Electrical noise from iphone charger, solution?

[bugflipper 10+ year member]

No need in explaining the noise, we all have heard that buzz associated with a weak ground or power wire near rca. It only does it when the iphone is charging, that's what I use to play music. Any noise filters for a 12 cigar plug? Or maybe ground the plug better? It does it in the dash plug as well as the rear console plug in.

Thanks

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[dgaf 10+ year member]

i use one of those power inverters, plugs into the cigarette lighter, then gives you 110vac outlet, then I plug my regular wall charger into that and to my phone, no more noise... also, charges A LOT faster...

 

[keep_hope_alive Premium Member]

^agreed, that works. those inverters have better power supplies and built-in noise filtering.

the problem is that the cheap cig lighter charger is producing noise that gets back into the power wiring.

a simple inductor in series with the cig lighter 12VDC lead may solve your problem. the inductor is a low pass filter, so switching noise is suppressed. the larger the inductor value, the better isolation you get. you can pick one up from Parts Express for a few bucks (iron core is cheaper than air core). just take note of the inductor ratings and AWG for the available power output. 18 AWG is typical and good for 10A (so add a 10A fuse).

like this:

N25-T AN IN-LINE ALTERNATOR NOISE CHOKE – 30 AMP  - $0.00 : Zen Cart!, The Art of E-commerce

P.I.E. NF-20 20 AMP In-Line Power Lead Noise Filter

 

[dgaf 10+ year member]

^agreed, that works. those inverters have better power supplies and built-in noise filtering.
the problem is that the cheap cig lighter charger is producing noise that gets back into the power wiring.

a simple inductor in series with the cig lighter 12VDC lead may solve your problem. the inductor is a low pass filter, so switching noise is suppressed. the larger the inductor value, the better isolation you get. you can pick one up from Parts Express for a few bucks (iron core is cheaper than air core). just take note of the inductor ratings and AWG for the available power output. 18 AWG is typical and good for 10A (so add a 10A fuse).

like this:

N25-T AN IN-LINE ALTERNATOR NOISE CHOKE – 30 AMP* - $0.00 : Zen Cart!, The Art of E-commerce

P.I.E. NF-20 20 AMP In-Line Power Lead Noise Filter

i've read this a couple times, and i'm still not grasping it...

there's three wires on this P.I.E. NF-20 20 AMP In-Line Power Lead Noise Filter so how would it wire in line with the feed to the cigarette lighter?

what's this issue actually called too?

thanks

 

[keep_hope_alive Premium Member]

you're just wiring an inductor in series with the power lead - inductors increase impedance with frequency. so at DC there is minimal resistance. but as frequency increases, so does impedance - exponentially. the size/value inductor you choose will determine what frequencies are filtered out.

some designs also use a transformer to perform the same function, but sink noise to ground. the three wires are:

red - 12VDC in

blue - 12VDC out

black - ground