# EasySolar-II GX 5kVA — persistent rubber/sulphur smell under combined AC load + MPPT, no overheating **URL:** \ **Category:** Q&A and troubleshooting\ **Tags:** easysolar\_all-in-one, beginner, vrm\ **Created:** [24 March 2026 17:41 UTC](https://community.victronenergy.com/t/easysolar-ii-gx-5kva-persistent-rubber-sulphur-smell-under-combined-ac-load-mppt-no-overheating/55431 "2026-03-24T17:41:32Z")\ **Posts on this page:** 1\ **Page:** 1
**Author:** ![AlexH](https://avatars.discourse-cdn.com/v4/letter/a/6f9a4e/32.png) [@AlexH](https://community.victronenergy.com/u/AlexH)\ **Post date:** [24 March 2026 17:41 UTC](https://community.victronenergy.com/t/easysolar-ii-gx-5kva-persistent-rubber-sulphur-smell-under-combined-ac-load-mppt-no-overheating/55431/1 "2026-03-24T17:41:32Z")
Hi, I have an EasySolar-II GX 5kVA (serial: HQ2523KW2Z7, firmware V558) installed 3-4 months ago with a Pylontech U5000 LFP battery, communicating via CAN/DVCC. Since installation, the unit emits a strong rubber/sulphur smell (similar to vulcanized rubber or ebonite) consistently when AC load exceeds 2-3kW while MPPT is simultaneously active and charging. The smell comes from the rear of the unit with no hot air discharge. What has been done so far: Installer checked all connections and wiring — no issues found Unit was sent to the distributor (Darcom Energy, Romania) for service Firmware updated to V558 Unit tested at 4000W AC + 2000W MPPT for 1-2 hours — smell not reproduced Unit returned with a diagnostic fee, defect unresolved Key detail: Testing was done without the actual Pylontech U5000 and without real installation cabling. The smell is 100% reproducible on-site under real conditions. My hypothesis: internal transformer/inductor impregnation varnish emitting under combined high electromagnetic load. No thermal alarm, no error codes in VRM. Has anyone experienced similar? Could this be a known batch issue with transformer varnish? Any advice on how to escalate beyond the distributor loop would be appreciated. Thank you.