--- title: "FoxESS ECS2900-H7 vs Deye GB-SL-EU (5 modules in series) - Battery Comparison | ComparePV" description: "Compare FoxESS ECS2900-H7 vs Deye GB-SL-EU (5 modules in series) side by side: usable energy, round-trip efficiency, power, cycle life and the full specification." source: "https://comparepv.com/compare-batteries/fox-ess-ecs2900-h7/gb-sl-eu-5-modules-in-series" updated: 2026-01-11 --- # FoxESS ECS2900-H7 vs Deye GB-SL-EU (5 modules in series) 11 differences, and they point both ways The largest is usable energy: 0.26 kWh apart. 7 of 18 comparable parameters are identical, with 15 more left out because at least one datasheet does not publish them. ## The two batteries | Attribute | A | B | | --- | --- | --- | | Battery | [FoxESS ECS2900-H7](https://comparepv.com/battery/fox-ess-ecs2900-h7) | [Deye GB-SL-EU (5 modules in series)](https://comparepv.com/battery/gb-sl-eu-5-modules-in-series) | | Manufacturer | FoxESS | Deye | | Usable energy | 18.14 kWh | 18.4 kWh | | Cells and voltage | LFP HV | LFP HV | [See 21 FoxESS offers](https://comparepv.com/offers?manufacturer=foxess&product_type=battery) [See 44 Deye offers](https://comparepv.com/offers?manufacturer=deye&product_type=battery) ## Where they differ Ranked by how much the difference matters, not by datasheet order. | Parameter | ECS2900-H7 | GB-SL-EU (5 modules in series) | Difference | | --- | --- | --- | --- | | Usable energy | 18.14 kWh | 18.40 kWh | 0.26 kWh apart | | Max system capacity | 20.2 kWh | 24.5 kWh | +4.4 kWh for GB-SL-EU (5 modules in series) | | Nominal energy | 20.16 kWh | 20.45 kWh | 0.29 kWh apart | | Nominal voltage | 403 V | 512 V | 109 V apart | | Weight | 228.3 kg | 254.0 kg | -25.7 kg for ECS2900-H7 | | Weight per kWh | 12.6 kg/kWh | 13.8 kg/kWh | -1.2 kg/kWh for ECS2900-H7 | | Max operating temperature | 55 °C | 60 °C | +5 °C for GB-SL-EU (5 modules in series) | | Inverter | None (battery only) | Built in (all-in-one) | None (battery only) vs Built in (all-in-one) | | Modules per stack | 2-7 | 2-6 | 2-7 vs 2-6 | | Operating voltage | 340.2-459.9 V | 179.2-691.2 V | 340.2-459.9 V vs 179.2-691.2 V | | Dimensions | 950x570x380 mm | 1760x540x385 mm | 950x570x380 mm vs 1760x540x385 mm | ## Every compared parameter | Parameter | ECS2900-H7 | GB-SL-EU (5 modules in series) | | --- | --- | --- | | Usable energy | 18.14 kWh | 18.40 kWh | | Nominal energy | 20.16 kWh | 20.45 kWh | | Depth of discharge | 90 % | 90 % | | Max system capacity | 20.2 kWh | 24.5 kWh | | Modules per stack | 2-7 | 2-6 | | Continuous discharge power | - | - | | Continuous charge power | - | - | | Peak discharge power | - | - | | Power per kWh | - | - | | Round-trip efficiency | 95.0 % | - | | Cycle life | 6000 cycles | 6000 cycles | | Cycle test depth | 90 % | 90 % | | Capacity at end of life | - | 70 % | | Self-discharge | - | - | | Voltage class | High voltage | High voltage | | Nominal voltage | 403 V | 512 V | | Operating voltage | 340.2-459.9 V | 179.2-691.2 V | | Cell chemistry | LFP | LFP | | Active cell balancing | - | - | | Thermal management | - | Yes | | Inverter | None (battery only) | Built in (all-in-one) | | Inverter power | - | - | | Grid connection | - | 3-phase | | Backup power | - | - | | Weight | 228.3 kg | 254.0 kg | | Weight per kWh | 12.6 kg/kWh | 13.8 kg/kWh | | Dimensions | 950x570x380 mm | 1760x540x385 mm | | Ingress protection | IP65 | IP65 | | Outdoor-rated | Yes | - | | Min operating temperature | -20 °C | -20 °C | | Max operating temperature | 55 °C | 60 °C | | Warranty | - | 10 yrs | | Warranted throughput | - | - | ## Related comparisons - [FoxESS ECS2900-H7 vs Dyness Tower Pro TP19](https://comparepv.com/compare-batteries/fox-ess-ecs2900-h7/dyness-tower-pro-tp19) - 13 differences, the largest is cycle life - [FoxESS ECS2900-H7 vs Deye GB-L20](https://comparepv.com/compare-batteries/fox-ess-ecs2900-h7/gb-l20) - 10 differences, the largest is usable energy - [FoxESS ECS2900-H7 vs Solplanet Ai-HB 200A](https://comparepv.com/compare-batteries/fox-ess-ecs2900-h7/solplanet-ai-hb-200a) - 10 differences, the largest is usable energy - [Deye GB-SL-EU (5 modules in series) vs Deye BOS-G20](https://comparepv.com/compare-batteries/gb-sl-eu-5-modules-in-series/bos-g20) - 10 differences, the largest is max system capacity --- Source: https://comparepv.com/compare-batteries/fox-ess-ecs2900-h7/gb-sl-eu-5-modules-in-series Not in this file, on the page: a written summary generated on request.