The panels are on the roof, the inverter is blinking green, and the app shows a number. For most villa owners, that's the moment of relief: it's done, it works. In reality, the first 90 days after install are more important than most people know. This is when workmanship issues show up, when production gaps become visible, and when the handful of setup problems that didn't surface during commissioning appear under real conditions.
This is a working checklist for that window. We walk through it ourselves when managing post-install handovers for clients' villas across Bali. Most items take 10 minutes to check. Most issues, caught early, get fixed in a single visit. The ones that get left alone for six months get harder and more expensive to sort out.
TL;DR
- The first 90 days after install are when most issues surface, not year three. Catch them now and they're minor. Ignore them and they compound.
- Days 1 to 7: verify daily production within 10% of commissioning baseline on clear days. Confirm battery cycles complete. No recurring inverter alarms.
- Days 8 to 30: check your PLN bill. Hybrid systems should show 50 to 70% monthly savings. Less than half that means something needs attention.
- First major rain = waterproofing test. Any ceiling stain or damp patch is a workmanship warranty claim. Report it immediately with photos.
- Common 90-day issues: one underperforming panel, battery not fully charging, afternoon inverter thermal de-rate, WiFi data dropout. All have straightforward fixes.
- If your installer doesn't respond within a few days in the first 90 days, that's a warning sign for the next 25 years of warranty. Escalate while the project is fresh.
Days 1 to 7: the commissioning baseline check
Right after your installer commissions the system, they should hand you a commissioning report, or at minimum show you live production on a sunny day and tell you what it should look like. Note that number. For a 6 kWp system in Bali with 5 peak sun hours, you should see around 26 to 30 kWh on a clear day, after accounting for inverter efficiency and cable losses. Screenshot it or write it down.
For the first week, check the monitoring app each morning and look at the previous day's production. Here's what you're comparing against:
Production within 10% of baseline on clear days. If your 6 kWp system is producing 24 to 27 kWh on a clear day, that's within normal range. If you're consistently seeing 16 to 18 kWh when the sun is out, something is wrong: a panel that wasn't connected properly, a shading issue that wasn't caught during the pre-install survey, or an MPPT tracker configured on the wrong settings. All of these are installer problems to fix, not yours to diagnose.
Battery completing full charge and discharge cycles. If your system includes a battery, the app should show it charging toward 90 to 100% during sunny afternoon hours and discharging back down overnight. If the battery never climbs above 60 to 70% even on clear days, the inverter charge profile may be set too conservatively (a settings change, not a hardware fault). Flag it.
No recurring alarm codes. One-time alarms in the first few days are common. The inverter is settling in, the PLN line at your villa may have edge events (frequency spike, brief overvoltage) that the inverter logs. What you don't want is the same alarm code appearing every day. Look it up in your inverter brand's manual (all the major brands, Deye, Growatt, Luxpower, Sungrow, publish these as PDFs and the monitoring apps usually link to them). If a specific alarm repeats for three consecutive days, call your installer with the code and the screenshots.
At this stage you're not trying to diagnose anything yourself. You're establishing that the system performs as promised. If it does, great. If something's off, document it before you call.
Days 8 to 30: the PLN bill check and rain test
By the end of the first month, you have real-world data: your first (or partial) PLN bill with the solar system running, and at least one significant rain event in Bali.
PLN bill drop. The clearest signal that the system is working as designed is your electricity bill. For a hybrid system (solar + battery + PLN backup), expect a 50 to 70% reduction in your monthly spend. For a grid-tied system without battery, expect 20 to 40%. If your Rp 5 million monthly bill dropped to Rp 1.8 million, that's consistent with hybrid performance. If it only dropped to Rp 4 million, something isn't producing at the expected rate, or your actual load is higher than the sizing assumed.
Compare actual savings to the estimate in your quote. If the quote said "Rp 3 to 4 million monthly savings" and you're only seeing Rp 1 million, that's a month-one conversation to have with your installer, not a month-six one.
The rain test. This one's free, courtesy of Bali's climate. After the first significant downpour, walk through every room that sits under or adjacent to a roof penetration point (where the panel mounting bolts go through the roof surface, usually visible as a row along the ridge or around brackets). Check the ceiling and upper interior walls. Any water stain, soft patch in paint, or smell of damp means the roof penetration wasn't properly sealed.
This is a workmanship warranty claim. Report it with photos and a request for the installer to come within a week. Don't wait. A slow drip in Bali's humidity will rot roof timber or corrode steel rafters within a wet season. Tile roofs are the most common source of this problem on Bali villas; proper terracotta-tile mounting uses specific flashing brackets and a waterproofing sealant layer, not just silicone. If your installer did it right, you'll have no issue. If they cut corners, you'll know by month one.
Days 31 to 90: the trend review and the sneaky thermal problem
By three months in, you have enough production data to see patterns, and the system has run through a range of real Bali weather: sunny days, cloudy spells, probably some wet-season rain.
Monthly production trend. Pull up the monthly view in your monitoring app (Growatt ShinePhone, Deye Solarman, Luxpower portal, Sungrow iSolarCloud, or whatever your inverter brand uses). Look at months one, two, and three side by side. Natural variation is normal as weather changes. What you don't want is a consistent downward drift. If month three is producing 15% less than month one on comparable weather, something has degraded: a panel junction may have loosened, a bypass diode may have failed, or new shade is appearing from vegetation that grew during wet season.
Afternoon thermal de-rate. This is the most common sneaky issue we see in Bali villa installs, and it's invisible if you don't know to look for it. Hybrid inverters work best at ambient temperatures below 40°C. If your installer mounted the inverter in a closed cabinet in a south-facing garage wall, an outdoor plastic enclosure that gets afternoon sun, or a utility room with no airflow, the inverter will reach 50 to 55°C by mid-afternoon and automatically throttle its output by 20 to 30% to protect itself. In the app, this shows as a flat or declining production plateau from around 1 PM to 4 PM on clear days, even though the sun is still strong.
The fix is relocation: the inverter needs to move to a shaded, ventilated location. It's a two to three hour job for the install team and it isn't expensive if you catch it at 90 days. Left unaddressed, sustained high ambient temperature also shortens the inverter's lifespan, which means a Rp 25 to 40 million replacement at year seven instead of year twelve.
WiFi and monitoring gaps. If your app shows blocks of missing data (hours or full days where nothing is logged), the inverter's WiFi dongle has lost connection. This doesn't affect system performance, but it means you lose alarm notifications if something breaks. For Bali villas with intermittent internet, the simplest fix is a dedicated 4G nano-SIM dongle for the inverter: around Rp 200 to 400k one-time hardware cost, plus Rp 50 to 100k per month for a basic data plan. Worth it if you're managing the villa remotely or aren't there full-time.
When this checklist doesn't apply
A few Bali villa situations make the standard 90-day checklist less relevant. If your system is full off-grid in a remote area (Munduk valley, deep East Bali coast, or a Gili island property) where there's no cellular coverage for monitoring, your early-period check relies on the inverter display and local readout rather than an app. In that case, ask your installer to schedule a physical 30-day follow-up visit as part of the project scope, not as an optional extra.
If you're an overseas owner and a property manager handles the villa day-to-day, brief them specifically on what a normal system day looks like in the app. Most property managers won't proactively report a production drop unless you've told them what to look for. A quick one-page summary from your installer, showing expected daily kWh and what an alarm notification looks like, goes a long way.
If you installed a simple grid-tied system without battery in a low-complexity urban Bali location (PLN solid, no shading issues, straightforward roof), your 90-day checklist is lighter: mostly just the bill check and the rain test.
Ready to plan your install?
If you're still in the pre-install stage, the best way to make the 90-day post-install period straightforward is to start with a thorough site survey, a detailed commissioning report, and an installer you can actually reach. We help you get to that point, from sizing to handover to the first rain test.
Or use the calculator first to get a baseline on system size.
Frequently asked questions
On a clear Bali day, your system should produce within 10% of the commissioning baseline your installer documented. For a 6 kWp system with 5 peak sun hours, that's roughly 26 to 30 kWh per clear day. If you're seeing consistently less on sunny days, flag it to your installer straight away, not at the three-month service visit.
