[Elecraft] KX2/KX3 DC Charging

[ktalbott at gamewood.net]

There are many inexpensive chargers available for the 3S1P battery pack
(12.6v charged, 11.1v nominal. The pack has charge controller PCB to prevent
over charge or under discharge.  It does NOT provide the connector for
balancing the cells.  I bet you have one of the 12.6V Li-ion chargers there
now.  It probably looks like a 12.6V wall wart with an LED in it. Best DC-DC
charger option is RC plane equipment like iMax B6 at  ~$29 (Amazon). The
more expensive ones also have AC input so you can use them anywhere.  If you
aren't addicted to the shrink wrapped packs, inexpensive 3-cell 18650
battery holders are available on eBay that allow you to manage your cells
independently.  BTW, you will probably need to change connectors to APP.
Ken ke4rg

-----Original Message-----
From: elecraft-bounces at mailman.qth.net <elecraft-bounces at mailman.qth.net> On
Behalf Of Todd
Sent: Friday, November 16, 2018 5:41 PM
To: K9MA <k9ma at sdellington.us>
Cc: elecraft at mailman.qth.net
Subject: Re: [Elecraft] KX2/KX3 DC Charging

There's not a whole lot of info out there, as well as not many making DC
- DC chargers that will work on LiPo or LiFePO4's.
I went down this road a couple months back looking for something to run my
KX2 mobile out in the boonies and still be
able to charge without use of a geny.   I stumbled upon an outfit out of 
VKland that seems to fit the bill.

Company called REDARC: 
https://www.redarc.com.au/battery-chargers/in-vehicle-chargers     They 
do have a US distributor now
from what I can tell.   Their unit also has Solar input - which would be 
a plus - and designed to handle the new
"smart alternators" that are common on newer vehicles...I didn't  know a
thing about these newer alternators until
I found this site.   This is a common deal in VK with all the 
"overlanders".  Dual batteries to run the fridge, radios, and other camp
assy's while in the "outback".  Charge off of solar while parked,  12vdc
while in motion, to keep the LiFePO4's (aux battery) charged.

I've used a goal zero inverter, and it works ok - if I don't use it and 
any radio gear at the same time.   ;-)


Todd KH2TJ


K9MA wrote:
> Hi Dennis,
>
> You're missing the charge controller. Li-Ion batteries are very fussy 
> about the way they are charged. While it would be more efficient to 
> run the charger directly on 12 Volts, such a charger for the Elecraft 
> batteries is not available, as far as I know. Even if it were, it 
> would probably cost more than the inverter. The inverter, of course, 
> also has other uses.
>
> Elecraft also makes it very clear that their batteries shouldn't be 
> charged with any other charger, and there are good reasons for that.
>
> 73,
> Scott K9MA
>
>
>
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