Power Adaptor Question (NEWBIE)

Guest
Before I go and start plugging things in I need to know this one
thing. I have a Philips VOIP841, the power adaptors that came with it
are 110VAC 60Hz only. I am now living in Belgium and of coarse cannot
plug my phone in without using the transformers. It seems easy enough,
and cheaper for me to just go out and purchase new AC to DC converters
for 220VAC 50Hz.

Original input: Proposed Input:
110VAC 60Hz 220VAC 50Hz
Original output: Proposed output:
7.5VDC 150mA ----handset charger------ 7.5VDC 300mA
7.5VDC 500mA ----base station----------- 7.5VDC 500mA

So here is my issue. I have two types of power outputs from my old AC/
DC converter. One is (7.5VDC 150mA) for the handset chargers, and the
other is (7.5VDC 500mA) for the base. I have found a universal AC/DC
220VAC converter for the 500mA base. But what I'd like to know is if
it's safe to use a (7.5VDC 300mA) converter on the handset charger
that originally requires (7.5VDC 150mA)?
 
On Apr 23, 8:56 am, Der...@gmail.com wrote:
Before I go and start plugging things in I need to know this one
thing. I have a Philips VOIP841, the power adaptors that came with it
are 110VAC 60Hz only. I am now living in Belgium and of coarse cannot
plug my phone in without using the transformers. It seems easy enough,
and cheaper for me to just go out and purchase new AC to DC converters
for 220VAC 50Hz.

Original input: Proposed Input:
110VAC 60Hz 220VAC 50Hz
Original output: Proposed output:
7.5VDC 150mA ----handset charger------ 7.5VDC 300mA
7.5VDC 500mA ----base station----------- 7.5VDC 500mA

So here is my issue. I have two types of power outputs from my old AC/
DC converter. One is (7.5VDC 150mA) for the handset chargers, and the
other is (7.5VDC 500mA) for the base. I have found a universal AC/DC
220VAC converter for the 500mA base. But what I'd like to know is if
it's safe to use a (7.5VDC 300mA) converter on the handset charger
that originally requires (7.5VDC 150mA)?
Click to expand...

Are 220V to 110V step-down transformers (100W, say) readily available
for cheap? They're very common (and fairly cheap) in the
Philippines. That might be cheaper than buying universal converters
(outrageously expensive here in the US).

You'll likely need to power other wall warts around the house too
anyway.

Michael
 
On Apr 23, 8:50 pm, "Paul E. Schoen" <pst...@smart.net> wrote:
Der...@gmail.com> wrote in message

news:70883867-70df-4d42-8e4e-a0804093b549@e39g2000hsf.googlegroups.com...





Before I go and start plugging things in I need to know this one
thing. I have a Philips VOIP841, the power adaptors that came with it
are 110VAC 60Hz only. I am now living in Belgium and of coarse cannot
plug my phone in without using the transformers. It seems easy enough,
and cheaper for me to just go out and purchase new AC to DC converters
for 220VAC 50Hz.

Original input:                                       Proposed Input:
110VAC 60Hz                                      220VAC 50Hz
Original output:                                     Proposed output:
7.5VDC 150mA  ----handset charger------  7.5VDC 300mA
7.5VDC 500mA  ----base station-----------  7.5VDC 500mA

So here is my issue. I have two types of power outputs from my old AC/
DC converter. One is (7.5VDC 150mA) for the handset chargers, and the
other is (7.5VDC 500mA) for the base. I have found a universal AC/DC
220VAC converter for the 500mA base. But what I'd like to know is if
it's safe to use a (7.5VDC 300mA) converter on the handset charger
that originally requires (7.5VDC 150mA)?

If the converter is a simple step-down transformer, and the chargers are
powered from 110 VAC 50 Hz, they might heat up. A larger converter
(transformer) with 220 VAC input and 110 VAC output might be more cost
effective, as it can be used for other appliances as well. But you still
need to make sure the appliance is rated at 50 Hz. Also, most step down
transformers produce an open circuit output higher than 50% of the input,
so a small device like a charger might see an even higher voltage, like
120-130 VAC. It might be best to obtain a charger designed for the 220 VAC
50 Hz supply.

Another option is to get a VF motor controller, which sometimes can be
obtained cheaply, and set the output to 110 VAC 60 Hz with a 220 VAC 50 Hz
input. But you have to be careful to set it up properly.

You could also get an inexpensive automotive type inverter, that takes 12
VDC and produces 120 VAC 60 Hz, and get a 12 VDC universal switching supply
(or a battery charger) rated for 220 VAC 50 Hz mains. You could even add a
battery to make your own UPS, or obtain one that can generate 120 VAC 60 Hz
from the 220 VAC 50Hz.

The chargers should not be damaged immediately if you try them on the
converters you have, but they might overheat after a while. So, you can
just check the case temperature at 5 minute intervals for about a half
hour. If it's not too hot (compared to how they were on US mains), they are
probably OK.

It's usually OK to use a converter rated higher than the device, but that
depends on the load regulation of its output.

Paul- Hide quoted text -

- Show quoted text -
Click to expand...
Just for sake of ease and less clutter around every outlet in my house
I'm going to just get a new 220V rated converter. And since it's only
charging the phone with two AAA batteries I'm gonna pray that the
300mA do not damage it. I did check my converter that is currently
pluged into my transformoer and you're right, it's really hot. I'll
guess I'll just unplug it now and wait for a new 220V rated converter.
I saw a "Jwin Jac32" on Amazon for $2.00. Thank you so much for your
input!!
 
On Apr 24, 4:45 pm, "Bob Eld" <nsmontas...@yahoo.com> wrote:
Der...@gmail.com> wrote in message

news:70883867-70df-4d42-8e4e-a0804093b549@e39g2000hsf.googlegroups.com...





Before I go and start plugging things in I need to know this one
thing. I have a Philips VOIP841, the power adaptors that came with it
are 110VAC 60Hz only. I am now living in Belgium and of coarse cannot
plug my phone in without using the transformers. It seems easy enough,
and cheaper for me to just go out and purchase new AC to DC converters
for 220VAC 50Hz.

Original input:                                       Proposed Input:
110VAC 60Hz                                      220VAC 50Hz
Original output:                                     Proposed output:
7.5VDC 150mA  ----handset charger------  7.5VDC 300mA
7.5VDC 500mA  ----base station-----------  7.5VDC 500mA

So here is my issue. I have two types of power outputs from my old AC/
DC converter. One is (7.5VDC 150mA) for the handset chargers, and the
other is (7.5VDC 500mA) for the base. I have found a universal AC/DC
220VAC converter for the 500mA base. But what I'd like to know is if
it's safe to use a (7.5VDC 300mA) converter on the handset charger
that originally requires (7.5VDC 150mA)?

Yes it is safe.  You can ALWAYS use a power source with a higher current
rating than what you need. You cannot go the other way, however. That is you
cannot ues a 150mA device where you need 300mA.- Hide quoted text -

- Show quoted text -
Click to expand...
Exactly the answer I was looking for.

Thank you!
 
On Apr 24, 4:45 pm, "Bob Eld" <nsmontas...@yahoo.com> wrote:
Der...@gmail.com> wrote in message

news:70883867-70df-4d42-8e4e-a0804093b549@e39g2000hsf.googlegroups.com...





Before I go and start plugging things in I need to know this one
thing. I have a Philips VOIP841, the power adaptors that came with it
are 110VAC 60Hz only. I am now living in Belgium and of coarse cannot
plug my phone in without using the transformers. It seems easy enough,
and cheaper for me to just go out and purchase new AC to DC converters
for 220VAC 50Hz.

Original input:                                       Proposed Input:
110VAC 60Hz                                      220VAC 50Hz
Original output:                                     Proposed output:
7.5VDC 150mA  ----handset charger------  7.5VDC 300mA
7.5VDC 500mA  ----base station-----------  7.5VDC 500mA

So here is my issue. I have two types of power outputs from my old AC/
DC converter. One is (7.5VDC 150mA) for the handset chargers, and the
other is (7.5VDC 500mA) for the base. I have found a universal AC/DC
220VAC converter for the 500mA base. But what I'd like to know is if
it's safe to use a (7.5VDC 300mA) converter on the handset charger
that originally requires (7.5VDC 150mA)?

Yes it is safe.  You can ALWAYS use a power source with a higher current
rating than what you need. You cannot go the other way, however. That is you
cannot ues a 150mA device where you need 300mA.- Hide quoted text -

- Show quoted text -
Click to expand...
Exactly the answer I was looking for.

Thank you!
 
Bob Eld wrote:
You can ALWAYS use a power source
with a higher current rating than what you need.
Click to expand...
....IF you discount *regulation*. A unit NOT used near its rating
may put out more voltage than you bargained for.

The newer switcher units (you can easily spot them
because they are much lighter than the old type which contain lots of
iron)
are likely to be considerably better in this regard.
 
On Apr 24, 7:45 am, "Bob Eld" <nsmontas...@yahoo.com> wrote:
Der...@gmail.com> wrote in message

... what I'd like to know is if
it's safe to use a (7.5VDC 300mA) converter on the handset charger
that originally requires (7.5VDC 150mA)?

Yes it is safe.  You can ALWAYS use a power source with a higher current
rating than what you need.
Click to expand...
Alas, the 'rating' is probably intended as a safety statement,
not as a real specification of the output. There are some
battery charger systems that require the wallwart to
limit the charging current to a safe value, for instance.

The only thing you can _always_ do is to reverse-engineer the
power adapter. You have to generate a list of the requirements
for the target device, and it isn't sufficient to read off the
shortform numbers on the adapter. It matters if there's
filtering or not, if there's voltage regulation, or current limiting,
and none of that info is in the '7.5VDC 150 mA' data given.
 
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