---
title: "BYD Battery-Box Premium HVS 7.7 vs FoxESS ECS2900-H3 - Battery Comparison | ComparePV"
description: "Compare BYD Battery-Box Premium HVS 7.7 vs FoxESS ECS2900-H3 side by side: shop prices, usable energy, round-trip efficiency, power, cycle life and the full specification."
source: "https://comparepv.com/compare-batteries/byd-battery-box-premium-hvs-7-7/fox-ess-ecs2900-h3"
updated: 2026-01-11
---

# BYD Battery-Box Premium HVS 7.7 vs FoxESS ECS2900-H3

ECS2900-H3 leads on the differences that matter

The largest is max system capacity: 7.4 kWh more room to expand. 4 of 19 comparable parameters are identical, with 14 more left out because at least one datasheet does not publish them.


## The two batteries


| Attribute | A | B |
| --- | --- | --- |
| Battery | [BYD Battery-Box Premium HVS 7.7](https://comparepv.com/battery/byd-battery-box-premium-hvs-7-7) | [FoxESS ECS2900-H3](https://comparepv.com/battery/fox-ess-ecs2900-h3) |
| Manufacturer | BYD | FoxESS |
| Usable energy | 7.68 kWh | 7.78 kWh |
| Cells and voltage | LFP HV | LFP HV |


## Price offers


| Shop | Country | Battery-Box Premium HVS 7.7 | ECS2900-H3 |
| --- | --- | --- | --- |
| Solaris Energy | Poland | 13 720 zł |  |
| Consor Energia | Poland | 31 000 zł |  |
| www.solar-outlet.nl | Netherlands | 3 298.95 € |  |

[See 119 BYD offers](https://comparepv.com/offers?manufacturer=byd&product_type=battery)

[See 31 FoxESS offers](https://comparepv.com/offers?manufacturer=foxess&product_type=battery)


## Where they differ

Ranked by how much the difference matters, not by datasheet order.


| Parameter | Battery-Box Premium HVS 7.7 | ECS2900-H3 | Difference |
| --- | --- | --- | --- |
| Max system capacity | 12.8 kWh | 20.2 kWh | +7.4 kWh for ECS2900-H3 |
| Usable energy | 7.68 kWh | 7.78 kWh | 0.10 kWh apart |
| Round-trip efficiency | 96.0 % | 95.0 % | +1.0 pp for Battery-Box Premium HVS 7.7 |
| Nominal energy | 7.68 kWh | 8.64 kWh | 0.96 kWh apart |
| Depth of discharge | 100 % | 90 % | +10 pp for Battery-Box Premium HVS 7.7 |
| Nominal voltage | 307 V | 173 V | 134 V apart |
| Weight | 129.0 kg | 100.3 kg | -28.7 kg for ECS2900-H3 |
| Weight per kWh | 16.8 kg/kWh | 12.9 kg/kWh | -3.9 kg/kWh for ECS2900-H3 |
| Min operating temperature | -10 °C | -20 °C | -10 °C for ECS2900-H3 |
| Cycle test depth | 100 % | 90 % | 10 pp apart |
| Max operating temperature | 50 °C | 55 °C | +5 °C for ECS2900-H3 |
| Ingress protection | IP55 | IP65 | IP55 vs IP65 |
| Modules per stack | 2-5 | 2-7 | 2-5 vs 2-7 |
| Operating voltage | 240-360 V | 145.8-197.1 V | 240-360 V vs 145.8-197.1 V |
| Dimensions | 995x585x298 mm | 470x570x380 mm | 995x585x298 mm vs 470x570x380 mm |


## Every compared parameter


| Parameter | Battery-Box Premium HVS 7.7 | ECS2900-H3 |
| --- | --- | --- |
| Usable energy | 7.68 kWh | 7.78 kWh |
| Nominal energy | 7.68 kWh | 8.64 kWh |
| Depth of discharge | 100 % | 90 % |
| Max system capacity | 12.8 kWh | 20.2 kWh |
| Modules per stack | 2-5 | 2-7 |
| Continuous discharge power | 7.68 kW | - |
| Continuous charge power | 7.68 kW | - |
| Peak discharge power | 15.36 kW | - |
| Power per kWh | 1.00 kW/kWh | - |
| Round-trip efficiency | 96.0 % | 95.0 % |
| Cycle life | - | 6000 cycles |
| Cycle test depth | 100 % | 90 % |
| Capacity at end of life | - | - |
| Self-discharge | - | - |
| Voltage class | High voltage | High voltage |
| Nominal voltage | 307 V | 173 V |
| Operating voltage | 240-360 V | 145.8-197.1 V |
| Cell chemistry | LFP | LFP |
| Active cell balancing | - | - |
| Thermal management | - | - |
| Inverter | None (battery only) | None (battery only) |
| Inverter power | - | - |
| Grid connection | - | - |
| Backup power | - | - |
| Weight | 129.0 kg | 100.3 kg |
| Weight per kWh | 16.8 kg/kWh | 12.9 kg/kWh |
| Dimensions | 995x585x298 mm | 470x570x380 mm |
| Ingress protection | IP55 | IP65 |
| Outdoor-rated | Yes | Yes |
| Min operating temperature | -10 °C | -20 °C |
| Max operating temperature | 50 °C | 55 °C |
| Warranty | 10 yrs | - |
| Warranted throughput | - | - |


## Related comparisons

- [BYD Battery-Box Premium HVS 7.7 vs Sigenergy SigenStor BAT 8.0](https://comparepv.com/compare-batteries/byd-battery-box-premium-hvs-7-7/sigenergy-sigenstor-bat-8-0) - 16 differences, the largest is continuous discharge power
- [BYD Battery-Box Premium HVS 7.7 vs FoxESS ECS4300H-H2](https://comparepv.com/compare-batteries/byd-battery-box-premium-hvs-7-7/fox-ess-ecs4300h-h2) - 15 differences, the largest is usable energy
- [BYD Battery-Box Premium HVS 7.7 vs Deye GB-L8](https://comparepv.com/compare-batteries/byd-battery-box-premium-hvs-7-7/gb-l8) - 17 differences, the largest is usable energy


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Source: https://comparepv.com/compare-batteries/byd-battery-box-premium-hvs-7-7/fox-ess-ecs2900-h3

Not in this file, on the page: a written summary generated on request.