Do I need a solar charge controller?
Quick answer - do I need solar charge controller?
A solar charge controller is needed in almost all situations.
Want to find out why, please read on…
Situations when a charge controller may not be needed
Very small solar panels relative to battery
You could argue if the solar panel watts/Ah of battery is less than 5% you do not need a solar charge controller. For example, if you wanted to ensure an engine starter battery is kept topped up when a campervan is not in use. However, we recommend you always install a charge controller, since even small panels <10W can overcharge and damage a 100Ah battery bank. This is especially true when a system is left unattended and doesn’t have regular loads.
Constant management of solar system
A solar charge controller may not be needed if you have time to turn the solar system on-off to manage the battery state of charge. For example, if you live on a boat and have constant access to the solar system. When you leave the boat the solar system would need to be turned off to prevent overcharge. However, the cost of a charge controller may turn out to be less than replacing your batteries if they are accidentally overcharged.
Occasional use
If you are using you solar system infrequently, you may not need a charge controller. For example, if you are using it for the annual holiday and are able to monitor the solar system actively during that holiday.
Grid tied
If you have a grid tied system, which means one connected to the electricity grid, you don’t need a solar charge controller. If you add batteries to your grid-tied solar system some form of charge controller would be needed.
No batteries
You don’t need a charge controller when you don’t have batteries. For example, if you connect solar panels directly to a load. However, the load would need to be able to run with the variable voltage/current the solar panels are delivering and not cause issues across the voltage/current range.