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Should I be "exercising" my battery regularly?


MdF
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Just a quick question regarding the battery alarm screen: Should I not set the first 2 rows SOC to 31% so as to always prevent a low battery alarm from sounding (Note: I have changed the Low Batt setting to 30% already)?

MdF

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1 hour ago, MdF said:

Just a quick question regarding the battery alarm screen: Should I not set the first 2 rows SOC to 31% so as to always prevent a low battery alarm from sounding (Note: I have changed the Low Batt setting to 30% already)?

MdF

Sounds cool to me, if that's how low you wish to run your batteries.

Mine are run down to 25%, 24% Batt Alarm, 23% Shutdown, and I never get woken up.

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Afternoon All,

Thank you to everyone who has posted on this topic, your assistance has been much appreciated.

So, I had a successful first night of running the battery during the night and recharging it again with solar the next day.

I'll be honest, things eventually clicked in to place for me in understanding this whole thread simply by watching what was happening on the system.

So, I started at midnight last night with a SoC of 83%. The battery SoC got to 48% at 7:03am this morning and reached 100% SoC via solar by 10:03am.

Just one last thing to understand and that relates to the Power column. My understanding is that if you set a SoC of 35% during the night with a power setting of say 2500, this means that the battery will only ever discharge to a maximum of 2500 wats at any one time should that be needed in the system?

Does this also mean that you can make these power settings to ensure that you have enough power in the system to get through the whole night and prevent say someone switching on the kettle at 4am and running the battery flat (so to speak)?

MdF

 

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2 hours ago, MdF said:

Afternoon All,

Thank you to everyone who has posted on this topic, your assistance has been much appreciated.

So, I had a successful first night of running the battery during the night and recharging it again with solar the next day.

I'll be honest, things eventually clicked in to place for me in understanding this whole thread simply by watching what was happening on the system.

So, I started at midnight last night with a SoC of 83%. The battery SoC got to 48% at 7:03am this morning and reached 100% SoC via solar by 10:03am.

Just one last thing to understand and that relates to the Power column. My understanding is that if you set a SoC of 35% during the night with a power setting of say 2500, this means that the battery will only ever discharge to a maximum of 2500 wats at any one time should that be needed in the system?

Does this also mean that you can make these power settings to ensure that you have enough power in the system to get through the whole night and prevent say someone switching on the kettle at 4am and running the battery flat (so to speak)?

MdF

 

I'm glad you are now utilizing your battery. Your understanding of the power column is correct. If you exceed that value, it will pull the remainder  from the grid. I don't know what will happen if grid is down though whether it trips or just gives off an alarm.

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5 minutes ago, phidz said:

I'm glad you are now utilizing your battery. Your understanding of the power column is correct. If you exceed that value, it will pull the remainder  from the grid. I don't know what will happen if grid is down though whether it trips or just gives off an alarm.

Never tried it myself, but I am pretty sure that it would trip (and log a corresponding error code).

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2 hours ago, MdF said:

Afternoon All,

Thank you to everyone who has posted on this topic, your assistance has been much appreciated.

So, I had a successful first night of running the battery during the night and recharging it again with solar the next day.

I'll be honest, things eventually clicked in to place for me in understanding this whole thread simply by watching what was happening on the system.

So, I started at midnight last night with a SoC of 83%. The battery SoC got to 48% at 7:03am this morning and reached 100% SoC via solar by 10:03am.

Just one last thing to understand and that relates to the Power column. My understanding is that if you set a SoC of 35% during the night with a power setting of say 2500, this means that the battery will only ever discharge to a maximum of 2500 wats at any one time should that be needed in the system?

Does this also mean that you can make these power settings to ensure that you have enough power in the system to get through the whole night and prevent say someone switching on the kettle at 4am and running the battery flat (so to speak)?

MdF

 

Yes, for the first week you spend a lot of time monitoring it, 2nd week less so, third week even less as you start to trust the system and gain a better understanding of it. After 1 year, I still check what mine is doing around 3x per day (more or less), using the Solarman web-based app in a browser. 

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Morning All,

Next question on this thread journey:

What is considered "good exercise"?

Should one try and run the battery down to your base limits (in my case 35% SoC before the alarm goes off) or is something like going from 100% to 70% SoC overnight still seen as doing some good?

MdF

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So my first attempt last night at trying to cycle the battery to 50% did not go as planned. The first attempt photo attached showing the settings I put in place yesterday afternoon exported the battery power to the grid and depleted the battery in less than an hour. I did not want it to export the battery power to the grid. The battery also did not charge at 5am through grid power and waited for solar before starting to charge.

I have now attempted again per the second attempt photo.

My aim is as follows:-

1) From 11am to 3am use the battery to power all loads until the battery is depleted to 50% and thereafter be supplied by grid.

2) From 3am the grid will supply all loads and recharge the battery.

3) When solar is available it will supply power all loads and export to grid.

Will the settings in the second attempt achieve this?

Does sol exp bat full only allow export once the battery is 100% or does it allow both export to grid and charge battery if the solar exceeds the charge current?

I want to make a start using the above settings and then adjust to what I think is optimal.

Any advice would be appreciated.

P.S. I have a spinning disc meter which is able to turn backwards although I know this is technically not allowed.

First Attempt.png

Second Attempt.png

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5 minutes ago, MdF said:

Morning All,

Next question on this thread journey:

What is considered "good exercise"?

Should one try and run the battery down to your base limits (in my case 35% SoC before the alarm goes off) or is something like going from 100% to 70% SoC overnight still seen as doing some good?

MdF

I guess it depends with what you want to achieve. If you only discharge to 70% SOC your battery will last longer than discharging it to 25% like I do. However your return on investment will be longer because you may be using the grid more.

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Thanks Phil, yip agree with you there.

I think my main objective would be to get the best "life span" out of my battery i.e. get it to work for the most number of years to produce the best SoC and power. There is a fine balance here between the two seeing that the battery was the most expensive component of my setup.

Lots to ponder indeed.

Edit: I think what I will have a look at is to start running the battery down a bit from earlier in the evening and not wait until midnight.

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Further to my previous post I have just checked on the system and when selected like my second photo the system does not export to grid at all.

The battery when connected via ethernet to the inverter always only shows at 99% is this maybe the cause of the problem or have I done something else wrong?

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14 minutes ago, MdF said:

Thanks Phil, yip agree with you there.

I think my main objective would be to get the best "life span" out of my battery i.e. get it to work for the most number of years to produce the best SoC and power. There is a fine balance here between the two seeing that the battery was the most expensive component of my setup.

Lots to ponder indeed.

Edit: I think what I will have a look at is to start running the battery down a bit from earlier in the evening and not wait until midnight.

Have a look at the this datasheet for the battery. I really wouldn't worry about the life span of the battery as long as i'm not discharging/charging it at high C rates.

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13 minutes ago, EnTAnGleD said:

Further to my previous post I have just checked on the system and when selected like my second photo the system does not export to grid at all.

The battery when connected via ethernet to the inverter always only shows at 99% is this maybe the cause of the problem or have I done something else wrong?

Hi EnT,

Your second attachment looks correct for what you are wanting to do.

However, I can not comment on what will happen in terms of you wanting to Export to Grid and how that will affect your setup. But I am sure there are others here how will be able to assist.

MdF

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40 minutes ago, EnTAnGleD said:

So my first attempt last night at trying to cycle the battery to 50% did not go as planned. The first attempt photo attached showing the settings I put in place yesterday afternoon exported the battery power to the grid and depleted the battery in less than an hour. I did not want it to export the battery power to the grid. The battery also did not charge at 5am through grid power and waited for solar before starting to charge.

I have now attempted again per the second attempt photo.

My aim is as follows:-

1) From 11am to 3am use the battery to power all loads until the battery is depleted to 50% and thereafter be supplied by grid.

2) From 3am the grid will supply all loads and recharge the battery.

3) When solar is available it will supply power all loads and export to grid.

Will the settings in the second attempt achieve this?

Does sol exp bat full only allow export once the battery is 100% or does it allow both export to grid and charge battery if the solar exceeds the charge current?

I want to make a start using the above settings and then adjust to what I think is optimal.

Any advice would be appreciated.

P.S. I have a spinning disc meter which is able to turn backwards although I know this is technically not allowed.

First Attempt.png

Second Attempt.png

I'm not very familiar with exporting, someone who has done it before might be able to help. I would suggest starting a new thread with the appropriate title

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2 hours ago, EnTAnGleD said:

So my first attempt last night at trying to cycle the battery to 50% did not go as planned. The first attempt photo attached showing the settings I put in place yesterday afternoon exported the battery power to the grid and depleted the battery in less than an hour. I did not want it to export the battery power to the grid. The battery also did not charge at 5am through grid power and waited for solar before starting to charge.

I have now attempted again per the second attempt photo.

My aim is as follows:-

1) From 11am to 3am use the battery to power all loads until the battery is depleted to 50% and thereafter be supplied by grid.

2) From 3am the grid will supply all loads and recharge the battery.

3) When solar is available it will supply power all loads and export to grid.

Will the settings in the second attempt achieve this?

Does sol exp bat full only allow export once the battery is 100% or does it allow both export to grid and charge battery if the solar exceeds the charge current?

I want to make a start using the above settings and then adjust to what I think is optimal.

Any advice would be appreciated.

P.S. I have a spinning disc meter which is able to turn backwards although I know this is technically not allowed.

First Attempt.png

Second Attempt.png

You need to tick priority load. Currently battery is getting priority, but you are probably not seeing it because they are full (you set it to charge from grid at 03H00, not sure why, can't you wait 4 hours until the sun can do it?).

Why have you ticked grid in all the other settings? I am not following, you are basically telling the inverter to charge the battery to 100% in all of them. This is not necessary.

Do you have non-essential loads (between grid and inverter)?

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14 minutes ago, YellowTapemeasure said:

You need to tick priority load. Currently battery is getting priority, but you are probably not seeing it because they are full (you set it to charge from grid at 03H00, not sure why, can't you wait 4 hours until the sun can do it?).

Why have you ticked grid in all the other settings? I am not following, you are basically telling the inverter to charge the battery to 100% in all of them. This is not necessary.

Do you have non-essential loads (between grid and inverter)?

I do not have non-essential loads between the grid and the inverter.

I am just playing with the settings and will then find a happy medium (I have a spinning disk meter that goes backwards so it does not matter whether the battery charges through grid or solar at this time).

My problem is the battery depleted by pushing back into the grid. I do not want the battery to feed the grid ever.

I only want excess solar to feed to the grid.

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So, if loadshedding happens, how does the Power setting in the Time of Use table affect power output to your required load?

In other words, if the power setting for any given row in Time of Use is set at say 2500 and loadshedding happens, the battery will only discharge a maximum of 2500 even if your load might be more?

MdF

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  • 2 weeks later...

Morning All,

So, I have been playing around with the settings for a week now and have settled on battery discharges overnight that results in an SoC of about 50% before solar starts to kick in and recharge.

Should I be discharging the batteries further or do you think the 50% discharge level is enough "exercise"?

MdF

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41 minutes ago, MdF said:

Morning All,

So, I have been playing around with the settings for a week now and have settled on battery discharges overnight that results in an SoC of about 50% before solar starts to kick in and recharge.

Should I be discharging the batteries further or do you think the 50% discharge level is enough "exercise"?

MdF

Do you draw from the grid after the battery is full? If yes I would use the battery more to save some money.

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Yes, we draw from the grid after the PV stops for the day. So I agree with you saying we should draw more from battery to save money.

The issue is that I only have 1 battery at 5.1kwh which I need to also keep partially charged in case there is loadshedding or a power outage.

It would be nice to run the battery down to about 30% SoC but then what happens if loadshedding kicks in in the morning? (catch 22)?

I obviously need to look at getting a second battery to improve storage but that comes at a cost at the moment.

MdF

Edited by MdF
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11 minutes ago, MdF said:

Yes, we draw from the grid after the PV stops for the day. So I agree with you saying we should draw more from battery to save money.

The issue is that I only have 1 battery at 5.1kwh which I need to also keep partially charged in case there is loadshedding or a power outage.

It would be nice to run the battery down to about 30% SoC but then what happens if loadshedding kicks in in the morning? (catch 22)?

I obviously need to look at getting a second battery to improve storage but that comes at a cost at the moment.

MdF

I wouldn't worry about loadshedding or a power outage during the day. Even on an overcast day i still get enough power for my essentials which is internet and work computers.

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That's a good point.

What I do think we can afford for now is to increase PV from 8 panels to 12 which should make a difference for providing extra power during the day for essentials and to charge the battery.

MdF

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i have a 4.8 kWh battery, which I run down to 20-25 % every night, "usually"load shedding is announced, so IF the SOC is low and there is no pv, i charge the batteries from the grid, the only time I got caught flat footed was on a stormy morning, with batteries at 20 % SOC and then we had a power outage, so had to shut down the inverter, so, yes, I don't cater for EVERY situation, but I am getting the most bang for the buck from my batteries.

I have a 6.4 kWp array and run all my major loads during the day, only have 250-450 watt loads at night.

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I posted the below message on another related thread but thought i would ask here as well since there are different people conversing here and wanted different perspectives on the topic.

My 5kw Sunsynk unit is basically set to 100% from 8am to 6pm. So the batteries only charge during the day when there is sufficient sun. Then discharge in stages from 6pm to the following 8am all the way down to 30% SOC. I have ticked the load priority checkbox so when load is high during the day, it stops charging the batteries for a period of time to attend to the load and blend with grid if necessary. So on a good sunny day my 7kw of batteries are usually charged by 1pm. Thereafter the PV attends to the load for the rest of the day.

Not really concerned whether these settings are good or bad based on a user's circumstances, i am more interested about the way the batteries work. So in a setup, theoretically, the battery could be charged and partially discharged multiple times in the day. If the load at any point in the day demands more than what PV can supply and if the the battery has the required SOC for that time of day, the system could engage the use of the battery to power the load in tandem with PV and maybe even grid. When load demand drops, PV may get back to charging the battery.

Just for context, I have 2 X 3.5KW Pylontechs (US3000C).

MY QUESTIONS ARE:

1. Is it good practice to regularly charge the batteries all the way up to 100%?? Read some conflicting theories that Lithium prefers charges up to 85-90% for longevity.

2. (During the day) When the battery charges up to maybe 80% then allowed to discharge to perhaps 65% and then charge up again, is this not using up a charging cycle of the battery??? If this is true, then does it mean that multiple charge cycles are used up each day, and therefore reducing the lifespan of the battery???

With lithium batteries quoting in excess of 6000 cycles (based on DOD), the above scenario, if true, could mean that the batteries state of health (SOH) could deteriorate well before the claimed 10 years that most lithium vendors make. 

Any comments on the above???!!! Not sure if this has been discussed in another thread before.

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