Battery counterweight

[+bryand]

iOptron came up with a remarkably sensible idea for solving several problems.  We need heavy lead-acid batteries to power our dew heaters, and we need counterweights.  So they produced the iOptron PowerWeight.  Or they did until summer 2018 when they discontinued it.

iOptron won’t supply the full PowerWeight, but they will supply the unique parts for them – everything except the battery cells themselves.  The cells turn out to be 2V/8 Amp-hr Cyclon cells in ‘E’ size, which are available in the UK for £93 for a set of 6 from Budget Batteries.

I wanted to fit the PowerWeight on my AZ Pro mount, which has quite a short c/w shaft.  That means I had to modify things to get both the PowerWeight and a normal counterweight on the shaft at the same time.  As a short-term measure, I could remove the shaft locking collar and the collet it acts upon.  That would gain me about 28 mm of extra shaft.

However, I thought I could improve on this by fitting my new cells into a custom wooden casing.  This would allow me to move the locking thumbscrew into the middle of the rig and open out the inboard end so it would fit over the shaft locking collar, gaining me more shaft space.  I got hold of some rather nice Walnut (two 6”x2” bowl blanks at £10.55 each) for the two ends of the casing.  The cells would be partly exposed in the middle.

Initially, I bought one Cyclon battery so I had something to measure and test fits for.  I bought a 1¾” sawtooth bit which turned out to be exactly the right size for the Cyclon, except for the part of the case where the join in the outer case  is: that’s thicker, so I needed to add a keyway for it.  That at least meant I could ensure the batteries were oriented correctly. 

I’d forgotten how porous walnut is as a wood: it took a fair bit of sanding sealer to get it to a state where it would take varnish, but the final result looks like it will last:

 

So is it worth the cost?  Obviously not, unless you count the satisfaction of having made something which does several  jobs; which  will  last; with a degree of elegance and uniqueness.

Oh, and it turns out the battery is enough c/w for my C9.25 on the AZ Mount Pro so it works fine - the battery feeds a dew controller Velcroed to the front of the mount to keep cables off the floor.

 

Edited November 11, 2018 by bryand
spelling

[BAZ]

That looks fantastic Bryan, a lovely it of shedwork.

[philjay]

Thats rather elegant, I like it

[Doc]

I done something very similar. I had a double dovetail clamp connected to the coubterweight bar and I clamped two 12v batteries in the dovetail clamps, worked a treat, yours look more elegant though.

 

 

 

Edited November 12, 2018 by Doc

[Tweedledee]

That looks very neat. ?

[+Bino-viewer]

I never understood why they discontinued the 'Powerweight' idea ?

Such a neat idea, and the bonus was better cable management.

 

Maybe it was because the heavy lead acid type battery had had its day in smaller, 

lower power uses like this, and when you look at it, the new lithium polymer (and lithium iron phosphate)

type cells are certainly far superior. But at a price of course.

Edited November 12, 2018 by Bino-viewer

[+bryand]

35 minutes ago, Bino-viewer said:

I never understood why they discontinued the 'Powerweight' idea ?

Such a neat idea, and the bonus was better cable management.

 

Maybe it was because the heavy lead acid type battery had had its day in smaller, 

lower power uses like this, and when you look at it, the new lithium polymer (and lithium iron phosphate)

type cells are certainly far superior. But at a price of course.

Agreed.  It's all very well having a built-in lithium battery to power the mount, but you still need power for the dew heaters etc.