Question on setting for Solis RHI(6)K48ES5G inverter with 4x 3000c pylontech batteries

[ashman24]

Hi,
I’m looking for some help. I have a Solis RHI(6)K48ES5G inverter with 4x 3000c pylontech batteries.

I am charging the batteries overnight at the cheap octopus tarrif.

What should I set my ‘time of use charge current set’ and my ‘time of use discharge current set’ as?

Thank you for your help!

 

[jgh]

Set the charge time period to cover the cheap-rate period. Set the charge current to enough to get to 100% from your typical beginning-of-charge-period fill level (this will depend on your house usage vs. your total battery cap, and any other energy (eg. PV) you source during the day).

If it's not enough, well, you won't get to full. That could be an issue for you, but isn't a technical problem.
It it's too much, the batteries will tell the inverter to stop. No problem.

Set the discharge period to zero (start and end the same times). The discharge current doesn't matter.
Leave the main mode setting on "self-use".

 

[rpdom]

The max charge current on that inverter is 100A (5kW), but it will probably drop to around 85A after 15 minutes to stop the circuits getting hot.

So I would set it to 85A which would charge your batteries from 20% to 100% in about 3.5 hours.

I think you said you have a 6 hour charge slot, so you could set it as low as 40A which will just about give you a full charge, but it doesn't hurt to charge your batteries at the higher rate. The charge rate will automatically drop as they get close to 100% and then they will be kept at around 97-100% until the charge time ends.

 

[ashman24]

The max charge current on that inverter is 100A (5kW), but it will probably drop to around 85A after 15 minutes to stop the circuits getting hot.

So I would set it to 85A which would charge your batteries from 20% to 100% in about 3.5 hours.

I think you said you have a 6 hour charge slot, so you could set it as low as 40A which will just about give you a full charge, but it doesn't hurt to charge your batteries at the higher rate. The charge rate will automatically drop as they get close to 100% and then they will be kept at around 97-100% until the charge time ends.

Thanks for your help, thanks for the taking the time! Just one more question. What would you set the max discharge A as? Thank you

 

[rpdom]

Thanks for your help, thanks for the taking the time! Just one more question. What would you set the max discharge A as? Thank you

In normal use I would just leave it as it isn't being used.

The discharge times and discharge current setting are only for Force Discharge where you want to discharge your battery to grid. Normally you wouldn't want to do that (only if you have plenty to spare and you are getting a good export rate at the time). It doesn't affect the normal use of the battery to power your load (there's another setting for that, but that's generally left alone).

If you do want to discharge to grid, you can set that to 100A without any problems.

 

[mjatkey]

Guys, just a couple of points, if you are on a TOU tariff that has a FIT payment of more than your overnight cheap rate you'd be better off running the inverter in Feed in Priority mode (providing the batteries can keep you going to the next night rate window).
This way you are exporting all the solar (once the house load is taken care of) at a rate higher than you can buy it for.
Also set the Overdischarge SOC of the battery to as low as the manufacturer will allow, you paid for the batteries so make them work.
Current setting wise set as high as needed to charge batteries to 100% and if like me you discharge and surplus say from 10pm, set the discharge rate to a level that allows the batteries to be back to Overdischarge SOC just before the night rate kicks in.

 

[jgh]

Although I don't see why on grid-efficacy grounds, I think that Octopus frowns on customers re-exporting energy they deliberately import for arbitrage, calling it "Brown energy". Anyone know their reasoning? Surely a distributed grid-scale energy store would be just as valid as concentrated commercial ones.

 

[ashman24]

Guys, just a couple of points, if you are on a TOU tariff that has a FIT payment of more than your overnight cheap rate you'd be better off running the inverter in Feed in Priority mode (providing the batteries can keep you going to the next night rate window).
This way you are exporting all the solar (once the house load is taken care of) at a rate higher than you can buy it for.
Also set the Overdischarge SOC of the battery to as low as the manufacturer will allow, you paid for the batteries so make them work.
Current setting wise set as high as needed to charge batteries to 100% and if like me you discharge and surplus say from 10pm, set the discharge rate to a level that allows the batteries to be back to Overdischarge SOC just before the night rate kicks in.

Hey! That sounds great! Any step by step advice on how you’ve set this all up would be fantastic! Sounds like a great way to make the most of your system. @mjatkey

 

[rpdom]

Guys, just a couple of points, if you are on a TOU tariff that has a FIT payment of more than your overnight cheap rate you'd be better off running the inverter in Feed in Priority mode (providing the batteries can keep you going to the next night rate window).

It's have to be more that a bit higher than the overnight tariff because of conversion losses (10-20%). Also the overnight time would have to be long enough to get a decent charge into your batteries.

Personally, unless I had a really good FIT rate (I don't, just the 15p/kWh fixed rate), I believe I'd be as well off with Self Use mode. I charge my batteries overnight when there's a cheap slot, then they stay fully charged from solar until dark, with all the excess being exported. Then they power me through the evening until the next cheap slot (if there is one - I'm on Octopus Agile), or the next morning if needed.

 

[mjatkey]

It's have to be more that a bit higher than the overnight tariff because of conversion losses (10-20%). Also the overnight time would have to be long enough to get a decent charge into your batteries.

Personally, unless I had a really good FIT rate (I don't, just the 15p/kWh fixed rate), I believe I'd be as well off with Self Use mode. I charge my batteries overnight when there's a cheap slot, then they stay fully charged from solar until dark, with all the excess being exported. Then they power me through the evening until the next cheap slot (if there is one - I'm on Octopus Agile), or the next morning if needed.

Yeah, I agree, but here in Ireland we have a 4hour EV window at 0.075cent per Kwh with a FIT of 0.20cent.
In terms of setting it up, if you have Solis, set the inverter to Feed in Priority mode, Time of use enabled then set charge to what ever your cheap rate EV window is (say 02:00hrs to 06:00hrs) , can also set any discharge window say after 10pm to flog back any stored energy to what ever Overdischarge SOC you have set, even taking account of AC to DC to AC losses it's worth it, of course if FIT payments change (they were 0.24cent last year) then it may not be worth while.

 

[jgh]

Also, here in Blighty we have to pay VAT on top of the quoted import rate, but don't get VAT back on the export.
So be careful on the /kWh numbers you use in calculating, if it's the same where you are.

 

[rpdom]

Also, here in Blighty we have to pay VAT on top of the quoted import rate, but don't get VAT back on the export.
So be careful on the /kWh numbers you use in calculating, if it's the same where you are.

The import rates I use include VAT, which makes it easier to work out.