Celestron PowerTank Modification

[cpartsenidis]

I decided to share my PowerTank modifications for those interested.

I wanted to eliminate my Canon DSLR battery so that the DSLR can obtain its power directly from the Powertank. The circuit used a LM317 Chip, which provides 1-12V output with a maximum of 1 Amp (1.5 peak) and also includes a LED display (volt meter). The voltage is adjusted using a small philips screw driver.

The most difficult part was cutting the Powertank's plastic so that the LED display would fix exactly. The end result was really pleasing and the LED display looks really nice.

The circuit's output was wired to the 3V output, as I've never used it. Ideally I wanted to place the LED display right next to the output, but I couldn't get the the Radio and Volume knobs off, so I decided to move the display to the other side.

I'll be posting additional modifications to this thread. Next mod includes a red digital voltmeter, connected directly to the 12V 17Ah battery, so I can monitor its voltage and a dual temperature sensor, so I don't need to carry my thermometer any more with me.

Hope you enjoy!

[Gina]

That voltage display looks a nice neat job

[cpartsenidis]

Gina, It actually looks much nicer than the photo. The photo really does it no justice

I personally would have preferred the LED display to be red colour, but was unable to find a compatible one, so I settled for the green one.

After opening the powertank and examining the internals, I must admit, it really isn't worth the money it sells for. The build quality is poor and circuit design very old.

[JamesF]

That looks like a very neat job.

There's not a lot in there when you open it up, is there? They obviously have an issue with the PCB design, too, as they've manually broken one of the tracks on the charge controller. I have no idea how many Synta sell, but you'd have thought they'd have that fixed.

James

[cpartsenidis]

James,

Mine was bought in December 2011 and its a 'newer' model with the LED light (instead of the bulb) and main PCB still has that cut you mentioned. The quality of the PCB board is amazingly low and the radio is the same build old radios used 15 years ago!

Taking in consideration the above and purchasing price here in Greece/EU which is around 160-190 euros, I consider it a complete rip-off.

The bad thing is that its darn useful as it successfully replaced my UPS and is easily able to take me through the night. In fact, with simple viewing, it hasn't ever fully discharged. We'll see how well it goes now with the DSLR camera on it as well

[Leo.A]

Just curious about the voltage meter (multimeter) fitting.

Would an amp meter be more useful to show the current draw?

I guess it's knowing the cut off voltage of where the battery is beyond use which is more appropriate.

I always prefer ammeters in my cars than voltage displays but that's just me.

I'm contemplating building my own powertank and haven't decided on batteries yet, weight is a big factor.

What happened to autocorrect since the upgraded (new look) forum?

Is there a setting I can use?

I have a horrid keyboard with close keys and even my incredibly good, son's typing goes astray on this stupid keyboard.

If it wasn't wireless and cheaper to maintain (batteries) than the old Aldi unit I had, I'd toss it.

[JamesF]

I assume the idea of the voltmeter is so you can see what voltage you're setting it to when you adjust it with the screwdriver, and so you don't forget what it's set to in three months time when there's a break in the cloud.

James

[pete_l]

I wanted to eliminate my Canon DSLR battery so that the DSLR can obtain its power directly from the Powertank. The circuit used a LM317 Chip, which provides 1-12V output with a maximum of 1 Amp (1.5 peak) and also includes a LED display (volt meter). The voltage is adjusted using a small philips screw driver.

I've recently discovered that you can get cheap switch-mode modules off eBay

These cost a little more that £1 with free delivery from China. The multiturn pot adjusts the output voltage and can supply 2 Amps with very little voltage droop. All you have to do is provide an input voltage of up to 35V to the inputs and you can get any lower voltage from the output side.

Being SMPS's they are very efficient, so they won't use up much battery power and won't waste much of it as heat.

Given the price, I now keep a few for casual projects, rather than ordering them when I have a particular project in mind.

[Gina]

I've recently discovered that you can get cheap switch-mode modules off eBay

These cost a little more that £1 with free delivery from China. The multiturn pot adjusts the output voltage and can supply 2 Amps with very little voltage droop. All you have to do is provide an input voltage of up to 35V to the inputs and you can get any lower voltage from the output side.

Being SMPS's they are very efficient, so they won't use up much battery power and won't waste much of it as heat.

Given the price, I now keep a few for casual projects, rather than ordering them when I have a particular project in mind.

Very interesting - thank you I'll get some

[cpartsenidis]

For those interested, the circuit I used was also purchased from ebay.co.uk and it cost just about 5 pounds, which includes shipping. I was actually surprised of the high quality!

Here is the circuit:

And Leo, I'm actually going to put an amp meter as you mentioned. I first wanted to get the DSLR supply sorted out and then proceed with the Volt/Amp meter for the battery and temperature/humidity sensor. This way, the Powertank will be an all-in-one tank

[Leo.A]

Wow, I'm going to search for those switch mode supplies, I want half a dozen in my sons kit (I studied electronics engineering many moons ago but have forgotten most of it, most of everything).

Do you have a part number or identifying number/name for the adjustable circuit in your last post?

I'm sure my son would like one or two of those too.

Thanks!

[cpartsenidis]

Leo,

Just go to ebay and search for "PX-1011:LM317" you'll fall right on it They are cheap, excellent build and well worth the money - you even get a free screwdriver