I had a Sunsynk 8kW inverter and 4x Ecco 5kWh LFP batteries installed last week.

The system is currently used as a battery backup only with panels being added early next year.

I have some concerns with the SoC on the system and just want to find out what is normal and how to go about debugging what is not.

Day 1 the SoC got up to 100% and then bounced around between 100% and 99% for a bit. Once load shedding kicked in the SoC went to 99% for a bit and gradually dropped as expected.

Day 2, 3 and 4 was much of the same apart from the SoC only touching 100% for an instant after charging and then staying at 99% flat.

Day 5 it would almost immediately drop from 99% to 97% at the start of load shedding.

Day 6 saw that go from 99% to 96%.

Day 7 was 99% to 95%.

Day 8 is now 99% to 94% but also charging back up to 98% for quite a while before going to 99%.

 

The LiBms screen on the inverter does show stats (and no alarms) so the comms is working fine.

On the LiBms screen it shows a Battery charge voltage of 56.0V and Battery voltage of 55.88V at 99% SoC (SoH at 100%).

 

The Batt charge screen under Battery Setup had the following values: Float V 55.2V, Absorption V 57.6V and Equalization V 57.6V

I changed those values to Float V 54.0V, Absorption V 56.0V and Equalization V 56.0V but that does not seem to make a difference (I suspect the BMS overrides it).

 

Once the SoC gets to 99% the battery is constantly drawing a small bit of power, between 7W and 22W) and the battery voltage is fluctuating between 55.88V and 55.90V.

I had a look at the BMS on the battery itself and I am seeing some OVP entries which makes me think the inverter is trying to charge the voltage too high.

 

A couple of questions from my side:

1) Is the SoC behavior expected/normal? (still balancing out over the first couple of cycles?)

2) Is it normal for the SoC to not go up to 100%? (again, maybe related to the first couple of cycles?)

3) Should I be changing the Batt charge settings?

4) Is it normal for the battery to draw a small bit of power when full (or 99%)? (or is it trying to charge it up further than it can considering the OVP records?)

5) What is the best way for me to confirm that everything is in order? (I'm sure I'm gonna have a harder time with the installer a month from now if there are actually issues.)

 

Any assistance or information would be greatly appreciated.

Please post your Sunsynk:

• Battery Settings
• System Mode Settings

See this post for my settings:
https://powerforum.co.za/topic/10730-sunsynk-8k-hubble-am2-16x400w-pv/?do=findComment&comment=143325
 

 

Edited December 14, 20222 yr by system32

Hi @system32, as requested:

Since your system does not have PV at this stage, I would use something like this:



This means, maintain a 100% SoC, use Grid to Charge.
Remember to tick "Use Timer".
If there is a powerfail / load shedding use battery until shutdown at 12% SoC.
Charge battery from grid at max of 60A*48V ~ 2.9kW - don't set this too high, as you need to allow other appliances to use Grid.


EDIT1:
If you have an "external N/E bond relay" you will need to enable "Signal Island Mode"
Not sure if "external N/E bond relay" is still required with newer model inverters as they may have a relay built in.
a) turn grid off
b) use a voltmeter to check the voltage on the "UPS" circuit:

• Earth + Neutral = should be zero
• Earth + Live = should be ~230V
• Neutral + Live = should be ~230V

EDIT2:
You have 4x Ecco 5kWh LFP = 20kWh
12%(2.4kWh) to 100%(20kWh) = 17.6kWh
17.6kWh/2.9kWh ~ 6hours to charge

EDIT3:
TIP: If your whole home is on UPS, add automation to disable geyser, dishwasher, pool, stove, washing machine during load shedding.

Edited December 14, 20222 yr by system32

Thanks for all the information @system32, it is appreciated.

 

Would setting up the System1 page as described not have the exact same behavior that I have now?

Batteries charges to 99%, power comes from the grid, batteries  get used during load shedding. Or does the Use Timer do something different that I might not be aware of?

 

3kW charging still leaves me with enough capacity. Usually charging is complete within an hour as I'm not dipping that low.

The installer also said that if you start using more than 5kw it will reduce the charging current because Priority Load is selected.

 

I'm not to sure about the N/E relay. What is the effect of enabling it if I don't have an external N/E relay?

What is the purpose of this mode?

Hi @TheV - have you managed to get clarity on this behaviour?

I'm seeing the same constant power draw to the battery @ ~22W, even when the battery is 'full'. I have a Hubble AM-5 battery, which is different from your setup, so this suggests the quirk lies with the SunSynk.

29 minutes ago, SpankyZA said:

Hi @TheV - have you managed to get clarity on this behaviour?

I'm seeing the same constant power draw to the battery @ ~22W, even when the battery is 'full'. I have a Hubble AM-5 battery, which is different from your setup, so this suggests the quirk lies with the SunSynk.

The installer told me the issues I was experiencing was specific to the 8kw Sunsynk and the Ecco batteries when using it in UPS mode (no panels). They have notified Sunsynk about the issue and it should be addressed in a future update.

I have since installed panels and the batteries are behaving as expected now.

Thanks for the quick response.

Okay, so it must be more widespread than just the 8kW + Ecco combo, because I have the exact same behaviour you described in the OP but with 5kW + Hubble. I am also not using any PV currently, and everything is on the UPS/load circuit.

23 minutes ago, SpankyZA said:

Thanks for the quick response.

Okay, so it must be more widespread than just the 8kW + Ecco combo, because I have the exact same behaviour you described in the OP but with 5kW + Hubble. I am also not using any PV currently, and everything is on the UPS/load circuit.

Must be on the UPS side of the software in general then. I hope they do fix it in a firmware update. I am sure there are lots of people that can't run panels and just needs to use the system as a load shedding UPS.

For sure.

I am going to email Sunsynk support to try create extra awareness on the issue.