Hello from Cambridgeshire

[lms10000]

Hi there,

I’m right at the start of my solar journey, having had a new system installed and last week. My spec is:

• 26 Jinko Tiger Neo 440W N-Type panels
  
  Fox ESS KH 9kW 1ph Hybrid Inverter inverter
  
  3x Fox ESS EQ4800-M 4.66kWh Li-ion battery

I tried to charge my batteries overnight for the first time last night, but it didn’t seem to work.

I set it to charge from 2-4 am. I can see from
the graph that the battery did stop discharging during that period (it just flatlines, and I appear to have switched to the grid) but the battery itself didn’t charge.

Any advice welcome! No doubt it’s user error on my part. Many thanks.

[Dave Foster]

Nice system


If it stopped discharging, it looks like you set a charge period but didn't toggle the charge from grid switch on.

I'm assuming you are using the older (simpler) charge periods - I would leave scheduler for another day, there are so many things that can go wrong with that.

So basically set a charge period from 02:00-04:00 but make sure you have 'Enable Charge from Grid' turned on.

You would normally have your minsoc's set at 10%

You can set it for just a few minutes to give it a quick test charge and prove it's working ok.

[lms10000]

Thanks so much Dave - I have actually set the mode scheduler for tonight, but will stick with the simpler version and make sure that charge from grid is enabled.

With the minsoc, do you set both the ‘battery reserve capacity’ and ‘system min SOC’ at 10%? I did that the other night and it went all the way down to 8%. I was concerned that it might do some damage to the battery, so reset to 20.

Thanks again for your help and sorry for the extra questions!

[Dave Foster]

I should have said you can’t have mode scheduler and use the ‘simple’ charge periods at the same time, they are mutually exclusive.

The mode scheduler has an added complexity of ‘maxSoC’ which only works properly on the very latest firmware versions and you might not yet have that, which is why I suggested it’s easier to use the older charge periods.

MaxSoC is how high you want the batteries to charge to from grid (solar charger will ignore this), so for example in the middle of summer you might decide to charge the batteries on low tariff overnight to 50% to keep space for solar charge during the day. In this example you would set maxSoC to 50%, but for a normal charge you would set it to 100% i.e. allow a full charge.

You can set both the minsoc’s to 10%, it’s not a problem for them to drop slightly below as the moment the voltage drops below a set limit the BMS will call for a maintenance charge to keep them above minsoc, it won’t let you do any damage. You tend to see the drop below on new systems or where the batteries haven’t seen a full cycle for some time, the BMS recalibrates the limits from experience so it is a good thing to do full cycles 10-100%.

[lms10000]

Many thanks again Dave. I tried the ‘simple’ method in the end and got it working.

I’m still awaiting my DNO approval, but once I have that I’ll get on a solar-friendly octopus tariff and start playing around with the mode scheduler.

I’ve also set the min socs to 10% based on your reassurance that it won’t damage the battery, so thanks for that too.