Power Regulation

[nightster]

 I just upgraded my guide cam to a nice Lodestar I found on the used market. This has cause me to change the setup a bit and I am thinking about power supplies again.  I use a large Deep Cycle 12v battery to power my imaging rig.  I have read many different topics concerning power. Some use multiple batteries, DC DC buck/boost converters, etc.

How sensitive is my 460 to the voltage changes cause by a discharging 12v battery?  Do I need to consider some type of regulator for the CCD or any of the equipment?  And in addition I am still looking for a USB hub that can be powered from 12v, any ideas?

[seo]

Hi Jeff,

A. If you're using your rig in places where the only means of powering it is only batteries and no mains power is available then try to have a fresh charged battery-ies with the proper Amps for the time you schedule to use it. Example : if you have a 12V battery rated at 60 Ah then your battery can give a total of 720 Wh (Watt hours) but it will be complete drained, that's if its full and properly charged, but if you do that then most propably your batter will be ruined (even if its a Gel battery and you manage to recharge it you'll have take a good 70-80% out if its life. With good deep cycle batteries and Gel batteries and to be in a "safe" discharge area you can stress your discharge up to 50-55% of the total Wh. So in relation with the previous example your max safe discharge will be around 360-380 Wh. So if you have lets say a CCD which needs a max of 2A at 12V when its cooled to its limits then you have a total consumtion of 24 W per hour, if you divide the lets say teh max average of 370 Wh / 24 Wh thats equal to 15,416 hours of usage before you start to harming the rechargeability of your main battery. So if you calculate the total consumption of your system you can find out how much "safe" time you'll have for each session if you have previously properly fully charged your battery.
If you're using your equipment in a mains power available area I suggest an AC to 12V DC stabilized Power Supply converter rated lets say at 20A and keep your battery as a backup.

B. Dropping down the supplying voltage when a CCD is operating will not harm it, it will only cut off its operation suddenly when it reaches its "down" voltage limit and of course ruin your session, So try to have a proper charged battery and calculate the time/consumption you'll have. Rising the voltage from the other hand is extremely dangerous to catastrophic even if your CCD has a protection for this scenario so putting an extra fuse or a properly calculated high Volatge protection in your system in a good idea.

C. You can easily make or buy a DC to Dc voltage converter, this link for example : http://www.amazon.co.uk/dp/B008VORADW/ref=wl_it_dp_o_pC_nS_img?_encoding=UTF8&colid=18ILLU685RTOP&coliid=I1I1P6J27KZV9H. In your case a 12v to 5v rated at 2-3 Amps and then you can supply your Usb hub. Keep in mind that Voltage converters can be made or found in many different voltages and Amps so you can easilly suplly from a 12V battery other equipment too.

[seo]

A follow up...

I omitted to write the following : The suggestion, in my opinion, of a 20A rated AC to 12V DC stabilized Power Supply converter was only for a max total system consumption of about 15A. The AC to DC stabilized converters all have an 1) Continuous max  Amp supply rating and 2) Momentary max Amp supply rating (for starting motors etc.) We only calculate for our system the (1) taking under consideration not to go over the 75 % of its continuous max  Amp supply rating (for thermal issues). So if for example your total system Amp consumption is 20A you need about 27A of continuous max  Amp supply rating.

[parallaxerr]

Here's another alternative for your USB power supply...

https://www.hobbyking.co.uk/hobbyking/store/__4319__TURNIGY_3A_UBEC_w_Noise_Reduction.html

I've used these over the years and they're excellent, clean switching regulators with 5v/6v selectable output. Don't think I could make one any cheaper! TIP - if you go for one, follow the link and let the page sit for a while then you'll get a first time buyer offer pop up and get it for about 30% less

[nightster]

Brilliant. I often forget the RC world is a good resource for power products.

[parallaxerr]

nightster, on 14 Oct 2015 - 1:18 PM, said:

Brilliant. I often forget the RC world is a good resource for power products.

Yes it sure is, I'm also using RC airplane 3S LiPo batteries to run my goto. They require a little extra technology to charge but are so small, lightweight and energy dense. This little 850mAh does me for two nights observing easily, probably 6hrs in total and no cord wrap