Do Tesla Powerwalls Discharge in Parallel or One at a Time?

[Yonki]

I have three Powerwall 2s. Each one can supply 5kW, and the three in parallel can provide 15kW. Obviously if I'm drawing more than 5kW, at least two Powerwalls will be supplying power. But if I'm using 3kW, does one Powerwall supply 3kW while the other two are idle, or does each Powerwall contribute 1kW? If they're always sharing equally, do they ever switch to just one for efficiency's sake (say I'm on vacation and the house is using less than 100W)?

 

[cwied]

My two Powerwalls discharge in parallel. I think the only time there might be a significant imbalance is if they reach fully charged (when charging) or the backup reserve (when discharging) at different times.

 

[Redhill_qik]

I have three Powerwall 2s. Each one can supply 5kW, and the three in parallel can provide 15kW. Obviously if I'm drawing more than 5kW, at least two Powerwalls will be supplying power. But if I'm using 3kW, does one Powerwall supply 3kW while the other two are idle, or does each Powerwall contribute 1kW? If they're always sharing equally, do they ever switch to just one for efficiency's sake (say I'm on vacation and the house is using less than 100W)?

They discharge in parallel, so if the house load is only 3kW then 1kW each.

 

[ptdusn]

My two Powerwalls discharge in parallel. I think the only time there might be a significant imbalance is if they reach fully charged (when charging) or the backup reserve (when discharging) at different times.

They charge in parallel also.

 

[cwied]

They charge in parallel also.

True. What I’m saying is I have observed one of my Powerwalls hit 100% before the other. The other kept charging for a minute or so after the first stopped charging.

 

[jgleigh]

The Gateway balances the multiple Powerwalls as best it can. It tries to keep them all at the same charge/discharge level.

 

[Matt-FL]

True. What I’m saying is I have observed one of my Powerwalls hit 100% before the other. The other kept charging for a minute or so after the first stopped charging.

I'm curious where you see the charge for individual powerwalls? The gateway only returns the total %, so wondering if I am missing something.

 

[cwied]

I'm curious where you see the charge for individual powerwalls? The gateway only returns the total %, so wondering if I am missing something.

You can see individual battery charges using the local API by requesting https://<powerwall ip address>/api/system_status. You get something like the following:

{
"command_source": "Configuration",
"battery_target_power": -2364.7474316420776,
"battery_target_reactive_power": 0,
"nominal_full_pack_energy": 26935,
"nominal_energy_remaining": 20163,
"max_power_energy_remaining": 0,
"max_power_energy_to_be_charged": 0,
"max_charge_power": 10000,
"max_discharge_power": 10000,
"max_apparent_power": 10000,
"instantaneous_max_discharge_power": 14000,
"instantaneous_max_charge_power": 14000,
"instantaneous_max_apparent_power": 11520,
"hardware_capability_charge_power": 0,
"hardware_capability_discharge_power": 0,
"grid_services_power": 0,
"system_island_state": "SystemGridConnected",
"available_blocks": 2,
"available_charger_blocks": 0,
"battery_blocks": [
{
"Type": "",
"PackagePartNumber": "1092170-03-G",
"PackageSerialNumber": "TG1180230009FR",
"disabled_reasons": [],
"pinv_state": "PINV_GridFollowing",
"pinv_grid_state": "Grid_Compliant",
"nominal_energy_remaining": 10051,
"nominal_full_pack_energy": 13504,
"p_out": -1200,
"q_out": -290,
"v_out": 249.70000000000002,
"f_out": 60.009,
"i_out": 24.200000000000003,
"energy_charged": 9654170,
"energy_discharged": 8322210,
"off_grid": false,
"vf_mode": false,
"wobble_detected": false,
"charge_power_clamped": false,
"backup_ready": true,
"OpSeqState": "Active",
"version": "63bc46d8c35d6e"
},
{
"Type": "",
"PackagePartNumber": "1092170-03-G",
"PackageSerialNumber": "TG11801700015J",
"disabled_reasons": [],
"pinv_state": "PINV_GridFollowing",
"pinv_grid_state": "Grid_Compliant",
"nominal_energy_remaining": 10112,
"nominal_full_pack_energy": 13431,
"p_out": -1150.0000000000002,
"q_out": 0,
"v_out": 249.8,
"f_out": 60.010000000000005,
"i_out": 23.700000000000003,
"energy_charged": 9698160,
"energy_discharged": 8344110,
"off_grid": false,
"vf_mode": false,
"wobble_detected": false,
"charge_power_clamped": false,
"backup_ready": true,
"OpSeqState": "Active",
"version": "63bc46d8c35d6e"
}
],
"ffr_power_availability_high": 8315.879947662354,
"ffr_power_availability_low": 10000,
"load_charge_constraint": 0,
"max_sustained_ramp_rate": 2500000,
"grid_faults": [],
"can_reboot": "Power flow is too high",
"smart_inv_delta_p": 0,
"smart_inv_delta_q": -290,
"last_toggle_timestamp": "2023-06-15T22:19:26.894985-07:00",
"solar_real_power_limit": 1.7976931348623157e+308,
"score": 10000,
"blocks_controlled": 2,
"primary": true,
"auxiliary_load": 0,
"all_enable_lines_high": true,
"inverter_nominal_usable_power": 10000,
"expected_energy_remaining": 0
}

 

[Matt-FL]

Awesome, thank for sharing that. Interesting how each of my powerwalls has a different 'nominal_full_pack_energy' amount... varies from 15078 to 14815.