In short
- Cold, a cell reaching its limit and the inverter’s own settings explain most stops.
- The highest cell voltage and the temperature at that moment usually point to the answer.
- An active alarm in the BMS is the case where a call to your installer is worth it.
A lithium battery charges only when the BMS allows it and the inverter asks for it. When charging stops early, one of the two has said no. BSLBATT Monitor shows the BMS side: cells, temperatures, current and alarms. That is usually enough to know which one.
It is cold
LiFePO4 cells must not be charged below freezing, and charging current is often reduced when they are just above it. On a winter morning in a garage, a battery may take very little until it warms up. Check the battery temperature: if it is low, the BMS is doing its job.
One cell reached its limit
Charging slows or stops when the highest cell reaches its upper voltage, even if the others are lower. The pack then shows something like 92 % while one cell is already full. Look at the highest and lowest cell at that moment. A wide gap at the top of charge means the cells need balancing time, which usually comes with a few full charges.
The inverter decided
Many inverters stop charging at a voltage or a percentage set by the installer, or limit the charge current at certain hours. If the BMS shows no alarm, normal temperatures and cells close together, look at the inverter settings rather than at the battery.
An alarm is active
When the BMS raises a protection, the alarm sensor turns on and the dashboard says which one. Temperature and cell voltage protections usually clear on their own. If an alarm stays, or comes back every day, note the time and the values and contact your installer with that history: it shortens the conversation.
A simple routine
Battery stuck while the sun shines: look at the temperature, then the highest cell, then the alarm. Three figures, one minute, and in most cases the answer.
Common questions
Can BSLBATT Monitor restart the charge?
No. It only reads the battery. It shows why charging stopped so you know where to look.
Is 92 % at the end of the day a problem?
Not on its own. If the cells are close together and no alarm is active, the inverter probably decided to stop there.
Should I get an alert when charging stops?
An alert on the BMS alarm is more useful: it fires only when the battery itself is protecting.
