On 12/3/2020 8:31 AM, Martin Gregorie wrote:
On Wed, 02 Dec 2020 22:19:51 -0800, Jay Campbell wrote:

On Friday, November 27, 2020 at 11:01:36 AM UTC-5, Mark Mocho wrote:
I've rewired and/or replumbed my panel three or four times over the
years as new equipment is added and old things are removed. Upgrading
flight computers, displays, radios, transponders and the like have
greatly enhanced the cockpit environment. One thing I have found
invaluable is John DeRosa's series of helpful tips on glider
maintenance. (http://aviation.derosaweb.net/presentations/) The
"Aviation Electrical Best Practices" presentation shows the "right" way
to go about wiring a cockpit. If you have any electrical skills,
whether in industrial or home wiring, you will find the particular
requirements for aviation are different. This guide steers you in the
right direction. Thanks to "OHM" for these guides.
As to "rewire the rat's nest": I have never purchased a "new" glider,
only a "used" one. In every case, there have been tubing and wiring
issues and in each case I undertook to re-wire and re-tube everything
I could get at. In every case, I have discovered something that was
at least puzzling if not down-right scary. You don't have to be a
wizard to discover problems and correct them. Just take it one thing
at a time, get everything neat, and you will have a lot more fun come
spring than if you don't.

Yes, I have been using his advice for a while now. Good stuff. I have
9 AH LA batteries and have always tested them this time of year by
putting a 10 ohm 25 watt resistor across the output and taken voltage
readings each hour down to 9 VDC or so. If the battery doesn't go 4-5
hours, I replace it. So how does one "check" a LiPo? Anyone done it?

As a side note, I was informed in the owner's literature never to put
two of their LiPo's in parallel, as you can with the LA type. Read the
manual if you have any parallel circuits in your ship before deploying
in this manner.

I use an old Pro-Peak Prodigy II to cycle and measure my battery capacity
each year. I sling 7.2AH SLAs once they drop below 5 Ah capacity but of
course ymmv.

The Pro-Peak Prodigy II handles multiple battery chemistries (SLA, NiCd,
NiMH, LiPo) and can discharge and recharge any of them. Check out your
local RC model shop or website and you'll find similar systems for
reasonable prices. Mine self-limits to 400mA discharge and charges at a
similar rate and can be run off a battery or a mains adapter: the
electric RC guys take their chargers to the flying field and charge
models from their car battery.


I followed others' recommendations and use the iMax B6
charger/discharger. Capable and cheap. But a test with a suitable
resistor, voltmeter and clock is also fine. I wouldn't discharge a
lead-acid battery down to 9V, that is damaging to its longevity. I'd
stop at 10.5V or 11V. Do that when the battery is new and you'll have a
baseline to compare to when the battery is older. For a lithium battery
you can do a similar test, just expect that the voltage will decline
much more gradually for most of the discharge, and then fall rapidly as
the battery nears exhaustion. There is very little additional capacity
below 11.5V or so. The built-in protection circuit may shut it down
between measurements if the voltage falls far enough. That's OK. Just
recharge it to turn it back on.