Being able to confirm whether an inverter battery is dead or about to fail in time can save you the frustration and inconvenience of the battery failing on you when you most need it!
In addition, knowing and using a reliable way to confirm whether a battery is dead can save you the time and effort that you’d otherwise spend going around in circles looking for the fault, or investing in a replacement battery that you do not need!
Therefore knowing if and when a battery is bad is really necessary to ensure that the inverter backup system is always available.
What signs, then, show that an inverter battery is dead and needs to be replaced?
Read on to find out what signs you should look out for to tell whether an inverter battery is dead and the reliable tests you can conduct to check whether the inverter battery is in good condition or not.
What Checks to Do
If you suspect that an inverter battery is dead, for example, if the inverter shuts down sooner than expected, first, rule out the following:
There are no voltage drops between the battery terminals and battery posts. There’ll be voltage drops if:
1. The inverter battery terminals are not firmly connected to the battery posts. If the battery terminals do not make good clean, solid contact when the inverter is powering an appliance, then they’ll be a voltage drop.
This can trigger a low battery alarm and shut down of the inverter giving the mistaken impression that the battery has lost its ability to hold charge.
2. There’s corrosion at the battery terminals. The buildup of corrosion around the battery terminals can cause a voltage drop at the inverter that then shuts down because the available voltage is lower than what it needs to operate reliably.
3. The battery cables may be undersized for the current drawn by the connected appliance or the length over which they need to supply current to the appliance.
Check the inverter owner manual for the recommended wire gauge to use for the inverter depending on the battery cable length used. As a general rule, keep the battery cables as short as possible.
Inverter battery Dead or Dying? What Shows
The signs below, though not confirmatory can point to an issue with the battery or battery connection. Note: Additional testing needs to be done to confirm that the battery is indeed dead.
1. Beeping sound attributed to a low battery warning and the eventual shutdown of the inverter sooner than usual. This might be because the battery is aging and losing its ability to hold charge. Additional tests need to be conducted though!
2. The battery voltage drops significantly over a short period even with no appliance connected! An example is when an AGM battery voltage drops from 12.6V to 12.2V over a couple of hours with no appliance connected.
3. Battery voltage fails to rise to the fully charged level of 14.5V for an AGM battery. This could point to a damaged battery cell.
4. The battery overheats during charging when using the usual charge rate (amps). This can point to a shorting cell in the battery.
5. The battery shows signs of physical damage. If the battery is bulging at the sides, cracked, or leaking then replace it. This is because while it may still be working, it is usually a matter of time before it fails. Also, it poses a risk to your safety when used in this condition.
Tests to Check whether Battery is Dead (The reliable Way)
To reliably confirm that the battery is dead, you can use:
- A good quality portable battery tester. You can use a portable battery tester to confirm the health of the battery. The tester will show a fail or replace status indicator if the battery needs to be replaced.
- Arrange to have the battery condition and capacity tested at a reputable car repair facility.
The surest way to confirm if an inverter battery is dead is to test it at an auto repair facility or use a good-quality battery tester.
That said if the battery voltage drops rapidly with no appliance connected, or the battery overheats during the charging process, then it may point to the battery about to die.
Note: additional testing is recommended.