Do it Yourself Telescope Field Battery
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Hopefully you haven't purchased one of those "all in one" power supplies for your telescope! You have seen them, they are nothing but a joke! Who needs a blinding white flashlight while you're under the stars!
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This will cover how to build a Telescope Field Battery that works!
I use this field battery for powering all of my Astrophotography imaging. This includes powering my laptop, mount, focusers, dew heaters, and cameras.
One thing to consider is the AH (Amp Hour) rating of a battery. Each item you run...draws amps. You need to add up all of the amps of your equipment, and then you can decide what battery to purchase. You will need a DEEP CYCLE battery. Regular car batteries cannot take the cycle of being discharged, and recharged.
In this example we will build a 125AH field battery. This means if you draw 10 amps you will be able to power your equipment for 12.5 hours. Most of those "All in One" power supplies have less than 20AH...makes for a short night when your imaging.
Here is the shopping list you will need:
| Qty |
Description |
Location and Cost (8/2009) |
| 1 |
Everstart Marine Maxx 125AH Deep Cycle Battery |
Walmart @ $75.00 |
| 1 |
Plastic Battery Box |
Walmart @ $7.48 |
| 2 |
ATC Fuse Holders |
Walmart @ $1.27 ea = $2.54 |
| 2 |
3 Way Power Strips with Power Switch made by BELL |
PepBoys @ $9.99 ea = $19.98 |
| 1 |
Pack of Stove Screws |
PepBoys @ $1.79 |
| 1 |
Pack of ATC 7.5AMP Fuses |
PepBoys @ $2.99 |
| 4 |
Eyelet Crimp Connectors |
|
| 1 |
Electrical Tape |
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| |
Project Approximate Cost |
$110.00 |
An Important Note About The Power Sockets: Try to get one with a switch. Bell seems to be the only
manufacturer
that supplies a no thrills switch.
You will need a hand drill, screw driver, wire strippers, razor blade, and cutting diagonals for this project.
First we will need to mount the power sockets to the top lid.
Remove the four screws that hold the two halves together.
Split the two halves.
Next, Clip the Cig Adapter OFF, and pull the cable through the back half.
Now you can take the Mount Plate off, and position it on the Lid.
Use the Stove Screws and mount the plate. The position of the screws are not important, just be sure it goes through the lid, tighten down so the mount plate is securely fastened.
Now use a small drill, and drill holes for the four screws that hold the halves together. Don't drill the mounting plate! Just drill through the lid. Also drill a small hole for the main wire cable to go through the lid.
Remove the Mounting Plate, and Now your lid should look like this...
Now drill the pre-drilled holes larger...large enough to pass your screws to hold the halves through.
Mount the Plate again, and grab your ATC fuse holder.
Drill two large holes through the plate, and the lid. These holes are for the fuse wires to go through. You can pull
the main wire through the lid too.
From the top you can see how the fuse wire slide down between plate, and lid.
After you pull the fuse wire through the lid...
Place the front half on after you feed the wire cable through...don't forget your fuse wires!
Screw the halves together...use the four screws you removed earlier.
The wires should look something like this.
One Side Done!
Repeat, and mount the other side.
Strip the wire, use a razor blade or sharp knife to expose the wires, and peel back 3 or 4 inches.
Cut the red wire. We will splice the fuse here.
Strip the red wire, and strip the yellow fusewire, turn the ends together, and use electrical tape to wrap it up. We left the negative wire intact, and did not cut it. We simply spliced a fuse in the positive lead.
Take your typical crimp-on connectors, and attach to stripped wires. I used some electrical tape for extra support.
Use the wing nuts supplied with the battery, and attach wires to battery. If you are uncertain of which wires are positive or negative, use a volt meter. The socket should have POSITIVE as the CENTER.
Place cover on, move wires to fit under the lid. The extra length of wire is good for recharging your battery. It will allow you place the lid to the side. Insert the fuses.
You should be able to see the red led light up now. Again, If you are unsure, check the power and make sure you have positive as the CENTER post inside the cig socket!
Take the extra fuses, place in a zip lock bag, and store inside the batter case. You can experiment around with different sizes of fuses. 7.5 AMP is about the most you should try. The sockets are rated for 5AMP, but I run 7.5AMP no problem.
You can use paper towels for covers. They are cheap, and work well. While you store your battery remember to recharge after use, cover plugs, and if you have a small trash bag you can use it as a dust cover.
