Where Can I Find a Step-Up Adapter for 12V to 400V Charging?

[Yrton]

Good day.
I'm looking for designing/purchasing a step up adapter with the capability of stepping up a 12v battery source (like a car battery) to 400v for the purpose of charging a 1800uf, 450v, capacitors to 400v.
Can you point me to the right direction?
Thanks.

 

[rootone]

This?
https://en.wikipedia.org/wiki/Boost_converter

 

[NascentOxygen]

Hi Yrton.

Will there be any charge drawn from the capacitor while it is connected to the 400v?

 

[jim hardy]

You do realize that 1800 uf charged to 450 volts contains 182.5 joules, about same energy as six firecrackers? It could really maim a hand.

Keep this contraption well away from tiny fingers .

old jim

 

[Tom.G]

Xenon Strobe Lamps (or Stroboscopes) used in photography do that to charge a capacitor to fire the lamp. There is often a small version (lower input voltage) built into throw-away film cameras. Also larger ones are used as stand-alone photoflash lights or stroboscopes ('strobes'). Try asking around at some local camera stores. Smartphones use an LED for lighting, so would not have such a step-up power supply.

[Digression]
Decades ago there were 535V batteries available to supply the high voltage for strobes. They were pricey and I doubt they are still available. I remember getting one of those batteries as a hand-me-down from a photographer. I could lay a finger across the terminals, not quite touching the second terminal, and drawing a sustained arc. Could hardly feel it due to the low current but really freaked out the unknowing!
[End Digression]

 

[Yrton]

This?
https://en.wikipedia.org/wiki/Boost_converter

 

[Yrton]

Thank you for the replies folks.
I've tried building a boost converter before in vein as for a project like this with such a massive step up a transformer design is needed.
There won't be any charge drawn from the capacitor when it's being charged.

 

[tech99]

Thank you for the replies folks.
I've tried building a boost converter before in vein as for a project like this with such a massive step up a transformer design is needed.
There won't be any charge drawn from the capacitor when it's being charged.

The capacitor might be charged at, say, 100mA average for 30 minutes. To do this you need to have a series resistor of say 400/100 = 4k.
A supply giving 400V at 100mA can be made and was used for mobile transmitters in the tube era. A big transformer is needed, around 2kg perhaps, and a simple cross connected transistor oscillator on the centre tapped primary. Clean oscillation obtains if just series base resistors are used, chosen to give the correct static bias.
May I emphasise the safety issues to you.

 

[Yrton]

Found this on eBay. Upon asking "multiple" sellers (Side note; and finding out that most of them are the same one), I was told that they don't know. If anyone had any experience with this, maybe someone does: https://m.ebay.com/itm/DC-DC-5V-12V-Step-up-to-300V-1200V-400V-900v-1000v-Boost-Converter-Power-Module-/152175524315?nav=SEARCH

 

[tech99]

I had a thought. You can buy AC inverters quite easily, and in the UK they give 230 Volts AC. If you add a rectifier you can get 1.4 x 230 = 322 Volts.
I also calculated the charging time incorrectly, and it is more like 30 seconds than 30 minutes.
If 322 Volts is not enough you can use a voltage doubler circuit.

 

[berkeman]

a step up adapter with the capability of stepping up a 12v battery source (like a car battery) to 400v for the purpose of charging a 1800uf, 450v, capacitors to 400v.

There won't be any charge drawn from the capacitor when it's being charged.

Um, what is the application? What is your experience so far in working with high voltages? What other projects have you built?

 

[anorlunda]

Found this on eBay. Upon asking "multiple" sellers (Side note; and finding out that most of them are the same one), I was told that they don't know. If anyone had any experience with this, maybe someone does: https://m.ebay.com/itm/DC-DC-5V-12V-Step-up-to-300V-1200V-400V-900v-1000v-Boost-Converter-Power-Module-/152175524315?nav=SEARCH

It says "Output current: 2 ~ 20mA." Your charging circuit must make sure that it does not draw too much current and trip or damage the converter. But the converter may just limit the current itself. There is not enough information in the Ebay ad to tell. You need to find the spec sheet on the converter.