Granted solar batteries do not last forever. At some point, depending on the quality of build and care provided you’ll need to replace them either way.
But what if, they appear to fail sooner than specified by the manufacturer?
Could it be that (in case you’re powering AC appliances using an inverter) the inverter is the cause? How do you confirm this?
And what can you do to avoid damage to what can easily make up at least 30% of the investment in your inverter backup or off-grid solar system?
Read on to find out.
Can an Inverter Damage Your Battery?
Yes, it is possible that the damage – reduced ability for the battery bank to hold charge or battery not charging anymore can be caused by an inverter.
A thing to note, while an inverter can damage your batteries, it’s only probably just one of several possible causes of failure.
Be sure to check and rule out that it is not any of the following:
- normal aging and failure of batteries,
- poor quality of manufacture, or
- even when the wrong charge settings are used (consistently).
4 Signs an Inverter is Damaging the Battery
If you frequently find the batteries deeply discharged and the inverter is unable to power on the next time you switch it on, then it’s likely a case of the inverters draining the battery.
Use a good quality digital voltmeter to measure the battery voltage.
A sub-11V voltage is a sign that the batteries are deeply discharged and the inverter has shut down as a result.
Frequently draining the batteries will shorten their life.
Signs a Battery is Probably Damaged
Your battery bank is probably damaged if:
1. The batteries become extremely hot during charging
The solar batteries get extremely hot even when using the recommended (or usual charging current – same solar panel and charge controller).
This can point to an internal short in the battery.
The sealed maintenance batteries may give off gas too or bulge at the sides.
2. Low voltage alarm on the inverter and shorter runtime on the battery
if the battery is still relatively new, you confirm that the inverter battery cables are firmly connected to the battery bank posts and that the battery should be fully charged yet:
the battery runtime is considerably shorter than it should be, and or there’s a low-voltage battery alarm
3. The Solar battery is not able to hold its voltage
The battery is not able to hold or maintain its voltage even with no appliance connected. You may charge it to 12.6V for instance and after an hour of resting – give or take the battery voltage drops to a sub 12.4V.
Why an Inverter Can Damage the Battery?
If find yourself replacing the batteries every so often and, assuming that you’ve ruled out other possible causes of damage such as poor quality of manufacture and using the wrong charge settings, it’s then probable that:
1. The batteries are undersized for the appliances and therefore discharged beyond the recommended depth of discharge. Now this can vary from one system setup to another but here are a few checks that you can do:
If your system has an energy meter, check the daily energy draw against the capacity of the battery. AGM batteries should be discharged to 50% of their capacity while LiFeP04 batteries may be discharged to as much as 80% of their capacity.
The additional power draw may be what’s causing damage. This may be because the connected appliances are running longer than was planned or you’ve connected more appliances than was initially provided for.
Check if any of these suggestions might be an issue.
2. You’ve connected appliances that exceed the manufacturer-specified maximum discharge current for the battery bank
The batteries may also be damaged if you exceed the recommended maximum discharge current for the battery.
This can happen if there’s a short across the battery terminals or you connected an appliance with a high current draw such as an electric heater or other.
Closing Thoughts
If your solar batteries are failing prematurely, it might be that the connected appliances are deeply discharging the battery bank or that the maximum discharge current for the batteries is exceeded.
Note: This is just but one of the possible causes of damage to solar batteries.
Confirm that you’re using the recommended charge settings for the battery, that they are not being overcharged, and that you’re using a reliable brand of battery.
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