Batteries for a Yaesu FT-891 (or the older FT-857)

Discussion in 'QRP Corner' started by N1RVN, Feb 6, 2017.

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  1. N1RVN

    N1RVN Ham Member QRZ Page

    Looking for battery pack recommendations for the new Yaesu FT-891 (pretty much the same as the older FT-857.

    Basically I'm asking what's the latest and greatest technology out there as of 2017... I would like the highest capacity possible in a light battery, obviously.

  2. N5EIT

    N5EIT Platinum Subscriber Platinum Subscriber QRZ Page

    LiFePO type batteries with an amp hour rating / watt hour rating that would run the radio of choice... (That would be my recommendation). I use a 6Ah / 72 watt hour LiFePO for my qrp rig. It's much lighter than SLA, etc.. and much safer than LiPo.

    Here's a link...
    I've been very happy with these.
    The 12Ah or 15Ah would probably work for your needs... "Probably"... BUT, Some testing would be required.

    Unfortunately, the 2A current draw on receive and 23A current draw on TX in the FT-891 doesn't concur with the theory of using a lightweight portable setup for extended ops. If you trickle charge it with a solar panel to keep it topped off, it'll help. There are some LiFePO motorcycle batteries that'll probably provide the current needed.
    Last edited: Feb 6, 2017
  3. N5EIT

    N5EIT Platinum Subscriber Platinum Subscriber QRZ Page

    I wanted to add this link as well. If you are running full power...
    More choices with higher current rating. Even though they say you can draw 2x the rated current, it will drastically reduce operating time. I tend to go the opposite way. Honestly, I'd just opt for a 40Ah LiFePO or higher current rated battery and hook a solar panel to it during op time if I was using that FT-891. That way you'll get plenty of op time... Overkill? Maybe? I don't tend to think it is though. I operate 100% portable battery /solar powered equipment and I've tried almost every way of doing so. This is just my 2 cents, I'm sure there are other people with other ideas.

    As you can see, it's hard to find a "lightweight" option that will work really well with many modern manufactured rigs. There is always a trade-off... I've found that Bioennopower is usually pretty true to their rating. Beware many claimed ratings out there and understand Ah/Wh ratings versus current draw of the rig. It can get expensive to run 100w effectively. The last thing we want is for our setup to cut back on power in the middle of chasing that DX station.
    Last edited: Feb 6, 2017
    KG5EXW likes this.
  4. F4HPX

    F4HPX XML Subscriber QRZ Page

    Yes I vote for LiPoFe as well.
    I have a pack 22 AH weighting about 3,5 KG less than half probably compared to Lead-Acid one of comparable capacity and maybe equivalent of Lead Acid of 7 AH
    I am using it currently with FT-897D, even at home, when the main power supply is occupied by Flex-6300.
    I will be using it for FT-891 when portable and FT-987D will not leave my shack - anyway is used for VHF/UHF mainly as of today.

    I would try LIPO or LiON but depending how sensitive it is for lower voltage - I am using it for KX2 - you should use 3 Cell batteries and not 4 as they are charging up to 4,25V each although 3.7V nominal
    (so to not exceed 15V as it could most likely damage radio).
    It's much better (the best) on the side weight/capacity but less safe for mishandling (fire or explosion) and a bit more complicated to recharge - here LIPOFE wins.

    In both cases they are NOT airlines friendly and usually banned from passenger flights once you start getting a little bit more capacity....
    Solar panels - yeah but to see if inverters do not make too much noise and depends on size and weight as well.

    And at the end what do we want to do ? Backpacking (then the weight is crucial) or transporting things in the car and then you can put more less everything inside ....

    KX2 is advertized being able to work 8 hours with 2600 mAH LION pack - mine is 3400 - lasting several hours but with not heavy transmit cycle on SSB with 10W - consuming up to 2 AMPs
    FT-891 with 100W seems to be drawing at least 16 AMPS so definitely these are not very efficient working QRP (KX2, KX3 and FT-817 would be much better choice here)
    but when you need more power I believe FT-891 is a nice choice.

    I have myself the same problem as I plan to do some SOTA activations.
    Not very confident yet with only 10W from KX2 on SSB (depending propagation) with a pocket battery
    but don't want to hike 18 kilometers with 10kg of gear on my back for less than 3 hours of fun having potential of full 100W.
    Last edited: Mar 8, 2017
  5. N1RVN

    N1RVN Ham Member QRZ Page

    Thanks everyone for your thoughts.

    I purchased two Bioenno LiFePO4 - lithium iron phosphate - batteries, 12 V 6 Ah (72 watt-hours) each. They are rated at 12 amps max continuous discharge current, with a peak current of 24 A for two seconds. I tested them at full 100W power on SSB and they work without any issues - power needs are relatively low overall for SSB voice as the output is modulated with the ops voice. Now for digital modes the situation is completely different, the output is blasting at full whatever power the unit is set to, but for digi modes all you need is 10 watts anyway.

    They weigh 0.7 kg each and the charge regulator circuit is included IN the battery, so they can be trickle charged while in use - which makes them a good candidate for adding a solar panel. Also, they are only 72 watt-hours each, so they should not pose any problems boarding a plane. Taking one with you even on a longer mountain walk should not kill you - at this time there is not much out there with a better weight/capacity.

    Operating time is hard to define because it depends a lot on how much you talk vs how much you listen. Most of us listen a lot more than talk (or so we should anyway), so it is my estimation that with an 80/20 listen/talk ratio one of them lasts for about 2.5 hours or so.

    Again, thanks for the help.
  6. KI5O

    KI5O Ham Member QRZ Page


    Any feedback regarding the above purchase? I share similar interests that you stated, and was wondering how the last year has gone with those batteries. I also have a FT-891 and I'm interested in traveling with the battery packs.

    Thank you!
  7. KC7JNJ

    KC7JNJ Ham Member QRZ Page

    I run the 12Ah from bioenno, I have had it about a year and it has been great. The only battery I have ever used with my HF radio that has lasted this long.
  8. NA5W

    NA5W Ham Member QRZ Page

    What kind of typical operating time are you guys seeing from the 12Ah batteries with the FT-891? Are you operating CW or SSB? What output wattage are you using? I have an FT-891 and want to start doing some SOTA activations, but don't want to buy a new radio if I don't need to. Most of my trips will only be day trips, so no need to be able to operate multi day at this point.

    Thanks for the feedback,

  9. KC8VWM

    KC8VWM Ham Member QRZ Page

    Running 2 x 65 watt hour LiFePo4 batteries or around 11AH total battery capacity.

    Idea here is to use one battery while the other one is charging on solar panels. I can just keep alternating between the two batteries for as long as I can. 2 fully charged batteries will provide almost 10 hours operating time.

    battery setup.jpg

    I timed a battery charge on my solar panels and it takes 3.5 hours for a fully depleted battery to become a fully charged battery pack.

    I get around 4- 5 hours operating time from each individual battery pack when used with an FT-817 so there's even some wiggle room left over.

    So it seems this entire arrangement will provide me with a practically unlimited source of power to operate my rig.

    I suppose I could buy one big 12AH battery pack but having the 2 smaller 5.5 AH batteries provides additional operating flexibility and adds other layers of versatility not available when operating everything from a single battery.

    So it's still a total of 11AH but if one battery should crap out for whatever reason, I can still operate everything from the secondary battery pack. Similarly, if I want to travel light, I can just throw one of the batteries into a backpack instead of taking along a bigger 12 AH one or something.
    Last edited: Apr 15, 2018
    N8AFT likes this.
  10. N8AFT

    N8AFT Subscriber QRZ Page

    Charles; What is the specs on your solar setup?

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