Batteries for photovoltaics by brands

Communication protocol and the approved combination list

A hybrid inverter does not simply push current into a battery. It reads state of charge, cell temperatures, permitted charge and discharge current and fault flags from the BMS, and it does that over a documented protocol. There is no universal mode, and a physically compatible connector proves nothing about whether the two devices will speak.

• CAN bus: the usual choice for high voltage stacks and most modern hybrids. Fast, robust, and the protocol is defined per manufacturer pairing rather than by an open standard.
• RS485: still common on 48 V systems and on Victron Energy style installations, often alongside a documented Modbus register map.
• Approved combination list: both the inverter maker and the battery maker publish one. A pairing counts only if it appears on the list you can actually obtain, in the revision you are buying.
• Firmware pairing: the list names firmware versions. Commission with the inverter and the BMS updated together, and record both versions in the handover documentation.

Module size and stacking granularity

Brands differ in the smallest block of capacity you can add. That granularity decides how closely you can match a real household load profile and how expensive the first expansion will be.

• Small modules of roughly 2 to 3 kWh let you tune capacity finely and are easier to carry up a staircase, but you need more of them and more interconnects.
• Large modules of 5 kWh and above cut the parts count and the commissioning time, at the cost of a coarser step and a heavier lift.
• Maximum stack height is fixed per family. Check the highest number of modules the BMS will address before you promise a future expansion.
• Floor loading and footprint matter in a plant room. A tall tower and a wall-mounted pack of the same capacity need very different space.

Warranty in years, cycles or throughput

Battery warranties are written on three different bases and the headline number tells you very little on its own. Read which of the three limits expires first for the duty cycle you expect.

• Years: a calendar limit, typically ten. Simple, but it says nothing about how hard the pack may be worked.
• Cycles: a count of full charge and discharge cycles at a stated DoD. Compare only at the same depth of discharge, because a cycle at 90 % DoD is not a cycle at 50 %.
• Throughput: total energy in MWh that may pass through the pack. The fairest basis for heavy self-consumption or arbitrage duty, and the one that bites first on a battery cycled twice a day.
• End-of-warranty capacity: the guaranteed remaining usable capacity, often around 70 to 80 %. A long term with a low retained figure is not generous.
• Conditions: ambient temperature range, minimum annual charging, mandatory monitoring connection and approved inverter pairing are all conditions that can void a claim.

Spare modules, and the risk of an orphaned system

Storage is a ten to fifteen year commitment made in a market that redesigns product families every two or three years. The question that matters in year seven is not whether the brand still exists, but whether that exact module is still built, still approved by your inverter's firmware and still stocked in the EU.

• Family longevity: prefer a platform that has already been in production for several years and is still being extended, over a brand new family with one revision behind it.
• EU service route: check that there is a European entity handling RMA, not only a factory contact. Shipping a failed module outside the EU is rarely economic.
• Backwards compatibility: some manufacturers allow a newer module revision into an older stack after a firmware update, others do not. Ask before you rely on it.
• Orphaned system: a stack whose family is discontinued and whose BMS no longer receives updates still works, but it cannot be expanded and a single failed module can end its useful life.

Own-brand ecosystem or open pairing

Manufacturers such as Huawei, SolarEdge, Goodwe, Solinteg and Solis sell inverters and matched storage as one system. That removes the compatibility question and gives you a single warranty counterparty, at the price of being tied to that ecosystem for the life of the installation. Independent battery makers such as Pylontech, Dyness, BYD, Soluna and Vision Battery are approved across many inverters, which gives more freedom on price, stock and future replacement, but leaves the version checking and the two-supplier warranty conversation with you.

Brand comparison checklist

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