craig bastin wrote:
>
> I had heard they were available but hadnt been able to find any in
> australia, I was looking
> at the dry charge race car batteries which come in at around 1.5kg 13.5volt
> 7Ah with about 200CCA
> cost is about $250 for them, which looks to be about the same as the LI-PO I
> must try harder to find
> the LI-PO batteries out here.
If it is 13,5 volt, it is not a LI-PO battery. Most likely it is a NiCd
or something quite similar. They are difficult for aircraft use as they
need a constant current charge, rather than a constant voltage charge.
What I'm considering now is to use the 11.1 Volt LI-PO battery solely
for starting the engine, and running the main fuel pump (Rotax 914).
These are happy with this voltage. The rest of the system will run on
the normal voltage as delivered by the alternator, backupped with a
lead-acid battery. As the lead-acid battery is now only intended to be a
backup for the avionics, and the backup fuel pump (914), only in case
the alternator fails, it can be much smaller (thus lighter). This setup
will save considerable weight, and add redundancy as well.
Frans Veldman
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