Advice please re Solis RHI overnight charge settings

[rhodes169]

I'm very new to solar and have limited technical expertise. I have 10 PV's connected to a Solis RHI Inverter and 4 Pylontech batteries. I want to be able to charge the batteries at a cheap overnight rate. I can handle the menu setup on the inverter but am unsure of the settings required. I have been experimenting with different time settings but last night the system drew 7Kw which I thought seemed excessive? Should I reduce the time the batteries are allowed to charge?
Any advice or past experience would be welcome.

 

[SeaGal]

Go into advance settings / storage mode / self-use and then time settings.

From there you can enable a charge current and specify the time in hours and minutes that it will charge up.

So, if you set (say) 60.00A charge rate, that will draw approx 3kW. You can then adjust one of the charge timings to suit the amount of kWh you need.

e.g. if you want to add 4.5kWh, just leave it at 60A and configure a charge time to run for 1.5 hours.

You may also want to set the discharge current to 0.00A and set a discharge timing to be the remainder of your night rate time. That way, during your night rate the house will draw from the grid, rather than the batteries. It makes no sense to charge batteries up and then discharge them during night rate as you will just waste money due to the efficiency of charging and discharging.

So, if you want to add 4.5kWh and you're on economy 7, charge up for 1.5 hours from 1am to 2:30am and then prevent discharge from 2:30am to 8am. HTH

Edited to add: Alternatively, leave the charge time for the whole 7 hours of cheap rate (or however long your rate is) and adjust the charge current down to give you the required total kWh of boost. I can't remember whether the RHI is more efficient at a higher or lower power setting though.

 

[SeaGal]

P.S. I almost didn't click on your posting - if you put more detail in the subject in future that would be helpful (e.g. "Advice re Solis RHI overnight charge settings" or similar).

 

[rhodes169]

Go into advance settings / storage mode / self-use and then time settings.

From there you can enable a charge current and specify the time in hours and minutes that it will charge up.

So, if you set (say) 60.00A charge rate, that will draw approx 3kW. You can then adjust one of the charge timings to suit the amount of kWh you need.

e.g. if you want to add 4.5kWh, just leave it at 60A and configure a charge time to run for 1.5 hours.

You may also want to set the discharge current to 0.00A and set a discharge timing to be the remainder of your night rate time. That way, during your night rate the house will draw from the grid, rather than the batteries. It makes no sense to charge batteries up and then discharge them during night rate as you will just waste money due to the efficiency of charging and discharging.

So, if you want to add 4.5kWh and you're on economy 7, charge up for 1.5 hours from 1am to 2:30am and then prevent discharge from 2:30am to 8am. HTH

Edited to add: Alternatively, leave the charge time for the whole 7 hours of cheap rate (or however long your rate is) and adjust the charge current down to give you the required total kWh of boost. I can't remember whether the RHI is more efficient at a higher or lower power setting though.

Many thanks for your quick response and advice. I’ll adjust my settings and monitor the results over the next few days. Apologies for the brevity in heading-I’m a newbie!

 

[Supervstech]

I fixed it for ya.

 

[Djstew]

In this scenario does the battery still charge during the day from excess PV power?

 

[SeaGal]

Yes. When set to self-use mode, any times that are not defined as being charge-from or discharge-to the grid will operate as follows:-

a) Any PV power will be used to supply the house load, if there is no PV power, battery power will be used to provide house load.
b) If the PV power is less than house load and there is remaining battery power, PV and battery will be used to provide house load.
c) If the PV power is greater than the house load, any surplus power will be used to charge batteries at the rate the batteries allow/request.
d) If the batteries are full, excess PV will be exported to grid, up to any limit defined in the export power (backflow) settings.

Also note that... (for at least the 3.6, 5, and 6kW versions)...
- there is a max power the Solis will provide to the house, which will depend on the model you have (e.g. 3.6kW version)
- the max power the Solid can provide from battery alone, is 3kW (this becomes a bit less as battery voltage decreases)
- the batteries will only charge at the rate they request (via the CANbus). So, if it is cold or they are nearly fully charged, they may not charge at full capacity
- if your PV is generating more power than the Solis model can, or needs, to provide to the house and the batteries requiring charge any excess will be directed to the batteries. e.g. with a 3.6kW Solis Hybrid, if the PV is generating 4.6kW and house load is 3.6kW, the batteries can still charge at 1kW.

 

[Mmibe]

Hi, I have tried following the above to take advantage of Octopus Go cheap rate to charge batteries. When I ran the new times though, it stopped putting excess pv into battery and started exporting. I left it for 15mins to check not just a temporary issue but kept exporting.
Have attached photo of times I input, is there another setting I need to change to fix issue?

 

[SeaGal]

remove the discharge settings - you have overlapping times - not sure how the Solis will handle that.

The solis shoud charge battery before export in self use mode if no charge/discharge times match,

 

[kenco8801]

Further to this I had a similar scenario:

I recently changed to an Octopus tariff to charge my EV overnight and so scheduled Solis to do the same for my batteries (i've recently signed up for a solar forecast so only do this when there is low solar energy predicted in the morning and/or all day)

Per @SeaGal 's post - when my car is charging overnight on the cheap rate, the batteries drain - it's OK if my car doesn't take up the full window of time, however I would rather stop this from happening and just charge the EV from the grid and the batteries overnight too.

I went into the Solis app and setup and configured as below - yet this resulted in the batteries discharging constantly during the 0530-2330 window ( luckily i made the change during the day and then watched it for a while).

Before I go and apply the inverse (2330-0530?!) am i getting something wrong? Can i force it to NOT discharge the battery overnight during specified times and then resume normal practice outside of this, based on demand from the house?

TIA

 

[SeaGal]

Further to this I had a similar scenario:

I recently changed to an Octopus tariff to charge my EV overnight and so scheduled Solis to do the same for my batteries (i've recently signed up for a solar forecast so only do this when there is low solar energy predicted in the morning and/or all day)

Per @SeaGal 's post - when my car is charging overnight on the cheap rate, the batteries drain - it's OK if my car doesn't take up the full window of time, however I would rather stop this from happening and just charge the EV from the grid and the batteries overnight too.

I went into the Solis app and setup and configured as below - yet this resulted in the batteries discharging constantly during the 0530-2330 window ( luckily i made the change during the day and then watched it for a while).

Before I go and apply the inverse (2330-0530?!) am i getting something wrong? Can i force it to NOT discharge the battery overnight during specified times and then resume normal practice outside of this, based on demand from the house?

TIA


View attachment 143590

Welcome to the forum! It's doing what you told it to do! i.e. discharge up to 50A between 05:30 and 23:30 (until it runs out of power, that is). This is only useful if you are being paid £££ to export to grid.

If you want the Solis to _not_ discharge between (say) 05:30 and 07:30, then set those times in the discharging time boxes, but also set the "Discharging Current1" to zero (0A). That will prevent the Solis from supplying batter power to your EV or house load during that time.

Or an alternative would be to remove the discharge completely and set the charge time of the Solis for the whole cheap period and reduce the charge current accordingly.