Power for Handheld VHF in Life Raft

[Dockhead]

Like many of us, I consider my DSC handheld VHF radio (from this year, a SH HX870) a primary signalling device for the life raft, first on the "grab list".

The value of this device in the liferaft is that you can signal any passing ship you can see, plus you can talk to SAR resources from quite a distance, if they are airborne. A DSC distress signal can't be ignored by a passing ship.

The value of this is hammered home by any number of accounts of sailors in life rafts who saw passing ships but could not get their attention.

However, one concern is power. Like most of us, I carry a battery tray and some vacuum-packed AAA's, but the Standard Horizon radios won't give full power on these batteries, and in general don't work that well.

What's really needed is a full normal battery.

My new HX870 is kept in a charge cradle now, mounted on a bulkhead near the nav table, and so I can be pretty sure that it will always be fully charged should I need to grab it.

But what about something like this:

High Quality 12V Portable Mini Jump Starter 38000mAh Car Jumper Booster Power Battery Charger Mobile Phone Laptop Power Bank Blue Color - Newegg.com

Something like this would hold enough power to recharge the HX870 a couple of times.

To be sure it's fully charged when you need it, it would also have to kept somewhere always charging, which is yet another thing to arrange, but maybe worth it.

[Dr. Strangelove]

A buddy of mine has one of those mini jump-starter thingys that you link to, or a similar one anyway.

It's impressive for it's size, and would indeed recharge a radio several times. I don't know how long it'll last in a marine environment, I'd probably replace it every couple of years and relegate the old one to car/land based duty.

That reminds me, I need to pick one up for the Jeep, thanks.

[barnakiel]

You are probably making it complicated.

How about a second HX battery, fully charged just before the important passage then vacuum sealed and dropped into your lifebag?

http://www.standardhorizon.com/Acces...s/SBR-13LI.jpg

No good?

So, check out LITHIUM AA bats. Commonly used in photography and way more powerful than plain alkalines. Maybe this is what you need.

While at that, look at Energizer Ultimate Lithiums (4th generation). Tested, independently, here:

Test of Energizer Ultimate Lithium AA

b.

[Dockhead]

Originally Posted by barnakiel

You are probably making it complicated.

How about a second HX battery, fully charged just before the important passage then vacuum sealed and dropped into your lifebag?

http://www.standardhorizon.com/Acces...s/SBR-13LI.jpg

No good?

So, check out LITHIUM AA bats. Commonly used in photography and way more powerful than plain alkalines. Maybe this is what you need.

While at that, look at Energizer Ultimate Lithiums (4th generation). Tested, independently, here:

Test of Energizer Ultimate Lithium AA

b.

Neither of these ideas will work. Rechargeable Lithium Ion batts have self-discharge, and may not have any charge when you take them out of the vacuum seal. This might be ok if you had a spare standard battery pack in some kind of charger, but you can't buy it for any of these radios (I had an ancient Motorola mobile phone which had a charger for extra batts, but never seen a marine VHF).

Lithium AAA's, non-rechargeable, do not work at all. Don't ask me how I know . The chemistry is different and they give lower voltage. You must use alkalines in the SH battery tray. I am slowly using up the supply of Energizer Ultimate Lithiums I bought for my previous Standard Horizon radio, for other purposes.

[Thorne]

I have the water proof hx471sb, I had to use it only once but it saved my rear.

It's great for getting local weather in the states, listening to pilots at the air port, listening to fm music when sitting in the cockpit or chatting to folks on cb radio, oh yeah, it works on vhf very well.

As for spare batteries I carry 2 extras. It comes with a charging station. I also have the battery pack that plugs straight into a cig lighter socket.

Battery packs for mine can be found here.
https://www.amazon.com/ExpertPower%C...ywords=hx471sb


Battery packs for yours can be found here
https://www.amazon.com/Standard-Hori...keywords=HX870

[barnakiel]

Originally Posted by Dockhead

Neither of these ideas will work. Rechargeable Lithium Ion batts have self-discharge, and may not have any charge when you take them out of the vacuum seal. This might be ok if you had a spare standard battery pack in some kind of charger, but you can't buy it for any of these radios (I had an ancient Motorola mobile phone which had a charger for extra batts, but never seen a marine VHF).

Lithium AAA's, non-rechargeable, do not work at all. Don't ask me how I know . The chemistry is different and they give lower voltage. You must use alkalines in the SH battery tray. I am slowly using up the supply of Energizer Ultimate Lithiums I bought for my previous Standard Horizon radio, for other purposes.

1) Lithium ion self discharge is 2 to 3% per month. How long are your passages? Our longest ever was 72 days. This is just 5% discharge. No issue.

2) Energizer Lithium Ultimate are 1.5 Volt nominal and 1.8 Volt not loaded. The tray takes 6. Calculate the voltages. Then we can talk again.

The unit does not care about battery chemistry, it only wants voltage and ampage.

Our much older SH handheld takes all kinds of AA so you must have either a faulty tray in the new one or else you are doing something wrong. Check polarity on the tray next time and test the tray with a VOM. Maybe it is a lemon and the culprit of all your worry.

And if you are still trying to create some challenge where there is none ... ;-) then have a look at the units used to kick start car engines. An example here. I bet this is like what you may like. Get an IPX67 one.

They will work with SH 12V cigarette cable.

Car Starter: Top 7 Compact Battery Jump Starters 2016

Now much as I love you I must abandon you ...

PS If you go the car jump starter road, PLS tell us your findings! I am buying one too.

PS NO, you do not want the spare docked in any charger onboard. If it is an emergency unit, it belongs in the bag.

Cheers,
b.

[SVNeko]

What about a folding solar charger?


Sent from my iPad using Cruisers Sailing Forum

[donradcliffe]

My grab bag included a 8 watt solar car charger, wired to a plug which charged the VHF. It could charge the VHF over and over, and was also used to maintain bigger batteries when I left the boat. I never tried it in the life raft, but it worked fine onin the cockpit.

If I was going to do it again today, I'd include a USB port on it.

[Dockhead]

Originally Posted by barnakiel

1) Lithium ion self discharge is 2 to 3% per month. How long are your passages? Our longest ever was 72 days. This is just 5% discharge. No issue.

2) Energizer Lithium Ultimate are 1.5 Volt nominal and 1.8 Volt not loaded. The tray takes 6. Calculate the voltages. Then we can talk again.

The unit does not care about battery chemistry, it only wants voltage and ampage.

Our much older SH handheld takes all kinds of AA so you must have either a faulty tray in the new one or else you are doing something wrong. Check polarity on the tray next time and test the tray with a VOM. Maybe it is a lemon and the culprit of all your worry.

No, Barnie -- the Energizer Lithium Ultimates have different voltages from Alkaline, and do not work. Standard Horizon specifically warn about this in the manual, and confirmed by technical support. The nominal voltage is the same, but the lithiums sag just enough for the radio to cut out. You must use alkalines in the battery tray. There have been a couple of threads on this.

As to vacuum sealing a charged spare battery -- that's probably a good idea -- IF you remember to take it out and recharge it. But compared to that, it's maybe better just to carry a bunch of sealed alkaline AAA's, which have a self-discharge rate of only 2% a YEAR. I am loathe to add to things to remember to futz with in the grab bag -- you should be able to forget about these things and they should work if you suddenly need them, which will always be completely unexpected.

A charged spare battery on a charging stand next to the radio would be ok, however -- a grab list item and you will certainly remember to take it when you take the radio.

Same principle would apply to the car jump starter battery pack. And that might be best of all since you can charge other devices with it as well.

[Dockhead]

Originally Posted by donradcliffe

My grab bag included a 8 watt solar car charger, wired to a plug which charged the VHF. It could charge the VHF over and over, and was also used to maintain bigger batteries when I left the boat. I never tried it in the life raft, but it worked fine onin the cockpit.

If I was going to do it again today, I'd include a USB port on it.

Would be good IF you have sunlight. In the winter up here we might have a week without any real sunlight.

[roland stockham]

I think you are on the right lines but wrong kit. Those small power packs are designed for mobile phones and do the job very well but are too small. Look at the smallest car booster power packs. It is the same idea but uses a small sealed 12v lead acid battery and they have a standard cigarette lighter socket that will either fit the radio batt charger or a 10-15w solar panel. It is more stuff to carry but gives enough power for VHF, a small short wave radio receiver (weather reports) and LED lighting (high power torch for signalling plus comfort at night).

[buzzstar]

Originally Posted by Dockhead

No, Barnie -- the Energizer Lithium Ultimates have different voltages from Alkaline, and do not work. Standard Horizon specifically warn about this in the manual, and confirmed by technical support. The nominal voltage is the same, but the lithiums sag just enough for the radio to cut out. You must use alkalines in the battery tray. There have been a couple of threads on this.

As to vacuum sealing a charged spare battery -- that's probably a good idea -- IF you remember to take it out and recharge it. But compared to that, it's maybe better just to carry a bunch of sealed alkaline AAA's, which have a self-discharge rate of only 2% a YEAR. I am loathe to add to things to remember to futz with in the grab bag -- you should be able to forget about these things and they should work if you suddenly need them, which will always be completely unexpected.

A charged spare battery on a charging stand next to the radio would be ok, however -- a grab list item and you will certainly remember to take it when you take the radio.

Same principle would apply to the car jump starter battery pack. And that might be best of all since you can charge other devices with it as well.

Sounds to me like a portion of the problem is a device (Standard Horizon) that does not operate with rechargeable batteries. Are there alternatives that do?

Rather than a grab list, a grab bag, perhaps supplemented by a list could be an improvement if budget and the circumstances of use allow.

[barnakiel]

Originally Posted by Dockhead

(...)

Same principle would apply to the car jump starter battery pack. And that might be best of all since you can charge other devices with it as well.

AND start the engine too ...

b.

[UNCIVILIZED]

There are small hand crank chargers available for cell phones, so odds are there are similar units for this application. And if not, it wouldn't be tough to put one together. Plus, solar still works even if there's cloud cover. So there's no need to rule it out. Also, you might even be able to swipe the power generator in one of those flashlights (torch) which you repeatedly squeeze to power them. And when you're up north remember to keep the batteries warm, in order to increase how long they perform.
Bottom line, anything can be recharged. It's more a question of how easily, & that's a function of desire & $. Why's this complicated?


PS: Anyone got a line on a pocket sized wave powered generator?

[Herb Miller]

Wow - something I can reply to.


I am using one of those car charger battery whiz-bang things for charging duties on a really small boat (SJ21). Read the specs. Some of the USB and other charging outputs are current limited. The main connectors that start a car require a minimum discharge amperage before it will kick in with the voltage. It would not drive my (very) small instrument package until I rigged a small 12-volt light in parallel with the output. The light drew about 1 amp. After that it worked fine.