I review roughly 200 solar and battery deliverables a year. Not just inverters—the whole installation package, from MPPT settings to terminal torque.
Before you type “SRNE inverter shows high PV voltage at night” into a forum, hear me out. Most of the time, that message is not a hardware fault. It’s a commissioning fault. And I can say that without defending the brand.
Since 2021, I’ve checked 200+ off-grid and hybrid installations. I’ve rejected SRNE units, too—one batch of SRNE charge controllers had terminal covers that didn’t seat cleanly. But the majority of trouble calls I audit end up being a voltage setting, a loose termination, or a poor disconnection order.
The charge controller is the first place I look
An SRNE charge controller doesn't care if your battery is lead-acid, gel, or LiFePO4. It cares about the voltage points you program. When someone says their LiFePO4 24V battery charger isn’t charging, I start by checking the battery type setting. If it’s set to “SLI” or “gel”, the lithium BMS will latch out the moment it sees the wrong cell voltage. Not ideal. Workable, but only after the user profile is corrected.
For an 8S LiFePO4 bank (the common 24V eight-cell arrangement at 25.6V nominal), I normally set these points:
- Absorption/bulk voltage: 28.8V
- Float: off (or 27.2V at the very most if the battery datasheet supports it)
- Low voltage reconnect: 25.6V
If you run a 29.2V absorption instead, that can work for balanced prismatic cells—but I don’t set it unless the manufacturer puts it in the cell datasheet. The same logic applies to a separate LiFePO4 24V battery charger: bulk to 28.8V, then stop. Leave a lead-acid float voltage on forever and the BMS will eventually disconnect on overvoltage.
SRNE inverter shows high PV voltage at night? Measure before you blame
Here’s the thing: I see that service ticket more often than I’d like. Usually it gets passed to me as a hardware complaint. But when I arrive with a calibrated multimeter, the inverter is often fine.
A PV input reading after sunset can come from a long DC cable run acting as a capacitor, a floating negative that’s open, or an MPPT in standby that samples the string voltage through a high-impedance divider. What I mean is: the number on your LCD isn’t always the number at the terminals under load.
Under IEC 62446-1, you verify the DC side before you fault the electronics. There is no process that lets you skip the array check. If the screen says 120V at 2am, leave the inverter alone and measure at the DC isolator. If you read the same 120V there, investigate the wiring, not the electronics.
Example from last year: battery storage installation at Brereton Green, 24V LiFePO4 bank, one 5kW SRNE hybrid, and a separate SRNE charge controller. The owner reported high PV voltage at night. Turned out the DC isolator was open but a negative pigtail had worked loose—the inverter was reading a free-floating cable voltage. Tightened the termination, re-ran the MPPT init, and it was back to zero after sunset. A 15-minute fix. The product was never the problem.
I'm not saying every SRNE inverter is beyond fault. If the same failure appears on multiple units with clean wiring, yes, it's hardware. But if the callbacks outnumber the batch defects, look at the specification chain first.
Which battery terminal do I disconnect first?
Short answer: the negative terminal.
On a battery bank, the negative is usually the common bus. If you take off the positive first, your spanner can touch the frame or an earthed surface while the positive cable is still live. Remove the negative first and you kill the loop before the risky side is exposed. When you reconnect, connect positive first, then negative—the last connection is then the non-earthed side.
One battery rule doesn't always carry to a DC-coupled storage system. I’ve only worked with batteries where the negative bus is bonded or reasonably predictable. If your inverter manual says something different, follow it. But every battery storage installation we sign off—including the Brereton Green site—uses disconnect negative first, reconnect positive first.
The honest limitation
Am I recommending SRNE for everyone? No. For a 10kW three-phase pure grid-feed system with no storage, I’d pick a different box. SRNE’s sweet spot is hybrid/off-grid solar with 24V or 48V battery banks, particularly when you need a charge controller and inverter from one ecosystem at a practical cost. But there is no “best”. There’s only “best specified”.
My experience is based on 100+ kWh residential and light-commercial projects. If you’re designing 100kWh-plus for a data centre, I can’t speak to that from first-hand data. You need a certified power engineer and a commissioning protocol that goes beyond this article. That’s not false modesty; it’s the honest limit of what I’ve verified.
There’s something satisfying about coming back a year later and seeing the same LiFePO4 bank holding 27.0V at rest. That’s what the right charging profile looks like. It doesn’t happen by luck.
So if you see high PV voltage at night on an SRNE inverter, start with the charge controller settings, then the DC wiring, then the disconnect order. The hardware might be fine. The spec is probably not.