My old (well used) SLA batteries are due to be replaced, and I’ve ordered a new 4.5 AH lithium ferrophosphate battery (LiFePO4) and wonder if anyone else here has tried or is using one of these and what their experience has been. There seem to be a lot of advantages with these.
The version I’ve ordered is advertised as a direct replacement for an SLA with built-in overcharge/discharge protection and they say that a special LiFePO4 charger isn’t necessary. If so, I could use an ordinary solar panel charger if needed. I checked with the Battery Minder people who told me not to use my desulvate/maintainance type of charger with it.
This battery is a little expensive, but not by much and should last a long time. I’m hoping that I can carry this battery for long-term backpacking and not even bring a charger along. My portable cw rig draws 750mA on transmit and 50mA on receive so I’m hoping to have enough capacity for 4 or 5, 1-hour activations or a week on the trail.
I’d appreciate the benefit of other’s experience with this.
No idea what caused it yet, the thing just gave up the ghost mid QSO. unplugged it a couple of times, seemed to work fine after that
As Richard pointed out, could have been RF interference doing strange things with the internal circuitry, I was about 40 yards away from a rather large radar station!
Other than that, it’s been fine, and certainly lighter than the equivalent slab.
I started briefly with SLA, then went to LiFePO4 and have recently tried a few LiPO batteries. I’m a bit frustrated with LiPO right now, as I’ve killed 2 of the 3 batteries I recently purchased from letting them discharge too far. My LiFePO4, albeit heavier, is looking better and better. I have a solar charging system that I take on longer multi-day trips. I’ll send you a photo of my system directly.
I recently purchased the 4Ah version of the Tracer Lithium Polymer battery for use with my FT817 and probably I’ve done four activations with this battery. The majority of the activations using this battery have been up to 3 hours long with the 817 turned on continuously and using ssb when transmitting. It is hard to gauge the actual time spent transmitting but between 50 and 60 chasers would be in the log after an activation with periods of prolonged ‘rag chewing’
At the end of all of these activations only one green led of the five leds would be extinquished. What this means as to how much capacity I have left in the battery I have yet to find out. I always ensure that the Tracer battery and the 817 internal batteries are fully charged before each each activation - ‘belts and braces’.
The saving in weight from initially my 7Ah ‘slab’ to the 8Ah Li-Ion used recently has been tremendous and my rucksack is considerably lighter and my step has more of a spring to it
Not a very scientific report but no problems so far with this latest battery.
That was certainly a strange situation!
The battery I chose is a LiFePO4 and doesn’t have all the bells and whistles that your battery pack does. So hopefully I can avoid any similar difficulties.
The saving in weight from initially my 7Ah ‘slab’ to the 8Ah Li-Ion
used recently has been tremendous and my rucksack is considerably
lighter and my step has more of a spring to it
Not a very scientific report but no problems so far with this latest
battery.
Thanks Allen, this is exactly the “hands-on” information I was hoping for. I look forward more spring in my step too!
I’ve been using a LiFePO4 for about six months now. Mine is a 22Ah Golf cart battery. It weighs in at just under three Kilos as opposed to the 7 Kilos of my old 22Ah Lucas AGM SLAB.
These cell are not not cheap at the equivalent of around 340 US Dollars in the UK (no doubt they’ll be about half this in the USA), however, the performance is outstanding. Unlike a SLAB, the LiFePO4 holds an almost constant voltage through the cycle. No doubt, it will drop like a stone when exhausted.
I Must have done over 50 activations with mine using the FT-857 and never managed to flatten it. LiFePO4 cells are fitted with a microprocessor controlled battery management system, which monitors the state of the battery and will immediately shut it down if it’s overloaded. Taking the load off usually cures the problem and the battery will reset.
One thing you should avoid is storing these cells in a discharged state… a big no no. After every activation, I would strongly advise topping them up. If you’re going to be storing them for more than three months, check them regularly and top-up.
LiFePO4 golf cart batteries are capable of delivering plenty of current and will easily cope with the 100 Watts of an FT-857. One of the good points about my Battery is it comes with a 5 Amp charger and can be recharged very quickly.
Once the battery is fully charged I was advised to remove the charger as leaving it in situ is not good for LiFePO4 cells.
The number of times a LiFePO4 can be charged seems to be a contentious point … mine was quoted at 1500 cycles but to be be honest, I have my doubts about such figures.
I Must have done over 50 activations with mine using the FT-857 and
never managed to flatten it.
Thanks Mike, It is encouraging to hear about your results and long term use of these. I’ll remember the advice on keeping it charged up. Haven’t settled on a charger yet, but I have an old motorcycle battery charger to start with. Just have to keep an eye on it.
Thanks a lot for this info. Perhaps I’ll run a discharge test like that on my battery with a 1 amp load. Really looking forward to getting out in the field with it!
A thing to note Fred, the capacity of a battery will depend on many factors especially the discharge current. So discharging at 1A will give you 1A Ahr capacity. Discharging at 10A gives you a 10A Ahr capacity and the 1A one will be a lot more than 10x the 10A Ahr rate. It’s easy to get a bigger view of the capacity than you may get when using it with something thirsty.
It’s not unknown for less-reputable battery vendors to claim much bigger capacities for their cells by using a gentle discharge rate compared to the competition.
Thanks Andy, you’re so right. Since my rig draws about 750mA on transmit at 12.6 volts, I definitely want to know how the new battery performs with a lower discharge current. Now if I can just find a brick around here to use for the test…
