The Thrifty Throttle 2 (am-2936a) takes a 9v battery. Anyone have any idea if we can wire it to 12 volts?
Without knowing the voltage regulator input rating, I can’t say. Best to stick with what it’s designed to use though.
Looks like it has a voltage regulator, but no guarantee that it it would take 12v. If you want to risk letting the smoke out, have at it.
Seems easy enough to put a 9v battery on.
Or you could make a simple inefficient voltage divider. It cant draw that much current.
The more common 5v VR is capable of accepting and input voltage range not one specific voltage. This one for example https://www.sparkfun.com/products/107 has an acceptable input range of 8-20v. It of course it not the one used on the thrifty throttle, it is just the first one that showed up in a search. If you can find the part number of the one used in the Thrifty Throttle then you can check it’s data sheet.
The other option is the diode trick. A silicon diode has a voltage drop of about .7v so string together 5 of them in series between the nominal 12v battery which is actually 12.6~12.7v when fully charged and you’ll have a ~9v input to the Thrifty Throttle. If you are using it for testing that will have a significant load that will cause significant voltage sag on the battery then you may want to use only 4 diodes.
If the voltage regulator were to accept the higher voltage it would come with increased temperature. The 9 volt battery is such an easy item to obtain why worry about other voltage sources.
The Voltage Regulator on the Thrifty Throttle 2 Board is rated for 18V.
However, we do not recommend using more than a 13V input.
Go for it! 18v rating, minor temp increase (the temperature increase is dependent on load, isn’t it? so something with a very small load like this won’t have much of a temperature increase).
It’s ok to use an inefficient voltage regulator, when you have way way more power available than you need.
But keep in mind I’m a mechanical engineer, not an electrical engineer, and I treat electronics in a practical way, not a theoretical way
I finally received a reply from Andymark. Apparently their new ticket system was sending a lot of messages to their Spam folder, and they just found out today.
“The Thrifty Throttle can handle up to 13.5V”