|
New to Ham Radio?
My Profile
Community
Articles
Forums
News
Reviews
Friends Remembered
Speak Out
Strays
Survey Question
Operating
Contesting
DX Cluster Spots
Propagation
Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers
Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net
|
|
1-10 of 10 messages
|
Page 1 of 1
|
|
How much battery for a 706Mk2g run portable?
|
Reply
|
|
by CHRISDX on November 1, 2009
|
Mail this to a friend!
|
Hi
I'd like to throw my Icom 706Mk2g in a bag and take it portable. I was looking at the odyssey PC625 dry cell battery, http://www.odysseybatteries.com/battery/pc625.htm and wondering if anyone has any idea what kind of power drain the radio would be on such a battery.
Or any other suggestions.
I thought about selling it and getting a 817nd but 5 watts just wouldnt be enough.
Don't care that the battery is 13 lbs, plus radio, antennas and some type of tuner. 20-25lbs is fine.
Thoughts?
|
| |
|
RE: How much battery for a 706Mk2g run portable?
|
Reply
|
|
by WA3SKN on November 2, 2009
|
Mail this to a friend!
|
You will draw less than 2 amps receiving and between 20-25 amps transmitting (full power, you can lower the output power).(consider using headset)
Now how long are you planning to operate and how much transmit/receive time are you expecting?
Oh, and check your manual... you don't want to take the battery below 10.4 volts ever, but many radios do not work with voltages below 11 volts.
-Mike.
|
| |
|
RE: How much battery for a 706Mk2g run portable?
|
Reply
|
|
by W5DXP on November 2, 2009
|
Mail this to a friend!
|
I have an IC-706MKII running from a 125 amphere*hour deep-discharge marine battery. It will last the better part of a day during a contest at full power.
--
73, Cecil, w5dxp.com
|
| |
|
RE: How much battery for a 706Mk2g run portable?
|
Reply
|
|
by K5LXP on November 2, 2009
|
Mail this to a friend!
|
Looking at their technical manual, these look like pretty decent batteries.
The 625 is rated for 27 minute reserve capacity with 25amp load. We can assume that this is down to 10.5V (1.75VPC).
So if you work that out, it's about 12Ah at 25 amps.
It also states 18Ah at the 20 hour rate, so that is in keeping with the reserve capacity spec and a fairly low internal Z (characteristic of an AGM).
I use my 706 for most of my portable operating and often just with a 7Ah gel cell with the power turned down. I use a marine battery for QRO. I've tested my 706 and it will run satisfactorily down to 10.8V or so.
Since I would consider your choice a "good" battery to run something like a 706 with, it comes down to calculating the load vs available Ah at that current draw, then factor duty cycle.
Let's calculate how long you can receive for assuming the published battery spec's and my empirical low voltage cutoff value for my 706.
At ~1.3A draw on receive, and 15.6Ah available power you get about 12 hours of solid receive time.
At ~20A draw and 10.3Ah available power you get about 1/2 hour of continuous transmit at 100W.
So you can see your actual run time will be somewhere inbetween based on your RX/TX duty cycle. I would estimate a "casual" field operation at 80% RX, 20% TX where a contest like Field Day might be closer to 50-50.
A spreadsheet using the constants for the battery, and time and current variables for the load can quickly predict anticipated run time. Using published or derived peukert constant data for your battery can yield very accurate results.
Mark K5LXP
Albuquerque, NM
|
| |
|
RE: How much battery for a 706Mk2g run portable?
|
Reply
|
|
by N1LO on November 2, 2009
|
Mail this to a friend!
|
Hello Chris,
That was very wise not to go QRP portable, especially in the bottom of the solar cycle.
I like to use my 706 suitcase portable @100W. In multiple tests, friends and I have found that it's far better to have 2 batteries in parallel. They will last longer than 2 single batteries used in succession.
Next: what size? For a weekend like field day, 2 60 amp-hour (AH) batteries in parallel will give you at least 16 hours of operating.
For a day trip, you could probably cut that in half to 2 30 AH batts.
Still, that can be a lot to carry, but you can divide the battery load across 2 people.
You can always dial the power down to 50 watts, do just as well, and go lighter.
So let me boil it down to recommendations:
1) Use 2 smaller AGM/non-spillable batteries in parallel.
2) Stop operating when the battery voltage drops to 11.5 or so to avoid permanent damage to them.
3) Limit power to 50W and choose the A-H size of batteries that supports your typical outing.
4) Turn the backlight off and keep the volume low or use headphones to limit current draw in RX.
5) Use a full size wire antenna, not some compromise 'wonder antenna'.
GL,
--...MARK_N1LO...--
|
| |
|
RE: How much battery for a 706Mk2g run portable?
|
Reply
|
|
by CHRISDX on November 2, 2009
|
Mail this to a friend!
|
Thank You! Mark, and the rest... the replies have given me the picture, and that battery would be in the ballpark for my purposes. I was concerned not to waste too many "radiobucks" on a batt that would turn out simply too small, or even too large.
One possible use is on my night job where there is often kill time, and all I can use now is the 2m HT. There is even a flag pole I could house up a wire antenna if the boss isnt around. ;)
Another purpose is just to toss it in the car, on the seat. Because I drive sometimes into not so great areas, would be good to easily be able to leave it at home.
And finally, as a portable "demo station". As a relatively new ham, I'd like to be able to interest others and what better way than carry this kit in from the car into their house and fire it up on 2m, or other lower bands of antenna space permits.
I think I will look now into antenna choices, and see what existing or possibly custom leather bag could hold the kit as compactly as possible. Also, need to look at compact tuners.
Anyway thank you again for taking the time to work the battery numbers on this project.
73s
Chris P
KB1SNJ
|
| |
|
RE: How much battery for a 706Mk2g run portable?
|
Reply
|
|
by G4AON on November 2, 2009
|
Mail this to a friend!
|
This battery is intended for vehicle starter motor applications and while their Technical Manual gives a glowing report on it's capabilities, it's written by the manufacturer. Lead acid batteries last longer if discharged only lightly and an IC706 used for half a day is not a light load for an 18 Ah battery.
I use a 110 Ah battery for vehicle based portable ops with a 100 Watt radio and it's performance is well within the capabilities of that size of battery, I wouldn't use an 18 Ah for that purpose myself.
73 Dave
|
| |
|
RE: How much battery for a 706Mk2g run portable?
|
Reply
|
|
by CHRISDX on November 2, 2009
|
Mail this to a friend!
|
The Odyssey is a dry cell, and deep cycle capable from what I can tell. My friend has one in his airplane, left the master switch on and discharged it totally. He zapped it with a sec of reverse polarity a couple times and then gave it a full charge. Been starting the plane ever since. You can also fast charge that battery with very high amps, and in fact it loves it. Being a dry cell, there is nothing to spill and it can be mounted or used in any poition.
It is also almost the exact width of the radio, and I have inquired about a custom leather bag 7"wid, 10" long, and 10" deep. With the Radio at one end, and batt at the other, that would leave decent space in the middle for the mic, MFJ 902 tuner and a couple portable antennas.
Will have to make a snap-open flap at the heat sink, for cooling then I can run it without pulling it outta the bag.
Looking for convenience here! :)
73s
Chris P
|
| |
|
RE: How much battery for a 706Mk2g run portable?
|
Reply
|
|
by KU3X on November 2, 2009
|
Mail this to a friend!
|
I had two IC 706's. I have one for mobile and the other was intended to be used QRP portable. When I checked the current drain at only 5 watts out, I did not keep the second Icom. At 5 watts out from that rig it drew 7 amps of current. I felt that 2 amp on standby and 7 amps for transmit the battery would not last long enough for me. If you plan on operating QRP, then you need a real QRP rig, like the FT 817 or the IC 703. I had the FT 817 and loved it. I now have the IC 703+ and again love it. Both rigs draw about 2 amps or less when transmitting at 5 watts output.
Just a little note about the 706 again..... by turning the power level down to only 50 watts out, you will only be loosing 1/2 of an S unit and that's not bad. But, that rig still draws about 12 amps when you transmit at 50 watts out.
The IC 703 will put out 10 watts and it draws less than 3 amps at the power level. The FT 897D uses only 5 amps of current at 5 watts out. That's a 2 amp saving over the IC 706 series.
Bottom line, big power....big battery. Little power.....little battery. I use a 7 ah gell cell for my QRP stuff and it lasts all day.
Barry, KU3X
|
| |
|
RE: How much battery for a 706Mk2g run portable?
|
Reply
|
|
by K5END on November 7, 2009
|
Mail this to a friend!
|
Chris, I think there is a bag as you describe on the market already, only it is nylon and not leather.
look at powerportstore.com
i've never used one of these so I cannot recommend it. but "it looks good in the picture."
|
| |
|
Email Subscription
You are not subscribed to this topic.
Subscribe!
My Subscriptions
Subscriptions Help
Check our help page for help using
Forum, or send questions, comments, or suggestions to the
Forum Manager.
|
|
|
