Difference in Amperage matter much?

[Mike]

Hi, I am trying to replace a DC adaptor:

Original adaptor from U.S.:
input 110v AC
Cycles????? unknown

output 5.8v DC with 1amp(1000ma)

I own a current DC adaptor which is for Japan:
input 100v AC 11VA Cycles 50-60Hz
output 5.8v DC 730ma

Is the difference in amps going to be a big problem?
The think is basically only charging 1.2recharge batteries.

Thanks!

 

[John Popelish]

Mike wrote:

Hi, I am trying to replace a DC adaptor:

Original adaptor from U.S.:
input 110v AC
Cycles????? unknown

output 5.8v DC with 1amp(1000ma)

I own a current DC adaptor which is for Japan:
input 100v AC 11VA Cycles 50-60Hz
output 5.8v DC 730ma

Is the difference in amps going to be a big problem?
The think is basically only charging 1.2recharge batteries.

The replacement has two strikes against it. It may be 37% overloaded
on current and have its core overloaded with 20 % excess voltage. It
may survive, but you have no compliant is it catches fire or melts its
thermal overload switch. What happened to the original?

--
John Popelish

 

[JeB]

On 26 Jan 2004 09:56:33 -0800, kaishain@yahoo.com (Mike) wrote:

Hi, I am trying to replace a DC adaptor:

Original adaptor from U.S.:
input 110v AC
Cycles????? unknown

output 5.8v DC with 1amp(1000ma)

I own a current DC adaptor which is for Japan:
input 100v AC 11VA Cycles 50-60Hz
output 5.8v DC 730ma

Is the difference in amps going to be a big problem?
The think is basically only charging 1.2recharge batteries.

you also must pay attention to the polarity of the plug.

 

[Don Bruder]

In article <a3c7b9f1.0401260956.64d826a2@posting.google.com>,
kaishain@yahoo.com (Mike) wrote:

Hi, I am trying to replace a DC adaptor:

Original adaptor from U.S.:
input 110v AC
Cycles????? unknown

The part above is of no meaning. The input side is a non-issue, aside
from considerations about what kind of socket it will be plugged into.
Obviously, an adapter made to work in the USA, with 110-120 volts at the
socket, isn't going to be happy if plugged into a 220 volts outlet, but
that's not particularly important.

output 5.8v DC with 1amp(1000ma)

THAT is the critical information. Regardless of what goes in, what comes
out *MUST* be 5.8 volts of DC, at 1 amp. It doesn't matter if the input
is designed for 110, 220, or 500KVolts - the output side is the critical
factor.

I own a current DC adaptor which is for Japan:
input 100v AC 11VA Cycles 50-60Hz
output 5.8v DC 730ma

Is the difference in amps going to be a big problem?

Perhaps not a *BIG* problem, but it will definitely be a problem. Exact
how much of one is something that I can't predict without a whole lot
more information than what you've offered. (information that you're
probably not going to be able to supply from the other side of an ocean
anyway...)

The think is basically only charging 1.2recharge batteries.

What it's doing with the juice is irrelevant. The only important factors
are the voltage/current/polarity the device wants. Everything else is
distraction that has no bearing on your question. No, that's not a
"chewing out" - just an attempt at education.


Now, having covere those preliminaries...

The 730 mA one you have will probably cook itself in fairly short order.

Your application needs (or at least, your old adapter supplied) 1 amp at
5.8 volts. When looking for a replacement, you *MUST* match or exceed
the amperage rating of the original. Using a supply with a lower output
will almost certainly burn it up, and may do so quite quickly, and with
a large amount of damge to the surrounding area. If you're lucky, it
will "hold you over" until you can get a proper one in place, but don't
count on it lasting any significant amount of time. Find an adapter
wired for your location's (Japan, US, Britain, whatever) AC system that
puts out 5.8 volts of DC at 1 amp or more, with a plug that puts the
proper polarity on the proper terminal of your device. Only then will
you have the "right" adapter.

Anything else is, at best, going to "smoke-test" itself as it tries
valiantly (but in vain) to supply what your device wants. At worst, it
will not only burn itself up, but possibly take along you, your
house/apartment building, maybe your wife and kids and/or neighbors, etc.

--
Don Bruder - dakidd@sonic.net <--- Preferred Email - SpamAssassinated.
Hate SPAM? See <http://www.spamassassin.org> for some seriously great info.
I will choose a path that's clear: I will choose Free Will! - N. Peart
Fly trap info pages: <http://www.sonic.net/~dakidd/Horses/FlyTrap/index.html>

 

[Mike]

John,

The original is a 110v DC adaptor for the U.S.
I can't use that original in JAPAN since the it's 100V here.
I'm not sure what cycles is in JAPAN or if that matters much,
except it seems the cylces are 50-60hz(my existing Japan DC adaptors
are showing that).

SO, I need to find an adaptor in Japan that will push out the same as
the original, which is 5.8v and 1amps

I would like to know why the replacement I suggested would be a bad
thing?
The replacement I currently have is a 100V(FOR JAPAN), pushing out
5.8v and 730ma.
How could the adaptor be overloaded since it can't supply enough
ampherage that the device requires in the first place?

 

[Mike]

I don't think I was clear.

I live in Japan, Yet the product I bought has ONLY a DC adaptor for US
current.

So I need to find a DC adaptor in Japan that will push out the same as
the original US adaptor.

Japan is 100v system
So I currently have a DC adaptor in Japan that works FINE with
Japanese voltage, and this adaptor pushes out 5.8v and 730ma

My concern is: providing a bit lower amperage(730MA) to the product
that's expecting a higher amperage(1000MA) will big a big problem?

Thanks again

 

[John Popelish]

Mike wrote:

John,

The original is a 110v DC adaptor for the U.S.
I can't use that original in JAPAN since the it's 100V here.
I'm not sure what cycles is in JAPAN or if that matters much,
except it seems the cylces are 50-60hz(my existing Japan DC adaptors
are showing that).

SO, I need to find an adaptor in Japan that will push out the same as
the original, which is 5.8v and 1amps

I would like to know why the replacement I suggested would be a bad
thing?
The replacement I currently have is a 100V(FOR JAPAN), pushing out
5.8v and 730ma.
How could the adaptor be overloaded since it can't supply enough
ampherage that the device requires in the first place?

I missed the fact that you are in Japan. My previous post was based
on the assumption that you were using a 100 volt supply in the US.

So disregard my comment about the excess voltage causing trouble. But
you may still have problems when your load draws 1000 ma from a supply
rated for only 730. This will produce almost twice the internal heat
compared to what the supply was designed for, unless the load just
happens to use only a fraction of the 1000 ma capability of the
original supply.

--
John Popelish

 

[Patrick Timlin]

kaishain@yahoo.com (Mike) wrote...

So I need to find a DC adaptor in Japan that will push out the same as
the original US adaptor.

Japan is 100v system
So I currently have a DC adaptor in Japan that works FINE with
Japanese voltage, and this adaptor pushes out 5.8v and 730ma

Well first off, "wall-wort" type adapters do not "push out" anything.
Instead they provide a output voltage and the load (the device powered
by the wall-wort) pulls whatever current it needs for whatever it is
it does. The product designer knows what types of current the device
uses so they then pick a Wall-wort that meets or exceeds those specs
for the current.

As an example, if I had a product that draws roughly a half-amp, then
I wouldn't pick a wall-wort that has a max rating of just a half-amp
since I would then be drawing the max rated current all the time.
Instead I would like some head room. So I might decide that if I want
to draw 0.5A most of the time, then to give me a little head room, I
might decide that 0.5A is no more than 80% of the max rating of my
wall-wort. So I would need a wall-wort that has a current rating of
625mA (aka 0.625A). Looking in my ACME Wall-wort catalog I might find
they make one model in my voltage output that puts out 0.5 amps, then
the next size up is 0.75A. So I then simply pick the 0.75A model and
away I go.

The whole point of that is whatever you are supplying power to with
your wall wort is not likely to be drawing 1000ma (1A), but something
less. The question is how much less?

My concern is: providing a bit lower amperage(730MA) to the product
that's expecting a higher amperage(1000MA) will big a big problem?

Since we can assume your product is not really drawing 1A, but instead
something less, you MIGHT be able to use the wall wort you have rated
for 0.73A. If your battery charger draws around that 0.7A or less,
then you are ok. If you are worried, check out other wall-worts made
for the Japanese market with the 5.8V rating and find one rated for 1A
or higher. Even if you get one rated for 100A, if your device only
draws 0.8A it will draw that same current regardless of the max output
rating of your wall wort.

However, if it was me and since it is just a battery charger and your
alternate wall-wort is pretty close, I might just go for it and give
it a try, at least for batteries that are not overly expensive to
replace (AA NiMHs for example). I might not be so keen to attempt it
for a charger that charges a $100+ laptop battery for example.

Patrick

 

[John Fields]

On 29 Jan 2004 13:22:05 -0800, westford97-google@yahoo.com (Patrick
Timlin) wrote:

Well first off, "wall-wort"
---

Wall-_wart_.

--
John Fields

 

[Mike]

Hi John,

Well I'm hearing the if one can't find a match on amperage, that it's
better to have more than less(as long as voltage is correct), is that
true?

I don't know how much load this device will cause on the DC adaptor.
I only know at this point that the original adaptor pushes out what I
said before.

If I can't find an EXACT match for a DC adapter, in your opinion, what
is the tolerance level that I can safely use and adaptor as a
replacement?

Meaning, If I had a 6.0V DC adaptor with 1000MA, would that be
better than a 5.8V DC adaptor with 730MA? Or is voltage more
important to match versus amperage or vice versa. Of course it's just
best to find an exact match, however if I can't.. I'm wondering just
how far and in which direction I can have a difference in amperage and
or voltage.

Thanks



John Popelish <jpopelish@rica.net> wrote in message news:<401893D0.BD7230CF@rica.net>...

Mike wrote:

John,

The original is a 110v DC adaptor for the U.S.
I can't use that original in JAPAN since the it's 100V here.
I'm not sure what cycles is in JAPAN or if that matters much,
except it seems the cylces are 50-60hz(my existing Japan DC adaptors
are showing that).

SO, I need to find an adaptor in Japan that will push out the same as
the original, which is 5.8v and 1amps

I would like to know why the replacement I suggested would be a bad
thing?
The replacement I currently have is a 100V(FOR JAPAN), pushing out
5.8v and 730ma.
How could the adaptor be overloaded since it can't supply enough
ampherage that the device requires in the first place?

I missed the fact that you are in Japan. My previous post was based
on the assumption that you were using a 100 volt supply in the US.

So disregard my comment about the excess voltage causing trouble. But
you may still have problems when your load draws 1000 ma from a supply
rated for only 730. This will produce almost twice the internal heat
compared to what the supply was designed for, unless the load just
happens to use only a fraction of the 1000 ma capability of the
original supply.

 

[John Popelish]

Mike wrote:

Hi John,

Well I'm hearing the if one can't find a match on amperage, that it's
better to have more than less(as long as voltage is correct), is that
true?

Yes. Unused capacity is better than over taxed capacity.

I don't know how much load this device will cause on the DC adaptor.
I only know at this point that the original adaptor pushes out what I
said before.

If I can't find an EXACT match for a DC adapter, in your opinion, what
is the tolerance level that I can safely use and adaptor as a
replacement?

Meaning, If I had a 6.0V DC adaptor with 1000MA, would that be
better than a 5.8V DC adaptor with 730MA? Or is voltage more
important to match versus amperage or vice versa. Of course it's just
best to find an exact match, however if I can't.. I'm wondering just
how far and in which direction I can have a difference in amperage and
or voltage.

Without knowing a lot of details about your load it is hard to say
what variations would be best tolerated. But I suspect that having .2
volts extra with all the current capacity that is needed is better
than having only 73% of the capacity required.

--
John Popelish

 

[Mike]

Ok, well obviously I'm not expert on this but understand what you're
saying.
I don't have any mean readily availble to determine the exact
requirements of my device, so therefore I just don't know if 730ma
will cut it or not.

I'm wondering what will happen though if my device is expecting 1000ma
and the wall-wart can only provide 730ma what will happen then?

Thanks for the advice

westford97-google@yahoo.com (Patrick Timlin) wrote in message news:<80185931.0401291322.7f38d815@posting.google.com>...

kaishain@yahoo.com (Mike) wrote...
So I need to find a DC adaptor in Japan that will push out the same as
the original US adaptor.

Japan is 100v system
So I currently have a DC adaptor in Japan that works FINE with
Japanese voltage, and this adaptor pushes out 5.8v and 730ma

Well first off, "wall-wort" type adapters do not "push out" anything.
Instead they provide a output voltage and the load (the device powered
by the wall-wort) pulls whatever current it needs for whatever it is
it does. The product designer knows what types of current the device
uses so they then pick a Wall-wort that meets or exceeds those specs
for the current.

As an example, if I had a product that draws roughly a half-amp, then
I wouldn't pick a wall-wort that has a max rating of just a half-amp
since I would then be drawing the max rated current all the time.
Instead I would like some head room. So I might decide that if I want
to draw 0.5A most of the time, then to give me a little head room, I
might decide that 0.5A is no more than 80% of the max rating of my
wall-wort. So I would need a wall-wort that has a current rating of
625mA (aka 0.625A). Looking in my ACME Wall-wort catalog I might find
they make one model in my voltage output that puts out 0.5 amps, then
the next size up is 0.75A. So I then simply pick the 0.75A model and
away I go.

The whole point of that is whatever you are supplying power to with
your wall wort is not likely to be drawing 1000ma (1A), but something
less. The question is how much less?


My concern is: providing a bit lower amperage(730MA) to the product
that's expecting a higher amperage(1000MA) will big a big problem?

Since we can assume your product is not really drawing 1A, but instead
something less, you MIGHT be able to use the wall wort you have rated
for 0.73A. If your battery charger draws around that 0.7A or less,
then you are ok. If you are worried, check out other wall-worts made
for the Japanese market with the 5.8V rating and find one rated for 1A
or higher. Even if you get one rated for 100A, if your device only
draws 0.8A it will draw that same current regardless of the max output
rating of your wall wort.

However, if it was me and since it is just a battery charger and your
alternate wall-wort is pretty close, I might just go for it and give
it a try, at least for batteries that are not overly expensive to
replace (AA NiMHs for example). I might not be so keen to attempt it
for a charger that charges a $100+ laptop battery for example.

Patrick

 

[Thomas C. Sefranek]

"Mike" <kaishain@yahoo.com> wrote in message
news:a3c7b9f1.0401291857.628e15c6@posting.google.com...

Ok, well obviously I'm not expert on this but understand what you're
saying.
I don't have any mean readily availble to determine the exact
requirements of my device, so therefore I just don't know if 730ma
will cut it or not.

I'm wondering what will happen though if my device is expecting 1000ma
and the wall-wart can only provide 730ma what will happen then?

The voltage will sag. (Drop)

Thanks for the advice

westford97-google@yahoo.com (Patrick Timlin) wrote in message
--

*
| __O Thomas C. Sefranek WA1RHP@ARRL.net
|_-\<,_ Amateur Radio Operator: WA1RHP
(*)/ (*) Bicycle mobile on 145.41, 448.625 MHz

http://hamradio.cmcorp.com/inventory/Inventory.html
http://www.harvardrepeater.org

 

[John Popelish]

Mike wrote:

Ok, well obviously I'm not expert on this but understand what you're
saying.
I don't have any mean readily availble to determine the exact
requirements of my device, so therefore I just don't know if 730ma
will cut it or not.

I'm wondering what will happen though if my device is expecting 1000ma
and the wall-wart can only provide 730ma what will happen then?

The output voltage will not be as high as the nameplate specifies and
the unit will get hotter than it was designed to stand. This second
effect takes a little time, so it might work long enough to measure
the output voltage under load to see if it stays within spec. If it
passes this test, then you can run it longer and check it often for
heat of burnt smell.

--
John Popelish

 

[Mike]

Well, as luck would have it.... I can't find anywhere a DC adaptor
with 5.8v and 1000ma.... I see plenty of multi-volt adaptors... and
6v DC seems to be the closest I can come to voltage.
Now I'm wondering just how much damange an extra .2 volts will do to
my product, because it seems like I have no other choice..
Ideas?

 

[John Popelish]

Mike wrote:

Well, as luck would have it.... I can't find anywhere a DC adaptor
with 5.8v and 1000ma.... I see plenty of multi-volt adaptors... and
6v DC seems to be the closest I can come to voltage.
Now I'm wondering just how much damange an extra .2 volts will do to
my product, because it seems like I have no other choice..
Ideas?

There is no way to know, without more information about the load. But
I will bet you a dollar that it will work. 0.2 volts is just not a
very big % extra. If the original was a regulated supply, not a raw
supply, then, who knows. But if the original was just a transformer,
rectifier and capacitor, then the output would vary more than 0.2
volts just from load swings and line voltage changes.

--
John Popelish

 

[Mike]

John Popelish <jpopelish@rica.net> wrote in message news:<401D3AEB.F6EA455B@rica.net>...

Mike wrote:

Well, as luck would have it.... I can't find anywhere a DC adaptor
with 5.8v and 1000ma.... I see plenty of multi-volt adaptors... and
6v DC seems to be the closest I can come to voltage.
Now I'm wondering just how much damange an extra .2 volts will do to
my product, because it seems like I have no other choice..
Ideas?

There is no way to know, without more information about the load. But
I will bet you a dollar that it will work. 0.2 volts is just not a
very big % extra. If the original was a regulated supply, not a raw
supply, then, who knows. But if the original was just a transformer,
rectifier and capacitor, then the output would vary more than 0.2
volts just from load swings and line voltage changes.

Thanks John. I'll give it a shot and keep my fingers crossed!