Daily guide · RS · 2026-09-03
What a home battery earned in Serbia this week, hour by hour
All numbers computed from the week's published auction results at publication and frozen — this article is an honest snapshot, not a page that rewrites itself. Reproduce via the API.
A 10 kWh home battery running one cycle a day earned 7,68 EUR across the six days covered this week, with an average peak-to-trough spread of 149,19 EUR/MWh at 90% round-trip efficiency. The best single day was 29 August, worth 1,66 EUR, when the cheap window averaged just 11,66 EUR/MWh against a 197,70 EUR/MWh evening peak. 30 August was close behind at 1,60 EUR, helped by an even lower charging cost of 4,88 EUR/MWh.
What stands out is how much the charging price, not the peak, drove returns. Peaks stayed in a fairly tight band, from 166,52 to 245,02 EUR/MWh, but cheap-window averages swung from under 5 EUR/MWh to 116 EUR/MWh. The weakest day, 28 August at 0,67 EUR, paired the lowest peak with a relatively expensive 82,50 EUR/MWh trough.
The practical takeaway: timing matters more than chasing the highest evening price. Charging usually landed in the 9:00 to 11:00 window, discharging around 18:00 to 19:00. Held steady, this pattern annualises to roughly 467 EUR.
A home battery makes money on one thing: the gap between the day's cheapest and priciest hours. Charge low, discharge across the evening peak instead of buying it, repeat daily. The size of that gap is set every afternoon at the day-ahead auction — so it's measurable, not hypothetical. Here is what one full daily cycle of a 10 kWh battery (at 90% round-trip efficiency — losses included, unlike most brochures) would have captured in RS this week.
€7.68
captured this week — one cycle per day, wholesale component, after losses
149.19
€/MWh average cheapest-2h → priciest-2h spread this week
≈€467
a year at this week's spreads — the honest run-rate, not the best-day fantasy
Day by day: the two windows that mattered
| Day | Charge (2h) | at €/MWh | Discharge (2h) | at €/MWh | Cycle value |
|---|---|---|---|---|---|
| 2026-08-27 | 11:00–13:00 | 116 | 19:00–21:00 | 243.5 | €1.03 |
| 2026-08-28 | 16:00–18:00 | 82.5 | 18:00–20:00 | 166.52 | €0.67 |
| 2026-08-29 | 10:00–12:00 | 11.66 | 18:00–20:00 | 197.7 | €1.66 |
| 2026-08-30 | 09:00–11:00 | 4.88 | 19:00–21:00 | 183.35 | €1.6 |
| 2026-08-31 | 09:00–11:00 | 54.93 | 18:00–20:00 | 224.11 | €1.47 |
| 2026-09-02 | 09:00–11:00 | 95.08 | 18:00–20:00 | 245.02 | €1.25 |
Local time, hourly auction means. Days where charging was negative-priced mean you were paid to fill the battery.
Do it automatically
The windows move every day — automation is the whole game. One API call returns a cost-optimal schedule your inverter or energy manager can follow, and there's a full battery simulator to backtest your exact capacity, power and cycle limits against realized prices before you trust it:
curl -X POST -H "Authorization: Bearer YOUR_KEY" \
-H "Content-Type: application/json" \
-d '{"zone": "RS", "capacity_kwh": 10, "max_power_kw": 5,
"round_trip_efficiency": 0.9, "max_cycles_per_day": 1}' \
https://voltcast.com/api/v1/optimize/batteryHome Assistant users get the schedule as a sensor via the integration. And because the value depends entirely on tomorrow's spread, the P10–P90 forecast — scored publicly every day — tells you whether tomorrow is worth a deep cycle at all.
Method & citation. Prices are hourly means of published day-ahead auction results (native 15-minute periods averaged; ENTSO-E/SMARD, attributed). Wholesale-price component only — grid fees and taxes come on top and vary by supplier. Cite as "Voltcast Research, voltcast.com/guides/battery-arbitrage-rs-2026-09-03".
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