat my hot water tank and then my under floor heating buffer tank. I don't need the UFH tank to be heated in thr summer months, but I just found out that the eddi has no way of disabling the 2nd output unless I unwire it. Does anyone else have a similar issue, or an idea for how to not have the eddi run the 2nd output?

If I can disable this, I would instead like to turn on other loads when I have excess energy in summer. Any tips for how that can be achieved, do I need something else monitoring the export and trip a relay?

Get an electrician to put an isolation switch in between the eddi and UFH tank. manually switch it off for the summer months.

slave1

What he said, it’s actually part of the installation in the Eddi manual so should have been done like this in the first place

graememk

tails_naf wrote: »

If I can disable this, I would instead like to turn on other loads when I have excess energy in summer. Any tips for how that can be achieved, do I need something else monitoring the export and trip a relay?

Yeah to run any other " diverts" the new system needs to at least know the import/export

But if it has more information ie how much is going to the immersion, coming from solar, etc

As relays can only switch on and off, and ideally you'll want something that knows how much is being used, and for the excess calculations.

For example, in my parents house, I have a oil radiator, in an outside office, kicking in when there is 800w of excess, and then the iboost takes whatever is left over. - it's either on or off, no in betweens

tails_naf

graememk wrote: »

Yeah to run any other " diverts" the new system needs to at least know the import/export

For example, in my parents house, I have a oil radiator, in an outside office, kicking in when there is 800w of excess, and then the iboost takes whatever is left over. - it's either on or off, no in betweens

Thanks, this makes sense. How did you set that up, what controls the oil radiator on/off?

graememk

tails_naf wrote: »

Thanks, this makes sense. How did you set that up, what controls the oil radiator on/off?

I will make a new post about it with more detail this evening, but the short and curlies of it, im using openenergy monitor stuff (emonpi/emonhub and emontx's) for monitoring and recording (and pretty graphs)

Got some wifi smart plugs that ive reflashed to work over mqtt (with tasmota)

Plan is also to get a dual fuel towel rack installed, so in the summer, its still warm when the heat is off.


Then I use node red for the smarts.. I also can feed my emonEVSE a solar excess value so i dont have to wait until my battery is full before putting some into the car.

mp3guy

graememk wrote: »

Oh they are up.. with them rates, I would lose money with a FIT!

If like me and many other people on here you happen to already have a modern GPU, it makes more sense to ignore FIT and just mine ethereum. You'll literally make multiples of the best tariff anyone offers, and on those sunny winter days get the benefit of heat. I know unkel has been doing this already too. Just don't go out to buy a GPU if you don't normally use one.

tails_naf

graememk wrote: »

I will make a new post about it with more detail this evening, but the short and curlies of it, im using openenergy monitor stuff (emonpi/emonhub and emontx's) for monitoring and recording (and pretty graphs)

Got some wifi smart plugs that ive reflashed to work over mqtt (with tasmota)

Plan is also to get a dual fuel towel rack installed, so in the summer, its still warm when the heat is off.


Then I use node red for the smarts.. I also can feed my emonEVSE a solar excess value so i dont have to wait until my battery is full before putting some into the car.

This sounds amazing, it's all stuff I'd love to do, I tinker with python and pis from time to time, but never had e ough time to pull it all together. One thing that's held me back is I don't want to store stuff on the cloud and pay for the privlige, some crowds that offer data logging services have monthly fees etc. Do you do that, or is everything stored local? If you ever do writh this up in detail, please let me know where to find the post.

graememk

tails_naf wrote: »

This sounds amazing, it's all tuff I'd love to do, I tinker with python and pis from time to time, but never had e ough time to pull it all together. One thing that's held me back is I don't want to store stuff on the cloud and pay for the privlige, some crowds that offer data logging services have monthly fees etc. Do you do that, or is everything stored local? If you ever do writh this up in detail, please let me know where to find the post.

Its all local.

I do send some to the emoncms.org for easy remote monitoring, (you get credit when you buy stuff from their store too), there is a fee for that. (but you could open ports on your router and port forward, or host your own server on a vps or whatever!) Small company in wales, all open source, quite an active community too.

I will do it, wont be this evening. been setting up a tado system! Just the thought of it is a bit daunting, but if your into tinkering, it would be right up your alley.

DrPhilG

Anyone else with Pylontech batteries?

I've had issues the last few days with slow charging, resulting in unnecessary export and water diversion.

I initially thought it was Eddi related, but having adjusted the export margins etc with no improvement, it's starting to look temperature related.

I'm not sure where to access the battery temperature, but I do have a sensor in the attic and the temperature up there has been sitting around 7-8 degrees most of the time.

The battery seems to max out at 930w when charging, but is able to discharge without any restriction.

I had also wondered if it was related to me recently changing the settings off overnight charging but I checked that last night to rule it out.

You can see here the "glass ceiling" of 930w earlier in the day, and then the shackles come off around 3pm.



What do we reckon folks? Combination of low temps and high sunshine? Anything that can be done to resolve it or does it just go with the territory of having your batteries in the attic?

championc

DrPhilG wrote: »

Anyone else with Pylontech batteries?

I've had issues the last few days with slow charging, resulting in unnecessary export and water diversion.

I initially thought it was Eddi related, but having adjusted the export margins etc with no improvement, it's starting to look temperature related.

I'm not sure where to access the battery temperature, but I do have a sensor in the attic and the temperature up there has been sitting around 7-8 degrees most of the time.

The battery seems to max out at 930w when charging, but is able to discharge without any restriction.

I had also wondered if it was related to me recently changing the settings off overnight charging but I checked that last night to rule it out.

You can see here the "glass ceiling" of 930w earlier in the day, and then the shackles come off around 3pm.



What do we reckon folks? Combination of low temps and high sunshine? Anything that can be done to resolve it or does it just go with the territory of having your batteries in the attic?

Could it possibly be the limitation of the Pylontech unit. There's been mention of the max discharge, so I'd expect a charging limitation too.

DrPhilG

championc wrote: »

Could it possibly be the limitation of the Pylontech unit. There's been mention of the max discharge, so I'd expect a charging limitation too.

They do have a limit of 1.2kw (I think) per pack. As I have 2 of them, they normally can charge or discharge at up to 2.4kw.

The fact that this 930w limit has happened early on and then relaxed in the early afternoon would suggest that it's temperature related. Plus the temperature recommendations are more relaxed for discharge, up to -10. So that would tie in with the fact that only my charge rate has been throttled, not discharge.

championc

DrPhilG wrote: »

They do have a limit of 1.2kw (I think) per pack. As I have 2 of them, they normally can charge or discharge at up to 2.4kw.

The fact that this 930w limit has happened early on and then relaxed in the early afternoon would suggest that it's temperature related. Plus the temperature recommendations are more relaxed for discharge, up to -10. So that would tie in with the fact that only my charge rate has been throttled, not discharge.

The Pylontech modules are daisy chained in parallel rather than being separate strings. If they were separate strings, then you should indeed get a max discharge rate of 2.4, but you only have a single exit connection from the "pack" and I wouldn't therefore be surprised if you are limited to 1.2. Your capacity is doubled, but possibly not the discharge rate.

I really just don't know how the modules interact when they all are interconnected.

DrPhilG

championc wrote: »

The Pylontech modules are daisy chained in parallel rather than being separate strings. If they were separate strings, then you should indeed get a max discharge rate of 2.4, but you only have a single exit connection from the "pack" and I wouldn't therefore be surprised if you are limited to 1.2. Your capacity is doubled, but possibly not the discharge rate.

I really just don't know how the modules interact when they all are interconnected.

I'll admit that I don't know how they're connected, but I definitely get double the charge and discharge rate. I've seen it happening, and in fact you can see it in action in that picture a few posts back. Once the restriction (presumably temperature related) stopped, it charged briefly at peaks of 2.1 and 1.9kw. Also a discharge of 1.6kw.

championc

DrPhilG wrote: »

I'll admit that I don't know how they're connected, but I definitely get double the charge and discharge rate. I've seen it happening, and in fact you can see it in action in that picture a few posts back. Once the restriction (presumably temperature related) stopped, it charged briefly at peaks of 2.1 and 1.9kw. Also a discharge of 1.6kw.

Strange indeed so.

DrPhilG

championc wrote: »

Strange indeed so.

I'll take a picture of the setup next time I'm in the attic.

E30M3

championc wrote: »

The Pylontech modules are daisy chained in parallel rather than being separate strings. If they were separate strings, then you should indeed get a max discharge rate of 2.4, but you only have a single exit connection from the "pack" and I wouldn't therefore be surprised if you are limited to 1.2. Your capacity is doubled, but possibly not the discharge rate.

I really just don't know how the modules interact when they all are interconnected.

Just on this to clarify I have 2 and the Charge and Discharge are routinely around 2.4 depending on Solar and drawdown of course. I would expect 3.6'ish from 3 both charge and discharge.

DrPhilG

And today was not the day I expected to see it in action, the forecast was terrible.

championc

DrPhilG wrote: »

And today was not the day I expected to see it in action, the forecast was terrible.

Also nice proof of the battery being able to charge at 2.4kW

DrPhilG

championc wrote: »

Also nice proof of the battery being able to charge at 2.4kW

Yeah bang on the limit, just hadn't expected to get that screenshot today.

It was short lived though, a brief flash of sun in the midst of a crap day. 5.4kWh total so far.

garo

I have a Pylontech and there is 10A charging rate restriction when it is too cold. That would be about 500W for one or 1000W for two 2.4kWh modules. I can see the temps on my inverter data page - Growatt. So the BMS definitely records and reports this data. Your inverter may or may not send this info into the cloud. The batteries do warm up with charging so if you leave them to charge they eventually hit the temps needed for the full charge rate. Temps do not restrict discharge.

DrPhilG

garo wrote: »

I have a Pylontech and there is 10A charging rate restriction when it is too cold. That would be about 500W for one or 1000W for two 2.4kWh modules. I can see the temps on my inverter data page - Growatt. So the BMS definitely records and reports this data. Your inverter may or may not send this info into the cloud. The batteries do warm up with charging so if you leave them to charge they eventually hit the temps needed for the full charge rate. Temps do not restrict discharge.

Yup, sounds about right for the issues I was hitting. Had no issues charging today, presumably just that cold snap last week. I'll get some insulation sorted for it at some stage. Although I may well be upgrading in the neat future so I'll be flogging the PylonTech.

DrPhilG

Aside from all the battery chat, can anyone clarify if my panel expansion plans are even possible?

I currently have 2 panel arrays, 2.8 and 3.4kWp. Both feeding into a Solis 5kw hybrid inverter on a string each.

At some point in the future, I'd like to double that to 12.5kWp.

However there are 2 problems with the plan.


1 - export management. I will have an export FiT limit of 6kw. That means that I will have to be able to balance and limit export. I realise that one of them can export at full pelt regardless, and therefore only 1 needs to manage its export, based on knowing what the total export is.

2 - if I have a storage battery connected to 1 inverter, then can only the array connected to that inverter charge the battery? Or can the inverter with the battery consume the potential export from the non battery one? This is the bigger issue. Single phase Solis inverters cannot be paralleled it seems.

mp3guy

DrPhilG wrote: »

Aside from all the battery chat, can anyone clarify if my panel expansion plans are even possible?

I currently have 2 panel arrays, 2.8 and 3.4kWp. Both feeding into a Solis 5kw hybrid inverter on a string each.

At some point in the future, I'd like to double that to 12.5kWp.

However there are 2 problems with the plan.


1 - export management. I will have an export FiT limit of 6kw. That means that I will have to be able to balance and limit export. I realise that one of them can export at full pelt regardless, and therefore only 1 needs to manage its export, based on knowing what the total export is.

2 - if I have a storage battery connected to 1 inverter, then can only the array connected to that inverter charge the battery? Or can the inverter with the battery consume the potential export from the non battery one? This is the bigger issue. Single phase Solis inverters cannot be paralleled it seems.

1. Right, once neither inverter is larger than 6kW, then only one of them needs export limit capability assuming it does this using a meter that both inverters are behind.

2. Depends on the inverter, my one can pick up the extra energy from a second inverter via the same shared meter mechanism that is used to control the export limit.

garo

With your dual inverter setup it may be better to go for an AC battery setup with it's own dedicated battery inverter. You can then buy two non-hybrid inverters - which are much cheaper - and flog your hybrid inverter off. Yes you may lose a small bit of efficiency but it will give you a lot more flexibility.


Re cold battery gating. I find the pylontech BMS is extremely aggressive in limiting charging in cold conditions. My own battery dials down to 10A when less than 18C internal temp. I contacted my inverter company but they were not able to tell me how to reduce this threshold.