[Elecraft] KX3 interal battery charger

[JP O'Connor]

Yes, that appears to be an example of the type of charge controller chips
utilized in the types of balancing chargers mentioned earlier in this
thread. For example, the iCharger 106B+ that I use can handle up to 8 cell
packs in balance charge mode for a variety of different chemistries.

On Thu, Jul 5, 2012 at 12:15 PM, Matthew Zilmer <mzilmer at magellangps.com>wrote:

> There are other ways to achieve charge parity (balance).  One of them is
> the multi-cell charge controller.  An example for LiPo chemistries is the
> AAT 3663.  Datasheet is available at  www.analogictech.com.  Doesn't help
> with AA's, but there is probably an equivalent out there for lower voltage
> single cells.
>
> Looks to me like Greg is correct about the difference between balancing
> and equalizing.  Xantrex / Trace refers only to "equalizing" with their
> controlled overcharge on solar charge controllers.  EQ is used with FLAs to
> "stir the pot" and disturb sulfation on the Pb plates, and the process
> basically allows the sulfates to debond from the lead.  With FLAs, I run an
> EQ for two hours about five times a year.
>
> Matt Zilmer, W6NIA
> KX3 #6 / FT
>
>
> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net [mailto:
> elecraft-bounces at mailman.qth.net] On Behalf Of JP O'Connor
> Sent: Thursday, July 05, 2012 8:58 AM
> To: Greg Troxel
> Cc: Elecraft at mailman.qth.net
> Subject: Re: [Elecraft] KX3 interal battery charger
>
> The balance charging operation requires access to each cell and requires a
> smart charger that is appropriately programmed for the specific chemistry
> and for the balance operation. The idea is to be sure that each cell is
> properly and fully charged without overcharging or damaging any of the
> other cells in the pack. This is quite common with the all the various
> lithium chemistries, and when using NiCd or NiMh smart chargers that charge
> each cell independently. Most of the inexpensive consumer NiCd and/or NiMh
> chargers do not treat each cell independently. Only the more expensive
> models include the test/refresh modes. Although NiCd and NiMh cells are
> often overcharged by many slow chargers, apparently that is not the best
> practice when performed on a regular basis. Thus, the smart chargers.
>
> If I am understanding correctly, a PbAcid (e.g. SLA) equalize charge
> operation does not have access to each cell and instead is an operation
> that uses a carefully controlled "overcharge" function, within the safe
> "operating envelope" of the battery, to bring up the lagging cells without
> damaging the stronger cells.
>
> It sounds like equalize and balance are two different operations, intended
> for different cell chemistry and charging styles.
>
> Starting with a fresh set of Eneloop (white label 1,900 mAh or black XX
> label 2,500 mAh) or other brand of "pre-charged" or low self-discharge
> (LSD) NiMh batteries that have had at least one test/refresh cycle
> performed, the need for removing the batteries from the KX3 for a
> test/refresh cycle should be VERY infrequent as long as they are not abused
> significantly. As Jim mentioned, hopefully this won't be too often. Who
> knows, even with heavy use, maybe the batteries won't need to be removed
> for over a year - or two. Yes, Greg, I plan to do things exactly as you
> stated: check after a few months, but then pretty much leave them alone in
> the radio for a long while as I see how things work out. I will be
> interested to hear from folks here on the reflector as experience is gained.
>
> With the traditional non-LSD high capacity NiMh batteries, the need for
> test/refresh may be a bit more frequent. For example, the Energizer 2600
> mAh (?) AA cells are notorious for extremely rapid self-discharge and may
> need a bit more care and feeding.
> 72/73 de JP WF4Z
>
>
> On Wed, Jul 4, 2012 at 3:25 PM, Greg Troxel <gdt at work.lexort.com> wrote:
>
> >
> > In "balance" vs "equalize", I also hear about equalization charge to
> > 12V SLA batteries without access to individual cells.  PbAcid cells
> > have a higher charge/discharge marginal ratio as they get full, so a
> > mild overcharge should tend to cause all cells to be fully charged.
> > NiMH is almost certainly similar, especially during low-rate
> > overcharge as is typical, so I'd expect that all cells end up full.
> >
> > To understand the KXBC3 behavior, it seems that one should use a Maha
> > C9000 or equivalent to measure/record the capacity ("refresh/analyze")
> > of all the cells, and then put then in the KX3 and use them for a
> > while, and then when the KX3 says they are charged pull them and do a
> > discharge measurement followed by a refresh/analyze.  I'll report back
> > later :-)
> >
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