Cruisers Forum
 


Join CruisersForum Today

Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on Cruisers Forums. Advertise Here
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 12-11-2018, 19:21   #1
Registered User

Join Date: Mar 2018
Posts: 33
do I really need 13.8 volts for Icom M802 SSB radio ?

I was reading the installation instructions for the Icom M802 SSB radio. It says to connect DC power wires to a "stable 13.8 volt supply". Ours has a pretty clean connection isolated from the rest of the DC power distribution panel. It is properly fused and circuit breaker/switched. But I assume like ours, most SSB radios installed on boats do not have a DC to DC voltage buster to increase the voltage from the typical 12.50 to 13.0 volts from the batteries up to the stable 13.8 that Icom recommends. So any thoughts as to how important it is to try and increase the voltage and if so what is on the market to achieve that ?
__________________

cgebluewater is offline   Reply With Quote
Old 12-11-2018, 19:37   #2
Moderator
 
roverhi's Avatar

Join Date: Aug 2005
Location: Kona, Hawaii, Carlsbad, CA
Boat: 1969 Pearson 35 #108 & 1976 Sabre 28
Posts: 6,466
Send a message via Yahoo to roverhi
Re: do I really need 13.8 volts for Icom M802 SSB radio ?

Thought one of the design features of the 802 over ham radios is that they worked on low voltages where Ham radios might notl. The ham radios are supposed to output fewer watts as the battery voltage drops. Can't say that I ever noticed it as I've always been able to get through even with voltage at 12 + or - with my ICOM 718 ham radio. So no, you should be fine on the radio at 12.7v or whatever resting voltage is on your battery and even get out with voltages at 12v or below though mabe with not as strong a signal.
__________________

__________________
Peter O.
'Ae'a, Pearson 35
'Ms American Pie', Sabre 28 Mark II
roverhi is online now   Reply With Quote
Old 12-11-2018, 21:20   #3
Registered User

Join Date: Feb 2013
Location: Lago de Izabal, Guatemala
Boat: Seafarer36c
Posts: 4,925
Re: do I really need 13.8 volts for Icom M802 SSB radio ?

My volts can get really low after a long attempt at an Email. I give up at about 12.6v.
Ecos is offline   Reply With Quote
Old 12-11-2018, 22:47   #4
Senior Cruiser
 
ronstory's Avatar

Cruisers Forum Supporter

Join Date: Sep 2015
Location: Portland, OR USA
Boat: C&C 35 MK-II
Posts: 176
Re: do I really need 13.8 volts for Icom M802 SSB radio ?

The ICOM M802's recommend voltage is 13.6V +/- 15%, or ~11.6V min
For the ICOM IC-7100 (which I own) is 13.8V +/- 15%, or ~11.7V min

So the marine version get's you a bit lower, but not much. That said, it the spec... they may do better than the min voltage in the real world.
__________________
Thanks,
Ron
ronstory is offline   Reply With Quote
Old 12-11-2018, 23:19   #5
Registered User

Join Date: Oct 2018
Location: Jacksonville Florida
Boat: allied 39
Posts: 130
Re: do I really need 13.8 volts for Icom M802 SSB radio ?

I never had a problem with the 802 with voltage bellow 13.8. To be honest I doubt I often had 13.8 when using it.
Generally sending emails over the pactor is not best done in the middle of the day and most of the nets are in the early am.....before hrs of solar panel output to make up the amps for keeping the beer cold.
Obviously make sure you can get plenty of juice to it. No long runs with voltage drop, they suck up the amps when transmitting!!
So, in my experience, no.
I think you will get a lot of experienced comments on this question.
Allied39 is offline   Reply With Quote
Old 13-11-2018, 11:20   #6
Registered User
 
Dougtiff's Avatar

Join Date: Jul 2015
Location: San Rafael, Ca.
Boat: Gaff rigged Ketch[Spray]37' on deck
Posts: 300
Re: do I really need 13.8 volts for Icom M802 SSB radio ?

Year's ago, a friend had a battery built with one more cell, so the voltage was always high, even on transmit.
Dougtiff is offline   Reply With Quote
Old 13-11-2018, 11:34   #7
Registered User
 
Capt.Don's Avatar

Join Date: Aug 2010
Location: Altadena, CA
Boat: Tartan 3500
Posts: 739
Images: 1
Re: do I really need 13.8 volts for Icom M802 SSB radio ?

I found with my old SEA 235 SSB, if battery voltage was low, I had trouble transmitting via Pactor modem. Always tried to make sure batteries were charged before checking email.
Don
Capt.Don is offline   Reply With Quote
Old 13-11-2018, 11:49   #8
Marine Service Provider

Join Date: Feb 2012
Location: Vienna, Austria
Boat: Vagabond 47
Posts: 293
Re: do I really need 13.8 volts for Icom M802 SSB radio ?

Simple answer: YES
moseriw is offline   Reply With Quote
Old 13-11-2018, 11:59   #9
Moderator
 
Jim Cate's Avatar

Join Date: May 2008
Location: cruising SW Pacific
Boat: Jon Sayer 1-off 46 ft fract rig sloop strip plank in W Red Cedar
Posts: 13,856
Re: do I really need 13.8 volts for Icom M802 SSB radio ?

Quote:
Originally Posted by moseriw View Post
Simple answer: YES
REAL simple answer is in post 4 above: 13.6 +/- 15%!

Jim
__________________
Jim and Ann s/v Insatiable II lying Sandy Bay, Hobart,
Jim Cate is online now   Reply With Quote
Old 13-11-2018, 11:59   #10
Registered User
 
wingssail's Avatar

Join Date: Jan 2010
Location: On Vessel WINGS, wherever there's an ocean, currently in Mexico
Boat: Serendipity 43
Posts: 347
Send a message via AIM to wingssail Send a message via Skype™ to wingssail
Re: do I really need 13.8 volts for Icom M802 SSB radio ?

Quote:
Originally Posted by moseriw View Post
Simple answer: YES
I would be very surprised if the 802 has less voltage tolerance than other ICOM SSB radios. Our experience is that the ICOM M700 continues to transmit with very low voltages (down to 11.6). When the sun is shining and solar is plentiful, voltage is no problem. Night time, and when you have not been motoring all day, the voltages can get low on our boat, the ICOM continues to transmit, uses about the same DC Amps of power during transmission, (often 20-30 amps), and our Pactor connections seem more affected by weather than voltage.

So I would say that your normal range of battery voltages will work.
__________________
Fred Roswold
Fred & Judy, SV Wings, Mexico
http://wingssail.blogspot.com/
wingssail is offline   Reply With Quote
Old 13-11-2018, 12:13   #11
Registered User

Join Date: Aug 2011
Location: Cruising full time in Panama
Boat: Irwin, custom Sloop, 45
Posts: 26
Re: do I really need 13.8 volts for Icom M802 SSB radio ?

Iíve had an ICOM M802 w/pactor modem on my boat since 2008, and know Iíve never supplied 13.8V to the radio, which works perfectly. Iíd be certain that you do not undersize the positive and negative power supply cables between the supplied power cable, and connect the connecting cables directly to your batter terminals. You should have no problems ala the 13.8v spec.
NirvanaBob is offline   Reply With Quote
Old 13-11-2018, 14:43   #12
Registered User

Join Date: Aug 2015
Location: Marina del Rey
Boat: Hunter 31
Posts: 687
Re: do I really need 13.8 volts for Icom M802 SSB radio ?

Best way to understand the impact is to connect via Winlink to a data server and then vary the voltage from an external power supply from 12V to 14V and observe the changes in the data rate. Everything else is just people talking about their perception of what an excellent connection means.
Pizzazz is online now   Reply With Quote
Old 13-11-2018, 15:05   #13
Registered User
 
El Pinguino's Avatar

Join Date: Aug 2013
Location: Somewhere in Patagonia
Posts: 4,858
Re: do I really need 13.8 volts for Icom M802 SSB radio ?

Quote:
Originally Posted by Pizzazz View Post
Best way to understand the impact is to connect via Winlink to a data server and then vary the voltage from an external power supply from 12V to 14V and observe the changes in the data rate. Everything else is just people talking about their perception of what an excellent connection means.
When connected to Sailmail with my 710 the data rate can vary substantially while I have steady voltage... I think its called propagation....

I have also found that if motoring in smooth seas ( not something you would do when running under full sail ) I can alter the data rate by altering my heading.... if pointing bow in general direction of station = poor ... point stern at station far better.... using the backstay....

I have repeated that experiment several times with the same result..

I'm with Jim's +/- 15% .. my batts are invariably in the 'low 12' region
__________________
Simple Celestial https://www.dropbox.com/s/a5blh1rgvi...ation.pdf?dl=0

A little bit about Chile http://www.cruiserswiki.org/wiki/Chile
El Pinguino is online now   Reply With Quote
Old 13-11-2018, 15:49   #14
Senior Cruiser
 
Toys_with_time's Avatar

Cruisers Forum Supporter

Join Date: May 2008
Location: Summer 1 sailing in the Med, summer 2 in Australia (earning $ to pay for summer 1)
Boat: FP Lipari, Katmazu
Posts: 245
Re: do I really need 13.8 volts for Icom M802 SSB radio ?

Quote:
Originally Posted by NirvanaBob View Post
Iíve had an ICOM M802 w/pactor modem on my boat since 2008, and know Iíve never supplied 13.8V to the radio, which works perfectly. Iíd be certain that you do not undersize the positive and negative power supply cables between the supplied power cable, and connect the connecting cables directly to your batter terminals. You should have no problems ala the 13.8v spec.
While we are on the topic of the M802, I finally finished the installation of my 802 and Pactor modem (only took me 7 years!) and then went to the ICOM manual to learn how to operate it and found the manual is next to useless. Anyone got any links or suggestions for a Dummies guide to operating the 802 and / or Pactor.

TwT
__________________
Live in the sunshine, swim the sea, drink the wild air........
Ralph Waldo Emerson, 1803-1882
Toys_with_time is offline   Reply With Quote
Old 13-11-2018, 16:19   #15
Registered User
 
Cpt Pat's Avatar

Join Date: Feb 2012
Location: Half Moon Bay, CA, USA
Boat: 1963 Pearson Ariel, Hull 75
Posts: 465
Re: do I really need 13.8 volts for Icom M802 SSB radio ?

I have a Kenwood TS-480SAT 100 watt HF SSB Ham radio aboard. I use a battery booster that has an adjustable floor voltage, where any voltage above 10 volts in produces an adjustable minimum output voltage. I just let my bats drop to 12.0 volts, transmitted (the max power out was less than 100 watts - as I recall about 60 watts), and adjusted the floor voltage for 100 watts output. The voltage turned out to be 13.2 volts. So now I had maximum power down to 10 volts on the bats (not that I ever intended to take my batteries that low).

Now that I have a lithium (LiFePO4) battery, it's no longer an issue since the lithium maintains 13.2 volts across nearly all of its discharge curve with very little voltage sag at the required 30 amps for transmitting. You might want to consider a lithium battery for your radios. You'll need some other electronics to properly charge and protect the lithium battery. If you dedicate the battery to just your radios, you'll also have an emergency power source if all your other power sources fail.


I also found my Tiller Pilot A/P stopped misbehaving after I switched it to the lithium for power. I'd been blaming the HF transceiver, when in fact the problem was caused by voltage sag while transmitting.
__________________

Cpt Pat is offline   Reply With Quote
Reply

Tags
icom, radio, ssb

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Icom AT-140 tuner with M802 HF radio (SSB) stopped tuning Daurin Marine Electronics 40 03-11-2017 14:45
[SOLD] iCom M802 Marine HF/SSB radio WITH TUNER, GROUNDPLANE, MORE! oddasea Classifieds Archive 10 17-04-2016 12:32
For Sale: For Sale - Icom M802 SSB Radio BocaIII Classifieds Archive 3 24-05-2015 20:06
ICOM M802 SSB radio and MAC jongroom Marine Electronics 6 02-01-2013 18:56
For Sale: ICOM M802 SSB, ICOM AT-140 Tuner, Pactor PTCIIpro with III Paul L Classifieds Archive 1 25-07-2012 19:34



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 20:58.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.