I bought the harbor freight 45watt, 12vdc charge controller solar kit.
Can I charge my two 24vdc batteries with this kit?
Do I need to buy a 24vdc charge controller?
Can I build a DIY step-up converter (12vdc to 24vdc)?
If you connect your two 12V batteries in parallel, + to+ and - to -. you have created a 12V battery with double the Ah capacity. Your panel will be charge that just fine, but it will take twice as long.
You will have to disconnect the charger before connecting the batteries in series again to power your load. A DPDT switch could be used to do that. Do not leave the 12V solar charger connected to only one of the two batteries while drawing a load off the two connected in series.
You could also buy a 24V panel, buy a 12V to 24V step-up charge controller, buy a second 12V panel...
See the attached block diagram of my solar panel system with batteries. Is that what you meant about connecting the batteries (24vdc each) in parallel? Also, where would I connect the DPDT switch?
Thanks Mike. The two 24vdc batteries came with a 24volt battery charger, have you heard of anyone changing the battery charger to an inverter? It stands to reason that in a battery charger you take the 110 a.c. input to charge (output) the 24volt battery. Therefore, is it possible to modify the battery charger and make it an inverter? I'm recycling some of my STUFF to stay 'green' at the same time.