PDA power consumption

Can anyone tell me what a typical power consumption for a PDA is? I
got ipaq 3950, but I guess they all must all be close.

On Feb 21, 4:00 pm, AK wrote:
Can anyone tell me what a typical power consumption for a PDA is? I
got ipaq 3950, but I guess they all must all be close.

Typically it is greater than zero amps and less than 1 amp :-) I bet
that did not help much.

It depends significantly whether you are charging the battery, whether
the screen backlight is on, and total power drawn will of course
depend on whether you have an extended battery pack or not. Worse case
the power consumed can be even greater than those pesky transponders
everybody worries about. And a PDA can draw current even when turned
off. For a iPAQ 4700/4705 you can see numbers ranging from 9 mA (PDA
of and fully charged), 440 mA (*OFF* and charging) to 610 mA worse
case. These are @ 12 volts equivalent, i.e. roughly the actual current
you should see drawn from your glider battery. How long the PDA draws
the maximum current will depend on how discharged its batteries are.
I'm too lazy to try to reproduce it here but there is a full table of
power draw for the iPAQ 4700 in my battery presentation at
http://www.darrylramm.com/glider-batteries.

If you are trying to work out how long your glider battery can power a
PDA for, don't forget the capacity of the battery can depend
significantly on the total simultaneous current drawn from it, and the
temperature, see the discharge curves in the battery presentation
above.

If you are working out how large a fuse or breaker to put in the
charging circuit, several amps will do. It does not really matter as
you are mostly protecting the wiring. Avoid small (1A) breakers as
they waste power. You may not need a breaker or fuse if the 12 volt
powered charging circuit has its own protection.

Cheers


Darryl

On Feb 21, 9:06*pm, Darryl Ramm wrote:
On Feb 21, 4:00 pm, AK wrote:

Can anyone tell me what a typical power consumption for a PDA is? I
got ipaq 3950, but I guess they all must all be close.

Typically it is greater than zero amps and less than 1 amp :-) I bet
that did not help much.

It depends significantly whether you are charging the battery, whether
the screen backlight is on, and total power drawn will of course
depend on whether you have an extended battery pack or not. Worse case
the power consumed can be even greater than those pesky transponders
everybody worries about. And a PDA can draw current even when turned
off. For a iPAQ 4700/4705 you can see numbers ranging from 9 mA (PDA
of and fully charged), 440 mA (*OFF* and charging) to 610 mA worse
case. These are @ 12 volts equivalent, i.e. roughly the actual current
you should see drawn from your glider battery. How long the PDA draws
the maximum current will depend on how discharged its batteries are.
I'm too lazy to try to reproduce it here but there is a full table of
power draw for the iPAQ 4700 in my battery presentation athttp://www.darrylramm.com/glider-batteries.

If you are trying to work out how long your glider battery can power a
PDA for, don't forget the capacity of the battery can depend
significantly on the total simultaneous current drawn from it, and the
temperature, see the discharge curves in the battery presentation
above.

If you are working out how large a fuse or breaker to put in the
charging circuit, several amps will do. It does not really matter as
you are mostly protecting the wiring. Avoid small (1A) breakers as
they waste power. You may not need a breaker or fuse if the 12 volt
powered charging circuit has its own protection.

Cheers

Darryl

I am trying to figure out what else I can have on the same battery as
PDA. Other equipment draws 600 mA with spikes to 1.7 A when
transmitting.

On Feb 21, 6:25 pm, AK wrote:
On Feb 21, 9:06 pm, Darryl Ramm wrote:



On Feb 21, 4:00 pm, AK wrote:

Can anyone tell me what a typical power consumption for a PDA is? I
got ipaq 3950, but I guess they all must all be close.

Typically it is greater than zero amps and less than 1 amp :-) I bet
that did not help much.

It depends significantly whether you are charging the battery, whether
the screen backlight is on, and total power drawn will of course
depend on whether you have an extended battery pack or not. Worse case
the power consumed can be even greater than those pesky transponders
everybody worries about. And a PDA can draw current even when turned
off. For a iPAQ 4700/4705 you can see numbers ranging from 9 mA (PDA
of and fully charged), 440 mA (*OFF* and charging) to 610 mA worse
case. These are @ 12 volts equivalent, i.e. roughly the actual current
you should see drawn from your glider battery. How long the PDA draws
the maximum current will depend on how discharged its batteries are.
I'm too lazy to try to reproduce it here but there is a full table of
power draw for the iPAQ 4700 in my battery presentation athttp://www.darrylramm.com/glider-batteries.

If you are trying to work out how long your glider battery can power a
PDA for, don't forget the capacity of the battery can depend
significantly on the total simultaneous current drawn from it, and the
temperature, see the discharge curves in the battery presentation
above.

If you are working out how large a fuse or breaker to put in the
charging circuit, several amps will do. It does not really matter as
you are mostly protecting the wiring. Avoid small (1A) breakers as
they waste power. You may not need a breaker or fuse if the 12 volt
powered charging circuit has its own protection.

Cheers

Darryl

I am trying to figure out what else I can have on the same battery as
PDA. Other equipment draws 600 mA with spikes to 1.7 A when
transmitting.

Typical sealed lead acid batteries will easilly be able to provide
power during these current spikes, and you would have awfully thin
wiring for this to be an issue for wiring. So if this is on a common
circuit breaker or fuse for this load make sure it is at least 3A,
maybe more and you are set. If there is only one fuse or breaker make
sure it is right at the battery, preferably mounted on the battery in
a way the leads to the breaker cannot ever short circuit even with
significant force applied. I'd make that breaker 5A usually.

Is the spike caused by radio transmission? For calculating power
consumption and battery life for things like radios typically assume a
transmition/reception ratio of a few percent unless you something more
accurate and just cheat by fudging battery capacity at this number
based on this percent between the battery capacity at the receive and
transmit current draws. This is only an issue with small batteries,
and not usually significant in gliders. But might be nice to have an
idea how long you battery runs with a stuck on microphone, or a
ballpark worst case battery life if you land out and are trying to
transmit a lot.

Darryl

AK wrote:
Can anyone tell me what a typical power consumption for a PDA is? I
got ipaq 3950, but I guess they all must all be close.


Hi AK,

I have carefully measured the current draw of each piece of equipment on
my battery in my ASW20. A few things to keep in mind are...

1. My PDA is a HP iPAQ model 2215 with a standard battery, not the
higher AH battery that is available.
2. The PDA battery is being charged by the 5 VDC tap from my Cambridge 302A
3. I have a Cambridge 303 talking to the 302A.
4. I am using a 14 VDC battery.

The measured current draws are...

Cambridge 302A/303 with PDA disconnected: 80ma.
Cambridge 302A/303 with PDA connected and turned ON: 280ma.

I seems that my 2215 requires about a 200ma charging current.

I hope this helps.

Paul
ZZ

On Feb 22, 8:53*pm, ZZ wrote:
AK wrote:
Can anyone tell me what a typical power consumption for a PDA is? I
got ipaq 3950, but I guess they all must all be close.

Hi AK,

I have carefully measured the current draw of each piece of equipment on
my battery in my ASW20. A few things to keep in mind are...

1. My PDA is a HP iPAQ model 2215 with a standard battery, not the
higher AH battery that is available.
2. The PDA battery is being charged by the 5 VDC tap from my Cambridge 302A
3. I have a Cambridge 303 talking to the 302A.
4. I am using a 14 VDC battery.

The measured current draws are...

* * * * * * * * Cambridge 302A/303 with PDA disconnected: *80ma.
* * * * * * * * Cambridge 302A/303 with PDA connected and turned ON: 280ma.

I seems that my 2215 requires about a 200ma charging current.

I hope this helps.

Paul
ZZ

Paul,

What does your PDA draw when the battery is topped off? Have you
compared the draw during charge vs. after charge? Once the charge
circuit is shut down (battery full), the current draw should lessen.

On my Dell Axim, the power button is red when charging, and green when
the battery is topped off. I haven't measured the current during
charge yet, but I bet it'll be a tapered charge, meaning the current
will lessen as the battery gets closer to being topped off. Without a
charge "indicator", it might be hard to tell just what the PDA
requires to run without the extra current required to charge the
battery.

I would imagine that most folks will make sure their PDA is fully
charged before powering it up from the ship's power supply. That's
something I will make sure of since I'm flying with only a 7ah battery
on board.


Dave

You have to be a bit careful when talking about PDAs power
consumption. The numbers like 200mA.. can be misleading. Yes it is a
very good idea to top off the battery prior to using PDA in a glider
because this is this much less charge that supply has to provide. Once
the battery is charged, all power supplied to PDA is being consumed
for PDA operation, battery is "off" unless supply voltage drops.
Having said that, PDAs do not consume power in a steady mode. It
depends what they are doing. Few years ago I was playing with couple
of them measuring supply currents. I do not have the data, so I cannot
give you actual numbers but current draw spikes went well above
1000mA. In some cases this may be a problem if your main battery is
nearing end of capacity.

The best thing you can do when powering a PDA from main glider battery
is to use an efficient switching DC to DC converter rather than a
"foot warmer" linear one. Modern switching converters are nearly 90%
efficient, so if a PDA requires 1000mA and you are using a 12V battery
the battery current is 5/12/0.9*1000mA = 460mA. A "poor" switching
converter is 75-80% efficient.

Cheers,
Henryk Birecki

wrote:

On Feb 22, 8:53*pm, ZZ wrote:
AK wrote:
Can anyone tell me what a typical power consumption for a PDA is? I
got ipaq 3950, but I guess they all must all be close.

Hi AK,

I have carefully measured the current draw of each piece of equipment on
my battery in my ASW20. A few things to keep in mind are...

1. My PDA is a HP iPAQ model 2215 with a standard battery, not the
higher AH battery that is available.
2. The PDA battery is being charged by the 5 VDC tap from my Cambridge 302A
3. I have a Cambridge 303 talking to the 302A.
4. I am using a 14 VDC battery.

The measured current draws are...

* * * * * * * * Cambridge 302A/303 with PDA disconnected: *80ma.
* * * * * * * * Cambridge 302A/303 with PDA connected and turned ON: 280ma.

I seems that my 2215 requires about a 200ma charging current.

I hope this helps.

Paul
ZZ

Paul,

What does your PDA draw when the battery is topped off? Have you
compared the draw during charge vs. after charge? Once the charge
circuit is shut down (battery full), the current draw should lessen.

On my Dell Axim, the power button is red when charging, and green when
the battery is topped off. I haven't measured the current during
charge yet, but I bet it'll be a tapered charge, meaning the current
will lessen as the battery gets closer to being topped off. Without a
charge "indicator", it might be hard to tell just what the PDA
requires to run without the extra current required to charge the
battery.

I would imagine that most folks will make sure their PDA is fully
charged before powering it up from the ship's power supply. That's
something I will make sure of since I'm flying with only a 7ah battery
on board.


Dave

wrote:
On Feb 22, 8:53 pm, ZZ wrote:
AK wrote:
Can anyone tell me what a typical power consumption for a PDA is? I
got ipaq 3950, but I guess they all must all be close.
Hi AK,

I have carefully measured the current draw of each piece of equipment on
my battery in my ASW20. A few things to keep in mind are...

1. My PDA is a HP iPAQ model 2215 with a standard battery, not the
higher AH battery that is available.
2. The PDA battery is being charged by the 5 VDC tap from my Cambridge 302A
3. I have a Cambridge 303 talking to the 302A.
4. I am using a 14 VDC battery.

The measured current draws are...

Cambridge 302A/303 with PDA disconnected: 80ma.
Cambridge 302A/303 with PDA connected and turned ON: 280ma.

I seems that my 2215 requires about a 200ma charging current.

I hope this helps.

Paul
ZZ

Paul,

What does your PDA draw when the battery is topped off? Have you
compared the draw during charge vs. after charge? Once the charge
circuit is shut down (battery full), the current draw should lessen.

On my Dell Axim, the power button is red when charging, and green when
the battery is topped off. I haven't measured the current during
charge yet, but I bet it'll be a tapered charge, meaning the current
will lessen as the battery gets closer to being topped off. Without a
charge "indicator", it might be hard to tell just what the PDA
requires to run without the extra current required to charge the
battery.

I would imagine that most folks will make sure their PDA is fully
charged before powering it up from the ship's power supply. That's
something I will make sure of since I'm flying with only a 7ah battery
on board.


Dave


Dave

I agree. I usually install my PDA in the glider either fully charged or
nearly so. That's why I said 280ma minus 80ma is ABOUT 200ma.

Knowing this and the approximate draw by other equipment in the glider
should get me close enough to properly match a battery pack to expected
flight time.

Paul
ZZ

ZZ wrote:

I agree. I usually install my PDA in the glider either fully charged or
nearly so. That's why I said 280ma minus 80ma is ABOUT 200ma.

Knowing this and the approximate draw by other equipment in the glider
should get me close enough to properly match a battery pack to expected
flight time.

It's more about "big enough", rather than "matching". Unless it involves
serious dollars or effort, put in one that's enough for possible future
additions, like a transponder and one of those brighter, panel-mounted
screens that are available now, and then make sure it's big enough to
run everything for serveral flights without charging. Need a 7 ah
battery but got room for an 18 ah unit? Go for it!

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly

* Updated! "Transponders in Sailplanes" http://tinyurl.com/y739x4
* New Jan '08 - sections on Mode S, TPAS, ADS-B, Flarm, more

* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org

"Eric Greenwell" wrote in message
news:ja3wj.4512$O64.3149@trndny03...
ZZ wrote:

I agree. I usually install my PDA in the glider either fully charged or
nearly so. That's why I said 280ma minus 80ma is ABOUT 200ma.

Knowing this and the approximate draw by other equipment in the glider
should get me close enough to properly match a battery pack to expected
flight time.

It's more about "big enough", rather than "matching". Unless it involves
serious dollars or effort, put in one that's enough for possible future
additions, like a transponder and one of those brighter, panel-mounted
screens that are available now, and then make sure it's big enough to run
everything for serveral flights without charging. Need a 7 ah battery but
got room for an 18 ah unit? Go for it!

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly

* Updated! "Transponders in Sailplanes" http://tinyurl.com/y739x4
* New Jan '08 - sections on Mode S, TPAS, ADS-B, Flarm, more

* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org

Yes, Eric. But keep an eye on the maximum weight of the "non-flying parts".
A heavy lead acid 18AH battery might put some gliders over that limit.