Deye/Sunsync failing to low voltage disconnect

[kolek]

The controls need to be powered from the battery. Otherwise it wouldn't be able to operate in a grid failure situation.

Hmm. I'm a computer engineer, someone like @SeaGal who's also an engineer might have a good opinion on this as well, but there's no hardware or software reason why the inverter controls MUST be powered exclusively from battery, they could design these things to run from either, and not overdischarging the battery is mission critical. If this is normal behavior in the inverter world, then what can I say? Pretty dumb design.

 

[Daddy Tanuki]

Hmm. I'm a computer engineer, someone like @SeaGal who's also an engineer might have a good opinion on this as well, but there's no hardware or software reason why the inverter controls MUST be powered exclusively from battery, they could design these things to run from either, and not overdischarging the battery is mission critical. If this is normal behavior in the inverter world, then what can I say? Pretty dumb design.

deleted

 

[timselectric]

So all inverters are behaving like this, more or less?

Yes, if they have a battery.

They're all just kinda joking around when they say "Battery shutoff voltage"

They do shut off the AC output, from battery.

and they're gonna continue pulling 50-70 watts off the battery forever whether you like it or not,

They will draw whatever they require to continue monitoring the situation and be ready to comply with the chosen settings.

regardless of the potential for damage to the battery, and the BMS LVD is your last line of protection in place to save your ass?

The BMS is the last line of battery protection.
But, your settings should keep your system from needing that.
You have to adjust your settings to accommodate this draw.

 

[kolek]

You have to adjust your settings to accommodate this draw.

Ok, this has been an eye-opener. Your Growatts are doing this too?

 

[timselectric]

Hmm. I'm a computer engineer, someone like @SeaGal who's also an engineer might have a good opinion on this as well, but there's no hardware or software reason why the inverter controls MUST be powered exclusively from battery, they could design these things to run from either, and not overdischarging the battery is mission critical. If this is normal behavior in the inverter world, then what can I say? Pretty dumb design.

If the inverter includes a battery option. This means that it's designed for off grid or grid failure backup. And must be powered by the battery to carry out its designed functions.
If it were powered by the grid. When the grid was lost, it would also be lost. Because it's power source is gone.

 

[timselectric]

Ok, this has been an eye-opener. Your Growatts are doing this too?

Yes, if a battery is connected.

 

[kolek]

And must be powered by the battery to carry out its designed functions.

This is an engineering question, and there's computer hardware and software logic designed specifically for "If/when do X/Y." I've written code for systems that do far more complicated things than having 2 power sources for 1 set of controls.

Beyond the scope of this thread, but it's not only technically possible, it's technically easy to have the controls capable of running by either battery or grid power, and it's pathetically bad design architecture to have it working this way.

Either way, I see that's not how this system works and will adjust my settings to work around it.

Thanks @timselectric for your help!

 

[timselectric]

This is an engineering question, and there's computer hardware and software logic designed specifically for "If/when do X/Y." I've written code for systems that do far more complicated things than having 2 power sources for 1 set of controls.

Beyond the scope of this thread, but it's not only technically possible, it's technically easy to have the controls capable of running by either battery or grid power, and it's pathetically bad design architecture to have it working this way.

Either way, I see that's not how this system works and will adjust my settings to work around it.

Thanks @timselectric for your help!

The way I handled it when I was connected to the grid. Was to set grid charging to just enough to cover the idle draw. (2a , if I remember correctly)
Which technically means that the grid is powering the inverter.

 

[kolek]

set grid charging to just enough to cover the idle draw.

That is a clever workaround. I'll look into doing the same. Thanks for that tip.

 

[kolek]

Was to set grid charging to just enough to cover the idle draw.

Set up TOU such that if anytime voltage falls below 50.2V, charge by 50W to offset this loss
Will have to see if this actually works. Deye firmware seems a little buggy.

 

[Daddy Tanuki]

magnums have a setting if voltage hits xx.xx volts then go back into bulk charging. I never bothered to set it as at most I might use a genset to charge the batteries. so it was only charging if the AGS commanded the genset to start.

 

[kolek]

TOU seems completely broken, doesn't seem to do anything no matter how I set it.
Only way I'm able to get around this issue and recharge the batteries is by switching from "load first" to "battery first."
That function actually works.

I would update the firmware but the only way Deye allows you to do that is by letting their engineers do it, and I really don't trust Deye to login to my system remotely. Everything they touch they screw up, and their support is totally useless, to the point that I think they deliberately pretend to misunderstand and fail to answer any questions so that they don't have to do any work.

If it was Sunsynk or Sol-Ark I wouldn't have a problem with letting them have access. In fact I'd actually pay money to have a support contract with SunSynk or Sol-Ark.

 

[LydMekk]

If you want to regulate more precisely the level of the battery, when the grid takes over etc. use the TimeOfUse table.

 

[kolek]

If you want to regulate more precisely the level of the battery, when the grid takes over etc. use the TimeOfUse table.

Right, TOU. That menu is doing nothing on my unit no matter how I set it. Maybe something is overriding my TOU settings somewhere but I've tried all kinds of things and nothing works. I think it's a bug in the Deye firmware.

My most recent attempt to test it was setting every time slot to charge from grid at 4000W if the voltage was less than 50.2V. (This was when my voltage was less than 50.2V.) That did nothing. Then I raised the voltage to 50.7V, that did nothing. Then I raised the voltage to 54V. That did nothing. This is regardless of whether the charging pattern is set to "load first" or "battery first."

And no I'm not forgetting to check the TOU checkbox at the top to activate it.

 

[Daddy Tanuki]

Right, TOU. That menu is doing nothing on my unit no matter how I set it. Maybe something is overriding my TOU settings somewhere but I've tried all kinds of things and nothing works. I think it's a bug in the Deye firmware.

My most recent attempt to test it was setting every time slot to charge from grid at 4000W if the voltage was less than 50.2V. (This was when my voltage was less than 50.2V.) That did nothing. Then I raised the voltage to 50.7V, that did nothing. Then I raised the voltage to 54V. That did nothing. This is regardless of whether the charging pattern is set to "load first" or "battery first."

And no I'm not forgetting to check the TOU checkbox at the top to activate it.

can you send me a pdf manual for it to look at? might find something you missed...fresh eyes never hurt.

 

[kolek]

Found the problem.
"Charge from grid" checkbox was off. Should have caught that one earlier.
Thank goodness it's not a firmware issue.

Now I'll go back and see if I can implement @timselectric clever suggestion to charge at a low voltage to offset the ongoing drop.

 

[Daddy Tanuki]

Found the problem.
"Charge from grid" checkbox was off. Should have caught that one earlier.
Thank goodness it's not a firmware issue.

Now I'll go back and see if I can implement @timselectric clever suggestion to charge at a low voltage to offset the ongoing drop.

Dude.... I am at a loss for words... thats like one of my dumbass mistakes.

 

[kolek]

Dude.... I am at a loss for words... thats like one of my dumbass mistakes.

Yeah no kidding. In my defense I'd be finding issues faster if I wasn't working with an interface from 1970.
I should be able to just plug this into my LAN and access the settings from a browser like a standard router, but Noooooooooooooooooo Deye cannot allow that, they need to be able to control and monitor your equipment and your access like something out of George Orwell's 1984.

 

[SeaGal]

Hmm. I'm a computer engineer, someone like @SeaGal who's also an engineer might have a good opinion on this as well, but there's no hardware or software reason why the inverter controls MUST be powered exclusively from battery, they could design these things to run from either, and not overdischarging the battery is mission critical. If this is normal behavior in the inverter world, then what can I say? Pretty dumb design.

IMHO it is normal as @timselectric said.

FYI my Solises also power from the DC side, PV if available or battery, if not. Not sure about the Deye/Sunsync, but my inverter has a setting for the SOC when it will stop powering AC from battery and another (lower) value which will do a force charge the battery from grid. If grid is not available, the inverter will shut down till the sun comes back up.

The quiescent draw of the Solis electronics is about 30W. However, much of that can be turned off (if you don't need to power by battery overnight) via RS485 modbus commands (and back on again in the morning) - no idea whether your inverter will do that though.

 

[LydMekk]

Yeah no kidding. In my defense I'd be finding issues faster if I wasn't working with an interface from 1970.
I should be able to just plug this into my LAN and access the settings from a browser like a standard router, but Noooooooooooooooooo Deye cannot allow that, they need to be able to control and monitor your equipment and your access like something out of George Orwell's 1984.

Install Solarman Business and you can do that. I can access my 3 both from the phone and from a browser on my PCs.
Blanket statements like that comes back and bites you in the a..

 

[Hedges]

I was told equalization should be set as low as possible to prevent equalization from happening, was told it should be deactivated for this battery type (standard EVE 280ah batteries) and 41V is as low as that setting will go.

By setting equalization voltage same as float, even if it equalizes it is just floating.
But I would set to same as boost.

Here is the discussion I had with someone in private messages:

"Equalize , the function, is only used for lead acid batteries, it will damage your lifepo4 cells, therefor it should be set to 0"

Me: "Unable to set equalization to 0. Lowest it goes is 40V."

"Depends on the firmware that your unit came with.
Setting it to 40v is fine too"

Equalization time is what should be set to zero.

Ok just got some mind-blowing information from @XO4001 via private message. He says that this is "normal" behavior for the Deye.

He says you need to set your shutdown voltage higher because even if you go below your shutdown voltage, the Deye inverter will continue pulling 50-70 watts out of the battery essentially forever, regardless of whether it's below the shutdown voltage setting, and the only way to stop it is to disconnect the battery or have your BMS step in when the voltage gets too low and shut down the battery.

INCREDIBLE if this is true. Is this normal behavior for inverters in general?

Is your inverter still producing AC, and drawing whatever wattage loads represent?
Or is 50 ~ 70W its standby draw?

My Sunny Island will consume 25W no-load, plus whatever loads demand.
In "standby" with no AC output, it draws 4W, that we can live with for a long time.

It may actually shut off at some low voltage, I've seen screen go blank.

Default operation is to shut off inverter (whether 4W or 0W I'm not sure) and 70% DoD (lead-acid), and low voltage probably triggers that regardless of actually kWh drained.

Default is to shed loads (assuming contactor wired to them) at 80% DoD, leaving inverter running and critical loads powered. That lets it restart everything on its own after charging up from PV in the morning.

If battery does get too low, Black Start requires user intervention.


Sounds like a higher voltage or SoC shutdown level is what yours needs.

 

[kolek]

Install Solarman Business and you can do that. I can access my 3 both from the phone and from a browser on my PCs.

Oh so you mean I can pay to install a 3rd party piece of proprietary crap to work around the proprietary private corporate network crap that Deye is shipping? Oh joy, what luck!

Why should I need to workaround it? I don't need to pay for a workaround to access a room full of other networked equipment that just works as it should.

Not only do you have to deal with Big Tech (or worse yet, Chinese companies like Deye) delivering crap, you have to deal with their mostly Gen Z fanboys for whom every problem is solved by installing another app on their much beloved iPhone. Dudes who've got an app for their iToothbrush which retracts its bristles and stops working if they fail to pay the monthly subscription fee.

"But it's so great! It monitors my gum health and auto-updates Instagram with pictures of my teeth."

 

[kolek]

@Hedges Hey buddy thanks for your input.
On the clever suggestion of @timselectric I've managed to solve this problem using TOU and it's been working fine.

Basically I'm just setting a minimum voltage on every time slot in TOU and marking the "Gen Charge" checkbox on each so that essentially sets a voltage floor for the battery. Not an elegant solution, but it seems to work.

 

[Daddy Tanuki]

you have to deal with their mostly Gen Z fanboys for whom every problem is solved by installing another app on their much beloved iPhone. Dudes who've got an app for their iToothbrush which retracts its bristles and stops working if they fail to pay the monthly subscription fee.

"But it's so great! It monitors my gum health and auto-updates Instagram with pictures of my teeth."

you owe me a keyboard ... cleaning out covfefe and snot costs money.