Re: Using 1.2 V NiMH batteries #iEXOS-100

Jerry Hubbell - Explore Scientific VP Engineering

On Mon, Aug 24, 2020 at 09:01 AM, <mehdi.tlili@...> wrote:
Would that affect the tracking performance or damage the motors? Or is there a voltage regulator built in?
Hi Mehdi,  thanks for you questions.
The PMC-Eight requires a nominal 12 VDC power supply. The internal voltage regulators for driving the motors are 10 VDC. The minimum voltage for the system where anything less than that is about 10.6 VDC. Any voltage below this will cause the motors to not provide enough torque and the system would fail. This doesn't impact the controller, or WiFi communications, only the motors. So the 9.6 VDC would definitely not work. If you want to use the rechargeable NiMH batteries, you would need to have at least 10 of them in series, and I would suggest 11 for more margin. The PMC-Eight will work fine with input voltages from 12 - 16 VDC. If you decide to build your own battery pack pay close attention to the connector polarity. The center pin is positive with the outside barrel negative. There is reverse polarity protection on the system, but it is best not to challenge it.
Jerry Hubbell
Vice President of Engineering

Explore Scientific, LLC.
jrh at
1010 S. 48th Street
Springdale, AR 72762

Author: Scientific Astrophotography: How Amateurs Can Generate and Use Professional Imaging Data
             Remote Observatories for Amateur Astronomers: Using High-Powered Telescopes From Home

Mark Slade Remote Observatory (MSRO) IAU MPC W54 Equipment
Wilderness, VA
: ES PMC-Eight G11 + Telescope Drive Master (TDM)
Scopes: ES 165 FPL-53 ED APO CF, ES 102 FCD100 ED APO CF
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