3 (hopefully quick fire) questions :)

cormie

Unfortunately I haven't a clue when it comes to electronics and I just have 3 queries:

1) I have a dash cam set up in my van, I have the power cable wired to the back of my radio, which I believe was 9v (done by an auto electrician) and I'll be replacing that camera with the one below which I think takes a 5v usb connection? (volts may not even be the right term, that's how bad I am)

The male on the right is the power cable for the old cam:

(that's a regular 3.5 audio jack on the left)

Then this is the usb female for the mini cam:


Would this work, or would the difference in rating need something else done so it doesn't blow the new 5v cam?

http://www.ebay.co.uk/itm/DC-Power-plug-adapter-3-5mm-1-35-female-socket-to-mini-USB-5v-NOT-AUDIO-/251403531593?pt=UK_CE_GPS_Accessories_Software_ET&hash=item3a88d17549


2) I'm about to buy this: http://www.amazon.co.uk/gp/product/B0088U4YAG/ref=ox_sc_act_title_1?ie=UTF8&psc=1&smid=A3H9QVQ3445GSN

I want to have 4.2a available if I ever need it. There's also this nicer looking, higher rated one, but it appears it's 2.4 max per port, as opposed to the above being 4.2 max shared between ports, so one port could be 4.2.

Anyway, the question is regarding charging phone batteries. My friend wants one too but says he'd prefer a low charge one .5amp/1amp or so as he says fast charging the battery will kill it quicker if done regularly? Is this true?

3) If I charge my phone and play music through the car head unit at the same time, there's a noise that seems to relate to the acceleration of the car, the higher the revs, the whinier the noise. I think this is called ground loop isolation and I've seen two videos here:

https://www.youtube.com/watch?v=0A_c_yIbCTA

https://www.youtube.com/watch?v=8PnLke3QURY

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The charger I linked to above may help too as there are some reviews saying it cut the noise compared to other chargers. Besides the charger and two video solutions above, is there anything else this could be before I start messing around?

Any help would be greatly appreciated

whizbang

You cannot use the Ebay cable that you have shown.

The plugin Adapter will work fine for the camera, and anything else that uses USB power.

There are very few devices that can use all the available power from that Adapter, so phones won't charge too fast no matter what they are plugged into.

Noise- suck it and see.. Unless the adapter specifically says isolated, there is no way of knowing.

cormie

Thanks a lot for the replies Adapters are in the post so fingers crossed!

I wasn't actually planning to use the adapter to power the camera, I had the wiring of my old camera installed by an auto electrician so was hoping I'd some how be able to power the USB port with the power from the cable that's currently there, not sure of thebest way to go about this though

whizbang

you need a Dolly Parton so..;)

cormie

I'm not getting the reference Is there an electronic device called a Jolene?

whizbang

a working 9 to 5 adapter!

Sorry, I'll get me coat..

whizbang

Even then, you may not be able to use an adapter.

Usb devices are supposed to communicate with the power supply, before using the power- so the camera may still need a usb power adapter.

cormie

haha, that's a good one Ok, did a google and can't find anything really that's premade that looks like it'll do the job. Unless I was to get a rechargeable battery pack, plug the 9v into that and then have the usb attached to that?

cormie

Well I received the adapters today and unfortunately the noise is still there when charging, I might have to go with one of the methods in the two videos so

whizbang

If you are using a regular 3.5 audio jack, get a spare lead, and try disconnect the ground/shield connection at one end.
It means cutting into the cable. That way there is only one ground connection, so there should be no ground loops

Also look for laptop audio isolators, they are similar to what's used in one of those videos.

cormie

Thanks for that. Yep, I'm connecting the music player to the head unit with a 3.5 lead fromheadphone jack to aux in. Do you mean a spare 3.5 to 3.5 audio lead and cut into that? How would I know which theground is? Brown wire is it?

Sorry, I'm pretty bad when it comes to this stuff! Would it be dangerous to get rid of the ground? hehe