Winston - you saying you dont bother with converters, just happens to work on a 6V with the socket wired in?
Apr 4, 2017 - 8:26AM
Re: Charging iPhone off 6v battery.
I have fitted a cigar lighter socket in my car and use if for my phone charger and my TomTom. My son uses it for his smart phone.
I just use the cigar lighter adapter supplied with each device.
These are rated 12 to 24 Volt but all work fine on 6 volts.
The phones are 3.5 volts so there's plenty of headroom and the TomTom is OK even though it's quite close at 5.5V.
It's obvious that many 7ers have "got away" with running phones and satnavs direct from the 6volt to 7.5 volt supply in a 7. I say "got away" advisably because if you read through the thread linked to above one person reported his satnav soon becoming terminal.
These things are designed to see a nice clean, regulated 5 volts and on the face of it 6 volts is not that much more. But as Martin Baker commented in that thread the 6v to 7.5v in a 7 is definitely not clean or well regulated.
Horrendous spikes of voltage can occur especially as a result of the crude (by modern standards) charging current control.
An obvious danger of taking the said 6 volt supply from some convenient point behind the dash board is of a temporary disconnection of the battery - a few milliseconds would be plenty - for the dynamo voltage to soar to perhaps 30 0r 40 volts.
I wouldn't do it myself but at the very least I would use a low drop out regulator as mentioned often in that thread. They are cheaper to replace if something does happen to it
If you must do it, take the 6 volt supply to the cigar socket with a wire direct from the battery where spikes are partially tamed by the battery and momentary connection problems would not expose the device to the unloaded dynamo's output.
This http://www.reuk.co.uk/wordpress/electric-circuit/lm2940-12v-1a-low-dropout-regulator/ is a good read..just think 6 volts wherever it says 12volts. Note the max current is 1 amp.
REUK also sell the 12 volt one ready made in a nice box for £3.99. An LM2940 5volt chip could be bought separately off eBay and substituted for the 12 volt chip it comes with. http://www.reuk.co.uk/wordpress/voltage-regulators/buy-12-volt-regulator/
of course there also the boost/buck switch mode converters from China. Although I've used them successfully I won't go there !
Before someone points out that the battery clamp itself is a contender for a loose connection I suggest drilling into the lead +ve post and taking the wire (via a fuse of course ) to a solder tag fixed with a self tapping screw in the hole just drilled :-)
Another thought ! I wrote the previous on the assumption that folk have modified a USB lead to connect directly with a 6 volt powered cigar socket..
Perhaps someone could clear that up.
I have no idea if any of the 12 volt charger plug/leads will work down to 6 volts (they do have a built in regulator that drops down to 5 volts) and its not unusual for them to accept a wide input range.. In that case there is a measure of protection. Any exceptional spikes would hopefully only blow the charger plug.
If you have an iphone and take advantage of the excellent Satnav it contains when driving, does this count as 'using the phone while driving' and leave you exposed to the recent increased penalties recently introduced?. (£200 + 6 points )
Just a thought.
Yes it does unless the phone is in a fixed holder/mount.
Apr 10, 2017 - 8:27AM
Re: Charging iPhone off 6v battery.
I fitted flashers to my 1931 Box but did not want to mess with the existing 6v electrics so I used a small 12v battery to connect the flashers to.
It occured to me then that the satnav could also be fitted.
The battery lasts several weeks with moderate use.
As a matter of interest have you thought of carrying one of these USB/Stareter packs. I know it is 12 volt but it will power your electronic devices and will start the car in an emergency,as long as the lights are all turned off to prevent the bulbs from blowing. I am 12 volts on my RP so I carry mine in the modern and the Seven.
On my Ruby I got around all these problems by fitting a 6 to 12 volt inverter
that I bought cheap on eBay. Yes made in China but works well and is only the size of a matchbox. It's out of sight under the dashboard wired to a fully insulated cig lighter socket. Not only will it work the sat nav and phone charger it also supplies enough to power my small tyre inflator.