I am having problems with the laptop driving my bartelised dob. I wanted some feedback on the solutions I have in mind.
I use small laptops to save weight and bulk. Currently I use a Toshiba Libretto 110ct. It is very compact - about the size of a Video cassette. I have turned off all power management in the BIOS but it will not run the motors smoothly unless I also remove the battery, it then runs the scope perfectly in the workshop. However, when I observed in the cold last night I had the following behaviour:
Tracking was fine. Manual slewing with the handpad was fine. Gotos would start OK but just before completion, the laptop would shut down. So the motors would run together OK at the start but I think the computer crash is occurring when the slew is switching from two motors back to one.
My power supply is 4 x 12 volt, 7AH SLA batteries wired in parallel. This supplies all my power (for laptop, motors serial bluetooth adapter and red LED light). I use a small inverter for the laptop.
I am thinking about doing one of the following:
- adding an independent power supply for the laptop - I could add another battery but wondered about just using one of the four I currently have and leaving the other 3 for the motors.
- A friend suggested adding a large capacitor in series with the power lead to the battery. He suggested this because I once had a similar problem with another laptop. However, in this case the laptop battery could be used. When the battery was in place the computer did not crash. My friend felt that battery was supplying a little extra current as back up. Any suggestions on the size capacitor required?
- This has all left me wondering if my power supply is inadequate?
I should also add that this issue with the laptop seems connected to my use of higher voltage for faster slews. When I run at 12 volts the laptop behaves itself.
Sorry for the long winded description. I would really appreciate any advice.
Thanks,
Rod.