Schleicher Power/Solar rotary switch specs?

I think there's a better way to address the problem... Each item on your panel has an associated double pole, center off power switch. So every item can be individually connected to one battery or the other. When you are powering up your panel, you assigned batteries to the various gadgets in a way that pretty much balances the load.

This approach means that there isn't any switching batteries in flight. You never need to think about it. It also means that you don't have to deal with the question of how low should I draw battery 1 down before switching to battery 2. For all battery types it's better to not be drawing them down deeply if you want to maximize their life; splitting the load evenly is thus better for overall battery life. And, of course, you preclude this problem of switching transient.

All -

Appreciate the suggestions and yes a bank of toggle switches would work; but would require me to monkey with the panel and the wiring, which I'm trying to avoid (its flying season!) :-)

Steve - That works and _does_ provide several benefits. But you either need to divide the load relatively evenly between your batteries, or do maths and ensure the Ah of your batteries matches the relative draw of each circuit (but then you have to remember which batteries to install where, in your glider).

The Cole-Hersee line is a bit bulky and doesn't appear to match the 6-position, 60-degree switch function of the Marquardt unit (which is OK from a functional standpoint, but means re-labelling the panel). I'll keep it in mind; but the hunt continues... :-)

--Noel

With the new lifepo batteries offering a higher nominal voltage, the solution of wiring all your avionic batteries in parallel with a high capacity low voltage drop schottky diodes in line with each batt makes a lot of sense. You will always be pulling from the best batterie(s) and you never have to do any switching....ever. You can find 18A diodes which have only a 0.4V forward drop at digikey. I've done this for over 10 years with lead acid batts and never had an issue even on long flights with a transponder running.

On Thursday, July 3, 2014 5:31:24 PM UTC-7, wrote:
wiring all your avionic batteries in parallel with a high capacity low voltage
drop schottky diodes in line with each batt makes a lot of sense.


Sure, that makes some sense and I could see doing that with many gliders. For those of us with a solar panel/charging system, though, the Schottky diodes are a problem. :-P I guess the thing to do would be to splice in the charging wires between each battery and its Schottky, eh?

--Noel

But you probably would prefer to charge only the battery (or batteries) you used, not all of them?
The multi-position rotary switch is nice. If you need to add another battery, no new switches are required.
Jim

On Thursday, July 3, 2014 9:32:44 PM UTC-7, JS wrote:
But you probably would prefer to charge only the battery (or batteries) you used, not all of them?

The multi-position rotary switch is nice. If you need to add another battery, no new switches are required.

Jim

Jim - I'd preserve the multi-position rotary switch that controls which battery the solar system is charging. AFAIK, that switch just ties into the supply wires for the "main" power switch (the one that he's suggesting I get rid of entirely). I'm a neophyte when it comes to electronics that aren't measured in bits and bytes; but I think that as long as the Schottky diodes are "downstream" of the charging wires, I should be OK.

What I'm not convinced of, is whether having all of the batteries ganged together in parallel could result in a charge imbalance (similar to when individual cells in a battery-pack wind up with imbalanced states of charge - although those are typically wired in series, not in parallel).

On 04/07/2014 01:08, Steve Koerner wrote:

I think there's a better way to address the problem... Each item on
your panel has an associated double pole, center off power switch.
So every item can be individually connected to one battery or the
other. When you are powering up your panel, you assigned batteries
to the various gadgets in a way that pretty much balances the load.

I have this in my panel. But instead of a whole row of switches I just
have two. The instruments are in two groups, one group on each switch.
Each group can be powered of on or the other battery or isolated completely.

Still if I need to switch the FLARM/Vario between batteries I loose my
GPS fix and final glide calcs in the vario. Not too cool.

I have also got a pair of diodes to draw from the best battery - but
that just powers the logger and the U/C warning. I would not want this
on my transponder as I often leave it on the weakest battery with the
intention of switching it off if the battery goes flat while I reserve
the good battery for more essential equipment like the radio and final
glide computer.

There is no single easy answer to this.

Ian

Sorry, Noel. I meant charging after flight. Why pull all the batteries out of the glider to top up when you only needed to use one?
For example yesterday the full panel (TXP, COM, VGA, FLARM and 2 varios) was on for only 4.5 hours so just one battery needed charging.
Jim

On Thursday, July 3, 2014 5:04:00 PM UTC-7, noel.wade wrote:
All -



Appreciate the suggestions and yes a bank of toggle switches would work; but would require me to monkey with the panel and the wiring, which I'm trying to avoid (its flying season!) :-)



Steve - That works and _does_ provide several benefits. But you either need to divide the load relatively evenly between your batteries, or do maths and ensure the Ah of your batteries matches the relative draw of each circuit (but then you have to remember which batteries to install where, in your glider).



The Cole-Hersee line is a bit bulky and doesn't appear to match the 6-position, 60-degree switch function of the Marquardt unit (which is OK from a functional standpoint, but means re-labelling the panel). I'll keep it in mind; but the hunt continues... :-)



--Noel

I found a near direct replacement, 4-amp, 6-position micro rotary switch that I've been using for 2 years. I looked a long time and could never find a make before break micro rotary switch. Instead I put a capacitor (several actually) and a power resistor across the circuit to keep continuity - which works well as long as the voltage isn't too low. With LiFePO4 batteries voltage drop isn't a problem. One of the positions is also battery 1+2 slaved together through a pair of power diodes so if one battery goes bad in flight it doesn't take down half my panel or the other battery (and my entire panel). Again, with LiFePO4 batteries' flat voltage curve the slight voltage drop through the power diodes isn't a problem. I never get a low battery warning now. If everything goes to hell, I saved one position on the switch for the 5 Ah SLA tail battery.

On Sunday, July 6, 2014 5:24:36 AM UTC-7, wrote:
On Thursday, July 3, 2014 5:04:00 PM UTC-7, noel.wade wrote:

All -







Appreciate the suggestions and yes a bank of toggle switches would work; but would require me to monkey with the panel and the wiring, which I'm trying to avoid (its flying season!) :-)







Steve - That works and _does_ provide several benefits. But you either need to divide the load relatively evenly between your batteries, or do maths and ensure the Ah of your batteries matches the relative draw of each circuit (but then you have to remember which batteries to install where, in your glider).







The Cole-Hersee line is a bit bulky and doesn't appear to match the 6-position, 60-degree switch function of the Marquardt unit (which is OK from a functional standpoint, but means re-labelling the panel). I'll keep it in mind; but the hunt continues... :-)







--Noel



I found a near direct replacement, 4-amp, 6-position micro rotary switch that I've been using for 2 years. I looked a long time and could never find a make before break micro rotary switch. Instead I put a capacitor (several actually) and a power resistor across the circuit to keep continuity - which works well as long as the voltage isn't too low. With LiFePO4 batteries voltage drop isn't a problem. One of the positions is also battery 1+2 slaved together through a pair of power diodes so if one battery goes bad in flight it doesn't take down half my panel or the other battery (and my entire panel). Again, with LiFePO4 batteries' flat voltage curve the slight voltage drop through the power diodes isn't a problem. I never get a low battery warning now. If everything goes to hell, I saved one position on the switch for the 5 Ah SLA tail battery.


http://www.mouser.com/ProductDetail/...Rt9TIA5Tpms%3d