5 replies to this topic

[JTS2002]

I've been powering my HEQ5 with an AC power supply set at 13.5 to boost its power a bit, just upgraded to an 8-inch imaging Newtonian and was wondering if it's safe to bump the power to 15 volts to help the tracking a bit more?

 

Thanks,

Trevor

[TelescopeGreg]

Probably not.  Besides pushing the voltage rating for the mount, a mount's (in)ability to track closely is in large part a function of the mechanical parts it is made of.  Those won't change with a different supply voltage. 

 

Do you have an autoguider?  That's by far the most effective means to improve a mount's tracking.  Also take some extra care getting everything balanced.  Small differences (1/8") in position of the scope or counterweights can make a difference when you're up against the mount's performance limits.

[JTS2002]

Thanks for the info, yeah I just started guiding with an OAG and was averaging around 0.9-1.3 RMS error at 1000mm FL which honestly isn’t bad, just seeing if I could improve it any, I’ve thought about hypertune if the mount myself aswell, it’s not the smoothest, some new bearing and good grease would probably go along way.

thanks for the reply!

[flightlogic]

And pushing to that voltage may do damage that seriously is disappointing and expensive.

Voltage may be detrimental on the low side... and is not uncommon.  As stated, the mount cares not ie. 13.8 vdc like a car under charge... or 14.2 vdc with an adjustable supply.  Just don't hit it with more.

[oatmeal]

Imaging at 1000mm (8in f/4 Newt?) is a tall order for an HEQ-5. Not impossible, but you've gotta be realistic with your expectations from such a setup.

 

Have you done a Rowan belt mod? When I had my HEQ-5, installing the belt mod improved tracking from ~1.2" average RMS to ~0.7", with occasional stretches of 0.5". However, I was imaging with a 15lb setup at around 400mm FL.

 

My HEQ-5 did not like when the voltage from my battery dropped under ~11.8v, so I added a boost converter to deliver a steady 13.8v. IMO, boosting the voltage beyond what you're using now just runs the risk of damaging your mount's electronics.

[jwestervelt]

low voltage carries a risk of increased current to make up the power consumption needs.  this is one reason while running portable that you have to be mindful of running your mount when the battery voltage drops.  i have noticed current warnings from my IEQ-30 when attempting to run below 11.5V, for instance.  

as for top end... it really comes down to manufacturer's suggestions.  15V is a bit steep for most of the schematics i have seen which accept an unregulated 12V input...

the mount should have an absolute input voltage maximum spec.  If it is a simple linear regulator, the increase could cause heat concerns.  if input voltage is going direct to your motors without regulation, there is a concern there as well.  without the schematics, you really have to take the manufacturer's suggestion as gospel.