lumpy darkness

Observation notes (with equipment details), photos, sketches, reviews, software tips, random thoughts, by an amateur astronomer.

SUNDAY, MARCH 13, 2022

DIY custom CLA sockets for SLA

This article is to help people get off the hamster wheel. For the do-it-yourself person with some comfort with car repair, you can set up power sources in a convenient and cost-effective way.

The amateur astronomer who is mobile needs power in the field. This will come from a battery. Or several batteries. No, you should not use your car.

In August 2000, I procured my first car booster pack with a sealed-lead acid (SLA) battery within. I plugged in my astro-gear to the integrated cigarette lighter adapter (CLA). Primarily I used it to fight dew. And it sure came in handy when I drained the car battery! The relatively small booster pack with carrying handle from Canadian Tire lasted me a good ten years before the SLA grew tired. It was a fantastic accessory.

In November 2009, I learned of a radio club getting rid of marine-style deep-cycle SLA batteries. "Back the truck up!" They were giving them away. They were in fair shape; the club was refreshing to brand new units. I kept 4 units for myself realising great potential (sorry, no pun intended) with these powerful batteries.

Having raw deep-discharge batteries meant I needed to do a few things to make them ready and easy to use for astronomical applications. I needed to rig up power plugs compatible with the current astro-gear so I built a box with CLA female plugs. This also forced an issue: the ability to recharge the batteries easily, safely, and effectively. Back to the local Canadian hardware, tire, and astronomy parts supply store... A "smart" charger was able to recondition and charge the marine batteries and was, once again, handy during car maintenance projects. And I needed an easy means of transporting the heavy batteries.

CLA socket box done

This page focuses on and documents the simple build of a box with 12 volt direct current (12VDC) CLA sockets to power your astronomy gear. You will see this box includes a gauge for quickly checking the battery level. The box contains two CLA female sockets, reducing the need for a spitter.

No soldering for this project, if you get a pre-wired gauge!

Again, the spirit of this build is that you don't need to go down the path of buying a booster pack. Many booster packs come with unnecessary elements like a radio or stupid bright white lights or tire air pump. Some boosters come with a proprietary battery not easily replaced! Most boosters come with "dumb" chargers that can kill the battery!

If you buy a raw battery and have your own adapter box with CLA sockets, you're better off. You will need an approrpriate charger though. This could be a full car battery charger or a small Battery Tender kit such as one offered by Deltran.

Warning: double check your polarity!

In general, centre pin positive for CLA connectors...

Warning: wear personal safety gear and appropriate clothing when charging seal lead acid batteries!

 

technical info:

  • dual outlets
  • fused, to avoid overloading and overheating
    • standard car-style large blade fuse
    • weather-proof fuse cover
    • 5 to 7 amps recommended for standard applications
    • 10 amps or higher for high loads *
  • analogue voltmeter, to quick assess battery level
    • crude but good for knowing the general health
    • surface voltage will read high immediately after charging
    • voltage should be high 12 volts, in general, for a healthy battery
    • voltage below 11 is usually very bad news
  • for powering astronomy equipment:
    • dew heater(s), primarily (see custom dew controller build)
    • telescope mount (see GoToStar system)
    • lights
    • portable hair dryer *
  • handy for charging a phone or computer in a pinch
  • independent of battery, i.e. easily swap in a new SLA as needed
  • case dimensions 9.5 x 6.0 x 2.5 cm

* a portable hair dryer will pop 5 or 7A fuses

build costs (per unit):

  • Sayal electronic parts CAD $20
  • digi-key parts (including shipping and taxes) CAD $20
  • Canadian Tire fasteners and fuse bits CAD $20
  • bits and bobs in my parts bins - free?
  • I built two units, two boxes actually, so to run two SLAs separately!

research and build time:

  • soft start date, on receiving raw SLA batteries: 28 Nov '09
  • end date, done dual-CLA outlet box: 7 Jan '11
  • some time shopping at Canadian Tire
  • some time browsing the electronic supply shops
  • an hour or so build time

lessons learned?

  • the project box used is a tad small but it worked
  • drill bits skate!

things I might add or change:

  • the connectors to the SLA battery as dependent on the battery's terminal type and may need to be changed
  • access to the fuse would speed a swap, so using a socket with external access would help; or the type of cover I used could be mounted outboard of the box
  • might need to bump the wire gauge if I plan to regularly push 10 amperes
  • a means of carrying an individual battery, a strap

 

 

SUNDAY, MARCH 13, 2022

everything needed

Parts for the CLA socket box build.

parts for the CLA socket build

  • parts
    • project box [Sayal]
    • CLA sockets, two, with integrated caps [Digi-Key Canada]
    • wire nuts, at least 2 (e.g. Marretts)
    • analogue voltage gauge by Hopesun [A1 Electronics]
    • fasteners for gauge, little nuts, bolts, washers
    • fine or small gauge wire for gauge, ideally red and black colours
    • fuse holder, water resistant [Canadian Tire]
    • push button, temporary or momentary on, single pole
    • wire, appropriate gauge for amperage, 22 AWG or bigger, ideally red and black colours
    • eyelet connectors for battery terminals (your mileage will vary, given the battery terminal type)
    • fasteners for battery terminals (I used appropriately-size bolts, nuts, and spring/lock washers) [Canadian Tire]
    • rubber grommet
  • computer resources
    • the world wide web
    • the amazing Evernote
    • Microsoft Visio (optional)
  • testing and verification
    • digital multi-meter
    • alligator jumper cables, for jumping
  • tools
    • side cutters
    • wire strippers
    • tiny screwdrivers
    • cutting knife
    • heat gun
    • drill
    • small bits for wires port and mounting holes
    • spade bit for push button
    • hole saw for gauge
    • pliers
    • soldering iron
    • sponge
    • eye protection
  • supplies
    • solder
    • water
    • shrink wrap
    • fuses, 5A, 7A, 10A... [Canadian Tire]

And I used a digital camera to photo-document things...

 

 

SUNDAY, MARCH 13, 2022

blog links - the build and other stuff

Scattered through the blog proper are detailed reports and updates on the build with some posts showing photos. There are some related articles linked, on using SLA batteries, etc. Reverse chronological order.

  • SLA with CLA adapter used in warm weather, 22 Mar '21
  • SLA with CLA sockets used in cold weather , 30 Jan '21
  • better way to test SLA batteries is with a calibrated ESV, 21 Mar '15
  • read about SLA battery and charger tips, 21 Sep '13
  • blew fuse with portable hair dryer, 15 Sep '12
  • see my talk about powering gear, 1 Aug '12
  • completed the dual-socket CLA adapter, 7 Jan '11
  • shoe-horned parts in small box, 31 Dec '10
  • obtained inexpensive panel meter from A1 Electronics, 20 Dec '10
  • used the deep-cycle batteries at Mew Lake, 11 Sep '10
  • with smart-charger topped up marine batteries in case, 27 Aug '10
  • what about a dual-battery source, parallel or separate? 23 Jan '10
  • cooler and cart for hauling two marine batteries around, 21 Jan '10
  • charged and tested the deep cycle batteries, 19 Jan '09
  • purchased a full smart car battery charger, 17 Jan '10
  • ordered CLA female sockets from Digi-Key CLA sockets, 15 Dec '09
  • received marine deep-cycle batteries, 28 Nov '09
  • considered building my own power system, 13 Nov '09
  • my first SLA battery for combating dew, 26 Aug '00

 

 

 

 

links

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