Batteries (again) - 2 Main Batts plus Tail Fin Batt wiring/switching

Hi,

Time to dust off a perennial topic

I looked through the archives and read Darryl Ramm's battery
presentation. Not an exhaustive search but I didn't find an answer to
my question.

At present we have two (fused) 12V 7Ah "main batteries" connected to
the Master switch via an SPDT "changeover" switch. We are adding a
smaller capacity tail fin battery as a "reserve".

Without using diode switching and keeping it as simple as possible for
multiple club pilots, I can see 3 possibilities that I've illustrated
he
http://www.avon-tech-solutions.co.nz...derBattery.pdf
- select 1 of the three batteries using two SPDT "changeover" switches
in "series"
- separately isolate the tail battery in parallel to the currently
selected master
- separately isolate the tail battery in parallel to the master switch

Each has its advantages and disadvantages. No doubt there are more
possibilities. I expect to add the recommended Volkslogger "hold up"
circuit separately (or power the logger and possibly a PDA from a
dedicated battery, much like the self contained battery/logger systems
previously discussed here on r.a.s.).

What wiring / switching schemes are you using for this 3 battery
arrangement?

Thanks for your suggestions.
Neil

Schleicher uses a rotary switch
Batt 1, Batt 2, Batt 3, Off.
If you can get one of these, it reduces to one switch.
--
Hartley Falbaum

"Neil Allison" wrote in message
...
Hi,

Time to dust off a perennial topic

I looked through the archives and read Darryl Ramm's battery
presentation. Not an exhaustive search but I didn't find an answer to
my question.

At present we have two (fused) 12V 7Ah "main batteries" connected to
the Master switch via an SPDT "changeover" switch. We are adding a
smaller capacity tail fin battery as a "reserve".

Without using diode switching and keeping it as simple as possible for
multiple club pilots, I can see 3 possibilities that I've illustrated
he
http://www.avon-tech-solutions.co.nz...derBattery.pdf
- select 1 of the three batteries using two SPDT "changeover" switches
in "series"
- separately isolate the tail battery in parallel to the currently
selected master
- separately isolate the tail battery in parallel to the master switch

Each has its advantages and disadvantages. No doubt there are more
possibilities. I expect to add the recommended Volkslogger "hold up"
circuit separately (or power the logger and possibly a PDA from a
dedicated battery, much like the self contained battery/logger systems
previously discussed here on r.a.s.).

What wiring / switching schemes are you using for this 3 battery
arrangement?

Thanks for your suggestions.
Neil

HL Falbaum wrote:
Schleicher uses a rotary switch
Batt 1, Batt 2, Batt 3, Off.
If you can get one of these, it reduces to one switch.

I just checked the Maplins online catalog (Maplins is the UK equivalent
of Radio Shack) for their standard range of panel mount rotary switches.
These are 1,2,3 and 4 pole types (12,6,4 and 3 positions). They have a
movable stop so you can blank off unwanted positions. Something like
these is available pretty much anywhere.

They are rated at up to 5 amps, so should be OK in a glider panel.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |