28V DC 'Cigarette lighter' sockets...

[Aucky]

phone, arguably, but there are a world of other toys useful to recording instructional flights and documenting trips, cameras, audio recording, navigation, weather, approach plates etc... waiting for it.. 'you could always use a map, blah...' i do, but the point is, used properly these devices can be good to help students benefit from debreifing their lessons, useful as nav aids, useful in the event of a radio failure (most new top end head sets providing bluetooth calling, give the tower a phone call and coordinate your runway crossing or state your intentions etc...)

I think it's understandable that there are uses for electronics that are not catered for as standard as the aircraft were designed before the gear was.

I wouldn't take a chance that a phone or something else not essential for flight my be slowly damaging itself or maybe the wiring in the helicopter while I'm blissfully unaware in the front.

Quite my reason for asking here as opposed to the 'suck it and see' approach, non essential? probably, but so is the flight and it's associated risks in many cases. Good fun worth documenting, yes please

Eye in the sky...

Gaseous & Tailboom - I agree that often it may be fine, but even the products that I have seen that have voltage regulators included designed for car use often stipulate an input range of approx 11v-18v.

With regards to the 24v-12v lorry voltage convertors etc... surely they are still not correct, because although the battery voltage is 24V the main bus in the R44 II is running at 28V from the alternator, and so surely are the components, the schematic clearly shows that the aux power feed is direct from the 28V bus... this is why I have gone for the 28V-12V from Sportys that EN48 linked

Aucky

[Gaseous]

Gaseous & Tailboom - I agree that often it may be fine, but even the products that I have seen that have voltage regulators included designed for car use often stipulate an input range of approx 11v-18v.

I think you misunderstood what I meant.

To clarify. Just because the regulator will work satisfactorily doesn't mean the device is safe to use. Its not fine unless it says suitable for 24v

[500e]

We use converters on lorry's, boats, trains.hovercraft, & it would not worry me to plug into aircraft socket which has a circuit breaker, with any sense you will put a quick blow fuse with a lower value than the CB in the supply to the converter & in the output line, but if you read the bumf most good units have fold back so if the OP has a short or excess current they disconnect.
they also draw only very low current when off load.
Read the specs from the links I posted, all good converters work over a given voltage,
the battery voltage will vary linked to charge rate condition of battery etc.
here is a clip of one.
Input voltage range
17-32Vdc
Output voltage
13.6Vdc +15% -20% at extremes of temperature, load, input tolerance, etc.
Intermittent output power
As stated, taken for a maximum of 2 minutes followed by 8 minutes rest.
Transient voltage protection
Meets ISO7637-2 International standard for 24Vdc commercial vehicles
Electrostatic voltage protection
Meets ISO10605, ISO14892, >8kV contact, 15kV discharge
Output noise
<50mV pk-pk (100mV on 24V units) at continuous load. Meets CISPR25 and VDE0879-3
Off load current (quiescent current)
<15mA
Power conversion efficiency
Typically: 90% for non-isolated units, 85% for isolated units
Isolation
>400Vrms between input, output and case, on isolated products only
Mean time between failures
>162 years (HRD4)
Operating temperature
-25ºC to +30ºC to meet this specification table
+30ºC to +80ºC de rate linearly to 0A
Storage temperature
-25ºC to +100ºC
Operating humid