an any-voltage-input phone charger

The goal is to have a voltage regulator that can accept a very wide voltage input (a buck-boost converter), and it can charge a cellphone at least.

The input could be a wide variety of things:

• 10 AA batteries (or AAA or C or D)
  • for 10 zinc-carbon batteries, the voltage range would be ~9 to ~15 volts
  • for 10 alkaline batteries, the voltage range would be 6.2 to 15.9 volts
• a 9-volt zinc-carbon battery would have a voltage range of ~6 to 9 volts.
• a car battery (lead-acid starter battery) would have a voltage range of ~11.6 to 12.8 volts.
  • If connected to a running vehicle, however, then you would see an alternator voltage of 13.9 to 14.8 volts.
• a 6 volt lantern battery would have an actual voltage range of ?? to ~6.3 volts.
• All-electric vehicles have a battery voltage of ~400 to 800 volts, which will probably be outside the range of this project, unless they contain a 12 volt "cigarette lighter" outlet via step-down electronics.

two voltage converters

The theory here is that 12 volts is SUCH a common voltage to use in vehicles that you probably have some electronics for it already — you probably have a phone modern fast-charger in your car, and you may even have a portable power station that charges from 12 volts.

(note that it's 12 v nominal, 11.6 to 14.8 v actual)

(there was an attempt to move to 24 volt or even 42 volt systems in consumer-level cars, but that didn't pan out for reasons; higher voltage systems may be found on some RVs, larger boats, and commercial/industrial/military vehicles)

Specific products include:

• there are a TON of golf cart step-down converters in the range of 25 to 200 watts, but they require >12 volt inputs
• golf cart converters that are both buck+boost:
  • brand "HomeLylife", input 8 to 40 volts, 72 watts
  • brand "Yipin", input 8 to 40 volts, 72 watts
  • brand "HomeLylife", input 8 to 40 volts, 138 watts at 13.8 volts out
    • This has lots of great reviews! (though that Amazon page has many semi-related products on it)
  • brand "Tobsun", input 8 to 40 volts, 138 watts at 13.8 volts out
    • may be a re-brand of the above?
  • brand "XWST", input 9 to 36 volts, with several products ranging from 120 to 360 watts
    • The reviews note some real problems. If input voltage drops too low, it's reported you need to restart it before it will resume operation.
• brand "Valefod", input 8 to 36 volts, 128 watts
• brand "Aoicrie", input 7 to 32 volts, 108 watts (adjustable voltage output too, but I likely wouldn't use that feature)
• brand "JacobParts", input 5 to 32 volts, 80 watts (adjustable output voltage too)
• products that include an ammeter:
  • brand "DROK", input 6 to 30 volts, 60 watts (adjustable voltage output too)
  • brand "CenryKay", input 5 to 30 volts, 35 watts (adjustable voltage output too)

a single voltage converter

Obviously this would be more efficient. However, it would need to integrate the latest fast-charge standards, which means it could lag behind a bit, if it sits in the emergency kit for too long.

Specific products:

• fast-charge standard "QC 3.0", brand "DROK", input 6 to 32 volts, 24 watt output max
• fast-charge standard "QC 3.0", brand "HiLetgo", input 6 to 32 volts
• fast-charge standard "QC 3.0", brand ??, input 6 to 32 volts, four USB Type-A ports
• fast-charge standard "none", brand "HiLetgo", input 6 to 20 volts, 15 watt output
• AliExpress, fast-charge standard "PD", brand ??, input 3 to 24 volts, allegedly 100 watts but for $8 I don't believe that
• random website, fast-charge standard "PD 3.0", brand ??, input 6 to 35 volts

accessories

For the 12 volt version, I would want a female cigarette lighter socket.

For all of them, I would want a variety of battery-holders, including:

• 10 AA batteries
• 10 AAA batteries (I couldn't find one on Amazon, other than possibly jury-rigging one from this)
• 9 volt batteries (maybe two soldered in series?)

For all of them, if they don't include terminal blocks, then get a butt-terminal-block, to make it easier to connect various inputs to.