Sunday, September 11, 2016

3rd party internal battery for KX2

KX2 and $36 Li-Ion battery
Someone on the YahooGroup for KX2/KX3 radios recently mentioned a lower priced alternative to Elecraft's internal battery for the KX2. I ordered this battery from China via eBay and will be the first to confess to being leery of Chinese products. Their quality seems to be hit and miss - my DJI Phantoms have been fantastic in every way; a lawn sprinkler turned out to be junk.

So I took a $36 gamble to see if this battery offered a level of quality to allow it to serve as a viable alternative to Elecraft's $60 battery and their required dedicated $25 charger. The battery arrived from a warehouse in Arizona, well packed and with a connector that I cut off and will replace with a suitable barrel connector.

Like the Elecraft battery, this one is a 3-cell lithium-ion pack rated at 2600 mAH, fits easily into the KX2 and has protective circuitry built in. Unlike the Elecraft battery, this one doesn't require a dedicated charger and can be charged by any charger suitable for lithium-ion batteries.

A perfect fit


I couldn't help but buy one and test its rated capacity at an average discharge rate that I believe is comparable to a KX2 in heavy use. My KX2 draws 185mA on receive and about 2 amps key down with ten watts out. This means that a string of dits would draw a bit over an amp. Assuming we listen more than we transmit, I settled on 400mA as a discharge rate for this battery.

Protection circuit is beneath the battery's heat-shrink material


Top of protection circuit


The capacity of this $36 battery after 3 charge/discharge cycles is about 2400mAH at a 400mA discharge rate. I have no doubt thatif discharged at a lower rate, the capacity would meet the 2600mAH specification.


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4 comments:

  1. Sounds like a great deal. My only concern is how the circuitry is designed and the protective circuitry. While the batteries look like those in a computer battery supply, I still have need to know more about the construction and cell matching. I assume that Elecraft has done all the engineering before they offered their packs under their store front. The Chinese battery, IMHO, I do not trust. Too many knock offs and short cuts. I have been burned by trying to save money for the last time and will by through a trusted vendor. Just sayin'.

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    Replies
    1. I understand your concerns having bought products from China myself that turned out to be less than advertised and lacking in quality. However, all of my RC (planes & copters) batteries are of Chinese origin and I have never once been disappointed in them in any way. These batteries are driven hard with outputs in the 25-40 amp range for my particular models. No fires, no swelling, no explosions despite crashes of the models from time to time :-(

      I monitor and test them regularly with the battery analyzer that made the discharge curve shown in this posting - I could accurately be called a battery geek! Due to my own experience with such batteries, I have no qualms whatsoever about putting one of these batteries in my KX2.

      One thing I don't like is having to buy a charger dedicated to a specific battery - not a battery chemistry type - a specific battery, as with that from Elecraft.

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  2. Agreed. I would have preferred a balancing lead so I can do it on my RC Charger. But I wanted to go the correct route with a charger that shuts down. When reading the specs on the charger itself, it is intended for the config for the Elecraft pack.

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  3. Here's another even cheaper option and I'll soon be a Guinea pig for this one too:
    http://www.ebay.com/itm/221174761739?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

    I like that it has a JST connector (that's the red one) for charging.

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