I'm building a project (remote measuring station), that will draw approximately 35mA for one second in 15 minute intervals (4 times per hour) continously. In the idle state, everything is going to be either in stand by mode or disconnected, thus drawing less than 1mA.
The problems I'm having are with power supply and storage. I intend to use either 2 or 3 batteries and a switcher voltage regulator to convert the voltage levels to 5V (all other components work at 5V). Now, I'm trying to charge these batteries with a mini solar panel, but don't know how to do things properly.
I guess if I use NiCd batteries I could charge them continously with a trickle charge drawn from the solar panel, but is that such a good idea, since the device might remain unatended for months to come. (I was told lead-acid batteries are better for this kind of usage, but they are not an option here due to size !.)
Basically I have been looking at this for a starting point:
**broken link removed**
The LM334 and LT1300 are not to be found in the local electronics shop (I found a MAX756 instead of LT1300 though). I'm unsure about a LM334 alternative though...the datasheet suggests a 10mA current, when the author of the schematics above mentiones much higher currents.
Ma solar panel specs:
9V with open contacts (6V nominal)
75mA max (60mA nominal)
_____________________________________
If you have any suggestions about how to do this properly (with durability and efficiency in mind), any links or other scematics, calculations or just simple comments, please be so kind and let me know .
Thanks
The problems I'm having are with power supply and storage. I intend to use either 2 or 3 batteries and a switcher voltage regulator to convert the voltage levels to 5V (all other components work at 5V). Now, I'm trying to charge these batteries with a mini solar panel, but don't know how to do things properly.
I guess if I use NiCd batteries I could charge them continously with a trickle charge drawn from the solar panel, but is that such a good idea, since the device might remain unatended for months to come. (I was told lead-acid batteries are better for this kind of usage, but they are not an option here due to size !.)
Basically I have been looking at this for a starting point:
**broken link removed**
The LM334 and LT1300 are not to be found in the local electronics shop (I found a MAX756 instead of LT1300 though). I'm unsure about a LM334 alternative though...the datasheet suggests a 10mA current, when the author of the schematics above mentiones much higher currents.
Ma solar panel specs:
9V with open contacts (6V nominal)
75mA max (60mA nominal)
_____________________________________
If you have any suggestions about how to do this properly (with durability and efficiency in mind), any links or other scematics, calculations or just simple comments, please be so kind and let me know .
Thanks