Hi,
They last about 2 years and then die. The dollar stores have a similar produce cheaper than Dollar General.
I did love mine while it lasted.
Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.