One Year On - Solar Installation

wingnut771 said:
The BMS only top balances cells when its charging at the top of the voltage curve, it doesn't have any effect on discharge current except looking for over current.

BMS looks at cell voltage high and low, pack voltage high and low and current too high, and temp.
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This is from solar assist

The batteries are from top to bottom

1. UP5000 added earlier this year
2. US3000C added last year
3. 3 x US3000B added together when the system was commissioned in 2020.

The BMS seems to use the batteries differently and I'm not sure if a busbar would have it discharge evenly. The same can be seen during the charging cycle.

Two pics taken a few minutes apart.

Screenshot_20221016_203733.jpgScreenshot_20221016_204621.jpgScreenshot_20221016_204814.jpgScreenshot_20221016_204825.jpgScreenshot_20221016_204835.jpg
 
AchmatK said:
This is from solar assist

The batteries are from top to bottom

1. UP5000 added earlier this year
2. US3000C added last year
3. 3 x US3000B added together when the system was commissioned in 2020.

The BMS seems to use the batteries differently and I'm not sure if a busbar would have it discharge evenly. The same can be seen during the charging cycle.

Two pics taken a few minutes apart.

View attachment 1401759View attachment 1401761View attachment 1401763View attachment 1401765View attachment 1401767
Click to expand...
I would expect the bigger capacity battery to charge and discharge with bigger amps than the 3000’s. Why there is a big difference between the C and B’s I’m not sure. I would guess internal resistance is different between the C and B.

The point to me about the busbars is to take the load off the cables so all the segments are equal instead of the load adding up down the string.

I guess you would only notice it when there are heavy loads being applied.

Do a test with 8kW and see if the wires get warm?
 
wingnut771 said:
I would expect the bigger capacity battery to charge and discharge with bigger amps than the 3000’s. Why there is a big difference between the C and B’s I’m not sure. I would guess internal resistance is different between the C and B.

The point to me about the busbars is to take the load off the cables so all the segments are equal instead of the load adding up down the string.

I guess you would only notice it when there are heavy loads being applied.

Do a test with 8kW and see if the wires get warm?
Click to expand...
Will check that.

My battery is set to 20% SOC.

I noticed that it discharges the 2 newer batteries more than the first 3 taking them down to 16% and the older batteries only to 24% to 26%.Screenshot_20221017_081004.jpg
 
AchmatK said:
Will check that.

My battery is set to 20% SOC.

I noticed that it discharges the 2 newer batteries more than the first 3 taking them down to 16% and the older batteries only to 24% to 26%.View attachment 1401889
Click to expand...
Did you balance them when connecting the new batteries? I would take the SOC values with a pinch of salt as they're all the same voltage. Maybe connect each battery separately then fully drain it to cut off then fully charge it, then connect back together and try again? A lot of work I know.
 
wingnut771 said:
Did you balance them when connecting the new batteries? I would take the SOC values with a pinch of salt as they're all the same voltage. Maybe connect each battery separately then fully drain it to cut off then fully charge it, then connect back together and try again? A lot of work I know.
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Yes. Did that.

When I added the new batteries I first charged all of them to 100% individually and then connected them together and let them balance until the lights switched off on the batteries and only then did I connect the entire bank to the inverter.

I also noticed that the voltage are the same. Solar assist does give more details than what I was getting before. Screenshot_20221017_083528.jpgScreenshot_20221017_083539.jpgScreenshot_20221017_083549.jpg
 
AchmatK said:
Yes. Did that.

When I added the new batteries I first charged all of them to 100% individually and then connected them together and let them balance until the lights switched off on the batteries and only then did I connect the entire bank to the inverter.

I also noticed that the voltage are the same. Solar assist does give more details than what I was getting before. View attachment 1401901View attachment 1401903View attachment 1401905
Click to expand...
I think they needed to be fully cycled so the SOC can reset. I think the old batteries haven't gone through a full cycle in a long time throwing the SOC estimate out. I'm just guessing though.
 
Not much PV available today at all and our domestic worker is here in addition to our son's nanny so have set our ESS to run off CoJ supply and keep the batteries charged :rolleyes: It looks like tomorrow will be more of the same so it better damn rain!
 
Neuk_ said:
Not much PV available today at all and our domestic worker is here in addition to our son's nanny so have set our ESS to run off CoJ supply and keep the batteries charged :rolleyes: It looks like tomorrow will be more of the same so it better damn rain!
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Actually had that my side on Friday and the domestic managed to still use 10 units of power with the geyser, had to top up batteries just before my LS slot.
Tonight it looks like batteries are fine, but no one was home and from this morning they were at 25% when we left.
 
Lupus said:
Actually had that my side on Friday and the domestic managed to still use 10 units of power with the geyser, had to top up batteries just before my LS slot.
Tonight it looks like batteries are fine, but no one was home and from this morning they were at 25% when we left.
Click to expand...

We’ve had a great run up until now, averaging around 2kWh from CityPower per day mainly due to the oven which isn’t run through our ESS at all. Tomorrow is forecast as cloudy again so I’ll set the batteries to be used from when we go to bed and hope we have enough PV to run the house and charge the batteries during the day, to minimise use of CityPower.
 
Neuk_ said:
We’ve had a great run up until now, averaging around 2kWh from CityPower per day mainly due to the oven which isn’t run through our ESS at all. Tomorrow is forecast as cloudy again so I’ll set the batteries to be used from when we go to bed and hope we have enough PV to run the house and charge the batteries during the day, to minimise use of CityPower.
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2kw is amazing from city power I'm still on 8kw :(
 
Lupus said:
2kw is amazing from city power I'm still on 8kw :(
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Only our electric oven, kettle, toaster, iron and bedroom AC are run only off CityPower with gas used for our stove and water heating with as many LED’s for lighting as possible. Our next house though, giving me grey hair already…
 
Neuk_ said:
Only our electric oven, kettle, toaster, iron and bedroom AC are run only off CityPower with gas used for our stove and water heating with as many LED’s for lighting as possible. Our next house though, giving me grey hair already…
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Wow still, my kettle, toaster and stuff is on solar, guess geyser and stove really do chomp
 
wingnut771 said:
How much hot water do you use? Got any mixer taps? What is the geyser temp set at?
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Whole house is mixer taps, 3 people and keep telling them not to use hot water from the taps for dishes, use the dishwasher. It's supposedly set to 55 but I think the thermostat might be broken as the water feels hotter.
 
Lupus said:
Whole house is mixer taps, 3 people and keep telling them not to use hot water from the taps for dishes, use the dishwasher. It's supposedly set to 55 but I think the thermostat might be broken as the water feels hotter.
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It's probably that then. Set all mixer taps to cold then impose penalties for putting them back in the middle. :P 55 is good, if thermostat was broken, water would be gushing out the overflow pipe constantly and boiling water coming out the taps. I think they not super accurate though, so maybe test with a temp probe and go according to that. I find with my geyser, it feels hotter sometimes and cooler other times, indicating to me that the thermostat lets the temp drop quite a bit before switching on again.
 
wingnut771 said:
It's probably that then. Set all mixer taps to cold then impose penalties for putting them back in the middle. 55 is good, if thermostat was broken, water would be gushing out the overflow pipe constantly and boiling water coming out the taps. I think they not super accurate though, so maybe test with a temp probe and go according to that. I find with my geyser, it feels hotter sometimes and cooler other times, indicating to me that the thermostat lets the temp drop quite a bit before switching on again.
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Yup noticed on Friday that with the mixer in the middle it still uses water from the geysers but it's not hot.
 
Lupus said:
Yup noticed on Friday that with the mixer in the middle it still uses water from the geysers but it's not hot.
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Yeah, every time you wash your hands with the mixer in the middle you using hot water without the hot water ever getting to the tap as it takes time to travel from the geyser and to heat the pipes.
 
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