Today's Message Index:
----------------------
1. 06:30 AM - Re: Back-Up Battery (Denny Baber)
2. 07:29 AM - Re: Back-Up Battery (Rick Neilsen)
3. 01:28 PM - Re: Back-Up Battery (Jerry-TS-MkII)
4. 03:10 PM - Re: Back-Up Battery (chris davis)
Message 1
INDEX | Back to Main INDEX |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Re: Back-Up Battery |
Good info on Lithium batteries. Also, they need to have the cells
"balanced". They only charge until the cell with the most charge is charged
and only discharge until the cell with the least cell is discharged. If
there is a great difference between the cells it will seem like the
capacity is reduced so it is a good idea to balance the cells on the ground
to increase capacity.
We only need the battery to use the starting motor but it is a nice back-up
if the charging system fails. The Rotax has two ignition systems that are
independent from the charging system and each other so I haven't heard of
ignition failures as much as fuel problems. Dead stick landings are usually
affected more by stalling than the wings falling off so I think practice is
more important than three batteries.
Respectfully,
Dennis Baber
Cape Coral, Fl
baberdk@gmail.com
305-814-7218
Stay Curious
Message 2
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Re: Back-Up Battery |
I installed a Aerovoltz iron lithium battery in my redrive VW powered Kolb
MKIIIC in the summer of 2014. The battery has provided great service. The
plane sits all winter while I'm in Florida and shows no measurable
discharge. I take my balancing charger out to the plane every spring and
check the battery cell balance. So far the voltages are within .1 volts and
the balance charger can't improve that balance. These LiFe batteries don't
seem to catch fire but they don't like to be over charged so I monitor the
voltage while flying. Areovoltz has published a advisory to not use their
batteries with some Rotax charging systems that have caused a battery melt
down. The battery weighs 10lbs less than my old lead acid batteries and has
lasted one year longer so far.
Denny I don't understand what you are trying to say "Dead stick landings
are usually affected more by stalling than the wings falling off so I think
practice is more important than three batteries"
Rick Neisen
Redrive WV Powered MKIIIC
On Thu, Feb 14, 2019 at 9:32 AM Denny Baber <baberdk@gmail.com> wrote:
> Good info on Lithium batteries. Also, they need to have the cells
> "balanced". They only charge until the cell with the most charge is charged
> and only discharge until the cell with the least cell is discharged. If
> there is a great difference between the cells it will seem like the
> capacity is reduced so it is a good idea to balance the cells on the ground
> to increase capacity.
> We only need the battery to use the starting motor but it is a nice
> back-up if the charging system fails. The Rotax has two ignition systems
> that are independent from the charging system and each other so I haven't
> heard of ignition failures as much as fuel problems. Dead stick landings
> are usually affected more by stalling than the wings falling off so I think
> practice is more important than three batteries.
>
>
> Respectfully,
> Dennis Baber
> Cape Coral, Fl
> baberdk@gmail.com
> 305-814-7218
>
> Stay Curious
>
>
Message 3
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Re: Back-Up Battery |
Reference cell balancing:
A small PC board is included in most serious "cordless" applications. Multi-function.
During discharge, it measures the total output current, and limits that.
Much like a active resettable fuse. Most are not adjustable, but instead selected
for the particular application current. Cells can be assembled in parallel
to boost current capacity, but that is not ideal, unless each has it's own
current control, and tied together with high current diodes. Still basically
in parallel, but also protected. And each cell voltage is monitored, and if
one cell is higher than others, a small leakage current is established, that
lowers the high cell voltage. It is minimal loss. The device also watches the
minimum total voltage and will shut it down, if too low.
During charge, the charging current and profile is regulated, AND the cells are
kept balanced, again by slight current bypass, for any cells which are too high.
If you simply take a rectified alternator output it will always be higher voltage
than the peak system battery voltage, to charge it to the max. (approx 13.8
for lead acid). With any of the high energy density cells, the charge regime
is very specific for the type of chemistry being charged. So that is why the
above control board is used (required), to charge properly, from a poorly regulated
engine source. And also why one pack can be "on-line" while the other
is charging unencumbered to it's proper maximum voltage and rate. With most of
these cells having a voltage of about 4 volts.. 3 cells will never be higher
than 12.6V. If a diode is used, that will drop .5-.6 volts so the 3 cells will
supply 12.1 max, down to 10.5. Some equipment can stand the higher voltage
provided by 4 cells (16.8 minus .5-.6 for 16.2 max). A starter motor would probably
be fine with the slightly higher voltage. Electronic devices are usually
regulated internally but.. look at the specs before proceeding.
Switching supplies can be used to boost or drop the battery voltage.. but that
adds significant complexity and cost for the high current applications.
The battery control boards are mass produced, and rather inexpensive. Each will
have specific cell count, and output current range.
Jerry
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=487589#487589
Message 4
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Re: Back-Up Battery |
George 2Which aerovoltz battery do you have and what did t cost ?
Thank u Chris
Sent from my iPhone
> On Feb 14, 2019, at 10:29 AM, Rick Neilsen <neilsenrm@gmail.com> wrote:
>
> I installed a Aerovoltz iron lithium battery in my redrive VW powered Kolb
MKIIIC in the summer of 2014. The battery has provided great service. The p
lane sits all winter while I'm in Florida and shows no measurable discharge.
I take my balancing charger out to the plane every spring and check the bat
tery cell balance. So far the voltages are within .1 volts and the balance c
harger can't improve that balance. These LiFe batteries don't seem to catch f
ire but they don't like to be over charged so I monitor the voltage while fl
ying. Areovoltz has published a advisory to not use their batteries with som
e Rotax charging systems that have caused a battery melt down. The battery w
eighs 10lbs less than my old lead acid batteries and has lasted one year lon
ger so far.
>
> Denny I don't understand what you are trying to say "Dead stick landings a
re usually affected more by stalling than the wings falling off so I think p
ractice is more important than three batteries"
>
> Rick Neisen
> Redrive WV Powered MKIIIC
>
>> On Thu, Feb 14, 2019 at 9:32 AM Denny Baber <baberdk@gmail.com> wrote:
>> Good info on Lithium batteries. Also, they need to have the cells "balanc
ed". They only charge until the cell with the most charge is charged and onl
y discharge until the cell with the least cell is discharged. If there is a g
reat difference between the cells it will seem like the capacity is reduced s
o it is a good idea to balance the cells on the ground to increase capacity.
>> We only need the battery to use the starting motor but it is a nice back-
up if the charging system fails. The Rotax has two ignition systems that are
independent from the charging system and each other so I haven't heard of i
gnition failures as much as fuel problems. Dead stick landings are usually a
ffected more by stalling than the wings falling off so I think practice is m
ore important than three batteries.
>>
>>
>> Respectfully,
>> Dennis Baber
>> Cape Coral, Fl
>> baberdk@gmail.com
>> 305-814-7218
>>
>> Stay Curious
>>
>>
Other Matronics Email List Services
These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.
-- Please support this service by making your Contribution today! --
|