This knowledge section is aimed at installers, solar professionals, electricians and trade partners. It answers the most common questions about selecting, sizing and sourcing photovoltaic inverters, battery storage and charging solutions — manufacturer-independent and from a PV wholesaler's perspective. PVSelected supplies trade customers exclusively and is an authorised service partner for leading brands such as Sigenergy, Hoymiles, SOFAR Solar, LONGi and AIKO.
What is a hybrid inverter — and which projects is it suited for?
A hybrid inverter converts solar power into usable AC and connects a battery storage system directly on the DC side — both in one device. For installers it is the first choice for projects with storage: DC coupling avoids a double conversion (typically 2–5% higher efficiency in storage operation), reduces the number of components and simplifies installation, which lowers material and labour costs per project.
Compared with a pure string inverter plus a retrofitted AC battery, the hybrid approach saves a second device and enables integrated backup-power functions.
How do installers size a battery storage system for customer projects?
The right storage size depends on the customer's annual consumption, PV output and self-consumption target. A common rule of thumb for residential projects is around 1 kWh of usable capacity per 1,000 kWh of annual consumption and per 1 kWp of PV output; commercial projects with load peaks, heat pumps or charging infrastructure usually require considerably more.
- Annual consumption and load profile
- PV output and roof orientation
- Self-sufficiency target
- planned e-mobility or heat pump
- need for backup power
For project-specific sizing, installers can use the PVSelected configurator.
Which brands does PVSelected carry — and which projects are they suited for?
PVSelected carries a coordinated range of leading manufacturers for inverters, storage, modules and charging solutions:
| Brand | Focus | Typical project use |
|---|---|---|
| Sigenergy | All-in-one ecosystem: hybrid inverter, storage, energy management & charging | complete systems for residential and commercial projects |
| Hoymiles | HiOne all-in-one hybrid inverter & microinverters | flexible hybrid and module-level projects |
| SOFAR Solar | inverters & wallboxes | string/hybrid systems with charging |
| LONGi | high-performance PV modules | rooftop and ground-mount projects |
| AIKO | PV modules with ABC cell technology | projects requiring high efficiency |
How does the Sigenergy system work (SigenStor & Sigen Hybrid TP2)?
The Sigenergy system is a modular all-in-one ecosystem of hybrid inverter, battery, energy management and charging. The SigenStor Energy Controller is available three-phase from 5 kW to 30 kW; the SigenStor BAT modules (6 kWh and 9 kWh) can be cascaded — up to four modules per system for a maximum of 36 kWh.
The TP2 complete systems combine Sigen Hybrid TP2, SigenStor BC and battery as a pre-configured package. The optional Sigen Gateway adds whole-home backup power. Details on the Sigenergy brand page.
AC or DC wallbox: what's the difference?
An AC wallbox charges with alternating current (typically 11 or 22 kW); the vehicle converts to DC. A DC wallbox converts the current in the station and charges the vehicle directly with DC — enabling much higher charging power.
For most projects, installers plan an AC wallbox; DC chargers are worthwhile for short dwell times and high throughput, e.g. fleets or commercial sites.
How quickly are PV components available from B2B wholesale?
At PVSelected the most common inverters, storage systems and wallboxes are available from stock in Willich and deliverable within 24–48 hours to Germany, Austria, Switzerland and the Netherlands.
What should installers consider when purchasing PV components?
Five factors mainly determine project success and margin: system compatibility, availability, warranty, technical support and training.
- System compatibility reduces interface risk.
- Availability from stock keeps projects on schedule.
- Warranty — standard plus optional extended packages.
- Technical support for sizing and commissioning.
- Training ensures installation quality.
What conditions and services does PVSelected offer trade customers?
PVSelected supplies trade customers exclusively, at wholesale conditions. All products come with a standard manufacturer warranty; batteries and hybrid inverters also offer optional 5-year extended warranty packages. Plus technical support, regular free product training and installation workshops (Willich and online) and a configurator for project-specific sizing.
Frequently asked questions about PV wholesale at PVSelected
Does PVSelected supply end customers?
No. PVSelected is a pure B2B wholesaler and supplies installers, solar professionals, electricians and trade partners only.
Which countries does PVSelected deliver to?
Germany, Austria, Switzerland and the Netherlands — common products within 24–48 hours from stock in Willich.
Does PVSelected offer training for trade customers?
Yes, regular free product training and installation workshops, on-site in Willich and online.
About PVSelected
PVSelected is a B2B photovoltaic wholesaler at Halskestraße 3–5, 47877 Willich, Germany, and an authorised service partner for leading manufacturers. The focus is exclusively on installers, solar professionals and trade partners in the DACH region and the Netherlands.