[Elecraft] KX3 Rechargeable Batteries

[David Olean]

I had a pair of huge lead acid AGM batteries die on me after a bit over 
six years of very light use in a solar panel and battery system. 
Consulting the factory, they stressed that the batteries were getting 
cycled each day that the Sun came out and the charger started charging 
the batteries. I used the batteries sparingly at my remote ham shack, 
discharging about 10 to 12 % typically on the days that I used them. 
Only once did I discharge them to almost 75% of full.  I should have 
used them more so I would not feel so cheated having them die so 
quickly.  My solution is to replace them with LiFePO4 batteries and 
disconnect them from the solar charger unless I need the batteries for a 
specific event.  They can go a few months with no charging.  I can keep 
the charge cycles at a much lower rate with LiFePO4. You can't do that 
with lead acid, or at least not as well.

Dave K1WHS

On 12/28/2018 4:56 PM, K9MA wrote:
> I think Bob is mainly referring to NiMH batteries. I am not sure about 
> the partial discharges, and whether each one counts as a whole cycle. 
> That is certainly NOT true of lead-acid and Li-Ion batteries, which 
> will survive many more partial discharges than deep ones. Li-Ion 
> batteries should not be stored for long periods fully charged, but at 
> 50-70 percent. Fortunately, their self-discharge rate is so low that 
> you would have to store them for years before you would have to worry 
> about them becoming completely discharged, which is bad for all types.
>
> 73,
> Scott K9MA
>
> On 12/28/2018 10:41, Bob McGraw K4TAX wrote:
>> Something I learned from one of our "tech reps" regarding 
>> rechargeable batteries and charge cycles.    I have successfully 
>> applied his advice for a multitude of and different types of my 
>> rechargeable batteries.
>>
>> If you use a battery and then recharge it, that is one charge 
>> cycle.   Likewise if you should use only 10% of the battery capacity 
>> and recharge it, that is also one  charge cycle.   And in the same 
>> vein, if you use 90% of battery capacity and then recharge it, that 
>> is also one recharge cycle.
>>
>> The point, every time you use the battery, regardless of the amount 
>> of discharge, and recharge it, that is one charge cycle. In other 
>> words, don't recharge until necessary.   And never leave a battery in 
>> the discharged state.  Always charge to full capacity.   Short 
>> charging cycles, because one perhaps is in a hurry and can't wait, 
>> only subtracts from the total number of charge cycles available.    
>> And there are only so many charge cycles with each type of battery.   
>> So every time you use and recharge a battery, click off one charge 
>> cycle.
>>
>> I've practiced this with several different types of batteries and 
>> find that my batteries last much longer and need less frequent 
>> replacement.
>>
>> 73
>>
>> Bob, K4TAX
>>
>>
>> On 12/28/2018 9:47 AM, Walter Underwood wrote:
>>> Eneloop Pro (labeled Eneloop XX for a bit) are rated for 500 charge 
>>> cycles. Regular Eneloop batteries are rated for 2100 charge cycles 
>>> but have lower capacity. Choose the one you prefer. I like the 
>>> higher capacity batteries.
>>>
>>> The Wikipedia page on Eneloop has a chart that clears this up to 
>>> some degree.
>>>
>>> https://en.wikipedia.org/wiki/Eneloop
>>>
>>> wunder
>>> K6WRU
>>> Walter Underwood
>>> CM87wj
>>> http://observer.wunderwood.org/ (my blog)
>>>
>>
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>