Details on the New SPOT 2

On Aug 5, 8:56*pm, Andy wrote:
On Aug 5, 6:27*pm, Darryl Ramm wrote:



On Aug 5, 4:58*pm, Andy wrote:

On Aug 5, 2:56*pm, Darryl Ramm wrote:

New SPOT: 3 x AAA Energizer Li Ultimate ~ 3 x 1.2 Ah = 3.6 Ah
Old SPOT: 2 x AA Li Energizer Ultimate ~ 2 x 3.0 = 6.0 Ah
(at any low current draw)

Are you saying the cells are in parallel in both units? *If they are
in series the capacity is the same for one cell as for 2 or 3 except
that the 3 cell unit may run at higher current because of the
increased voltage and have even lower battery life.

Andy

No I am summing battery capacity and ignoring voltage. If you want
nominal Watt.h then multiply by 1.5 volts. To first order it does not
matter how the batteries are configured. *LDO regulators/charge pumps
have relatively low loss and will be used internally to shift
voltages,,and *I assume they are not completely incompetent on basic
power supply engineering.

Darryl
Darryl

If one cell has a capacity of 1 amp hour then 1000 of those cells in
series still have a capacity of 1 amp hour. * Do you disagree with
that basic concept?

Andy

I have already explained my logic. If you want the right dimensions
multiply by the voltage. I just left that off, becasue it is a
constant. What matters is the total power capacity. Not how the
batteries are configured.

Darryl

Yes, I suppose I could install a coo-coo clock in the glider so that
when the bird comes out, its beak will push the help button once every
hour. *And then I will hope that all who view my public spot page will
not be confused by the concept that help means OK and OK means help.

We used SPOT Help mode for tracking last season at Omarama. Getting
pilots to push the button once an hour was a challenge. We got good
interest from the contest guys though, with nearly half the contest
pilots using SPOT.

We don't use the SPOT public page. The messages get delivered by email
to my server and all points displayed on one map. One page for the
whole fleet so the contest director only has one place to look.

For the coming season I'm supporting tracking mode as well.

--
Philip Plane

Martin Gregorie wrote:
On Wed, 05 Aug 2009 11:11:47 -0700, Andy wrote:

On Aug 5, 10:10Â am, MarkHawke7 wrote:
I'm trying to get a direct answer from my contacts at SPOT
Mark,

Since you have contacts there I'd be interested to know why they changed
from 2xAA to 3xAAA cells. Was case size the only consideration, or
perhaps the increased voltage increases the uplink TX power? In any
event I'd far rather have the longer life of AA cells than a smaller
case size.

I suspect we're in the minority and Joe Hiker would far rather have small
and light than long battery life.

Hopefully the Mk 2 will provide the best of both worlds, which would be
either:
- add an external power socket while retaining the 3 x AAA internal
cells

- replace the AAA cells with a 1500 mAh LiPoly rechargable and
a mini-USB charging socket. Alkaline AAA cells are 1250 mAh.

My SPOT will provide over 250 hours of tracking with the two AA cells,
which is more than a years flying for me. How many hours will the new
SPOT last?

Frankly, I don't care how many batteries they use or what the amphour
capacity is, as long they last a "long" time and it warns me when there
are 20-30 hours life left. I have no interest in external power or
rechargeable batteries, because that would not be simpler, more
reliable, or cheaper than the present system. Adding altitude and
cutting the subscription costs are the only priority items for me.

Eric Greenwell

On Aug 5, 10:30*pm, Eric Greenwell wrote:
Martin Gregorie wrote:
On Wed, 05 Aug 2009 11:11:47 -0700, Andy wrote:

On Aug 5, 10:10Â am, MarkHawke7 wrote:
I'm trying to get a direct answer from my contacts at SPOT
Mark,

Since you have contacts there I'd be interested to know why they changed
from 2xAA to 3xAAA cells. *Was case size the only consideration, or
perhaps the increased voltage increases the uplink TX power? *In any
event I'd far rather have the longer life of AA cells than a smaller
case size.

I suspect we're in the minority and Joe Hiker would far rather have small
and light than long battery life.

Hopefully the Mk 2 will provide the best of both worlds, which would be
either:
- add an external power socket while retaining the 3 x AAA internal
* cells

- replace the AAA cells with a 1500 mAh LiPoly rechargable and
* a mini-USB charging socket. Alkaline AAA cells are 1250 mAh.

My SPOT will provide over 250 hours of tracking with the two AA cells,
which is more than a years flying for me. How many hours will the new
SPOT last?

Frankly, I don't care how many batteries they use or what the amphour
capacity is, as long they last a "long" time and it warns me when there
are 20-30 hours life left. I have no interest in external power or
rechargeable batteries, because that would not be simpler, more
reliable, or cheaper than the present system. Adding altitude and
cutting the subscription costs are the only priority items for me.

Eric Greenwell

Eric

I expect cutting subscription costs and adding altitude are mutually
exclusive.

Reporting ~2-3x (depending on how they do this) the data in track
mode, as the new model will (repeat sending the past two position
reports) , may reduce the battery life, so also having a reduced
battery capacity compared to the first generation is worth noting.
They also do things that may lower power consumption, so the only take
away is this is something again we'll want to check out.

I would like to see tracking at reporting frequencies on 1-2 minutes,
that combined with reporting additional altitude data would again
reduce battery life. At that point I'd expect a device that was
primarily powered from the ships power would make sense.

Darryl

Has anyone considered getting a "spare" battery door and fitting a 3v
regulator inside a dummy AA cell fed with 12v through a grommet in the
door?

Leaving the original door and two new Li cells taped to the installation
should deal with any "walk out" scenarios.

Paul
G-CFRS/D-ENBW

At 05:53 06 August 2009, Darryl Ramm wrote:
On Aug 5, 10:30=A0pm, Eric Greenwell wrote:
Martin Gregorie wrote:
On Wed, 05 Aug 2009 11:11:47 -0700, Andy wrote:

On Aug 5, 10:10=C2 am, MarkHawke7 wrote:
I'm trying to get a direct answer from my contacts at SPOT
Mark,

Since you have contacts there I'd be interested to know why they
chang=
ed
from 2xAA to 3xAAA cells. =A0Was case size the only consideration,
or
perhaps the increased voltage increases the uplink TX power? =A0In
any
event I'd far rather have the longer life of AA cells than a
smaller
case size.

I suspect we're in the minority and Joe Hiker would far rather have
sma=
ll
and light than long battery life.

Hopefully the Mk 2 will provide the best of both worlds, which would
be
either:
- add an external power socket while retaining the 3 x AAA internal
=A0 cells

- replace the AAA cells with a 1500 mAh LiPoly rechargable and
=A0 a mini-USB charging socket. Alkaline AAA cells are 1250 mAh.

My SPOT will provide over 250 hours of tracking with the two AA cells,
which is more than a years flying for me. How many hours will the new
SPOT last?

Frankly, I don't care how many batteries they use or what the amphour
capacity is, as long they last a "long" time and it warns me when
there
are 20-30 hours life left. I have no interest in external power or
rechargeable batteries, because that would not be simpler, more
reliable, or cheaper than the present system. Adding altitude and
cutting the subscription costs are the only priority items for me.

Eric Greenwell

Eric

I expect cutting subscription costs and adding altitude are mutually
exclusive.

Reporting ~2-3x (depending on how they do this) the data in track
mode, as the new model will (repeat sending the past two position
reports) , may reduce the battery life, so also having a reduced
battery capacity compared to the first generation is worth noting.
They also do things that may lower power consumption, so the only take
away is this is something again we'll want to check out.

I would like to see tracking at reporting frequencies on 1-2 minutes,
that combined with reporting additional altitude data would again
reduce battery life. At that point I'd expect a device that was
primarily powered from the ships power would make sense.

Darryl

Has anyone considered getting a "spare" battery door and fitting a 3v
regulator inside a dummy AA cell fed with 12v through a grommet in the
door?

Leaving the original door and two new Li cells taped to the installation
should deal with any "walk out" scenarios.

Paul
G-CFRS/D-ENBW

At 05:53 06 August 2009, Darryl Ramm wrote:
On Aug 5, 10:30=A0pm, Eric Greenwell wrote:
Martin Gregorie wrote:
On Wed, 05 Aug 2009 11:11:47 -0700, Andy wrote:

On Aug 5, 10:10=C2 am, MarkHawke7 wrote:
I'm trying to get a direct answer from my contacts at SPOT
Mark,

Since you have contacts there I'd be interested to know why they
chang=
ed
from 2xAA to 3xAAA cells. =A0Was case size the only consideration,
or
perhaps the increased voltage increases the uplink TX power? =A0In
any
event I'd far rather have the longer life of AA cells than a
smaller
case size.

I suspect we're in the minority and Joe Hiker would far rather have
sma=
ll
and light than long battery life.

Hopefully the Mk 2 will provide the best of both worlds, which would
be
either:
- add an external power socket while retaining the 3 x AAA internal
=A0 cells

- replace the AAA cells with a 1500 mAh LiPoly rechargable and
=A0 a mini-USB charging socket. Alkaline AAA cells are 1250 mAh.

My SPOT will provide over 250 hours of tracking with the two AA cells,
which is more than a years flying for me. How many hours will the new
SPOT last?

Frankly, I don't care how many batteries they use or what the amphour
capacity is, as long they last a "long" time and it warns me when
there
are 20-30 hours life left. I have no interest in external power or
rechargeable batteries, because that would not be simpler, more
reliable, or cheaper than the present system. Adding altitude and
cutting the subscription costs are the only priority items for me.

Eric Greenwell

Eric

I expect cutting subscription costs and adding altitude are mutually
exclusive.

Reporting ~2-3x (depending on how they do this) the data in track
mode, as the new model will (repeat sending the past two position
reports) , may reduce the battery life, so also having a reduced
battery capacity compared to the first generation is worth noting.
They also do things that may lower power consumption, so the only take
away is this is something again we'll want to check out.

I would like to see tracking at reporting frequencies on 1-2 minutes,
that combined with reporting additional altitude data would again
reduce battery life. At that point I'd expect a device that was
primarily powered from the ships power would make sense.

Darryl

On Aug 6, 4:45*am, Paul Jessop
wrote:
Has anyone considered getting a "spare" battery door and fitting a 3v
regulator inside a dummy AA cell fed with 12v through a grommet in the
door?

Leaving the original door and two new Li cells taped to the installation
should deal with any "walk out" scenarios.

Paul
G-CFRS/D-ENBW

At 05:53 06 August 2009, Darryl Ramm wrote:

On Aug 5, 10:30=A0pm, Eric Greenwell *wrote:
Martin Gregorie wrote:
On Wed, 05 Aug 2009 11:11:47 -0700, Andy wrote:

On Aug 5, 10:10=C2 am, MarkHawke7 *wrote:
I'm trying to get a direct answer from my contacts at SPOT
Mark,

Since you have contacts there I'd be interested to know why they
chang=
ed
from 2xAA to 3xAAA cells. =A0Was case size the only consideration,
or
perhaps the increased voltage increases the uplink TX power? =A0In
any
event I'd far rather have the longer life of AA cells than a
smaller
case size.

I suspect we're in the minority and Joe Hiker would far rather have
sma=
ll
and light than long battery life.

Hopefully the Mk 2 will provide the best of both worlds, which would
be
either:
- add an external power socket while retaining the 3 x AAA internal
=A0 cells

- replace the AAA cells with a 1500 mAh LiPoly rechargable and
=A0 a mini-USB charging socket. Alkaline AAA cells are 1250 mAh.

My SPOT will provide over 250 hours of tracking with the two AA cells,
which is more than a years flying for me. How many hours will the new
SPOT last?

Frankly, I don't care how many batteries they use or what the amphour
capacity is, as long they last a "long" time and it warns me when
there
are 20-30 hours life left. I have no interest in external power or
rechargeable batteries, because that would not be simpler, more
reliable, or cheaper than the present system. Adding altitude and
cutting the subscription costs are the only priority items for me.

Eric Greenwell

Eric

I expect cutting subscription costs and adding altitude are mutually
exclusive.

Reporting ~2-3x (depending on how they do this) the data in track
mode, as the new model will (repeat sending the past two position
reports) , may reduce the battery life, so also having a reduced
battery capacity compared to the first generation is worth noting.
They also do things that may lower power consumption, so the only take
away is this is something again we'll want to check out.

I would like to see tracking at reporting frequencies on 1-2 minutes,
that combined with reporting additional altitude data would again
reduce battery life. At that point I'd expect a device that was
primarily powered from the ships power would make sense.

Darryl

I had one of the earliest SPOT unites and at the time had seen
significantly incorrect battery life claims and was worried about
this. There is so much space inside the original SPOT messenger case
that it looked possible to install an external power socket and
regulator to bypass the internal batteries while also leaving them
there. However as Eric points out, the track battery life is so
outstandingly good that this is just not needed. I suspect the new
model would require a dummy battery set as you suggest. But again,
that is really not my concern, I'd just buy more batteries. The
concern is with a unit (not the newly announced SPOT messenger)
transmitting every minute or so and also transmitting altitude. I
expect then you will want to use external power.

BTW back to the newly announced messenger - the easy power comparison
for the new SPOT messenger I can find is this - SPOT claims that the
original SPOT messenger supports sending 911 alerts for up to 7 days
(SPOT web site), they claim the new one does this for 4.6 days (from
Doug Ritter's blog, the spec sheet claims 4.7 days). There is no
change in the "911" message behavior AFAIK, Howver since the new
device's track mode sends more data, so maybe a wild ass guess for a
decrease in track time in the new model is is 4.6/7 * 1/3 ~ 20% of the
track time we are seeing with the first generation units. (assuming
sending 3x extra data requires 3x as much total power which is just a
very worse case total wild ass guess). So not that it helps much but
all this says is that I expect to see track battery life in the
20%-60% of what we see with the first generation unit. I'll have a
better guess later once I model the actual RF power consumption. We'll
have to just wait and see.

Darryl

I am impressed with how long the batteries last and have changed my
mind about the need to external power.
Altitude is not that big of an issue for me either.

The two things I would like to see is to

1. make the OK button work without canceling the Tracking.

2. The external power would be nice if the unit would power up into
tracking mode when power was applied. I currently need a checklist to
make sure I have everything turned on as it is. Anything I can connect
to the master switch is helpful.

Brian

The new version of the hardware will have a dedicated Tracking
button. I don't know for sure that you will be able to send an OK
while tracking but having a seperate button is a good sign.

-Mark
On Aug 6, 11:35*am, Brian wrote:
I am impressed with how long the batteries last and have changed my
mind about the need to external power.
Altitude is not that big of an issue for me either.

The two things I would like to see is to

1. make the *OK button work without canceling the Tracking.

2. The external power would be nice if the unit would power up into
tracking mode when power was applied. I currently need a checklist to
make sure I have everything turned on as it is. Anything I can connect
to the master switch is helpful.

Brian

On Aug 5, 10:53*pm, Darryl Ramm wrote:
On Aug 5, 10:30*pm, Eric Greenwell wrote:



Martin Gregorie wrote:
On Wed, 05 Aug 2009 11:11:47 -0700, Andy wrote:

On Aug 5, 10:10Â am, MarkHawke7 wrote:
I'm trying to get a direct answer from my contacts at SPOT
Mark,

Since you have contacts there I'd be interested to know why they changed
from 2xAA to 3xAAA cells. *Was case size the only consideration, or
perhaps the increased voltage increases the uplink TX power? *In any
event I'd far rather have the longer life of AA cells than a smaller
case size.

I suspect we're in the minority and Joe Hiker would far rather have small
and light than long battery life.

Hopefully the Mk 2 will provide the best of both worlds, which would be
either:
- add an external power socket while retaining the 3 x AAA internal
* cells

- replace the AAA cells with a 1500 mAh LiPoly rechargable and
* a mini-USB charging socket. Alkaline AAA cells are 1250 mAh.

My SPOT will provide over 250 hours of tracking with the two AA cells,
which is more than a years flying for me. How many hours will the new
SPOT last?

Frankly, I don't care how many batteries they use or what the amphour
capacity is, as long they last a "long" time and it warns me when there
are 20-30 hours life left. I have no interest in external power or
rechargeable batteries, because that would not be simpler, more
reliable, or cheaper than the present system. Adding altitude and
cutting the subscription costs are the only priority items for me.

Eric Greenwell

Eric

I expect cutting subscription costs and adding altitude are mutually
exclusive.

Reporting ~2-3x (depending on how they do this) the data in track
mode, as the new model will (repeat sending the past two position
reports) , may reduce the battery life, so also having a reduced
battery capacity compared to the first generation is worth noting.
They also do things that may lower power consumption, so the only take
away is this is something again we'll want to check out.

I would like to see tracking at reporting frequencies on 1-2 minutes,
that combined with reporting additional altitude data would again
reduce battery life. At that point I'd expect a device that was
primarily powered from the ships power would make sense.

Darryl

OK I've better modeled power consumption of the SPOT messenger. I
measured the actual current draw of my first generation SPOT messenger
in track mode.This was done with a logging multimeter which can see
the LED power consumption spikes and they are averaged out. In track
mode the messenger looks like it is in a dormant state for most of the
10 minutes before sending a message, it wakes up some time before the
message is ready to be sent and runs the GPS to get a fix, how long
the GPS stays on varies but it looks around 20 seconds on average.
Presumably if it has problems getting a fix it will run for longer.
With the GPS running the consumption is about 35mA. Actually sending
the message over the Globalstar modem consumes ~530 mA for about 1.5
seconds. All these numbers are rough, I'm not interested in being too
precise since there is a lot of hand waving involved.

So it is easy to model what power consumption would be for sending a
message very 5, 2, and 1 minute by just assuming the GPS and
Globalstar loads occur more frequently at those periods. To model also
sending altitude data I ignore any additonal processing or longer fix
time that may bre required by the GPS engine and just assume the only
cost is doubnling the Globalstar modem load per message (since it
likely must send two packets of data to encode location and altitude
as I've mentioned in a separate post). Crunch those numbers and I end
up with.

Guesstimated Track Battery Life (DAYS): (SPOT "1" with 2 x AA
Batteries)

Track Reporting Period 10 min 5 min 2min 1min
Position 14.2 10.6
5.6 3.1
Position+Altitude 8.3 5.6
2.7 1.5

Of course the only number here that is meaningful today is the 14.2
days of battery life for transmitting position every 10 minutes, which
is all that the first generation SPOT messenger actually does
(Convenient how I fudged the numbers to give 14.2 days, SPOT claims 14
day battery life for the first generation SPOT messenger in track
mode).

Now that was all assuming battery capacity and GPS power load etc. of
the first generation SPOT Messenger. As discussed before the new SPOT
messenger has a different GPS chipset, although I suspect it has the
same Axonn STX2 Globalstar Modem. So going out on a limb, if you
assumed the same GPS and STX2 power consumption for the new model
messenger and factored in the fact that the STX-2 in the new model
messenger has to transmit three location packets with each position
report and it has a reduced battery capacity 60% for the change from 2
x AA to 3 x AAA lithium batteries. The above table would look like...

Guesstimated Track Battery Life (days): (SPOT "2" with 3 x AAA
Batteries)

Track Reporting Period 10 min 5 min 2min 1min
Position 3.3 2.1
1.0 0.5
Position+Altitude 1.3 0.8
0.3 0.2

Again the only number that makes real sense today is whether the
actual track battery life of the second generation SPOT unit will
really be around 3.3 days or not. These numbers may be significantly
off, I hope it is better than this. The messenger may be significantly
more power efficient than I've assumed here. Axonn (who design the
actual hardware) may well have reduced power consumption from the GPS
chipset, Globalstar modem and other components. If somebody want to
send me their brand new second generation SPOT messenger I'll be happy
to pull it apart and have a poke around.

But the point is for people who want high frequency reporting, say
once every few minutes and altitude reporting I think you are in an
expected battery lifetime where you are going to want SPOT to design
the device for external power. The reason for that is not battery cost
(getting as high as several dollars per day of tracking time for the
worse numbers above) it is the "oh crap" cost of forgetting to check
the battery and replace them or forgetting to carry spare batteries.
We'll see far too many of these failures if the battery life is a
total of a few days.

Anyhow that's the back of my envelope and I'm sticking to it.

Darryl