# Voltage doubler help

Discussion in 'Electronic Repair' started by WbSearch, Sep 22, 2003.

1. ### WbSearchGuest

I'm looking to make/purchase a voltage doubler so I can charge some small
devices while on my boat. The boat is a 12 volt system and I would like to get
at least 26.1 volts DC, around 0.75 amps. Is ther an easy solution for me?
Thanks.

2. ### BobCGuest

26.1 volts in not a real common voltage; 28 is a bit more common.

In general, a voltage doubler circuit starts with an AC signal. In
order to 'increase' or double the voltage, you are going to have to
first create and AC signal. It will have to be equal to or greater than
26 volts(RMS)(or 13 if you plan to double it) and then rectify it (an
possibly regulate it) to get DC again ... OR
Put two 12 volt batteries is series. 12V lead-acid batteries are at
about 12.6 volts when fully charged giving you about 25.2 Volts. I do
not now if this is high enough ??? ... OR
You may be able to find a 12 to 28 volt DC-TO-DC converters and go from
there? OR
You might buy a standard 120 Volt inverter (of 'at least' 25 Watts) and
plug a 26.1 power supply into it ... You may already have one of those.

3. ### Sam GoldwasserGuest

That's what I'd recommend. It may be a bit less efficient than an optimal
direct solution but beats messing around with something you would like
to depend on.

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4. ### SofieGuest

-------------------------

Here are some solutions:

#1 A 12 VOLT DC to 120VAC inverter that
will allow you to "plug in" an appropriate charger.

#2 Two batteries in series...... the extra battery
can be disconnected and charged as needed. The
good news is that because the current draw is less
than an amp... it could go for days without recharging.

5. ### WbSearchGuest

Thanks to all for your replies. I usually assume a project is easier than it
is. The inverter is probably the best solution as the charger input is 120
vac. I have by passed it in the past in a pinch to charge with 2 n- 12 volt
batteries in series, but it is not a very easy solution for me, and I am
looking for a portable unit. I had a very small Compac computer charger that
plugged into a cigarette lighter, but the output was only 18 volts. I was
looking for a similar unit @ 26- 28 volts. Thanks again for the input.

6. ### BobCGuest

The compact charger is most likely a small switching regulator
(inverter, rectifier). If you look around, you may find one that is
close enough to suit. 120 VAC inverters are small, common and basically
cheap these days. They are also handy to have around ... on a boat is
is nice to have 120 VAC available, esp. in an emergency.
Good Luck,
Bob