EasySolar II 24/3000/70 GX - MPPT ERROR 38

Been troubleshooting something on my garden office setup that I suspect others here might have encountered, so thought I'd post and see if anyone's had similar.

My EasySolar II 24/3000/70 GX threw an MPPT Error 38 yesterday afternoon — PV input has been disabled ever since. From what I can gather, Error 38 relates to an input shutdown triggered by the BMS, but I'm not entirely sure whether the fault actually originated with the BMS or whether the MPPT itself decided to protect the batteries and flagged it that way.

A few questions I'm trying to work through:

• Has anyone seen this error triggered by a comms dropout between the GX device and the BMS, rather than an actual battery fault?
• Is there a safe way to reset this without risking the battery bank, or does the root cause have to be identified first?
• Could high ambient temperatures in a sealed garden office be a contributing factor? It's been warm this week.

My battery bank is Fogstar Drift LiFePO4 cells with a Daly BMS — not a fully Victron-integrated setup, which I suspect might be relevant here. I can see the batteries are sitting at a perfectly healthy state of charge in the VRM portal, so it doesn't appear to be an undervoltage situation.

I've already checked the wiring connections at the PV terminals and nothing looks amiss. About to dig into the VRM history logs to see if there's a BMS alarm event that correlates with the timing.

Has anyone else worked through this on a similar EasySolar II install? Particularly interested if you're running a non-Victron BMS.

@SmartSolarMaster Error 38 is input shutdown due to over-voltage on the battery side — the MPPT is seeing the battery voltage exceeding its absorption setpoint threshold and killing input as a protective measure.

Few things worth checking in your situation:

• BMS communication — if you're running lithium (Fogstar Drift or similar), confirm the DVCC settings in VenusOS are actually receiving valid SOC/voltage data from the BMS. A comms dropout can cause the charger to lose its voltage ceiling reference
• Battery cable resistance — loose terminals create voltage drop discrepancies between measured and actual
• Absorption voltage setpoint — in VictronConnect, double-check it isn't set above your battery manufacturer's spec

The EasySolar II's integrated MPPT is the 150/70 variant — worth pulling the full error log via Remote Console rather than just the live alarm, as it'll show you how frequently it's triggering.

What battery chemistry are you running?

@DodgyRoamer is right on the cause, but worth adding — on the EasySolar II the MPPT and inverter/charger share the same GX brain, so if your BMS is cutting out momentarily (even a brief disconnect) the MPPT can see a sudden voltage spike with nowhere to dump current. Classic lithium BMS protection trip cascading into Error 38.

Had something similar in my shepherd's hut with a Fogstar Drift 24V and Victron SmartShunt. Turned out my BMS high-voltage cutoff was set aggressively and the absorption stage was nudging it over the edge.

Check your VE.Configure absorption voltage — on 24V lithium it wants to be around 27.2-28.4V depending on your cells. Also look at the BMS logs if you have them; the trip usually precedes the MPPT error by a second or two.

@SmartSolarMaster had this exact drama on my static caravan — turned out my Fogstar cells were drifting out of balance and the top-cell voltage was spiking well above what the pack average suggested, so the MPPT wasn't being paranoid, it was doing its job correctly while my BMS sat there doing absolutely nothing useful.

Check your cell-level voltages individually, not just the pack total — a 24V nominal pack can look "fine" at 27V overall while one group quietly tries to touch the sun.

Also double-check your DVCC absorption setpoint in VRM/Cerbo; if someone's bumped it up thinking "more voltage = faster charge" you'll chase Error 38 forever wondering why.

@SmartSolarMaster worth checking your absorption voltage setting in VictronConnect — on a 24V system people often leave it at the default and forget the EasySolar's MPPT will push hard if it thinks the bank needs a full cycle.

On my tiny house build I had something similar after a firmware update quietly reset my charge profile. The MPPT was targeting 29.2V absorption on what was actually a 25.6V LiFePO4 bank. BMS kicked in, latched off, MPPT saw voltage spike — classic Error 38 cascade.

Pull the VRM history if you've got the GX data logging enabled — the voltage graph will show you exactly when it trips and whether it's gradual creep or sudden. That'll tell you if it's a settings issue or genuinely a drifting cell like @ForestDaz mentioned.