The Stovebolt Site Forums The Shop Area The Electrical Bay Phone charger on a 54 3100 6v?

I understand that a car phone charger reduces 12 volts to an output of 5 volts to charge a phone.
Any reason not to simply install a USB phone charger in my 54 3100 6 volt truck?

You could try, but it might or might not work depending on whether or not it has an LDO (low drop out) regulator.

You have to have a minimum voltage difference between the input and the output that varies somewhat based on the specific design.

Try one and see what happens. Worst case it just won't work. You might try an adapter that supports USB-PD since they have to have boost converters anyway. I think they would be more likely to work than some random one.

Can you plug it into the cigarette lighter?

My truck is a base model. No cigarette lighter. Hoping someone can tell me if it would work or not before I spend a bunch of money at a failed enterprise.

Good excuse not to worry about the phone. Turn it off and drive. Check messages at your destination.

An electronics place like Radio Shack should have a "voltage doubler" available that will support a USB charger. The current draw is super low for most USB devices, so there's not much risk of overloading the doubler by demanding too much current from it. A "6V" charging system actually operates at 7.5V against a fully charged battery, so the output of a doubler will be 15V.
Jerry

All the usb chargers I’ve tried in my 6v truck work just fine
The modern ones all buck the voltage down
So worst case they need literally like 0.1v more than the regulated output to function
So just try it and see, if it works good, if not try a different one.
-s

A typical regulator requires minimum ~1VDC between the input and output voltages. An LDO is typically in the 0.3VDC range.

I will throw a couple adapters on my bench supply this weekend and see when they drop out. With an operating voltage of 7.5 like HRL mentioned, I would expect any of them to work. With the engine off and just the battery voltage as the source, you could get some weird switching issues and much more parasitic drain than you expect.

I would recommend ignition switching the power if you do go down this route.

I have 6v truck and just bought this so I can run a 12v dash fan. 6V to 12V Step Up Converter. Amazon. $13.99 I added a lighter plug receptacle to the bottom of my dash. I can plug any 12v accessory into it.

Don't overload it! That would be the ideal approach to adding a USB port to a 6 volt vehicle, however.
Jerry

Yes, I checked before installing. Fan only uses 1.3 Amp. I can't imagine a phone charger uses any more.

Probably considerably less than 1 amp. I could see the possibility of an electrical novice trying to run a heater blower with a 15 amp current draw and getting a "positive smoke check", though!
Jerry

Now we are thinking like NASA engineers on Apollo 13. We need to keep the amperage below 3 amps for start up.

From what I've read it depends on the desired rate of charge and not a lot more than that. About a year ago I got a new phone and it was clear it needed a minimum of a 2 amp to charge as designed. I have 2 A/C "wall warts" I can use with it. One takes in .5 amp and outputs 5v at 3 amps and it charges the phone fairly fast. It also provides 9v at 1.6 amps and 12v at 1.2 amps. The other outputs 5v at 2 amps and it charges slightly more slowly and will be warm in use. My wife's phone wants at least 2.4 amps to charge and will charge using 2 amps but again it will charge more slowly. Now for what it may or may not be worth, I have another (older) A/C plug-in charger which takes in .15 amp and outputs 5v at 1 amp. It will charge the more amp-hungry phones plus iPads and any other similar device. It just takes several hours to do it. So I wondered about the 9v and 12v output stuff and did some looking. Here is an article I saw back then which I thought was interesting: https://www.pcmag.com/how-to/what-is-fast-charging

The simplest way to rough out the current draw is to look at the wattage output. 15W-30W is pretty normal these days, which works out to 3A-6A at 5V. Once you take switching losses into account, it would be about the same current on the 6V input or roughly half that current on a 12V input.

@Jon: USB Fast Charge has evolved into USB Power Delivery. This is a decent summary: https://www.makeuseof.com/tag/usb-pd-power-delivery-charger/

Thanks for the link. $220 to $330 for a charger is outside my price range, but I might get one of these for $14.99: https://www.microcenter.com/product/647731/inland-3a-usb-type-a-usb-type-c-wall-charger

Around 2016 I swapped an electric outlet for one which had USB charging also and it works really well. I might do the same thing on another outlet with this: https://tinyurl.com/jp7cep6y

Jon, that $14.99 charger plugs into the 110v AC outlet in your house, not the 6 or 12 volt DC outlet in your truck.

bought a couple USB PD 12V plugs for under $10 on prime day. The really expensive ones exist, but are not the norm.

I knocked out the blind for my trucks cigar lighter and installed a cheap Auto Zone replacement lighter several years ago. Still charges my phone fine. 6 volt system with alternator. Max output is about 7.5 volts.

RonR