T o d d P a t t i s t wrote:

I've run 12 volts and I've run 14 volts. The charger
comment above is the main disadvantage of 14 volts. The
secondary disadvantage is the "non-standard battery stack"
may not want to fit into your standard-sized battery
location.

An advantage to 14 volt is more radio power/longer range on
transmit. Modern radios don't cut out at lower voltage, like
older radios that assumed 13.8 volts, but they all drive the
output stages off the full voltage - the more voltage, the
more output power.

Other advantages are that you can run the battery longer
before it gets too low, and for any switchmode DC-DC
downconverters, such as I use for my IPAQ's 5 volt...

What about getting the best of both worlds? It seems agreed that only
the radio's performance improves with higher voltage. Why not keep a
12V system with its easy charging and standard sizes but add a DC-DC UP
converter into the radio circuit so that a constant 13-14V is supplied
to the radio even though the battery supply voltage drops?

I have no technical skill in electronics - meaning my ego isn't involved
if I'm told it's a stupid idea. Would it just be a further drain on the
battery or would it usefully improve the radio's range? Does such a
converter exist?

More specifically on batteries, my glider has 4 x 6V 12ah cells arranged
in two series pairs connected in parallel (no, not my idea, the
manufacturer did it) which have reached the end of their life. The
original cells are clearly a carefully matched set (marked 6.47, 6.47,
6.45, 6.46).

How important is it that I match the replacements - and on which
characteristics? The Yuasa website seems to imply that the only
important things are that the cells be the same and the same age.

Oh ...and the cells are almost impossible to remove from the glider so
they have to be charged in place in the series/parallel configuration.

Any advice welcomed.

Graeme Cant