Multi-battery management¶
The integration manages up to 6 batteries as an aggregated system, distributing power intelligently to maximise efficiency.
Efficiency principle¶
Based on the Venus efficiency curve (peak ~91% between 1000–1500 W), batteries are activated only when total power exceeds 60% of combined capacity. Running fewer batteries at higher power is more efficient than spreading the same load across all of them.
The following measurements show DC power consumption/output, AC power at the meter (internal clamp) and at the wall outlet (external clamp), and the resulting efficiency at each power level:
Charging
| % of max | Setpoint (W) | DC internal (W) | AC internal (W) | AC external (W) | η internal | η external |
|---|---|---|---|---|---|---|
| 3 % | 63 | 41 | 58 | 68 | 70.7 % | 60.3 % |
| 5 % | 125 | 105 | 123 | 136 | 85.4 % | 77.2 % |
| 10 % | 250 | 232 | 247 | 262 | 93.9 % | 88.5 % |
| 15 % | 375 | 357 | 372 | 387 | 96.0 % | 92.2 % |
| 20 % | 500 | 481 | 497 | 513 | 96.8 % | 93.8 % |
| 25 % | 625 | 604 | 621 | 639 | 97.3 % | 94.5 % |
| 30 % | 750 | 727 | 743 | 766 | 97.8 % | 94.9 % |
| 35 % | 875 | 850 | 871 | 892 | 97.6 % | 95.3 % |
| 40 % | 1000 | 973 | 995 | 1019 | 97.8 % | 95.5 % |
| 45 % | 1125 | 1095 | 1120 | 1146 | 97.8 % | 95.5 % |
| 50 % | 1250 | 1245 | 1271 | 1274 | 98.0 % | 97.7 % |
| 55 % | 1375 | 1339 | 1369 | 1401 | 97.8 % | 95.6 % |
| 60 % | 1500 | 1460 | 1494 | 1530 | 97.7 % | 95.4 % |
| 65 % | 1625 | 1581 | 1618 | 1658 | 97.7 % | 95.4 % |
| 70 % | 1750 | 1702 | 1743 | 1786 | 97.6 % | 95.3 % |
| 75 % | 1875 | 1823 | 1868 | 1916 | 97.6 % | 95.1 % |
| 80 % | 2000 | 1942 | 1992 | 2044 | 97.5 % | 95.0 % |
| 85 % | 2125 | 2062 | 2117 | 2175 | 97.4 % | 94.8 % |
| 90 % | 2250 | 2183 | 2242 | 2304 | 97.4 % | 94.7 % |
| 95 % | 2375 | 2304 | 2366 | 2436 | 97.4 % | 94.6 % |
| 100 % | 2500 | 2424 | 2491 | 2567 | 97.3 % | 94.4 % |
Discharging
| % of max | Setpoint (W) | DC internal (W) | AC internal (W) | AC external (W) | η internal | η external |
|---|---|---|---|---|---|---|
| 3 % | 63 | 80 | 63 | 60 | 78.8 % | 75.0 % |
| 5 % | 125 | 160 | 124 | 118 | 77.5 % | 73.8 % |
| 10 % | 250 | 284 | 249 | 243 | 87.7 % | 85.6 % |
| 15 % | 375 | 416 | 373 | 368 | 89.7 % | 88.5 % |
| 20 % | 500 | 550 | 498 | 494 | 90.5 % | 89.8 % |
| 25 % | 625 | 685 | 623 | 619 | 90.9 % | 90.4 % |
| 30 % | 750 | 820 | 747 | 745 | 91.1 % | 90.9 % |
| 35 % | 875 | 956 | 872 | 870 | 91.2 % | 91.0 % |
| 40 % | 1000 | 1092 | 997 | 996 | 91.3 % | 91.2 % |
| 45 % | 1125 | 1230 | 1121 | 1121 | 91.1 % | 91.1 % |
| 50 % | 1250 | 1369 | 1246 | 1246 | 91.0 % | 91.0 % |
| 55 % | 1375 | 1507 | 1370 | 1372 | 90.9 % | 91.0 % |
| 60 % | 1500 | 1647 | 1495 | 1497 | 90.8 % | 90.9 % |
| 65 % | 1625 | 1789 | 1620 | 1623 | 90.6 % | 90.7 % |
| 70 % | 1750 | 1931 | 1745 | 1748 | 90.4 % | 90.5 % |
| 75 % | 1875 | 2073 | 1869 | 1874 | 90.2 % | 90.4 % |
| 80 % | 2000 | 2218 | 1994 | 1999 | 89.9 % | 90.1 % |
| 85 % | 2125 | 2362 | 2118 | 2124 | 89.7 % | 89.9 % |
| 90 % | 2250 | 2508 | 2243 | 2250 | 89.4 % | 89.7 % |
| 95 % | 2375 | 2654 | 2368 | 2375 | 89.2 % | 89.5 % |
| 100 % | 2500 | 2801 | 2492 | 2501 | 89.0 % | 89.3 % |
Selection priorities¶
Discharge¶
Highest SOC first: the most charged battery discharges first to balance the state of charge across the system.
Charging¶
Lowest SOC first: the least charged battery receives energy first.
Hysteresis¶
To avoid "ping-pong" activation/deactivation, three hysteresis levels are applied:
| Hysteresis | Value | Description |
|---|---|---|
| SOC | 5 % | An active battery stays active until another exceeds it by 5% SOC |
| Lifetime energy | 2.5 kWh | Breaks SOC ties using accumulated lifetime energy with an advantage for the active battery |
| Power | ±100 W | Activates the 2nd battery at 60% of combined capacity; deactivates at 50% |
Power distribution¶
Once active batteries are selected, the total power calculated by the PD controller is distributed among them proportionally, respecting each battery's individual power and SOC limits.
Compatible modes¶
Multi-battery distribution applies in all modes: - Normal PD control - Solar charging - Predictive grid charging
