David,
The AH capacity of the LiPo4 batteries supplied as like-for-like replacements of
lead acid batteries is very much reduced (despite higher voltage and higher
CCA). One reason they are so light is because the overall pack size is made to
be the same as the lead acid "equivalent", but the actual cells hide shyly in
one corner of that package; it is largely fresh air.
So the "equivalent" LiPo4 battery will not stay alive for as long a time for
those
essential systems that rely upon it, presuming the alternator or an associated
part of its system has failed.
Duncan Mcf.
----Original Message----
From: davidjoyce@doctors.org.uk
Date: 10/09/2017 10:33
Subj: RE: Europa-List: Battery
Brian, A lot of years ago I found myself over horizon to horizon thick forest,
somewhere near the Czech border with all my electrical instruments showing no
signs of electricity and my assumption was that my 914 was running on the fuel
left in the carb bowls Fortunately my standard checking system found that both
master and alternator switches were off and order was restored before everything
went quiet (I had just returned my pee bottle to its place under my left
thigh support and in doing so had managed to catch the toggle switches with my
trouser bottom. I felt that I had to share this slightly embarrassing incident
with the Europa community via Matronics in the spirit of the club, and Andy
Draper pointed out that if my wiring was as per manual the 914 would continue
as the first pump is driven directly from the alternator before its output gets
to the alternator switch. I have subsequently deliberately switched everything
off and found this to be true.
Which makes me wonder about the exclusion of 914s from the Lithium battery
approval. Clearly if your battery blows up you won't be able to get started, but
on the face of it if it happens in flight you can still expect to get home,
(assuming you can find the way!)
Regards, David Joyce, GXSDJ
On 2017-09-10 08:43, Brian Davies wrote:
For those of you operating under the LAA system there is a Standard Mod SM 14337
that gives details of approved Lithium batteries. Just a note of caution when
using batteries with a Battery Management System (BMS) that automatically
disconnects
the battery if over or under charged. The Rotax built in alternator
produces avionics damaging voltages when the battery is disconnected. An
overvolt
protection circuit should be fitted to guard against this.
At the moment the Mod cannot be used for the 914 because it relies on a working
electrical system. The range of batteries will be updated as more data becomes
available from the manufactures. What has already become clear is that not
all lithium batteries are suitable.
Brian
G-DDBD
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of Greg Fuchs
Sent: 09 September 2017 20:30
Subject: RE: Europa-List: Battery
Paul,
The ETX36C has been used successfully for years. The Rotax 914 charging system
needs to be slightly modified to bring the charging voltage into the range the
lithium battery likes (Jim and Heather brought that to my attention). A diode
on the 'C' terminal of the Ducati regulator is adequate to fool the regulator
into thinking the battery is at a slightly lower voltage than it actually is
and so it will up its charge voltage, placing the battery into proper charging
range. I think its 13.9 to 14.6 volts per the data sheet, if memory serves.
This lithium battery has cell protection. It has internal circuitry that can
remove
the battery from the circuit due to too low or too high voltages (i.e. when
it is overcharged or drained). A happily charged battery will not disconnect
---From the airframe. It is wise to have a good metal battery box for these
in the unlikely event of a thermal fiasco. A thin Fiberfrax layer can likely do
wonders too.
The weight savings is amazing.. When you hold them in your hand, they feel like
a fake toy battery, but they will spin the engine right up for sure.
Greg
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of Paul McAllister
Sent: Friday, September 08, 2017 7:13 AM
Subject: Europa-List: Battery
Hi All,
My trusty Odessey battery has died and gone to heaven (or wherever batteries
go).
I am seeking peoples experience with the new style Lithium batteries, and in
particular
what can be sourced in the US.
Thanks, Paul
Virus-free. www.avg.com
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