On 8/22/2010 5:29 PM, Martin Gregorie wrote:
On Fri, 20 Aug 2010 19:43:51 -0700, Eric Greenwell wrote:

On 8/20/2010 5:48 PM, Martin Gregorie wrote:

I'd seriously suggest a visit to your local RC model shop to look at
battery chargers. $60 - $100 gets you a cycling charger that can not
only peak charge a partially discharged SLA battery without harming it,
but can measure its capacity. Record the measured capacity every year
and bin the battery when it shows a 30% drop and you may even save
money.

What units do you suggest? The ones in that price range I'm familiar
with (like the LN5014 Multiplex) discharge at a low rate (~0.4 amps) and
charge at only 14.0 volts, not really a peak charger, which should use
14.6 at least.

snip

More recently (5 years ago) I bought a Pro-Peak Prodigy II charger for
cycling and measuring bigger batteries than my Vencon can handle (mine
was built for accurate operation on smaller batteries), such as those
used in electrically powered models. I currently use it at least once a
year to cycle and check my SLAs and to charge the AA cells my camera
uses. It has separate programs to deal with lead-acid, NiCd/NiMH and Li-
poly batteries and is capable of charging up to 18 NiMH cells in series
off a 12v DC supply: consequently I can run it off one SLA while its
cycling another: I know that sounds like perpetual motion and ought not
to work but it does, honest! It can charge and discharge at up to 5 amps:
you set the charge and discharge currents before starting the run. It
shows what's happening while running and beeps when the run is ended. You
can read off the capacities before turning it off or starting another
run.

The Pro-Peak appears to be identical to the Multiplex LN5014 that I
already have. I like the charger, it works well, it's simple to use, and
is very handy for the glider and other purposes, but I still wish for
one that charged 12 volt SLA batteries at 14.6 volts instead of 14.0,
and would discharge at 1 amp or more, instead of only 0.4 amps.

Maybe someone has another recommendation?

--
Eric Greenwell - Washington State, USA (netto to net to email me)

- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm http://tinyurl.com/yb3xywl

- "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what you need to know tinyurl.com/yfs7tnz