Re: Ubitx batteries / charger #ubitx
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I have and use several of the 3S and 4S charge controllers. These have between-cell connections
for charge balancing. Seems to work well because I have rebuilt a number of old Ni-Cad drills
so that they now use Li-Ion cells. Drills work really well with Li-Ion or Li-Po battery packs.
From on-line anecdotes it seems that people trying to use Ni-Cad chargers on Li-ion cells is culprit
in many of the horror stories.
My one complaint about the Ebay sourced 3S and 4S charge controllers is that they usually like
source voltages that are only a couple of volts above the string you are trying to charge. This
limits what voltage wall-wart you can use to trickle charge your Lithium based battery packs.
This Li-Ion thing has spawned some research and design work here to see just how much radio
can be powered from a single 18650 cell. The current is more than adequate but making sensitive
circuits that run on 3.4 to 4.0 volts is a challenge. End result I seem to be looking for is ability
to use a simple 1S charge controller (they are less than US$1.00 from Ebay) to manage several
18650 cells in parallel. Transmitting using MOSFETs in class-C or class-E is not difficult but
at low voltages there is not much margin for noise immunity and overload in receiver circuits.
If doing much work with 18650 type cells it is probably worthwhile to make a simple spot-welder
for attaching the cell connectors.
On Fri, Apr 19, 2019 at 4:39 PM Jerry Gaffke via Groups.Io <email@example.com> wrote:
Daniel's three cell lithium ion 18650 holder with protection from fasttech.com looks promising.