ES-G11-PMC8 power options

Steve Lang


Thought I would ask here first, as I'm working through getting my ES-G11-PMC8 fully commissioned into the soon to be built obs.

I've built a number of power supplies in the past for previous telescope equipment. I have a big long description and background and lots of context which I won't bore you with, but the short version is;

1) I understand from previous threads that the PMC8 for other models must have 12V in order for the steppers to function. Is this also true for ES-G11-PMC8? What is the minimum DC voltage? (I understand the max could be around 16V-18V, poss 25V and AGM SLA batteries which I have often get below 12V, with max often being only 12.9V)

2) Is there likely to be any problems using a DC-DC converter esp. a buck/boost module to 'guarantee' a 'regulated' 12V supply, irrespective of what the incoming voltage is? (would slight ripple cause any negative affect?)

3) If I was to look at getting a LifePo4 battery (only a nice to have as I currently have plenty of SLA AGM batteries), would it make sense to look at a 16V LifePo4 battery (12.5V-18V) and just use a DC-DC buck converter to make it 12V and a boost to make it 19V? I could then avoid buck/boost altogether?

4) Similar reasoning as above, I could put two 12V SLA's in series and get 21.6V - 25.8V (nominal 24V), and only run buck converters.

5) Even if the PMC-8 will be reasonably tolerant of 11.6-12.9V, I still have a QHY camera, dew heaters and other things that need to deal with that range. (Cooling of peltier may be affected, what else could go wrong here?)

Any comments/suggestions/answers appreciated :-)

Cheers -

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