Choosing a solar battery feels like it should be about brand and price. In practice the first real decision is technical: is it a low-voltage or a high-voltage battery? That single choice shapes how much power your home can draw at once, where the battery can live, and how big the system can grow. This guide explains the difference in plain terms — written for you, the homeowner, not the installer (we handle the installation) — then shows how the four battery families we fit, APX, AURA, AXE and HOPE, compare, so you can see which one suits your home.
Low-voltage vs high-voltage solar batteries: what it actually means
Every lithium home battery stores energy in cells. The difference is how many cells are stacked in series, which sets the battery’s voltage. A low-voltage (LV) battery runs at around 48–51.2 V. A high-voltage (HV) battery stacks more cells to reach roughly 100–500 V. Both can store the same kilowatt-hours — what changes is how that energy moves through your system.
How much power your home can pull at once
Power equals voltage times current, and current is what creates heat and losses. For the same power a high-voltage battery draws far less current — a 5 kW load needs over 100 A at 48 V but only about 12 A at 400 V. That has a real consequence: a 48 V battery is current-limited — a single string tops out around 5 kW — so when several big appliances run together it can throttle. A high-voltage battery delivers more power to your home at the same moment, which matters if you run an oven, heat pump, EV charger and induction hob together. High voltage also wastes less energy as heat and moves it more efficiently through the system.
Where the battery can live in your home
This is the difference homeowners feel most. High-voltage APX is IP66 weatherproof, so it can be mounted almost anywhere — a garage, a utility room, even an exterior wall — which usually means a tidier, more convenient spot. Low-voltage batteries (AXE, HOPE) are IP20 and more sensitive to their surroundings: they want a stable, dry, well-ventilated indoor location, away from damp and heat. We always place them correctly, but a high-voltage battery simply gives more freedom over where it goes.
How big the system can grow
High-voltage batteries scale cleanly — you add capacity in series with minimal extra wiring, which keeps a growing system efficient. Among low-voltage options our HOPE range scales the furthest, up to a 240 kWh system for serious off-grid or commercial setups. The plug-and-play AURA is the exception: it’s a single 5 kWh unit that doesn’t stack, by design — it trades expandability for simplicity.
What each battery pairs with
A battery has to speak the same language as the rest of your system. You don’t have to work this out yourself — we match it for you — but it’s useful to know what goes with what:
- APX (high-voltage) pairs with Growatt MIN, MOD and MID hybrid inverters — the backbone of most grid-tied and hybrid homes.
- AXE and HOPE (low-voltage) pair with Growatt SPF / SPE inverters — built for off-grid and hybrid systems.
- AURA is the flexible one: it works alongside virtually any inverter, and it can even run on its own with no inverter at all — charging from a wall socket and feeding stored energy back through it. It’s the simplest way to add storage to almost any home.
How to choose your solar battery in 5 steps
Step 1 — On-grid/hybrid or off-grid?
If you stay connected to the grid and mainly want to store daytime solar for the evening (self-consumption), you’re in hybrid/on-grid territory — high-voltage APX is the natural fit. If you want full backup independence or live off-grid, the low-voltage HOPE and AXE families are built for that. And if you just want to add storage to an existing home with minimal fuss, AURA works almost anywhere.
Step 2 — Size the capacity to your real consumption
Size the battery to the energy you use after the sun goes down, not your total daily use. A typical Spanish home stores 5–10 kWh; larger homes or those aiming for near-total independence go 15 kWh and up. APX, AXE and HOPE are modular and expandable; AURA is a fixed 5 kWh unit ideal for smaller needs.
Step 3 — The right voltage class for your system
High voltage (APX) for grid-tied and hybrid homes that want maximum power and efficiency; low voltage (AXE, HOPE) for off-grid and backup; AURA when you want a battery that fits any setup or none. We pair the battery to your inverter as part of the design — this step is really about which family matches your goals.
Step 4 — Compare what actually ages: depth of discharge, cycles, warranty
Two batteries with the same kWh are not equal. Depth of discharge (DoD) is how much you can safely use each cycle; cycle life is how many charge/discharge rounds before noticeable degradation. A battery with 98% DoD and more than 6000 cycles delivers far more usable energy over its life than one with 90% DoD and a shorter rating — often the better value even at a higher price.
Step 5 — Pick the model
With grid type, capacity, voltage class and longevity in hand, the model picks itself from the four families below — and we confirm the exact match for your inverter as part of the system design.
The Enera battery range, compared
APX — high-voltage, the all-rounder for grid-tied homes
Our recommended choice for most grid-connected and hybrid homes. High-voltage LiFePO4 storage (around 450 V) from 5 to 30 kWh, cobalt-free, 90% depth of discharge, and a 10-year warranty. Because it’s high-voltage it delivers more power to your home at once and runs more efficiently; because it’s IP66 weatherproof it can go almost anywhere, indoors or out. It pairs with Growatt MIN, MOD and MID hybrid inverters and scales cleanly as your needs grow.
AURA — universal, the simplest way to add storage
A 5 kWh plug-and-play LiFePO4 battery with a 10-year warranty and unmatched flexibility: it works with virtually any inverter, and it can even run with no inverter at all — charging from a socket and feeding energy back through it. That makes it the easiest way to add storage to an existing home or to start small. It’s a single unit and doesn’t stack, so it’s ideal for moderate needs rather than large off-grid systems.
AXE — low-voltage modular, for off-grid and hybrid
Low-voltage 51.2 V LiFePO4 storage, stackable from 5 to 30 kWh in 5 kWh modules, 92% depth of discharge, with a 5-year warranty (extendable to 10). It pairs with Growatt SPF/SPE inverters — a flexible backbone for off-grid and hybrid systems. Being low-voltage (IP20), it’s best given a stable, dry indoor home.
HOPE — low-voltage, built for deep cycling and large systems
Low-voltage 51.2 V LiFePO4 with the best longevity in our range — 98% depth of discharge and more than 6000 cycles — and the highest ceiling, scaling up to a 240 kWh system. If you cycle hard every day or need serious off-grid capacity, HOPE delivers the most usable energy over its life. Like AXE it’s low-voltage (IP20) and belongs in a stable, dry indoor location.
At a glance
- APX: HV (~450 V) · 5–30 kWh · 90% DoD · 10-yr · IP66 (flexible placement) · with MIN/MOD/MID · grid-tied & hybrid
- AURA: Universal plug-and-play · 5 kWh · 10-yr · any inverter or none (socket charge/discharge) · single unit, no stacking
- AXE: LV (51.2 V) · 5–30 kWh · 92% DoD · 5-yr (10 opt.) · IP20 indoor · with SPF/SPE · off-grid & hybrid
- HOPE: LV (51.2 V) · up to 240 kWh · 98% DoD · >6000 cycles · 5-yr · IP20 indoor · deep cycling, large off-grid
Which battery for which home
- Most grid-tied homes maximising self-consumption: APX — high power, efficient, flexible placement, scales with MIN/MOD/MID inverters.
- Add storage simply, or to an existing system: AURA — works with any inverter or none, the easiest battery to live with.
- Off-grid or full backup independence: HOPE for the deepest daily cycling and the largest systems (to 240 kWh), or AXE as a cost-effective LV backbone.
- Planning to grow later: APX scales most efficiently; HOPE scales highest. AURA stays a single 5 kWh unit.
Cost vs value over 10 years
Low-voltage batteries usually have the lower entry price, which makes them attractive for a first, smaller system. But the cheapest battery per kWh today is rarely the cheapest per usable kWh over its lifetime. Higher depth of discharge and a longer cycle rating mean more energy delivered before replacement — which is why HOPE’s 98% DoD and >6000 cycles, or APX’s power, efficiency and 10-year warranty, often win on total cost of ownership. Decide on lifetime value, not sticker price.
See it on your own roof: Auto-design and Builder
The right battery depends on how much solar your roof produces and how much you use at night. Two free Enera tools take it from there. Auto-design maps an on-grid system on your actual roof — production and self-consumption — and shows the batteries compatible with that system, so you choose the one that fits. About a minute, no signup.
Prefer to build it yourself? The Builder lets you configure a complete system component by component — on-grid or off-grid — and see compatible batteries as you go.
Try Auto-design → Open the Builder →
Frequently asked questions
Is a high-voltage or low-voltage battery better for a home?
For most grid-connected homes, high-voltage (like our APX) is the stronger all-rounder: it delivers more power to your home at once, runs more efficiently, and can be placed almost anywhere thanks to its weatherproof rating. Low-voltage batteries (AXE, HOPE) come into their own for off-grid and backup systems and for very large capacities. If you simply want to add storage with no fuss, the universal AURA fits almost any home.
Can a battery deliver enough power for my whole house at once?
This is where voltage matters. A 48 V low-voltage battery is current-limited — a single string tops out around 5 kW — so running several big loads together can throttle it. A high-voltage battery like APX delivers more power at the same moment because it moves energy at much lower current. If you run an EV charger, heat pump and induction hob together, high voltage keeps up where low voltage can struggle.
Can AURA really work without an inverter?
Yes. AURA is plug-and-play: it can charge from a wall socket and feed stored energy back through it, so it can act as standalone storage with no inverter at all — or sit alongside virtually any inverter you already have. It’s a single 5 kWh unit and doesn’t stack, which keeps it simple.
What capacity (kWh) do I need?
Size it to your evening and night-time consumption, not the whole day, since panels cover daytime use directly. Most Spanish homes land between 5 and 10 kWh; aim higher for large homes or near-total independence. APX, AXE and HOPE expand later; AURA is a fixed 5 kWh.
What is depth of discharge (DoD) and why does it matter?
DoD is how much of the battery you can safely use each cycle. A 10 kWh battery at 90% DoD gives 9 kWh usable; at 98% DoD it gives 9.8 kWh. Higher DoD means more usable energy from the same nominal size — HOPE leads our range at 98%.
How long do these batteries last?
All are LiFePO4, the most durable mainstream lithium chemistry. Cycle ratings range from several thousand to over 6000 cycles (HOPE), which is well over a decade of daily use. Warranties run from 5 years (AXE, HOPE) to 10 years (APX, AURA).
Are lithium (LiFePO4) solar batteries safe?
Yes. LiFePO4 is cobalt-free and the most thermally stable mainstream lithium chemistry, far less prone to overheating than the NMC cells used in laptops and phones. It’s the standard for home energy storage precisely because of that safety margin.
Where in my home does the battery go?
It depends on the type. High-voltage APX is weatherproof (IP66), so it can be installed almost anywhere — including a garage or an exterior wall. Low-voltage batteries (AXE, HOPE) prefer a stable, dry, ventilated indoor spot away from damp and heat. We assess your home and place the battery in the best location as part of the installation.