Panasonic EverVolt AC Series EVAC-105 vs SimpliPhi AccESS
The Panasonic EverVolt AC Series EVAC-105 wins this battery comparison by a clear margin. It delivers 17.1 kWh of usable storage with 9 kW continuous output and a 6,000-cycle rating, backed by a longer 15-year warranty. The 1.9 kWh capacity advantage provides 3 additional hours of essential-load backup.
Key Differences
- • Panasonic EverVolt AC Series EVAC-105 provides 17.1 kWh vs 15.2 kWh usable capacity.
- • SimpliPhi AccESS achieves 96% round-trip efficiency vs 92%.
- • Panasonic EverVolt AC Series EVAC-105 offers a longer 15-year warranty vs 10 years.
- • SimpliPhi AccESS is rated for 10,000 cycles vs 6,000.
Specifications Breakdown
Usable Storage Capacity
The Panasonic EverVolt AC Series EVAC-105 provides 17.1 kWh of usable capacity (17.1 kWh total, 100% DoD), while the SimpliPhi AccESS offers 15.2 kWh usable (15.2 kWh total, 100% DoD). At an average essential-load consumption rate of 750 watts, the Panasonic EverVolt AC Series EVAC-105 provides approximately 22.8 hours of backup versus 20.3 hours for the SimpliPhi AccESS. The Panasonic EverVolt AC Series EVAC-105's 1.9 kWh capacity advantage translates to roughly 3 additional hours of essential-load backup during a grid outage. The Panasonic EverVolt AC Series EVAC-105 is scalable up to 4 units (68 kWh total), while the SimpliPhi AccESS scales up to 4 units (61 kWh total).
Power Output
The Panasonic EverVolt AC Series EVAC-105 delivers 9 kW continuous and 11 kW peak power, while the SimpliPhi AccESS provides 6.72 kW continuous and 8 kW peak. The Panasonic EverVolt AC Series EVAC-105's higher continuous output means it can simultaneously power more demanding appliances during an outage. A central air conditioner typically draws 3-5 kW, a refrigerator 0.1-0.2 kW, and an EV Level 2 charger 7-11 kW. Peak power rating matters for motor-driven loads with high startup current, such as air conditioners, well pumps, and sump pumps. The Panasonic EverVolt AC Series EVAC-105's 11 kW peak is capable of starting most residential HVAC systems.
Battery Chemistry & Cycle Life
The Panasonic EverVolt AC Series EVAC-105 uses LFP chemistry with a rated cycle life of 6,000 cycles (approximately 16.4 years of daily cycling), while the SimpliPhi AccESS uses LFP with 10,000 cycles (approximately 27.4 years). Both use LFP chemistry, which is considered the gold standard for residential energy storage due to its inherent safety, long cycle life, and environmental friendliness. The SimpliPhi AccESS's additional 4,000 cycles translates to approximately 11.0 more years of daily use before reaching the rated end of life.
Round-Trip Efficiency
The Panasonic EverVolt AC Series EVAC-105 achieves 92% round-trip efficiency versus 96% for the SimpliPhi AccESS. This means for every 10 kWh of solar energy stored in the SimpliPhi AccESS, 9.6 kWh is recoverable, compared to 9.2 kWh for the other. Over 10 years of daily cycling with 15 kWh average daily throughput, the more efficient battery saves approximately $329 in energy that would otherwise be lost as heat (at $0.15/kWh average retail rate). Higher round-trip efficiency is especially valuable in time-of-use rate environments where you are storing cheap off-peak energy for expensive peak-hour consumption.
Warranty & Long-Term Protection
The Panasonic EverVolt AC Series EVAC-105 carries a 15-year warranty, while the SimpliPhi AccESS offers 10 years. The Panasonic EverVolt AC Series EVAC-105 provides 5 additional years of manufacturer protection against capacity degradation and defects. Battery warranties typically guarantee the unit will retain 60-70% of original capacity by end of warranty, so the length of coverage directly impacts your financial risk over the system's lifetime.
Specification Comparison
| Specification | Panasonic EverVolt AC Series EVAC-105 | SimpliPhi AccESS |
|---|---|---|
| Capacity | 17.1 kWh | 15.2 kWh |
| Usable Capacity | 17.1 kWh | 15.2 kWh |
| Power Output | 9 kW | 6.72 kW |
| Chemistry | LFP (Lithium Iron Phosphate) | LFP (Lithium Iron Phosphate) |
| Efficiency | 92% | 96% |
| Cycle Life | 6,000 | 10,000 |
| Weight | 150 kg | 227 kg |
| Warranty | 15 years | 10 years |
| Scalable | Yes | Yes |
5-Dimension Head-to-Head Analysis
1. Storage Capacity
Winner: Panasonic EverVolt AC Series EVAC-105The Panasonic EverVolt AC Series EVAC-105 provides 17.1 kWh versus 15.2 kWh — 1.9 kWh more usable storage. At typical essential-load consumption of 0.75 kW, this equals approximately 3 additional hours of backup power. The capacity difference is moderate.
2. Power Output
Winner: Panasonic EverVolt AC Series EVAC-105The Panasonic EverVolt AC Series EVAC-105 delivers 9 kW continuous versus 6.72 kW. This is enough to run a central AC unit, refrigerator, and general household loads simultaneously. The power difference is modest for most backup scenarios.
3. Chemistry & Longevity
Winner: SimpliPhi AccESSBoth use LFP chemistry with Panasonic EverVolt AC Series EVAC-105 at 6,000 cycles vs SimpliPhi AccESS at 10,000 cycles. LFP chemistry provides excellent thermal stability, long cycle life, and no cobalt dependency.
4. Round-Trip Efficiency
Winner: SimpliPhi AccESSThe SimpliPhi AccESS achieves 96% round-trip efficiency versus 92%. Over 10 years of daily cycling with 15 kWh throughput per day, the more efficient battery saves approximately 329 dollars in energy that would otherwise be lost as heat (at $0.15/kWh). The difference is moderate but compounds over the battery's lifespan.
5. Warranty Coverage
Winner: Panasonic EverVolt AC Series EVAC-105The Panasonic EverVolt AC Series EVAC-105 offers a 15-year warranty versus 10 years. This is among the longest battery warranties in the residential market.
Panasonic EverVolt AC Series EVAC-105
The Panasonic EverVolt AC Series EVAC-105 is the AC-coupled variant of the EverVolt 2.0 platform, delivering 17.1 kWh of LFP storage with 9 kW of continuous backup power. As an AC-coupled system, it retrofits seamlessly with any existing solar installation regardless of inverter brand. The 15-year warranty reflects Panasonic's confidence in the LFP cell chemistry and advanced thermal management system. Four units can be combined for 68.4 kWh of total storage, making it one of the highest-capacity residential AC-coupled configurations available on the market.
Pros
- + 17.1 kWh is among the largest single-unit residential battery capacities
- + 9 kW continuous output supports heavy loads during backup
- + 15-year warranty with LFP chemistry for exceptional longevity
- + AC-coupled design retrofits with any existing solar inverter
Cons
- - Heavy at 150 kg, requiring robust mounting or floor placement
- - AC-coupled conversion adds slight efficiency loss compared to DC-coupled
- - Premium pricing reflects Panasonic brand and larger capacity
SimpliPhi AccESS
The SimpliPhi AccESS is an all-in-one energy storage system that integrates SimpliPhi's cobalt-free LFP batteries (4x PHI 3.8 modules = 15.2 kWh) with a Sol-Ark inverter and automatic transfer switch in a single pre-wired enclosure. This turnkey design dramatically simplifies installation and is rated for both indoor and outdoor use.
Pros
- + All-in-one pre-wired system reduces installation time by 50%+
- + 15.2 kWh capacity with integrated Sol-Ark inverter
- + Cobalt-free LFP with industry-leading 10,000 cycle life
- + NEMA 3R rated for outdoor installation without additional enclosure
Cons
- - Heavy at 227kg — requires concrete pad or reinforced mounting
- - Premium pricing for the integrated convenience
- - Limited expandability beyond 4-unit parallel configuration
Choose Panasonic EverVolt AC Series EVAC-105 If...
- ✓ You need more backup storage to cover overnight consumption or extended outages
- ✓ You need to power demanding appliances (AC, EV charger) simultaneously during outages
- ✓ A 15-year warranty gives you the confidence you need
- ✓ Homeowners with existing solar systems who want a high-capacity, high-power AC-coupled battery backed by Panasonic's reliability
Choose SimpliPhi AccESS If...
- ✓ Maximum battery longevity (10,000 cycles) is your top priority
- ✓ You want to minimize energy losses during daily charge/discharge cycling
- ✓ Homeowners and installers seeking the simplest possible solar+storage installation with premium US-made components
Our Recommendation
We recommend the Panasonic EverVolt AC Series EVAC-105 for most buyers in this comparison. It wins 3 of 5 key dimensions and offers a clear advantage in the metrics that matter most for a battery purchase. The SimpliPhi AccESS remains a good product, but the Panasonic EverVolt AC Series EVAC-105 delivers better overall value for the majority of installations.
Frequently Asked Questions
Which is better, Panasonic EverVolt AC Series EVAC-105 or SimpliPhi AccESS?
The Panasonic EverVolt AC Series EVAC-105 wins this battery comparison by a clear margin. It delivers 17.1 kWh of usable storage with 9 kW continuous output and a 6,000-cycle rating, backed by a longer 15-year warranty. The 1.9 kWh capacity advantage provides 3 additional hours of essential-load backup.
Which battery lasts longer?
The Panasonic EverVolt AC Series EVAC-105 is rated for 6,000 cycles versus 10,000 for the SimpliPhi AccESS. SimpliPhi AccESS lasts approximately 11 more years of daily cycling. LFP chemistry generally outlasts NMC in cycle life testing.
Which battery provides more backup power?
The Panasonic EverVolt AC Series EVAC-105 provides 9 kW continuous (11 kW peak) versus 6.72 kW continuous (8 kW peak) for the SimpliPhi AccESS. Panasonic EverVolt AC Series EVAC-105 can run more appliances simultaneously during an outage. A central AC typically needs 3-5 kW, a refrigerator 0.2 kW, and an EV charger 7-11 kW.
Can I expand Panasonic EverVolt AC Series EVAC-105 or SimpliPhi AccESS storage later?
Panasonic EverVolt AC Series EVAC-105: Yes, up to 4 units for 68 kWh total. SimpliPhi AccESS: Yes, up to 4 units for 61 kWh total. Both offer the same scalability.
Which battery chemistry is safer?
Both use LFP (Lithium Iron Phosphate) chemistry, which is the safest lithium battery chemistry for residential use. LFP does not undergo thermal runaway, uses no cobalt, and is inherently stable.
Related Resources
Last updated: February 2026