Icom 7000 for portable operation.

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David Tsang:
Greetings,

First time here and not too familiar if there is another place that receives more traffic, but I am interested in utilizing an Icom 7000 for portable use.

Currently a Lance Corporal in the USMC, and am aboard a Naval vessel in the Philippines.  My idea is this: I love the 7000, plan on using in my car as well as on backpacking/expeditions.  However the alternate use is to use it wherever I am while on deployments.  I want to build a battery pack that will fit in a pelican case (1300-1400 model size) that also has an integrated charging system.  Also what about antenna choice?  I would like it to break down into a case of similar size or a backpack if possible.

What are some of my options?  I am great with a soldering iron and can build most things and have a basic idea of electrical theory and components.  Please shoot some ideas around and again if there is a better place to post please let me know.  Thanks very much.

LCpl Tsang, Dave A.
USMC

Code4@zero-signal.org

Moe:
First, thank you for your service to our country.  Since no one else has answered, I'll take a shot, having some experience operating off batteries in boats and RV, but not ham radios.

You need to define your requirement for this portable system.  

For example, let's say that's 4 hours of total operation in which you'll be listening 75% of the time at the IC-7000's 1.6 amp draw (3 hours x 1.6 amps = 4.8 amp-hours) or roughly 5 AH, and transmitting at full power 25% of the time (1 hour total) at the 22 amp draw for 22 AH.  That puts you at about 27 AH consumed.

You definitely want a deep-cycle battery.  Starting batteries, including those for motorcycles, won't hold up to repeated deep discharges.

If you want to get good cycle-life out of a deep-cycle battery, you won't discharge it below 50%, so you're looking at a 55 amp-hour battery now.  You can take it down to 25% but then you may be replacing it twice as often.  Another problem with very deep discharge is that the voltage is lower, and can drop below that needed during transmit.

In this example, the sealed absorbed glass mat (AGM) Optima D34M dual-purpose (deep-cycle and start) marine battery will give you those 55 AH (actually closer to 52-53 AH at 22A due to the Peukert Effect which I won't get into).  It's 43.5 pounds and 10" long by 6-7/8" wide by 7-13/16" high but can be carried and operated on its side since it's sealed and the electrolyte is in the fiberglass mats.  It's also pretty rugged against shock and vibration.

http://www.optimabatteries.com/publish/optima/americas0/en/config/product_info/marine/technical_specs.html

The only downside to the Optima spiral-wrap "six pack" design is it doesn't make efficient use of the length x width x height volume.  AGMs are also available in traditional form factor with more amp-hours (and weight) in the same volume.  Lifeline makes high-quality traditional form-factor AGM batteries, as do others.

A good, sealed charger for it might be the Guest 2610A sealed marine 3-stage 10 amp charger, at about 6 pounds and 5.5" tall by 7.75" wide by 2.42" deep.  It'll be a little deeper if you mount it on 1/2" standoffs to allow air to circulate behind it.  It probably needs to be used in a vertical position either upright or sideways to allow good air flow over it.

http://www.marinco.com/scpt/ProdPage.php?loadItem=2610A_Guest%20Recreational

If you're thinking solar power, on a clear, sunny day, you'll need about 100 watts of panel(s), facing south and tilted up at your latitude plus or minus about 10 degrees depending on time of year, to put back about 30 AH for this example of 27 AH daily use.

This is just one example of many possible scenarios.   Hope it helps.

David Tsang:
Thank you for your technical reply!  It was what I needed to get some ideas going.  I am also currently looking at digikey's site at the battery selection there.  I may hit you up for some further questions, if you do not mind.  Could you send me your email?  I am at code4@zero-signal.org

And I appreciate your thanks as well,

Dave

Moe:
You're welcome, Dave.  My example was very rough and overstates the energy used during transmit. The furnace in an RV doesn't operate continuously, rather cycles on and off, with the duty cycle dependent largely on outdoor wind-chill.  For example, a 9A furnace fan running 33% duty cycle runs an average of 3A, not considering Peukert Effect.

The same can be said with transmitting.  Morse Code is nowhere near 100% duty cycle, and SSB runs a lower average power.  You may find the 55AH Optima lasts 8 hours or more for you before dropping below 50% charge.

I tell RVers and boaters there's no substitute for KNOWING the amp-hours you use rather than trying to calculate an estimate of them.  A good amp-hour meter like the Xantrex X-10 integrates instantaneous current over time.  If you're going to operate off batteries, it's a much more accurate way of estimating battery state of charge over using a voltmeter or checking specific gravity.  And it's a good thing to use before designing and building an alternative energy system.

Bonnie:
Here is a photo of my IC-F7000 rig in a Pelican case:
http://www.hfpack.com/aleportable/icf7000.jpg

It is not suitable for backpacking use, but it is "transportable" and it runs ALE (Automatic Link Establishment).

My main backpacking rig is a Vertex VX-1210.

For more info about HF Portable, see the HFPACK.COM website:
http://hfpack.com

For more info about ALE see the HFLINK.COM website:
http://hflink.com

73 Bonnie VR2/KQ6XA

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