[RE-wrenches] Relay Drivers

[Kent]

Drake,

The Morningstar relay driver doesn't output voltage; it can sink current 
or measure voltage. Normally the outputs are wired to the same source 
that powers the relay driver - it is the power source that is putting 
out voltage. It shouldn't be a problem to run a 12-volt relay from a 
separate 12-volt source (or 12 volts derived from the 48-volt source) as 
long as the ground of the separate source is common with the relay 
driver ground. Simply add a 48V to 12V converter to the project and you 
can operate one to four 12-volt relays, or a mix with some being 12 and 
others being 48 volts.

Kent Osterberg
Blue Mountain Solar


On 7/21/2026 6:35 AM, Drake Chamberlin via RE-wrenches wrote:
> Hello,
> The Morningstar relay driver is a great device. It can measure 48VDC 
> nominal and operate relays based on the measured voltage. The problem 
> is that, if it is measuring 48VDC nominal, it outputs the same.
> Is there anything besides a charge controller that can measure 48 VDC 
> nominal and put out a small 12VDC current? The 12VDC output of an 
> Outback or Midnite charge control is perfect.
> If a relay driver, with several channels, could do this, it would be a 
> very useful device. Does anything like this exist?
> Thanks,
> Drake
>
> /Drake Chamberlin/
>
> /Athens Electric LLC/
>
> /Ohio Electrical Contractor’s License 44810/
>
> /NABCEP Certified PV Installation Professional/
>
>
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