S500 B
SolarEdge S500B power optimizer for photovoltaic modules up to a nominal 500 W, increased to 650 W on installations after 1° April 2024.
It is the high-voltage version of the S series: maximum Voc 125 Vdc, MPPT 12,5-105 V, output up to 80 V. Allows minimum strings of 6 modules on single-phase inverters. MC4 connectors, IP68, 25-year warranty.
The SolarEdge S500B power optimizer is the high input voltage variant of the S series. It accepts modules up to 500 W rated — 650 W on installations after 1 April 2024 — but the figure that truly sets it apart from its S500 sibling is the maximum absolute input voltage of 125 Vdc, compared with 60 Vdc for the base model.
What a Voc of 125 V is really for
An optimizer is sized based on the module’s open-circuit voltage at the minimum design temperature, not on the STC value at 25 °C. On a winter morning at -10 °C, a module’s Voc typically rises by 10-12% compared with the nameplate value: a 500-550 W module in 132-cell format, which declares 45-50 V at 25 °C, can approach or exceed 60 V. With the S500, that module would be outside specification; with the S500B, there is ample margin.
The 12,5-105 V MPPT window also makes it the right optimizer for high-voltage modules and non-standard formats, including bifacial modules with significant rear-side gain. In return, one thermal detail must be considered: power derating already starts above +75 °C ambient temperature, compared with +85 °C for S440 and S500. On dark metal roofs without a ventilated air gap, this is a difference to take into account.
Short strings: the lesser-known design advantage
On single-phase SolarEdge Home Wave and Home Hub inverters, the S500B allows strings with a minimum of 6 optimizers, compared with the 8 required by S440 and S500. On three-phase Short String systems the minimum is 8, and on 230/400 V three-phase systems it is 14. This is why it is chosen for small roof pitches, highly fragmented roofs, or projects where one section of the roof hosts only a few modules: with the base series, those strings would not start.
SolarEdge S500B technical specifications
| Rated DC input power | 500 W (650 W for installations after 01/04/2024) |
| Maximum absolute input voltage (Voc) | 125 Vdc |
| MPPT operating range | 12,5 – 105 Vdc |
| Maximum continuous input current | 15 A |
| Maximum Isc of connected module | 16,5 A with Home Hub inverter — 15 A with other SolarEdge inverters |
| Maximum / weighted efficiency | 99,5% / 98,6% |
| Maximum output current / voltage | 15 A / 80 Vdc |
| Standby safety voltage | 1 ± 0,1 Vdc per optimizer |
| Maximum system voltage | 1000 Vdc |
| String length (single-phase inverter) | Minimum 6 — maximum 25 optimizers |
| Connectors and cables | MC4 — input 0,1 m, output (+) 2,3 m / (−) 0,1 m |
| Dimensions | 129 × 155 × 30 mm with flat bracket (version -1GM4MRM) — 129 × 165 × 45 mm with curved bracket (version -1GM4MBM) |
| Weight | 720-790 g depending on the bracket |
| Protection rating | IP68 — relative humidity 0-100% |
| Operating temperature | -40 °C / +85 °C (derating above +75 °C) |
| Compliance | IEC 62109-1 class II, IEC 61000-6-2/6-3, CISPR 11, EN 55011, UL 94 V-0, RoHS |
| Fire safety | VDE-AR-E 2100-712:2018-12 |
| Warranty | 25 years |
The S500B is available in two mechanical versions: -1GM4MRM with flat bracket and -1GM4MBM with curved bracket. Electrically they are identical; only the attachment to the module frame changes. If you have a specific mounting constraint, let us know when placing your order.
Frequently asked questions
When is the S500B preferable to the S500?
In two cases. First: when the module Voc at the minimum design temperature approaches or exceeds 60 V, typically with 132-cell format or high-voltage modules. Second: when the layout requires short strings, because the S500B starts from 6 optimizers instead of 8 on single-phase inverters. If neither condition applies, the S500 does the same job at a lower cost.
Can I put S500B and S500 in the same string?
They are both part of the S series and therefore technically belong to the same family, but they have different operating windows and output voltages: 60 V for the S500 and 80 V for the S500B. A mixed layout must always be checked with the SolarEdge design tool before ordering. However, mixing S series and P series in the same string in new installations is explicitly prohibited.
What is the difference between the -1GM4MRM and -1GM4MBM versions?
Only the mounting bracket: flat on the RM version, curved on the BM version. The electrical characteristics are identical. The curved bracket is designed for frame profiles where the flat attachment does not sit correctly. If you are replacing a unit on an existing system, it is best to order the same version already installed, so you do not have to modify the mounting.
Is derating at +75 °C a problem in Italy?
This refers to the ambient temperature measured behind the module, not the air temperature. On a summer day in Central-Southern Italy, on a dark sheet-metal roof with the optimizer mounted flush, these values can be reached during the middle hours of the day. The result is a temporary reduction in power, not a fault. A mounting arrangement that allows air to circulate behind the module effectively solves the problem.
Is the S500B also suitable for 600 W modules?
For installations after 1 April 2024, the permitted rated input power increases to 650 W, so yes, a 600 W module is included. The two real limits still have to be met: maximum Voc 125 V at the minimum design temperature and module Isc within 16,5 A with Home Hub inverter or 15 A with the others. For installations before that date, the limit remains 500 W.