I thought you might find this interesting. It is an easy to use DC-DC converter that will take 9 to 36 volts input and output a steady 24 volt at 10 amps. They are commonly called buck converters or up / down converters. This one will take a high or low input voltage and output 24 volts.
These come in different input ranges and output voltages. Great for DIY solar projects and supplying voltages for odd appliances.
Warning: Electricity always carries the risk of burns, fire, shock, electrocution, etc. If you do not know, learn first or do not do it.