Storage
Batteries and invertor
- Cost Analysis: Procurement and Shipment of 60kWh LFP BYD Batteries from China to Uganda
- Battery as a service Provider
- SRNE
- FENECon - Germany
- Solei Power - Uganda
- Arbitrage Tracker (gw-pi2, Sezibwa)
- Arbitrage Window and Thresholds (decision record)
- NFE Daily Brief (gw-pi2, Sezibwa)
Cost Analysis: Procurement and Shipment of 60kWh LFP BYD Batteries from China to Uganda
1. Executive Summary:
This report provides a comprehensive cost estimate for purchasing and shipping a 60kWh Lithium Iron Phosphate (LFP) battery pack manufactured by BYD from China to Uganda. The analysis encompasses the estimated purchase price in China, various shipping options and their associated costs, and the import duties and taxes applicable in Uganda. The total estimated cost is subject to considerable variation depending on factors such as the prevailing market price of batteries, the chosen shipping method (sea or air freight), and the specific import duties levied by the Ugandan authorities at the time of import. This report outlines a potential cost range to aid businesses in Uganda in their procurement planning and financial forecasting for such a significant component.
2. Introduction:
BYD (Build Your Dreams) stands as a prominent global manufacturer of rechargeable batteries, including Lithium-ion and LFP chemistries, with a significant presence in the electric vehicle and energy storage sectors.1 The company's LFP batteries are particularly recognized for their enhanced safety features and cost-effectiveness, making them a preferred choice for a wide array of applications, from electric vehicles to stationary energy storage systems.1 Given BYD's established position in the battery market, this report aims to provide a detailed cost analysis for an entity in Uganda seeking to procure a 60kWh LFP battery pack from this leading Chinese manufacturer. This analysis will delve into the primary cost drivers, including the initial purchase price of the batteries in China, the logistical expenses associated with shipping to Uganda, and the governmental levies in the form of taxes and duties imposed by both countries. Understanding these components is crucial for accurate budgeting and informed decision-making for any organization undertaking such an international procurement.
3. Estimated Purchase Cost of 60kWh BYD LFP Batteries in China:
The landscape of lithium-ion battery pricing in China has been characterized by a notable downward trend, primarily influenced by decreasing raw material costs and heightened competition among manufacturers.4 This trend is particularly evident in the pricing of LFP batteries, which generally exhibit a more competitive cost structure compared to Nickel Cobalt Manganese (NCM) batteries.6 Recent industry reports suggest that the price of LFP battery cells in China, which stood at approximately $70 per kilowatt-hour (kWh) in the near past, was anticipated to undergo substantial reductions throughout 2024, with further potential decreases projected for 2025.4 Some forecasts even indicated the possibility of LFP cell prices falling below $56/kWh by mid-2024 and potentially reaching as low as $36/kWh by 2025.4
Examining online marketplaces such as Alibaba and Made-in-China reveals a variety of BYD LFP battery products listed by different suppliers, with prices varying based on factors like capacity and the specific vendor.16 Given these fluctuating market conditions and supplier-specific pricing, it becomes apparent that a precise, fixed purchase price is difficult to ascertain. Instead, a more realistic approach involves considering a price range based on the available data.
Based on the per kWh price ranges identified in the research, the estimated purchase cost for a 60kWh BYD LFP battery pack in 2024 can be projected. Utilizing the lower end of the price spectrum at around $49/kWh 12 and the higher end at approximately $70/kWh 4, the following cost range can be estimated:
Table 1: Estimated Purchase Cost Range of 60kWh BYD LFP Batteries in China (2024)
| Price per kWh (USD) | Estimated Cost for 60kWh Pack (USD) |
| Low Estimate: 49 | 2,940 |
| Mid Estimate: 60 | 3,600 |
| High Estimate: 70 | 4,200 |
This suggests that the purchase cost for a 60kWh BYD LFP battery pack could range from approximately $2,940 to $4,200 based on 2024 price levels. It is important to note that potential price reductions anticipated for 2025 could further lower these estimates.
For sourcing these batteries, platforms like Alibaba and Made-in-China serve as potential avenues, hosting numerous suppliers and distributors of BYD batteries.16 Several specific companies have been identified as offering BYD battery products.16 Additionally, BYD itself operates an energy storage division, which could be a direct point of contact for procurement.25 While online platforms offer a broad selection of suppliers, engaging directly with BYD or their officially recognized distributors might provide enhanced assurance regarding product quality and potentially more favorable pricing terms, especially for substantial orders like a 60kWh battery pack.
4. Shipping Cost Analysis: China to Uganda:
Transporting a large and heavy item like a 60kWh battery pack from China to Uganda necessitates careful consideration of the available shipping methods, each with its own implications for cost and transit time. Sea freight generally emerges as the more economical option for such substantial cargo.37 Within sea freight, two primary options exist: Less than Container Load (LCL) for smaller shipments that don't fill an entire container, and Full Container Load (FCL) for larger volumes.37 The typical transit time for sea freight from China to Uganda ranges from 5 to 8 weeks.38
Conversely, air freight offers a significantly faster transit time, typically between 7 to 10 days for standard air freight and 2 to 4 days for express services.38 However, this speed comes at a considerably higher cost compared to sea freight.37
Estimating the precise shipping costs requires considering the weight and volume of the 60kWh LFP battery pack. Research suggests that a battery pack of this capacity can vary in weight depending on the manufacturer and design, ranging from approximately 438kg for a Tesla Model 3 battery 40 to over 700kg for a Delong battery pack.41
Based on these weight figures, the estimated cost for air freight, which is typically calculated per kilogram, can be projected. Using a cost range of $7.5 to $10 per kg 37, the air freight cost for a 60kWh battery pack could range from $3,285 (438kg * $7.5/kg) to $7,120 (712kg * $10/kg).
For sea freight, the cost is often determined by volume, particularly for LCL shipments, with rates ranging from $150 to $190 per cubic meter.37 While the exact volume of a 60kWh battery pack was not explicitly available in the research, its substantial size likely makes an FCL shipment (using a 20-foot container) a more practical approach. The cost for an FCL 20-foot container from China to Uganda is estimated to be between $4,000 and $6,000.37
Table 2: Estimated Shipping Cost Comparison (Sea vs. Air Freight)
| Shipping Method | Cost Metric | Estimated Cost (USD) | Transit Time |
| Sea Freight (LCL) | $150 - $190 / m³ | Requires Volume Data | 5 - 8 weeks |
| Sea Freight (FCL 20ft) | Per Container | $4,000 - $6,000 | 5 - 8 weeks |
| Air Freight | $7.5 - $10 / kg | $3,285 - $7,120 | 7 - 10 days (Std) |
The selection of the shipping method will have a significant impact on the total cost. Sea freight offers substantial cost savings but necessitates a longer lead time, while air freight provides speed at a considerable premium.
Engaging a freight forwarder is a common practice for international shipments to manage the complexities of logistics and customs procedures.37 These services typically involve additional fees covering documentation, customs clearance in China, and overall shipment coordination. Furthermore, it is important to anticipate potential surcharges such as fuel adjustments, port handling fees, and other miscellaneous charges that can add to the base shipping costs. Therefore, when budgeting for the shipment, an allowance for freight forwarder fees and these potential unforeseen surcharges should be included to ensure a more accurate overall cost estimation.
5. Tax and Duty Implications:
In China, the research material does not explicitly mention specific export taxes levied on batteries. While standard export procedures and minor administrative fees might be applicable, significant export duties on this commodity appear unlikely based on the provided information. Nevertheless, it is prudent to verify this with the chosen supplier or a freight forwarder based in China to preempt any unexpected charges at the point of export.
Uganda, on the other hand, has specific import duties and taxes that will apply to the incoming battery pack. Notably, Uganda recently imposed a 25% import duty on electric vehicles, hybrid vehicles, and electric motorcycles.48 While batteries are not explicitly listed in this category, their fundamental role as a core component in both electric vehicles and energy storage systems strongly suggests that they are highly likely to be subject to this new import duty. Under the East Africa Customs Union (EACU) common external tariff, most finished products attract a 25% duty, further supporting the likelihood of this tariff applying to the battery pack.50 This import duty is expected to be a significant contributor to the overall cost of importing the 60kWh LFP battery pack.
In addition to import duties, Uganda levies a Value Added Tax (VAT) at a standard rate of 18%.50 This VAT is typically calculated on the Cost, Insurance, and Freight (CIF) value of the imported goods, which includes the purchase price, shipping costs, and the import duty itself.52 Therefore, the 18% VAT will be applied on top of the combined cost of the battery, its shipment, and the 25% import duty, leading to a further increase in the total expenditure.
Other relevant taxes in Uganda include a 1.5% infrastructure tax on imports, designed to fund railway infrastructure development.50 Additionally, a 15% withholding tax may be applicable to imported goods and services, although the specific applicability to batteries warrants confirmation with the Ugandan tax authorities.50 While these taxes are individually lower than the import duty and VAT, they will collectively contribute to the overall tax burden associated with the import.
It is important to highlight that the Ugandan government offers potential tax exemptions and incentives for local manufacturers involved in the electric vehicle sector. Entities manufacturing electric vehicles, electric batteries, or charging equipment, and meeting specific criteria such as employing at least 80% Ugandan citizens, utilizing at least 80% locally sourced raw materials (where available), and meeting minimum investment thresholds, might be exempt from the 25% import duty and stamp duty.48 If the importing entity qualifies under these provisions, they could potentially realize significant reductions in the final cost.
To provide an estimated range for the import duties and taxes in Uganda, the following table illustrates the potential breakdown based on the low and high estimates for the purchase cost and shipping (using sea freight as the lower shipping cost):
Table 3: Breakdown of Estimated Ugandan Import Duties and Taxes (Based on Sea Freight)
| Item | Low Estimate (USD) | High Estimate (USD) |
| Estimated Value of Goods (Purchase + Shipping) | 6,940 | 10,200 |
| Import Duty (25% of Estimated Value) | 1,735 | 2,550 |
| VAT (18% of (Estimated Value + Import Duty)) | 1,561.20 | 2,295 |
| Infrastructure Tax (1.5% of Estimated Value) | 104.10 | 153 |
| Potential Withholding Tax (15% of Estimated Value) | 1,041 | 1,530 |
| Total Estimated Taxes and Duties | 4,441.30 | 6,528 |
Note: The "Estimated Value of Goods" in the Low Estimate scenario uses the low purchase cost ($2,940) + the low end of the FCL sea freight cost ($4,000). The High Estimate uses the high purchase cost ($4,200) + the high end of the FCL sea freight cost ($6,000).
6. Total Estimated Cost and Breakdown:
Consolidating the estimated purchase cost, shipping cost (considering both sea and air freight for a comprehensive range), and the total estimated taxes and duties, we can arrive at an overall cost projection:
Table 4: Consolidated Total Estimated Cost Range
| Cost Component | Low Estimate (USD) | High Estimate (USD) |
| Estimated Purchase Cost | 2,940 | 4,200 |
| Estimated Shipping Cost (Sea Freight) | 4,000 | 6,000 |
| Estimated Shipping Cost (Air Freight) | 3,285 | 7,120 |
| Estimated Taxes and Duties | 4,441.30 | 6,528 |
| Total Estimated Cost (Sea Freight) | 11,381.30 | 16,728 |
| Total Estimated Cost (Air Freight) | 10,666.30 | 17,848 |
The total estimated cost for purchasing and shipping a 60kWh LFP BYD battery pack from China to Uganda could range significantly, potentially from approximately $10,666.30 (low purchase cost + low air freight + low taxes/duties) to $17,848 (high purchase cost + high air freight + high taxes/duties). If sea freight is chosen, the range would be approximately $11,381.30 to $16,728.
7. Key Considerations and Recommendations:
For any entity in Uganda looking to undertake this procurement, several key considerations and recommendations should be taken into account:
- Supplier Negotiation: Actively engage in negotiations with potential battery suppliers in China to secure the most competitive purchase price, especially when dealing with larger order volumes.
- Incoterms: Clearly define and agree upon the Incoterms with the chosen supplier. These terms dictate the responsibilities and costs associated with transportation and delivery, including who bears the risk at different stages of the shipping process.
- Shipping Insurance: Secure adequate shipping insurance to protect against potential damage or loss of the valuable cargo during its transit from China to Uganda.
- Quality Control: Implement stringent quality control measures in China, preferably through on-site inspections before shipment, to ensure the battery pack meets the required technical specifications and quality standards.
- Customs Clearance in Uganda: Partner with a reputable and experienced customs broker in Uganda. Their expertise will be invaluable in navigating the import clearance procedures, ensuring compliance with all Ugandan regulations, and potentially expediting the process.
- Verification of Import Duties and Taxes: It is strongly recommended to directly contact the Uganda Revenue Authority (URA) or consult with a qualified tax professional in Uganda. This step is crucial to obtain the most up-to-date and accurate information regarding import duties, VAT rates, and the applicability of any potential exemptions for battery imports. The information provided in this report is based on currently available data but is subject to change.
- Exploring Local Suppliers: While the focus of this report is on importing from China, it might be worthwhile to briefly explore the possibility of sourcing similar batteries from local suppliers within Uganda or the broader East African region. However, the availability and cost-effectiveness of BYD LFP batteries through these channels may be limited.
- Long-Term Cost Analysis: When evaluating the overall cost, consider the long-term benefits associated with LFP batteries, such as their extended lifespan, high cycle life, and potentially lower maintenance requirements compared to other battery chemistries. These factors can contribute to a more favorable total cost of ownership over the operational life of the battery pack.
By carefully considering these recommendations and conducting thorough due diligence, the procuring entity in Uganda can better navigate the complexities and costs associated with importing a 60kWh LFP BYD battery pack from China.
Battery as a service Provider
SLS energy based in Rwanda
Cost: USD 4.40-6.48 kwh of system capacity available per month. Also depends on the duration of the lease.
SRNE
See product catalog here: https://www.srnesolar.com/
They have a factory showroom in Naguru.
Pricing from the factory showroom below. Full price list here:Uganda SRNE item price list.pdf
- 5.12 KW battery - 3.22m UGX
- 6kw inverter - 3.74m UGX
- 10kw inverter - 4.611m UGX
- 12kw inverter - 7.673m UGX
Quote from a thirrdparty local supplier is attached here. Quote-105 (1).pdf.
Datasheet here: SRNE_HESP series_EU_48V_3.6_6kW_230V_Single-Phase_Hybrid_Solar Storage Inverter_Datasheet_V1.2[20250618] (1).pdf
Modbus Protocol: SRNE Solar Charge Inverter MODBUS Protocol1.96 (1).pdf
FENECon - Germany
Solei Power - Uganda
They are offering LFP batteries (locally manufactured) with BMS.
They quoted:
Arbitrage Tracker (gw-pi2, Sezibwa)
Cumulative record of the TOU battery arbitrage on gw-pi2 (Sezibwa). Each night the inverter discharges the battery during a peak-tariff window and recharges it from the grid at the off-peak rate from 00:00. Daily progress goes to the Element business room; this page is the running record. It is rebuilt from the OpenEMS backend by scripts/arbitrage_tracker.py in the nfe-modbus-energy-logger repo.
Settings and why they were chosen: Arbitrage Window and Thresholds (decision record).
Last updated: 2026-10-14 06:31 EAT.
Totals
| Measure | Value |
|---|---|
| Nights armed | 14 |
| Energy shifted to peak | 58.8 kWh |
| Estimated net saving | 11,122 UGX |
| Average per armed night | 4.20 kWh, 794 UGX |
| Projected per month at that rate | 23,834 UGX |
Night by night
| Night | Config | Window | Start | SoC start | SoC end | Shifted (kWh) | Peak (kW) | Lowest pack (V) | Saving (UGX) | Recharge 00-06 (kWh) | Notes |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 2026-09-26 | v12 | 22:00-23:59 | 22:03 | 78% | 48% | 3.08 | 6.1 | 50.96 | 582 | 5.9 | first armed night |
| 2026-09-27 | v13 | off | 0 | 0 | 4.5 | disarmed: SoC 65% after the 27 Sep overload outage | |||||
| 2026-09-28 | v14 | 21:30-23:30 | 21:33 | 87% | 64% | 2.28 | 4.6 | 51.45 | 432 | 4.1 | window moved to 21:30-23:30 |
| 2026-09-29 | v15 | off | 0 | 0 | 5.5 | disarmed: SoC 61% after the 05:15-07:51 grid outage | |||||
| 2026-09-30 | v17 | 21:00-23:00 | 21:03 | 87% | 60% | 2.75 | 6.3 | 50.94 | 519 | 4.5 | window 21:00-23:00, no more manual disarms |
| 2026-10-01 | v18 | off | 0 | 0 | 5.7 | skipped: two outages left SoC at 51% before the window | |||||
| 2026-10-02 | v18 | off | 0 | 0 | 1.7 | still disarmed (re-arm missed) | |||||
| 2026-10-03 | v19 | 21:00-23:00 | 21:03 | 64% | 38% | 2.64 | 4.4 | 51.10 | 499 | 7.0 | re-armed with the v17 profile |
| 2026-10-04 | v19 | 21:00-23:00 | 21:03 | 84% | 63% | 2.17 | 2.2 | 52.17 | 410 | 4.3 | |
| 2026-10-05 | v21 | 18:00-23:59 | 19:22 | 15% | 9% | 0.08 | 1.9 | 49.32 | 15 | 10.8 | driver rules live: start at 30% or above, floor 15%; 0.9 kWh of the discharge was during an outage (backup, not counted) |
| 2026-10-06 | v21 | 18:00-23:59 | 18:04 | 89% | 25% | 5.04 | 4.0 | 51.14 | 953 | 8.4 | 1.5 kWh of the discharge was during an outage (backup, not counted) |
| 2026-10-07 | v21 | 18:00-23:59 | 18:04 | 89% | 25% | 6.56 | 5.0 | 51.00 | 1,239 | 8.3 | |
| 2026-10-08 | v21 | 18:00-23:59 | 18:04 | 89% | 21% | 6.88 | 5.5 | 50.22 | 1,300 | 8.7 | |
| 2026-10-09 | v21 | 18:00-23:59 | 18:04 | 79% | 28% | 5.18 | 4.3 | 50.88 | 980 | 8.0 | |
| 2026-10-10 | v21 | 18:00-23:59 | 18:04 | 65% | 15% | 4.96 | 4.1 | 51.10 | 938 | 9.4 | |
| 2026-10-11 | v21 | 18:00-23:59 | 18:04 | 54% | 15% | 3.59 | 4.3 | 50.26 | 679 | 9.2 | |
| 2026-10-12 | v21 | 18:00-23:59 | 18:00 | 77% | 15% | 6.12 | 4.4 | 50.52 | 1,157 | 9.0 | |
| 2026-10-13 | v21 | 18:00-23:59 | 18:03 | 89% | 15% | 7.51 | 5.1 | 50.34 | 1,419 | 9.3 |
Outages and reliability
Every grid outage, with how the battery carried it and how much of the reserve that night's arbitrage had already used. This is the record for judging what the deeper discharge costs in backup.
| Measure | Value |
|---|---|
| Outages | 16 (27.4 h) |
| Outages where the site went dark | 1 |
| Outages that started after an arbitrage night, before the recharge | 0 |
| Of those, site went dark | 0 |
| Date | Start | End | Duration | SoC at start | Lowest SoC | Lowest pack (V) | Battery supplied (kWh) | Site dark | Arbitrage use before (kWh) | Notes |
|---|---|---|---|---|---|---|---|---|---|---|
| 2026-10-01 | 10:45 | 14:12 | 3h27 | 93% | 60% | 52.16 | 3.4 | no | ||
| 2026-10-01 | 20:20 | 20:42 | 0h22 | 56% | 52% | 51.92 | 0.5 | no | ||
| 2026-10-03 | 15:10 | 16:49 | 1h39 | 90% | 66% | 52.10 | 2.5 | no | ||
| 2026-10-04 | 16:35 | 16:52 | 0h17 | 90% | 87% | 52.60 | 0.3 | no | ||
| 2026-10-05 | 06:40 | 09:27 | 2h47 | 96% | 68% | 52.07 | 3.0 | no | ||
| 2026-10-05 | 10:35 | 13:44 | 3h09 | 66% | 37% | 51.70 | 2.9 | no | ||
| 2026-10-05 | 13:50 | 14:42 | 0h52 | 37% | 31% | 51.91 | 0.5 | no | ||
| 2026-10-05 | 15:25 | 17:17 | 1h52 | 30% | 15% | 50.91 | 1.6 | no | ||
| 2026-10-05 | 19:25 | 20:55 | 1h30 | 15% | 9% | 49.32 | 1.0 | yes, 48 min no data | ||
| 2026-10-06 | 19:20 | 20:06 | 0h46 | 81% | 64% | 52.00 | 1.7 | no | ||
| 2026-10-09 | 16:50 | 17:55 | 1h05 | 90% | 79% | 52.62 | 1.1 | no | ||
| 2026-10-10 | 10:45 | 10:47 | 0h02 | 93% | 93% | 52.92 | 0.0 | no | ||
| 2026-10-10 | 12:30 | 12:54 | 0h24 | 92% | 89% | 52.80 | 0.3 | no | ||
| 2026-10-10 | 15:15 | 17:39 | 2h24 | 88% | 65% | 52.32 | 2.4 | no | ||
| 2026-10-11 | 02:15 | 08:20 | 6h05 | 100% | 60% | 52.28 | 4.0 | no | 0.0 | |
| 2026-10-12 | 17:20 | 18:04 | 0h44 | 89% | 77% | 51.99 | 1.3 | no |
Where to tweak
- Unused battery headroom: the battery ends the window with an average 0.6 kWh above its floor (45% before the driver rules, 15% from v21) (115 UGX a night if shifted too).
- Peak energy still bought from the grid: 2.2 kWh a night between 18:00 and midnight falls outside the window. That is the ceiling for more shifting, limited by battery size and the backup reserve.
- Voltage margin: the lowest pack voltage so far is 49.32 V against the 50.4 V disarm trigger and 48.8 V inverter cut-off.
- Spread: each shifted kWh earns about 189 UGX net (666.5 peak minus 429.7 off-peak at 90% round trip). A new quarterly tariff changes this directly.
Method
- Shifted energy: battery discharge (ess0/ActivePower > 0) integrated over the configured window, with 10 minutes added at the end for the inverter clock lag. Only minutes with the grid present count; discharge during an outage is backup, not arbitrage, and is shown in the notes.
- Saving: shifted kWh at the peak rate, minus the off-peak cost of putting that energy back at 90% round-trip efficiency. It is energy only (no service charge, VAT or battery wear).
- Recharge: battery charging between 00:00 and 06:00. It includes refilling any evening outage use, so it can exceed the shifted energy.
- Config history: ADR-016 in the microgrid-gateway repo (v12 22:00-23:59, v13 off, v14 21:30-23:30 from 28 Sep, v17 21:00-23:00 from 30 Sep, v18 off 1-2 Oct, v19 re-armed from 3 Oct, v21 from 5 Oct: 18:00-23:59 with the driver's 30% start and 15% floor).
- Outage: a minute counts as an outage when any phase of the inverter's grid-side meter (meter0) reads under 150 V or the inverter reports machine state 3 (off grid). Minutes with no data during an outage mean the edge lost power, which means the site went dark; an outage counts as dark at 5 such minutes or when SoC fell to 10% (the inverter's cut-off point seen on 24 Sep).
- Arbitrage use before an outage: the energy that night's window took from the battery (grid present), for outages that start after the window and before 06:00. It is the backup the site did not have because of arbitrage. An outage that starts inside the window is marked, because from then on the discharge is backup.
Arbitrage Window and Thresholds (decision record)
This page records how the nightly TOU arbitrage window and battery thresholds at Sezibwa (gw-pi2) were chosen and changed. For the running night-by-night results see the Arbitrage Tracker. The engineering record is ADR-016 in the microgrid-gateway repository.
Current settings (from 30 Sep 2026)
| Setting | Value |
|---|---|
| Discharge window | 21:00 to 23:00 (config v17, microgrid-gateway PR #77) |
| Start threshold | 75% battery at window start, otherwise skip the night |
| Floor | 45%, stop discharging when reached |
| Recharge | from the grid at the off-peak rate from 00:00 (unchanged) |
How the thresholds are enforced. Until now, the 75% start rule and the 45% floor were enforced by hand, by deploying a "disarm" config and later a "re-arm" config. That meant a change and a deploy after every outage day. It stops now:
- The edge software will enforce both rules itself: skip the night if the battery is low at 21:00, stop at 45%, and resume the next night automatically. The work is tracked in microgrid-gateway issue #78.
- Until that is live, the window stays armed every night and nobody switches it off by hand. The inverter's own protections still apply (it switches the load to the grid at 10% when the grid is present, and cuts the load at 48.8 V).
Why 21:00 to 23:00
Site load inside each candidate window, over 75 to 77 nights (1 Jul to 28 Sep 2026). Battery use is corrected for the two real nights, which used about 20% less charge than the load alone predicts.
| Window | Average load | Heavy night (1 in 10) | Ends at, from a typical 86% start | Heavy nights ending below 45% | Ends at, from a 75% start |
|---|---|---|---|---|---|
| 21:30 to 23:30 (previous) | 3.5 kWh | 4.5 kWh | 59% | 0% | 48% |
| 21:00 to 23:00 (chosen) | 3.8 kWh | 4.8 kWh | 57% | 4% | 46% |
| 21:00 to 23:30 | 4.4 kWh | 5.3 kWh | 53% | 9% | 42% |
| 22:00 to 23:59 | 2.9 kWh | 4.0 kWh | about 64% | 0% | about 53% |
21:00 to 23:00 shifts slightly more energy than the previous window and stays clear of the floor on normal nights. 21:00 to 23:30 adds little energy, and from a 75% start it would end below the floor on most nights.
Typical start level. On normal evenings the battery is at about 86% at 21:00. It is lower only after a daytime outage (27 and 29 Sep started at 65% and 61%).
Outage timing. Of 14 outages seen from 25 Aug to 30 Sep (grid absent at least 30 minutes), 2 started between 21:00 and 06:00. The battery is refilled by about 01:30 after each night's discharge.
Value
Each kWh shifted from the peak rate (666.5 UGX) to the off-peak rate (429.7 UGX, at 90% round trip) saves about 189 UGX. Across the options above, arbitrage is worth roughly 15,000 to 20,000 UGX a month. The larger saving is solar (see "Solar Sizing Re-run, Sept 2026").
History
| Date | Config | Change |
|---|---|---|
| 26 Sep | v12 | First armed night, 22:00 to 23:59 |
| 27 Sep | v13 | Off after the overload outage (battery 65%) |
| 28 Sep | v14 | Window 21:30 to 23:30 |
| 29 Sep | v15 | Off after the morning outage (battery 61%) |
| 30 Sep | v16 | Re-armed 21:30 to 23:30 |
| 30 Sep | v17 | Window 21:00 to 23:00, start 75%, no more manual switch-offs |
NFE Daily Brief (gw-pi2, Sezibwa)
NFE daily brief
Written each morning by Claude Haiku from the day's data. Newest first, last 30 days.
2026-10-13
Daily brief, Sezibwa Rentals battery, 13 October 2026
The evening arbitrage window ran from 89% to 15% battery charge, discharging 7.5 kWh. The battery held the 15% floor.
There was no grid outage today (0 minutes).
Evening voltage on phase L3 was below 207 V for 189 minutes. The lowest L3 reading was 197.6 V. This matches the known evening pattern.
Modbus read errors totalled 230. That is within the normal range, which allows about 100 per day plus the nightly burst from midnight to 2 AM while the battery charges.
Needs attention: nothing.