Radio battery backup

[frankdrebin]

Originally Posted by peterchech

There are adapters that would allow you to plug the handheld into the mast antenna. I don't know how much power would be lost from a 5w handheld going up 30' or more of coax, but that info can be found online.

Depends on the characteristics for the coax used. VHF frequencies are lossy through coax. With HF, losses are next to none. Figure your losing 3db/100 feet ballpark estimate. (near half) But the money quote is... even with the loss through 30 feet of coax, your signal strength will be much improved over that "ducky" antenna.

[FastbackFill]

Thanx for the wealth in information flooding in.
I am overwhelmed with the great ideas.
Yes I think I will buy a 5 watt hand held.
Untill I figure out which way to double up my power supply.
Thanks again.
If I do get around to wiring up a second battery i will post some photosand prices.
Once agin thank heaps to all of you.

Fastback Fill here in Rocky
Queensland
Australia

[MedSailor]

If you get a second deep cycle, you have to install it in with your charging system because they self discharge. They are expensive, heavy and require maintenance. Here are some options that I think would be easier.

How about 2 of these for a nice 13AH 12V battery that will require no maintenance for the next 10 years. They are usually called "lantern batteries" Buy the alkaline (ie duracell or energizer) not the "heavy duty" ones.


You could have 4 wired together for a 26AH battery @ 12V if you like. You could even get "fancy" with pre-wiring them, duct taping them together, and having bullet butt connectors so you could switch over from primary supply to this pack in a flash and without tools. Here are the connectors I'm talking about. They're available at any marine and some automotive stores as "bullet connectors" They are in-line connectors that can be clipped and un-clipped by hand. Great for switching from primary in-line wiring to a secondary battery:



You could also carry around one of these so that in the above scenario where all your house batteries are dead, you can still start your engine. Note the 12V cigarette receptacle where you could power the VHF as well. This setup is a sealed lead acid and could be charged once a season. Stay away from the many cheap ones, as they won't start your engine. I've used the one in the picture the "Jump-n-carry 1700" to start a 4cyl diesel genset on a boat.

Do you have a handheld 12V spotlight of 1-2million calndlepower? If not you should. Saved my butt more than once coming into an anchorage later than expected. Be sure to buy a rechargeable one that has a 12v battery (most do and they're sealed lead acid batteries requiring once a season charging. Make up some connectors to use this sealed battery to power the radio in a pinch and store them with the spotlight.

Hope these ideas help.
MedSailor

[hellosailor]

medsailor, I know that spotlight, I bought one for 60c 9after rebate) three weeks ago. And for 60c it is a great light, but, ah, it may be a bit deceptive, there's just a tiny 2.3AH 6V battery inside it.

The lantern batteries can also be deceptive, some are made with four "F" calls inside, which is normal. Others are made cheap with four D cells inside, and the capacity varies 100% from one brand/line to another. They'll also provide only 12 volts, when most "12" volt radios are designed to run on 13.8 (alternator power) or 12.6 (good car battery power, so they may work well, or not.

Simplest solution is to buy a "jump box" and keep that as a spare for the radio OR for the engine start but you've got to be careful there too and read the actual battery capacity inside. I've used a 17AH battery to start a small diesel, that's about the size of a cigar box. Some jump boxes (like from that spotlight maker) use a 8AH battery, which is REALLY pushing things.

The small "gel" batteries haven't been gel cells for years, they're all AGM batteries now. Sold bare for alarm systems and exit lights around $1.50 per amp-hour in 6 or 12 volts and if you charge them up once every 90 days, they should be nearly fully charged even 90 days later.