MPP solar 11kw with Pylontech US5000 - low battery error

[ns31]

Hi all, I have 2x US5000 batteries with an 11kw mpp solar inver, from what I can see these are the same as the victron inverters.

When the batteries are low I receive an 04 low battery alarm. The inverter is set to SBU. setting 12 is at 46V, if I increase this to 48V will it help?

The battery being low is expected so why is there an alarm? Is the setting too low? Thanks

 

[BentleyJ]

An MPP Solar inverter is most definitely not the same as a Victron product. Not bashing MPP Solar, they offer a good value priced product.

Regarding the low battery alarm, raising the setting will make the problem worse as it will happen sooner during the discharge cycle. Here is an analogy: If your car is always running out of Petrol then the solution is to just disconnect the fuel gauge wire!!

Either your batteries are not getting a full charge or your loads are using all of the available storage capacity so more batteries and/or charging capacity is needed.

 

[ns31]

The batteries are fully charged, then depleted in the evening as expected. At this point utility/grid kicks in. So I'm not sure why an alarm is required if battery use is expected behaviour?

 

[ns31]

...also I should have said voltacon, not victron, I think they're the same inverter white labelled

 

[Lt.Dan]

...also I should have said voltacon, not victron, I think they're the same inverter white labelled

It's Voltronic.

The pylontech batteries are also 15s, not the typical 16s like most are used to, so the actual disconnect voltage should be (2.5v X 15 =) 37.5v. I don't think the MPP models will even go that low, so setting it to the lowest option might be the only way to go.

 

[ns31]

It's Voltronic.

The pylontech batteries are also 15s, not the typical 16s like most are used to, so the actual disconnect voltage should be (2.5v X 15 =) 37.5v. I don't think the MPP models will even go that low, so setting it to the lowest option might be the only way to go.

Thanks, I can set it to 37v or 38v so I'll try 38 and hopefully the low battery voltage warning won't kick in

 

[ns31]

Even at 48V it sounds an alarm, why is this if running the battery down is intended behaviour?...

 

[Lt.Dan]

Is the battery out of balance and triggering LVD? This could cause the inverter to see a sudden disconnect and throw this alarm

 

[ns31]

They were balanced before plugging in. At 48V the app logs an alarm but there's no audible noise from the inverter, and no battery shutdown warning, so it's an improvement but I wouldn't expect to see an alarm

 

[wattmatters]

Are you using a communications cable between the batteries and the inverter?

If so, is the MPP battery protocol selected the correct one for your batteries?

If not then what battery settings have you set for the inverter to use?

 

[ns31]

yep, comms all setup and working great. Its on the PYL protocol, most battery settings are therefore configured automatically. The only ones I can manually configure are the 'back to grid voltage' which is 48V and 'back to discharge (battery)' voltage which is 52V. I'm using SBU and OSO modes

 

[Lt.Dan]

Can you get a better description of "Battery Weak"? It might mean something else entirely and we're just chasing our tails.

 

[ns31]

Can you get a better description of "Battery Weak"? It might mean something else entirely and we're just chasing our tails.

The WatchPower app really isnt the most helpful is it! I'll have to look into how to hook up a PC...

 

[Lt.Dan]

The WatchPower app really isnt the most helpful is it! I'll have to look into how to hook up a PC...

Does it throw an error on the display screen? I wonder if it gives an error code that can be referenced to the manual.

 

[ns31]

It did throw an 04, which the manual states is 'Battery Voltage is Too Low' however, since I increased the minimum to 48V, the inverter no longer throws this error, its only listed in the app. Maybe the error is logged for info only, although it seems odd to log it as an 'error' rather than a warning

 

[SenileOldGit]

Shouldn't your 'Back to grid' voltage be much lower than 48V? My setting is 45.3V. The higher you have that setting, the sooner your inverters will think the battery voltage is too low (too low according to the setting you have chosen, i.e. 48V) and the sooner the inverters will go back to grid power and stop using the batteries, which is the opposite of what you want.
I charged my Pylontech US5000s at 51.8V, (they are 15 cell units, not 16 cells like previous Pylontechs (I think that is the case about the previous Pylontechs) so the voltage you charge US5000s at is less than smaller Pylontech batteries).

 

[SenileOldGit]

The WatchPower app really isnt the most helpful is it! I'll have to look into how to hook up a PC...

You just need a USB lead from the inverter into your PC, and MultiSIBControl software (www.multisibcontrol.net) or Solar Assistant running on a Raspberry Pi (MultiSIBControl is easier to do if you already have a PC.)

 

[ns31]

Shouldn't your 'Back to grid' voltage be much lower than 48V? My setting is 45.3V. The higher you have that setting, the sooner your inverters will think the battery voltage is too low (too low according to the setting you have chosen, i.e. 48V) and the sooner the inverters will go back to grid power and stop using the batteries, which is the opposite of what you want.
I charged my Pylontech US5000s at 51.8V, (they are 15 cell units, not 16 cells like previous Pylontechs (I think that is the case about the previous Pylontechs) so the voltage you charge US5000s at is less than smaller Pylontech batteries).

Originally it was 46v but the inverter threw an 04 battery error code so I increased it.

This does seem to be a case of finding the best settings to switch between battery and grid

 

[SenileOldGit]

Yes, but you should have DECREASED it, not increased it.

 

[Lt.Dan]

Yes, but you should have DECREASED it, not increased it.

He's getting an error for "battery weak" and you want to use the battery harder?