Page 1 of 2 12 LastLast
Results 1 to 10 of 17

Thread: LiFePo4 Battery Use

  1. #1
    Membership #: 292 Free member KJ6YVT's Avatar
    Name
    Larry
    Join Date
    3rd Aug 2015
    Posts
    5
    Thanks
    0
    Thanked 1 Time in 1 Post

    LiFePo4 Battery Use

    Because Icom radios are rated at 13.8 V DC ±15% input (11.73 V DC to 15.87 V DC), I'm a bit concerned about the nominal 13.2 V four-cell LiFePo4 battery's terminal voltage being a bit low. That only provides a 1.47 volt reduction in battery output voltage before reaching the lower limit of Icom's specification. I'm wondering of a five-cell LiFePo4 battery with a terminal voltage of 16.5 volts would be high enough to cause damage to, say, and Icom IC-718? That's only 0.63 volts too high.

    I'm thinking:

    A 60Ah five-cell (3.2V Cells) LiFePO4 battery made of cells similar to these: <http://www.ebay.com/itm/171782395812> or these: <http://www.ebay.com/itm/171748308512>

    A 100 Watt Renogy 12V Solar Panel Monocrystalline Foldable Charging Kit with 10A built in charge controller: <http://www.ebay.com/itm/281556876312>
    Open-Circuit Voltage (Voc): 21.6V
    Maximum Operating Voltage (Vmp): 18.0V
    Maximum Operating Current (Imp): 2 X 2.78A
    Short-Circuit Current (Isc): 6.17A

    Either an IC-718 (3.8 Kg), IC-7100, or a Kenwood TS-480HX with 200 watts out, perhaps a solid-state amplifier

    A suitably sized antenna tuner

    Perhaps a 6-80 Meter Alpha EzMilitary antenna rated 500W in a 16" bag: <https://amateurradiostore.com/all-al...a-16-bag-p-286> Weight: 3 pounds

    Or a Screwdriver

    So, I'd end up with a moderately sized Pelican case, a 33.1 Lbs 19.9 X 27.2 X 2.8 In folding solar panel, a 3 lb 16" antenna bag, and perhaps a computer tablet. Such a station should be robust enough to provide reliable 24 hour communications despite occasional overcast and ~1.5 hours talk time through the night, and with bright sun, fully recharged in ~6 hours the next day.

    What am I missing?

  2. #2
    Membership #: 2 Full Member Article Contributor
    Award Moderator
    M0LMK's Avatar
    Name
    Matt
    Join Date
    18th Mar 2015
    Location
    Kent - JO01ri
    Posts
    609
    Thanks
    292
    Thanked 78 Times in 53 Posts

    Re: LiFePo4 Battery Use

    I use a 13.2V LiFePo4 battery with my FT-857 and have no issues. The voltage drop curve is much shallower than other battery types so it works very well. Check the specs for the input voltage of the radio and check what the minimum is. Most are 13.8V +/-15% (so 11.7V to 15.9V) so will be happy with a 13.2V LiFePo4.

    You should also note that you can not charge a LiFePo4 battery properly with the PV panel and charging kit that you linked to. You need a proper LiFePo4 charger with balancing inputs if you want to make sure you don't damage the battery so a simple 10A charge controller is bad news. You could use it with a big SLA battery like a 110AH marine battery but not with a LiFePo4 or LiPo battery.
    Matt - M0LMK


  3. #3
    Membership #: 84 Free member Award Moderator G0DZB's Avatar
    Name
    PeterO
    Join Date
    25th Apr 2015
    Location
    Colchester JO01lv
    Posts
    192
    Thanks
    2
    Thanked 59 Times in 50 Posts

    Re: LiFePo4 Battery Use

    Quote Originally Posted by KJ6YVT View Post
    What am I missing?
    The kitchen sink ? :-) You don't quite seem to understand the "portable operation" state of mind ! KISS is the way to start, not building a replica of your home station to put in a large vehicle.

    "The inherent stability of this wide-band antenna makes constant retuning unnecessary" And use an antenna that isn't going to turn a large proprotion of your battery power in to heat !
    Last edited by G0DZB; 4th Aug 2015 at 16:49.
    Best 73 tu
    Peter G0DZB

  4. #4
    Membership #: 2 Full Member Article Contributor
    Award Moderator
    M0LMK's Avatar
    Name
    Matt
    Join Date
    18th Mar 2015
    Location
    Kent - JO01ri
    Posts
    609
    Thanks
    292
    Thanked 78 Times in 53 Posts

    Re: LiFePo4 Battery Use

    Yes, that does look like a poor antenna choice for efficient operation. Get some real wire in the air...
    Matt - M0LMK


  5. #5
    Membership #: 292 Free member KJ6YVT's Avatar
    Name
    Larry
    Join Date
    3rd Aug 2015
    Posts
    5
    Thanks
    0
    Thanked 1 Time in 1 Post

    Re: LiFePo4 Battery Use

    Quote Originally Posted by M0LMK View Post
    I use a 13.2V LiFePo4 battery with my FT-857 and have no issues. The voltage drop curve is much shallower than other battery types so it works very well. Check the specs for the input voltage of the radio and check what the minimum is. Most are 13.8V +/-15% (so 11.7V to 15.9V) so will be happy with a 13.2V LiFePo4.
    Thank you for sharing your personal experience with LiFePo4 batteries powering your station. I'm still in the initial planning stage, and appreciate any data points offered.

    I recall reading somewhere that LiFePo4 cells should not be discharged below 2.7 volts, or a battery terminal voltage of 11 volts. So, if the LiFePo4 battery is nearly exhausted at 11.7 volts due to its flat discharge profile, I can see that my fears are unfounded. Do you in fact find that the battery is nearly fully discharged when the voltage drops to 11.7 volts?

    What sort of voltage drop/performance do you find when attempting to transmit at near that voltage?
    Does the added (~22 amp) load drop the voltage well below the 11.7 volt minimum.
    Does the PA continue to output rated power?

    Quote Originally Posted by M0LMK View Post
    You should also note that you can not charge a LiFePo4 battery properly with the PV panel and charging kit that you linked to. You need a proper LiFePo4 charger with balancing inputs if you want to make sure you don't damage the battery so a simple 10A charge controller is bad news.
    I presume you are referring to the charge controller included in the Renogy 12V Solar Panel Monocrystalline Foldable Charging Kit. Are you able to recommend a suitable solar charge controller replacement that is compatible with 4-cell LiFePo4 batteries? Can the output of the included Renogy charge controller be fed into a charger that is compatible with LiFePo4 technology?

    From what I've read of LiFePo4 technology, it seems to be superior to all others for this application in the current marketplace. Do you agree? Is there something better on the horizon?

    Thank you again for sharing your knowledge


    Best regards,
    Larry

  6. #6
    Membership #: 306 Free member G4CFS's Avatar
    Name
    Glyn
    Join Date
    4th Aug 2015
    Location
    Bishops Waltham, Southampton
    Posts
    6
    Thanks
    1
    Thanked 0 Times in 0 Posts

    Re: LiFePo4 Battery Use

    What am I missing?[/QUOTE]

    A reality check.

    If it doesn't fit into a rucksack and can be carried on your back whilst walking to you operating location it should be left at home.

    I use a FT-817 5 watts powered by a LiFePO4 4.2Ah battery into a 60/40/20M linked dipole on a 7 metre roach pole. Have worked all over the northern hemisphere in SSB and CW. I may stretch to a 35 watt linear if desperate. All this fits into a 35 litre rucksack with room for my flask of coffee and sandwiches plus water proofs and bothy bag.

    73 Glyn

  7. #7
    Membership #: 58 Free member Article Contributor
    Award Curator
    G4YVM's Avatar
    Join Date
    22nd Apr 2015
    Posts
    190
    Thanks
    0
    Thanked 38 Times in 37 Posts

    Re: LiFePo4 Battery Use

    Ha ha. Good advice. Personally I can't fathom why anyone uses more than a few watts when portable either. Maybe 25 tops.

    I use my self contained kx1 with just a few watts of cw and simple aerials. It just never fails. Why use more?

    D

  8. #8
    Membership #: 292 Free member KJ6YVT's Avatar
    Name
    Larry
    Join Date
    3rd Aug 2015
    Posts
    5
    Thanks
    0
    Thanked 1 Time in 1 Post

    Re: LiFePo4 Battery Use

    Quote Originally Posted by G0DZB View Post
    The kitchen sink ? :-) You don't quite seem to understand the "portable operation" state of mind ! KISS is the way to start, not building a replica of your home station to put in a large vehicle.
    Thank you for taking the time to enlighten me about the group's apparent philosophy. While the station I proposed may not be "man portable" due to the size/weight of the photovoltaic panels, it is reasonably compact and light enough to be carried some distance to a favorable operating location (under a tree?). I don't see how eliminating any of the components (XCVR, battery, photovoltaic system, tuner, antenna) can be eliminated and still retain functionality. Do you know something about that that I don't?

    Quote Originally Posted by G0DZB View Post
    "The inherent stability of this wide-band antenna makes constant retuning unnecessary" And use an antenna that isn't going to turn a large proportion of your battery power in to heat !
    I became aware of that particular antenna in this YouTube video: My New Solar Powered HF Ham Radio Portable System 3-5-2015. It would seem that the anonymous OM (Mike?) who recorded that video had some years of portable experience, and had done a commendable job of constructing a functional station. I found his choice of antennas to be reasonably light weight (~10 lbs), broad banded, and able to handle enough power to be reliably heard around the world in SSB mode during favorable propagation. Of course, the gain provided by a directional antenna would increase station functionality considerably. How do you feel about BuddiePoles? Another antenna contender is the 5-bandfolding hex-beam. Photographs

    From your photographs on QRZ.com, I can see that you have a very portable station indeed. However, it was unclear what means you use to recharge your batteries. I'm contemplating my proposed portable station for emergency use, when mains power may be unavailable, and petrol conservation may be desirable, thus the photovoltaic system. That should be capable of powering the station indefinitely without necessity of any ancillary hardware, connections or consumables other than sunlight.

    As you apparently find the suggested '6-80 Meter Alpha EzMilitary antenna' inappropriate, I would be interested in your recommendations for suitable antennas. And any other suggestions you may be able to offer.

    The second contact I made after receiving my FCC license, while operating on a dipole strung on the carpet on the second floor, was with John Maguire, W1CDO. At the time, John was sitting in a tavern in Klamath Falls, Oregon, sipping a glass of Merlot while operating his radio station located in Roswell, New Mexico, via his iPhone. Now, that is a real portable station!

    Thank you for taking the time Peter, to share your knowledge with this rather recently licensed (2012) Amateur.

    Best regards,
    Larry

  9. #9
    Membership #: 58 Free member Article Contributor
    Award Curator
    G4YVM's Avatar
    Join Date
    22nd Apr 2015
    Posts
    190
    Thanks
    0
    Thanked 38 Times in 37 Posts

    Re: LiFePo4 Battery Use

    No, that's not portable at all. It's a very fixed station with a long but invisible connection wire.

    I'm sorry we're popping our philosophy at you, each to his own I guess.


    73

    D

  10. The Following User Says Thank You to G4YVM For This Useful Post:

    M0LMK (5th Aug 2015)

  11. #10
    Membership #: 292 Free member KJ6YVT's Avatar
    Name
    Larry
    Join Date
    3rd Aug 2015
    Posts
    5
    Thanks
    0
    Thanked 1 Time in 1 Post

    Re: LiFePo4 Battery Use

    Quote Originally Posted by M0LMK View Post
    Yes, that does look like a poor antenna choice for efficient operation. Get some real wire in the air...
    Hello Matt,

    Thank you for your comment.

    Are you able to provide some suitable antenna recommendations? Something 6-80 meters, light weight, and suitable for 500 watts?

    I welcome your experienced input.

    Best regards,
    Larry

  12. The Following User Says Thank You to KJ6YVT For This Useful Post:

    M0LMK (5th Aug 2015)

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •