Ok so I have a great 12V solar battery system working very well at the observatory
See a picture of the power setup
HERE
And I just got a Skywatcher 12" GOTO dob seen
HERE outside at the observatory
I want to use a smaller 40ahr SLA battery (visible on the shelf in the photo of the battery setup above) to power the Dob outside.
My question is: When I leave of a night, is it safe to simply connect the smaller battery to the two larger batteries (in parallel) and have it charged and maintained with them and leave it unattended in this way?
When the Sun is up the solar regulator bulk charges the big batteries at 14.6V and when they are full floats them at 13.7V (set per battery spec sheet)
Or should I consider using a 12V DC to DC charger instead? Like
THIS one
Cheers for any feedback
Mike