Fault-finding
The inverter is not charging the battery
Work through four things in order: the battery's low-voltage cut-off may have latched, the charge settings may not match the cells fitted, a DC breaker or fuse between bank and inverter may have opened, or the bank may simply be at end of life. Only the last one costs real money.
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Check the protection between bank and inverter
Start with the DC breaker or fuse on the battery leg. An opened fuse presents exactly as 'not charging' and is the cheapest possible cause. Check it before anything else — and if it has opened, find out why rather than simply replacing it, because a fuse that blows twice is telling you about a fault further along.
Compare charge settings against the cells fitted
Absorption and float voltages, charge current limit and low-voltage cut-off have to match the actual battery, not the inverter's factory defaults. This is a common inheritance problem: a bank replaced by someone who never revisited the settings will be charged to the wrong voltage, which either undercharges it permanently or shortens its life.
See whether the bank has latched off
A bank taken below its cut-off can latch into a protective state that a normal charge cycle will not lift. Lithium banks with a battery management system do this deliberately. Recovery depends on the BMS and sometimes needs a specific reset procedure rather than more charging — check the manual before assuming the bank is dead.
Measure actual capacity before condemning it
If settings and protection are sound, measure a full charge and discharge against the commissioning figure. A bank delivering a fraction of its original capacity is at end of life. That is a real answer, and it is worth reaching by measurement rather than by a supplier's assertion that you need a new battery.
Why is my solar inverter not charging the battery?
The battery charges in summer but not in winter. Is it faulty?
Probably not. Short winter days with low sun angle can leave insufficient generation to both run the house and refill the bank, particularly if the charge current limit is set conservatively. Check whether the array is actually producing enough during daylight before replacing anything — this is a sizing symptom, not a fault.
Can wrong charge settings damage a battery?
Yes, in both directions. Charging above the cells' specification cooks them; charging below it leaves the bank chronically undercharged, which on lead-acid causes sulphation and permanent capacity loss. Settings matched to the cells fitted is one of the cheapest and most neglected things in a solar installation.
How do I know when a bank is genuinely finished?
By a measured full charge and discharge compared against its commissioning capacity, not by how it feels. A bank that delivers substantially less than it originally did, with correct settings and healthy connections, has reached the end of its useful life. Anything short of that measurement is guesswork.
Rather have it done?
The inverter and battery bank are where a solar system is won or lost: sizing, ventilation, cabling and protection decide whether the bank lasts eight years or three. A lithium bank with a hybrid inverter installed properly starts near PKR 320,000 for a household essential load.
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