EPIRB Batteries

OceanSprint

OceanSprint

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EPIRB Battery Life

I think we are all shocked by the terrible tragedy that is unfolding in the Atlantic, and we all wish everyone involved the very best.

One aspect of this shocking incident is the short battery life of PLBs and EPIRBs. I would have thought that, with today's technology, this could be extended?

Liferafts could have spare batteries?

The beacon could go onto a longer-life mode after 12 hours, broadcasting fewer fixes, but then lasting longer?

Could EPIRBS receive confirmation that they have been heard, and then go onto a "broadcast only when polled" mode that search and rescue teams could use ?

I am not a god-fearing man, but we all pray for a good outcome, and also good can come out of it with changes to safety kit?

PS My wife and I have both signed the petition and will be encouraging others to do so !
 
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OceanSprint said:
I think we are all shocked by the terrible tragedy that is unfolding in the Atlantic, and we all wish everyone involved the very best.

One aspect of this shocking incident is the short battery life of PLBs and EPIRBs. I would have thought that, with today's technology, this could be extended?

Liferafts could have spare batteries?

The beacon could go onto a longer-life mode after 12 hours, broadcasting fewer fixes, but then lasting longer?

Could EPIRBS receive confirmation that they have been heard, and then go onto a "broadcast only when polled" mode that search and rescue teams could use ?

I am not a god-fearing man, and we all pray for a good outcome, but also good can come out of it with changes to safety kit?
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Surely EPIRBS do have quite long battery life - 48 hours or more. The reports of this recent yacht seem to indicate that the signals received came from PLBs which are far smaller devices and I suspect that the battery life is already stretched to the limit.
 
OceanSprint said:
I think we are all shocked by the terrible tragedy that is unfolding in the Atlantic, and we all wish everyone involved the very best.

One aspect of this shocking incident is the short battery life of PLBs and EPIRBs. I would have thought that, with today's technology, this could be extended?

Liferafts could have spare batteries?

The beacon could go onto a longer-life mode after 12 hours, broadcasting fewer fixes, but then lasting longer?

Could EPIRBS receive confirmation that they have been heard, and then go onto a "broadcast only when polled" mode that search and rescue teams could use ?

I am not a god-fearing man, but we all pray for a good outcome, and also good can come out of it with changes to safety kit?

PS My wife and I have both signed the petition and will be encouraging others to do so !
Click to expand...

Given that most EPIRBS are 'return to service agent' for battery replacement, there'd have to be a redesign to allow a user-swap in less than ideal circumstances.

Going into long-life mode seems a very good idea, though, and presumably something that could be coded onto a cheap chip and incorporated pretty easily.
 
It's unfortunate that the GPS protocol was designed before things like EPIRBs and PLBs were practical - otherwise it would have been possible to reserve a timeslot in the transmission that could have been used to do a handshake back to the beacon to confirm receipt.
 
I thought even PLBs had a minimum battery life of 24 hrs even in extreme conditions.

It is very worrying that with at least 2 PLBs available they seem to have lost the signal so soon.

I have always worked on the assumption that the battery on my PLB would last long enough for me to be rescued - if that is not the case then a rethink is required.
 
bedouin said:
I thought even PLBs had a minimum battery life of 24 hrs even in extreme conditions.

It is very worrying that with at least 2 PLBs available they seem to have lost the signal so soon.

I have always worked on the assumption that the battery on my PLB would last long enough for me to be rescued - if that is not the case then a rethink is required.
Click to expand...

I don't think that is the implication at all - the PLB will only work if it is out of the water - if two PLBs were set off near simultaneously, it seems likely to me that the crew were separated and in the water, not a liferaft - the signals were presumably lost when they were no longer able to hold the device out of the water.
 
SteveSarabande said:
Once activated can plb's be turned off? Seems this is a way to extend battery life. Just activate every few hours for 5 minutes
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They can certainly be turned off - to allow for unintentional activation. Not sure if they can be turned on again without a factory reset.
 
There are 24hr (min) and 48hr (min) PLB's, most are 24, there is at least one make that you can change the batteries in.

All EPIRBS are 48hr min, and most can be switched off (ours could) so it left the potential to switch it on at a regular intervals to extend battery life. That was our plan, instructions to crew.
 
AFAIK PLBs can be turned on and off at will: they will simply restart their transmissions when switched back on. We have two PLBs on board and the intention is to use them one after the other if possible. The idea of a handshake between PLB and satellite is attractive on first examination but would mean the PLB would need to receive signals as well as transmit. In addition, the satellites would need modifications to enable them to handle the conversation, so not something that will happen until at least the next generation of SAR satellites get to the drawing board. On the other hand, you could put a satellite phone into the grab bag.
 
SteveSarabande said:
Once activated can plb's be turned off? Seems this is a way to extend battery life. Just activate every few hours for 5 minutes
Click to expand...

I have not used a PLB and can only comment based on the manual (http://www.oceansignal.com/pdf/manual/1364301061_PLB1_User_Manual.pdf) of RescueME PLB1: the PLB can be switched off, however, when activated it sends the alert only after 50s to allow switching off if activated accidentally. Also, the PLB needs to acquire its position each time it is activated which potentially could lead to higher power consumption when switching on/off.
My PLB is quoted to last more than 24 hours. I would expect that when activated in the middle of a ocean for 24 hours one could estimate the further positions (after the battery dies) based on previous positions (currents and weather) and move the search area accordingly.
And an another thought, if a search party is nearby and is receiving 121.5MHz signal on the final approach and PLB is switched off then the search might be more difficult to perform.
 
maby said:
It's unfortunate that the GPS protocol was designed before things like EPIRBs and PLBs were practical - otherwise it would have been possible to reserve a timeslot in the transmission that could have been used to do a handshake back to the beacon to confirm receipt.
Click to expand...

I'm sure I read somewhere of a scheme very like this which is being planned. Can't remember what they were piggybacking on for the downlink. Obviously it will take some years to come into operation.

Pete
 
duncan99210 said:
.... The idea of a handshake between PLB and satellite is attractive on first examination but would mean the PLB would need to receive signals as well as transmit. In addition, the satellites would need modifications to enable them to handle the conversation, so not something that will happen until at least the next generation of SAR satellites get to the drawing board. ...
Click to expand...

That's why I was suggesting that the better solution would be to include a handshake timeslot in the GPS protocol - the PLB or EPIRB is receiving those signals already. If the two systems had been designed together, it would seem to be the obvious solution, but they were not.
 
The simplest improvement seems to be to have EPIRBS that Have a built in ability to accept an external power supply in addition to internal batteries. External power supplies could include batteries, solar, wind or hand-wound generators in life rafts.
 
maby said:
I don't think that is the implication at all - the PLB will only work if it is out of the water - if two PLBs were set off near simultaneously, it seems likely to me that the crew were separated and in the water, not a liferaft - the signals were presumably lost when they were no longer able to hold the device out of the water.
Click to expand...
I think the PLBs were set off some hours apart.

A PLB that won't work if the wearer is in the water is really not much use at all. I am sure they are all waterproof - but the antenna is such that they may not transmit well if not attended
 
GPS and SARSAT are not the same satellites. A GPS handshake protocol is meaningless.

My strategy offshore would always be on for 4 hours then off for 2 hours on for 1 until rescue. I'm also amazed that no one makes a solar assisted epirb/plb. Given that it doesn't need to continuously transmit and that it doesn't need to be very powerful I'm quite sure that a unit with a built in solar panel could easily extend transmit life by days.
 
Buck Turgidson said:
GPS and SARSAT are not the same satellites. A GPS handshake protocol is meaningless.

....
Click to expand...

Yes, of course they are different satellites, but the two systems could have been designed to provide an integrated system. It would be very easy for the GPS system to accept a data feed from SARSAT that lists PLBs currently being received and forward this on in a reserved timeslot - if the two systems were being designed simultaneously today, I'm sure that they would be cooperating in this way - they were not designed together and they do not interface - which is a pity.
 
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