Solar powered alarm sirens – Do they work?
This is a subject for which there is plenty of debate.
In short, the answer is yes they work perfectly, providing it is positioned in the correct place.
Take the solar siren for the Sentry Pro alarm as an example, this siren runs directly from the battery built within the siren, the solar panel then re-charges that battery as and when required. The battery will run the siren for approximately 22 days in standby conditions, which is longer than a lot of comparable sirens on the market. During the spring and summer months, there may be short periods where cloud cover is particularly thick, limiting the siren in being able to re-charge, but because of the extensive battery life this doesn’t cause a problem. The winter months however can cause a problem, especially in December to February where daylight hours are particularly short, during this time, the placement of the siren is absolutely crucial in allowing all year round performance. In the winter months, as the sun rises from the south-east, it is important that the siren can benefit from the maximum amount of sunlight during these months, so placement on an unobstructed southerly or easterly facing wall is key. If you can place your siren in this position, you should be able to enjoy all year round charging of the siren with no problems at all. If the only place you can put the siren is on a north or west facing wall, you are more than likely going to need to manually re-charge the siren once or twice during the winter months. In this scenario, you may well be better off going with a 12v external siren instead and have it hard wired.