A home battery that won't charging is rarely the battery itself. In the field, most "not charging" calls trace back to inverter settings, a tripped breaker, or a communication handshake failure — not a dead pack. Before you replace hardware, work through these eight checks in order: start with what's visible on screen, move to what's physically connected, then escalate to firmware and BMS faults. This sequence cuts a typical 3-hour diagnostic down to 45 minutes.
1. Check the Inverter Fault Code First
Don't open the cabinet yet. Read the inverter display and write down the active fault code.
- "No battery" or "communication lost" → CAN/RS485 wiring issue, not a battery fault.
- "PV low" or "insufficient PV voltage" → the solar array isn't hitting MPPT threshold. Check string voltage on a sunny day.
- "Grid overvoltage" or "frequency error" → export limitation or grid code setting blocking charge.
- "BMS fault" or "overtemperature" → the battery management system has tripped. Go to check 6.
A code like "communication timeout" on a Dawnice HZEB-LCT paired with a Deye hybrid almost always means the CAN H/L wires are swapped — not a dead BMS.
2. Verify the Battery Circuit Breaker
Walk to the battery cabinet. On the back or bottom of the HZEB-LCT wall-mounted unit, there's a DC disconnect switch and a fuse holder.
- Is the DC breaker switched ON?
- Is the fuse intact? Pull it and look for a blown filament.
- Are the battery terminals tight? A loose torque connection shows "charging" on screen but zero current flow.
We see this most often after a homeowner turns the switch off during a storm and never flips it back.
3. Confirm the Inverter Battery Type Setting
This is the #1 software setting that stops charging. On the hybrid inverter setup menu, the battery profile must match the actual hardware.
- If you installed a Dawnice HZEB-LCT (51.2V LiFePO4), the inverter setting must be LiFePO4 / Lithium , not lead-acid.
- Lead-acid charge profiles cap at 56.4V and never trigger the absorption phase that LFP needs.
- Also check the charge current limit — some installers leave it at the factory default of 10A when the system can accept 100A+.
On a DWH 10–16K inverter, this lives under Battery → Battery Type → User-defined . Set it to LiFePO4 with charge voltage 58.4V and float 54.0V for the HZEB-LCT series.
4. Check Solar Input (PV) Voltage
If the battery only charges from solar and not from grid, the MPPT may not be waking up.
- On a sunny day, read the PV input voltage on the inverter screen.
- The DWH series starts charging from PV at ~120V DC. If your array reads 80–100V, you're below threshold.
- Old rooftops with partial shading or series string under-sizing are the usual cause.
A 10-year-old 3kW array on a cloudy day may never reach MPPT threshold on a modern 10kW inverter. The homeowner sees "no solar charging" and blames the battery — it's actually the string voltage.
5. Test the Grid Side
If solar isn't available and the grid isn't charging either:
- Check the grid relay and AC input breaker.
- Read the grid voltage on screen. Some regions run at 253V+ in the evening, and the inverter's overvoltage protection trips and disables charge.
- Confirm the tariff/charge window setting. Some installers program "charge from grid only during off-peak hours" — if the homeowner checks at 2 PM, the battery intentionally isn't charging.
This last one generates more service calls than any hardware failure.
6. Battery Temperature and BMS Status
LFP batteries stop charging below 0°C and above 45°C — by design, not fault.
- On the Dawnice HZEB-LCT screen, read the cell temperature.
- A garage in winter reading -2°C means the BMS has suspended charge to protect the cells. It will resume automatically when it warms above 5°C.
- If the temperature reads normal but the BMS shows a fault, log into the BMS and check the alarm history. Overvoltage on one cell, internal communication loss, or fan failure all trigger a charge inhibit.
Don't replace a 90kg wall-mounted battery pack over a temperature fault — it's doing what it's supposed to do.
7. Verify SoC Ceiling and Reserve Settings
Somewhere in the inverter or EMS settings, there's a charge limit and a backup reserve.
- Is the charge limit set to 100%? Defaults sometimes sit at 80%.
- Is the backup reserve set above the current SoC? If reserve is 30% and SoC is 25%, the system won't charge past 30% until grid outage logic clears.
- On three-phase systems running the DWH 8–24K, check the EMS schedule — peak shaving settings can intentionally hold the battery at 40% during high-tariff hours.
8. CAN / RS485 Communication Wiring
If everything above checks out and the inverter still says "no battery":
- Power off both inverter and battery.
- Swap the CAN H and CAN L wires. A reversed pair on a Dawnice battery and a Deye/Sunsynk hybrid produces exactly one symptom: no charging, no fault.
- Check the termination resistor. Most CAN buses need 120Ω at the end of the line.
- Confirm the inverter firmware supports the specific battery model. A 2-year-old Sunsynk firmware may not recognize a newer Dawnice BMS protocol.
Ninety percent of "battery not charging" calls end at check 3 or check 5 — a wrong battery type setting or a tariff schedule that's doing exactly what it was programmed to do. Ten percent need a firmware update or a CAN swap. Almost none need a battery replacement.
If you've walked all eight checks and still can't find it, send us the inverter fault code, battery screen photo, and the CAN wiring diagram — Ruibit Energy supports installers through commissioning and field diagnostics on every Dawnice system we ship.
Frequently Asked Questions
Q1: Why is my home battery not charging from solar?
Check the PV input voltage first. The DWH series hybrid inverters start solar charging at around 120V DC. An old, shaded, or under-sized string may read 80–100V — below the MPPT wake-up threshold. This is a solar array problem, not a battery fault.
Q2: The inverter says "no battery" but the battery is on. What's wrong?
It's almost always CAN communication. Power off both units, swap the CAN H and CAN L wires, and confirm the 120Ω termination resistor. A reversed CAN pair produces exactly one symptom: no charging, no fault code.
Q3: Can a cold garage stop my battery from charging?
Yes, by design. LiFePO4 batteries suspend charging below 0°C to protect the cells. The Dawnice HZEB-LCT will resume automatically once internal temperature rises above 5°C. This is not a hardware failure — don't replace the pack.
Q4: Why won't my battery charge above 80%?
Check the inverter charge limit setting. Factory defaults often cap charging at 80%. Also check the backup reserve — if it's set to 30% and the SoC is near that, peak shaving logic may intentionally hold the battery in a narrow band.
Q5: The battery charges from grid but not from solar. What's the issue?
Two common causes: PV string voltage below MPPT threshold (check on a sunny day), or the solar charge current limit set too low in the inverter menu. Read the actual PV wattage on screen — if it shows 0W at midday, it's a string or wiring issue.
