clean 12v from battery?

Hi, first post here. I'm relatively new to electronics and I could do with a bit of help with my project. My goal is to install a front and rear facing camera system on my motorcycle, but, I'm a bit worried about plugging the cameras and DVR straight to the motorcycle's electrics. Specifically the high voltage (+14V) when the engine revs up and the potential for surges. First question; is it OK to plug in my cameras and DVR which run on 12V without regulation or surge suppression to the battery (also 12V)? Ok, not straight to the battery but via a relay switched by the ignition key. If not, what sort of circuit would I need to regulate the voltage and supress surges? I did a bit of research and I've designed a circuit around the LT1185 LDO regulator (below). It has a drop out of about 600mV at 2A which should be good for the cams and DVR. Finally, how can I adapt the circuit to deal with surge? If necessary that is. Many Thanks, Dave

Image didn't upload, didn't read :( Anyway, uploaded to imageshack; https://img571.imageshack.us/img571/3857/dsc09770medium.jpg

You are reading way too deep into it. 14 volts is the norm.

i am an idiot wrote: You are reading way too deep into it. 14 volts is the norm.

I'm aware lead acid batteries are normally around 14V, my worry is the alternator which pushes the voltage up over 14V, closer to 15V. Not only that, what about surges? e.g. the surge from the starter motor? I forgot to mention in case it's relevant, this stuff will be fitted to a Honda CBF125, a cheap bike.

Ditto. To clarify, if they are for a 12V automotive or battery system, then they will (should!) handle typical 12V system fluctuations including voltage spikes (typically 100V - 400V). Such designs typically handle up to 16V and down to maybe 8V. (Typical voltages are 14.4V max long term charging voltage; 12.7V full battery; ~11.5V for a 100% discharged battery; and during cranking down to 10V or 9V and maybe 8V for a bad battery.) If it is for a "regulated 12V" supply, that's different. It may only tolerate say 11.5V - 12.5V. But a 12V automotive camera etc means the typical 8 or 10V to 15 or 16V variation, plus normal spikes.   

oldspark wrote: ... If it is for a "regulated 12V" supply, that's different. It may only tolerate say 11.5V - 12.5V. But a 12V automotive camera etc means the typical 8 or 10V to 15 or 16V variation, plus normal spikes.

In that case the camera I've chosen should be ok but the DVR looks like it could be a problem, look up "C-DVR", it doesn't look like it's designed for automotive use. The C-DVR is the cheapest DVR I could find which can continuously record when it's powered on. DVR's designed for automotive use are too expensive for me, hence, the trouble of stitching together a cheaper alternative. I'm still waiting for the C-DVR to turn up, when it does, would it be possible to find out if it's good to run without regulation by examining the circuitry?

When you get the DVR, if it comes with a 110 volt wall wart to power it, plug that in and read the voltage getting to the DVR.

i am an idiot wrote: When you get the DVR, if it comes with a 110 volt wall wart to power it, plug that in and read the voltage getting to the DVR.

It should be 12V, which I neglected to mention in my OP. Both camera and DVR run on 12V.

When you get the unit, if it has a power supply that plugs into the wall, plug it in and use a meter and read the actual voltage that the supply puts out. It will more than likely be around 16 volts.

I'm not expecting the DVR to arrive any time soon, so to pass the time I'll make some assumptions. Assuming the power supply is pretty much 12V, would that suggest I'd need a regulated 12V supply? Now, let's assume I need a regulated 12V supply. Would the circuit in post 2 be ok?