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.
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:
- 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
- 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
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