JA Solar is represented in stock by the JAM series — monocrystalline modules from 415 to 620 W at 20.6–23.0% efficiency. The number straight after JAM gives the whole-cell count: JAM54 means 108 half-cells in a 1722×1134 or 1762×1134 mm frame (415–450 W, 21.5–22 kg), JAM72 means 144 cells at 2279×1134×35 or 2285×1134×35 mm (535–565 W, 27.3–32 kg), and JAM66 means 132 cells in the longest frame, 2382×1134×30 mm (620 W, 33.1 kg).
Two items are bifacial: JAM72D30-535/MB and JAM72D30-540/MB, both with rear glass. The rest are monofacial. The highest efficiency in stock is 23.0% on the JAM66D45-620/LB, the lowest 20.6% on the JAM72D30-535/MB. Over the same roof area the first module yields roughly 12% more power. Where area is the constraint, count watts per square metre rather than watts per module.
Open-circuit voltage runs 37.45–50.28 V and current at maximum power point 12.90–15.42 A. The compact JAM54 frames, at around 37–39 V Voc, allow longer strings for the same inverter input voltage than the 144-cell modules at around 50 V. That is usually the deciding argument when choosing a format for a given MPPT.
