2 Batteries

Interested to know how many batteries competition pilots believe should be fitted to their gliders and what configuration?

ie seperate battery for loggers or complete battery duplication (all systems switchable between batteries)

Roy Edwards Contest Director

Two batteries (6,5 Ah and 4 Ah tail batt) for the main circuit. Seperate 6,5 Ah for bugwipers, shoeheaters and backup for logger. The powersource for the logger can be switched without power interuption.

Two 6,5 AH batteries will probably do as well but why bother if you have room for three

With two batteries I like to use a C&K switch 7211 which is a 3 pos switch ON-ON-ON which I use as ON-ON-OFF and you do not loose power in changing batteries. It is all easy to use Ian Mc Phee Box 657 Byron Bay NSW 2481 Australia Tel +61 2 66 847 642
www.mrsoaring.com

Why have a switch? Why not simply wire them in parallel? (assumption they are both of the same nominal voltage)

-Doug

My switch has two positions separate and both. in the separate position I have one battery the runs the battery and one that runs the varios. In the Both position the batteries run through a set of low bias diodes that cause both the battery and the Radio to run off the strongest battery and separates the batteries so the strong battery does not try to charge the weaker one.

I normally run in the separate position but if my radio battery starts running low I can switch to both to power th e radio. The Vario battery seldom runs low and acts as a backup for my radio.

Thats why I have a switch.

Brian Case CFIIG/ASEL HP16T N16VP

Here we go again.

May I suggest a quick search of http://groups.google.com/ in r.a.s. and a subject of 'batteries'. You will find this worked to death. Basically you will find the following positions on the matter (in no particular order):

a) Use 2 batteries with a make before break switch. b) Use 2 batteries with both wired in parallel. c) Use 2 batteries with diodes to prevent reverse current into the other battery. d) Use 2 batteries with a regular ON-OFF-ON switch and switch it quickly. The capacitance in the nav computers and loggers have enough capacity to handle the changeover. e) And of course, David Kinsell's approach of 1 bigassed battery.

You forgot 'adding a seperate capacity'

Anyway, the original posting was about the number of batteries, not how they are connected. I haven't seen many answers to that.

Thanks for tipping me off to the prior discussions, Larry. There seems to be a variety of 'solutions' in use, each claimed to be used with good success. I can see that there are some pros and cons to any of the techniques. I'll have to think some more about this one before forming my own 'opinion'.

Regards,

-Doug

Having followed both the previous and current threads, I would be interested in seeing schematics (in a legible *.pdf or *.jpg file) of each of the options. Might as well work on the panel/batteries this winter....

How about it, folks?

Not a good idea to wire batteries in parallel. If there is room for two, go with two and wire in series to desired voltage.

Carry three batteries if you can. My preference is a large capacity battery to run insturments and GPS (12V 12AH). I use a secondary battery (tail fin 12V 4AH) to power my radio only. I have a third battery (12V 7AH) to run a secondary GPS that is switched to run the panel and primary GPS if needed. For local soaring, I do without the third battery.