Anyone else had this happen

[rwg]

Hi

good to hear that Solax are responsive when contacted for customer support and also that everything seems to be working as it should. Obviously the batteries are a big investment at about £2500 each, so best that the system keeps them in good shape even at the cost of a bit of extra electricity use now and then.

Ex-sparky. I like the idea of multiple tarriff and charge at night, but since we are on a single tarriff meter at the moment, a multi-price tarriff would probably mean a smart meter and I don't really want one of them. Having the batteries really messes with energy company direct debit estimation. We had one battery during June/July/August and were managing less than 3kWh on many days and very little gas too due to only hot water running. We kept getting 'we can reduce your direct debits' messages. Of course now in winter we generate little, so both electricity and gas much higher. I expect we will be getting 'we need to increase your direct debits' soon

cheers,

Robin

 

[Ex-sparky.]

Hi Robin
I’m not on a smart meter the night rate is economy 7 it been installed since the house was built (1997) I assume you can still get it, it’s designed to encourage using off peak electricity my off peak is 1:00 am till 8:00 am 7 hours hence economy 7.

Gary

 

[rwg]

I don't think you can get new economy 7 meters any more these days - they seem to be more a legacy thing where you can find a tarriff for one if you already have it, but no new installs.

There is a thing from Octopus called 'Octopus Go' which is 12p/unit between 00:30 and 04:30, but that requires a smart meter (one of the modern ones, not an original one).

cheers,

Robin

 

[rwg]

Going back to the original topic of the thread (which was why does the Solax inverter stay on 10% charge overnight and then start discharging again in the morning down to 5% when the panels come active), I wonder if I have worked out part of the reason.

As noted above, the Solax batteries protect themselves from charging at cold temperatures, with no charging allowed at all if the cells fall to freezing and reduced charge rates at low temperatures above freezing. The 'discharge the last bit in the morning' could be an attempt to counter this. Discharging the battery from 10 down to 5% will tend to warm it a bit (maybe a degree or two?), which may bring it above freezing if it has frozen, or warm it enough to give a higher allowable charge rate when the solar panels get going properly. If the system discharged down to 5% in the evening, any heat would get lost by the time the sun came up in the morning.

I have had trouble this last week or so keeping my batteries up to a high enough temperature for them to charge on the brighter days we have had now and then. For space reasons they are on the outside of the garage wall, and were getting down to zero and refusing to charge at all. My solution so far is

* Battery cosy made from silver bubble wrap insulation and tape
* A couple of bits of offcut Celotex as a temporary roof to provide some shelter until I have time to make a better one
* A car seat heating pad on each battery under the bubble wrap cosy, running from a 12V PSU in the garage

The insulation helps, the heater makes a big difference when switched on, bringing the temperature up about 1 degree per hour. Obviously I will have to remove all the insulation when the weather starts to properly warm up in March or so.

I have a smart plug on order so I can rig something up to automatically turn on the heater when the battery cell temperature falls below 0.5C or when the charge rate limitation due to low temperature is causing excess energy to be exported.

Note that the temperature that is relevant to the charge rate is the minimum cell temperature, which is not the same as the one shown in the Solax app. For the geeks out there, you can read the min/max cell temperature along with a lot of other info from the solax inverter via the wifi plugin thing, using modbus over TCP. If you are interested in more details, let me know.


cheers,

Robin

 

[Howard B]

There is a thing from Octopus called 'Octopus Go' which is 12p/unit between 00:30 and 04:30, but that requires a smart meter (one of the modern ones, not an original one).

cheers,

Robin

We are on Octopus Go and managed to get a 7.5p rate between 00:30 & 04:30. I set my 16.4kWh batteries to charge to 100% between these hours. I can download about 12kWh in that time frame and will probably use 9kWh -12kWh per day dependent on whether we use the dishwasher, washing machine, oven etc.
Today the sun is shining and the solar has produced 6.5kWh, so we have done the washing and have the Mitsubishi inverter heater providing the heating during the day. Batterioes still sitting at 95% charged.

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[Skituscany]

We are on Octopus Go and managed to get a 7.5p rate between 00:30 & 04:30. I set my 16.4kWh batteries to charge to 100% between these hours. I can download about 12kWh in that time frame and will probably use 9kWh -12kWh per day dependent on whether we use the dishwasher, washing machine, oven etc.
Today the sun is shining and the solar has produced 6.5kWh, so we have done the washing and have the Mitsubishi inverter heater providing the heating during the day. Batterioes still sitting at 95% charged.

We have the same tariff and we set our Solax 9kWh batteries to charge between these times. Provided that the batteries are still above the minimum SOC% when the time arrives, all is good. However, if they have drained down to the minimum SOC% [whatever figure I set it to, e.g. 10%, 15%, 20%, even 40%] then the inverter goes into IDLE and it IGNORES the charge from grid. Any ideas?

 

[Skituscany]

We have the same tariff and we set our Solax 9kWh batteries to charge between these times. Provided that the batteries are still above the minimum SOC% when the time arrives, all is good. However, if they have drained down to the minimum SOC% [whatever figure I set it to, e.g. 10%, 15%, 20%, even 40%] then the inverter goes into IDLE and it IGNORES the charge from grid. Any ideas?

FYI, to force it to execute the timed charge when it's gone into IDLE mode, I have to switch the inverter to OFF via the app, wait a minute or so and then set it back to ON.

 

[Howard B]

We have the same tariff and we set our Solax 9kWh batteries to charge between these times. Provided that the batteries are still above the minimum SOC% when the time arrives, all is good. However, if they have drained down to the minimum SOC% [whatever figure I set it to, e.g. 10%, 15%, 20%, even 40%] then the inverter goes into IDLE and it IGNORES the charge from grid. Any ideas?

Not sure, never happened to me though I have never gone below 20%.

 

[Skituscany]

Not sure, never happened to me though I have never gone below 20%.

Thanks, Howard. Do you have the Min SOC% set to 20%? What happens to your system when it drops to 20% - does it go into IDLE? I'm presuming that you've got a Solax inverter? Is that correct?

 

[rwg]

If you have a version with emergency power outputs, you can set it to Backup mode, which prevents it going idle. There are drawbacks to this though...

• Minimum 30% reserve percentage for emergency use
• Hot standby mode once the battery gets down to the reserve level slowly drains the battery further - after about 12-16 hours it will charge for about 1 hour to 90 minutes at 400W to top up again

cheers,

Robin

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[Skituscany]

If you have a version with emergency power outputs, you can set it to Backup mode, which prevents it going idle. There are drawbacks to this though...

• Minimum 30% reserve percentage for emergency use
• Hot standby mode once the battery gets down to the reserve level slowly drains the battery further - after about 12-16 hours it will charge for about 1 hour to 90 minutes at 400W to top up again

cheers,

Robin

Thanks, Robin, that's really helpful!
Do I take it that getting stuck in idle and failing to force-charge when operating in self-use mode is a known issue?
May I assume that when in backup mode, system will take force-charges at the scheduled time(s)?
Anyhow, I've changed over to backup mode right away to see how that goes

 

[rwg]

Hi,

not that exact situation, but I have seen comments online about the trouble of getting the inverter to wake up from idle mode in other situations and also found myself that even trying to turn on 'force charge' manually via the app or panel buttons is a bit hit and miss when in idle mode.

I've been running ours in backup mode through the winter as there is not enough sun to fully charge the batteries, but in the next few weeks I may switch back to the default mode. In backup mode it doesn't go idle.

If you have the inverter on your network and are happy tinkering with computers, you may be able to do something by sending commands to it over the modbus protocol. It's a bit of a learning curve, but there is some basic documentation from Solax (see https://gbc-solino.cz/wp-content/up...sTCPRTU-V3.21-English_0622-public-version.pdf). I have had success tinkering with this and been able to switch the work mode of the inverter using modbus as a test. On page 45 of the above document, there is a suggestion that writing to register 0x01C allows you to set the system to on or off. If (and I don't know this for sure) the system responds to modbus in Idle mode then maybe you could automate something to send the off command then the on command at the right time to wake the inverter up. There is a program called 'modbuspoll' for Windows that has a 1 month trial that is as easy-to-use as it gets for this.

cheers,

Robin

 

[Skituscany]

Hi,

not that exact situation, but I have seen comments online about the trouble of getting the inverter to wake up from idle mode in other situations and also found myself that even trying to turn on 'force charge' manually via the app or panel buttons is a bit hit and miss when in idle mode.

I've been running ours in backup mode through the winter as there is not enough sun to fully charge the batteries, but in the next few weeks I may switch back to the default mode. In backup mode it doesn't go idle.

If you have the inverter on your network and are happy tinkering with computers, you may be able to do something by sending commands to it over the modbus protocol. It's a bit of a learning curve, but there is some basic documentation from Solax (see https://gbc-solino.cz/wp-content/up...sTCPRTU-V3.21-English_0622-public-version.pdf). I have had success tinkering with this and been able to switch the work mode of the inverter using modbus as a test. On page 45 of the above document, there is a suggestion that writing to register 0x01C allows you to set the system to on or off. If (and I don't know this for sure) the system responds to modbus in Idle mode then maybe you could automate something to send the off command then the on command at the right time to wake the inverter up. There is a program called 'modbuspoll' for Windows that has a 1 month trial that is as easy-to-use as it gets for this.

cheers,

Robin

Thanks, Robin. I'll post how it works out for me in backup mode.

As for Modbus, can it work via the WiFi dongle or do I need to connect ethernet into my router or even RS485 to some computer [not so easy]?

 

[rwg]

Hi, you can do modbus over the WiFi as long as you have the name or ip address of the inverter. Connect on port 502.

Cheers


Robin