Hi,
The VFD does have a “12v” out but while I was checking things I happened to probe between this post and the comm post and it was showing 13.2volts. I do remember reading somewhere in the gecko manual not to let this be over 12v. Is this a problem?
Yes, it may be. Its quite common for a 'nominal 12V' supply to be somewhat more, as in your case 13.2V.
As you know 12V is the common output voltage of an automotive 6 cell flooded lead acid battery. In fact when absolutely
fully charged you might expect 2.2V per cell for a total output voltage of 12.6V. When in automotive service when the engine runs
the generator (old school)/altenator will elevate the voltage to charge the battery. A modest charge rate could be secured by
charging at 13.2V. A more aggressive charge rate as is the norm for modern cars is 14.2V to 14.5V.
With the long history of 12V use in automotive service then '12V' can be a bit flexible.
I don't recall seeing anything in the G540 manual, but I take your word that it is there, the recommendation not to exceed 12V.
If that is the recommendation I would stick to it. It is worth an email to Gecko to get a little more info.
The simplest solution I can think of would be to drop the voltage slightly with a 9.1V Zener diode and a resistor. That would
mean that the variable output voltage of the G540 would be 0 to 9.1V, slightly less than spec but close enough. 9.1V is a
standard Zener voltage. You might enquire from Gecko about the expected G540 current draw from the nominal 10V supply,
it maybe that a Zener will get a bit hot and bothered.
Another alternative is to use a low dropout voltage regulator. You might get away with a very common and dirt cheap LM317.
It would require two resistors to set the voltage but you can set it very accurately.
Let me know if you need some help to regulate the 13.2V output of your VFD. Electronics is 'my thing'.
Craig