Hi,

I just added some new batteries to my web site tonight. They have been
highly recommended to me by several sailplane pilots.

New - Bioenno Power Lithium Iron Phosphate LiFePO4 12V Glider Batteries

- Enhanced cycle life - up to 2000 charge cycles! After 2000 charge cycles,
the battery still holds 75-80% of its original capacity.
- Lower weight - less than half the weight of lead-acid batteries! If you
are accustomed to using lead-acid batteries - you will be shocked the first
time you pick-up one of these batteries.
- Constant and stable discharge voltage - Lead-acid batteries gradually lose
voltage over time as they discharge - dropping below 12V early-on. LiFePO4
batteries have a much more gradual decrease in voltage until they are nearly
fully discharged - staying at 13+V for most of their discharge cycle - so
they are able to power your sailplane radio and instruments at higher
voltages for longer periods of time. Higher voltages assure maximum transmit
power from radios and transponders.

http://www.cumulus-soaring.com/bioenno.htm

Best Regards,

Paul Remde
Cumulus Soaring, Inc.

A comment on lithium batteries since I have two in my glider and a
digital volt meter mounted on the panel... I don't notice much voltage
drop as I did with lead batteries other than when I transmit. The data
available for the batteries indicates a rapid decline and shutoff when
the battery is nearly spent. I don't think that's a problem since the
shutoff voltage is around 9.6 volts and your radio will quit
transmitting before reaching that limit.

The reason I post this is because I was using a lithium powered
flashlight the other day while working on my car and, when the battery
reached it's limit, it simply shut off. It was so sudden that I thought
the bulb had burned out. No dimming as you're used to with standard
batteries. Changing the bulb had no effect so I swapped batteries with
my drill and the light worked again. Charging the battery took less than
an hour.

On 4/15/2015 11:27 PM, Paul Remde wrote:
> Hi,
>
> I just added some new batteries to my web site tonight. They have
> been highly recommended to me by several sailplane pilots.
>
> New - Bioenno Power Lithium Iron Phosphate LiFePO4 12V Glider Batteries
>
> - Enhanced cycle life - up to 2000 charge cycles! After 2000 charge
> cycles, the battery still holds 75-80% of its original capacity.
> - Lower weight - less than half the weight of lead-acid batteries! If
> you are accustomed to using lead-acid batteries - you will be shocked
> the first time you pick-up one of these batteries.
> - Constant and stable discharge voltage - Lead-acid batteries
> gradually lose voltage over time as they discharge - dropping below
> 12V early-on. LiFePO4 batteries have a much more gradual decrease in
> voltage until they are nearly fully discharged - staying at 13+V for
> most of their discharge cycle - so they are able to power your
> sailplane radio and instruments at higher voltages for longer periods
> of time. Higher voltages assure maximum transmit power from radios and
> transponders.
>
> http://www.cumulus-soaring.com/bioenno.htm
>
> Best Regards,
>
> Paul Remde
> Cumulus Soaring, Inc.

--
Dan Marotta

On Thursday, April 16, 2015 at 8:04:05 AM UTC-7, Dan Marotta wrote:
> A comment on lithium batteries since I have two in my glider and a
> digital volt meter mounted on the panel...* I don't notice much
> voltage drop as I did with lead batteries other than when I
> transmit.* The data available for the batteries indicates a rapid
> decline and shutoff when the battery is nearly spent.* I don't think
> that's a problem since the shutoff voltage is around 9.6 volts and
> your radio will quit transmitting before reaching that limit.
>
>
>
> The reason I post this is because I was using a lithium powered
> flashlight the other day while working on my car and, when the
> battery reached it's limit, it simply shut off.* It was so sudden
> that I thought the bulb had burned out.* No dimming as you're used
> to with standard batteries.* Changing the bulb had no effect so I
> swapped batteries with my drill and the light worked again.*
> Charging the battery took less than an hour.
>
>
>
>
> On 4/15/2015 11:27 PM, Paul Remde
> wrote:
>
>
> Hi,
>
>
>
>
> I just added some new batteries to my web site tonight.* They have
> been highly recommended to me by several sailplane pilots.
>
>
>
>
> New - Bioenno Power Lithium Iron Phosphate LiFePO4 12V Glider
> Batteries
>
>
>
>
> - Enhanced cycle life - up to 2000 charge cycles! After 2000
> charge cycles, the battery still holds 75-80% of its original
> capacity.
>
>
> - Lower weight - less than half the weight of lead-acid batteries!
> If you are accustomed to using lead-acid batteries - you will be
> shocked the first time you pick-up one of these batteries.
>
>
> - Constant and stable discharge voltage - Lead-acid batteries
> gradually lose voltage over time as they discharge - dropping
> below 12V early-on. LiFePO4 batteries have a much more gradual
> decrease in voltage until they are nearly fully discharged -
> staying at 13+V for most of their discharge cycle - so they are
> able to power your sailplane radio and instruments at higher
> voltages for longer periods of time. Higher voltages assure
> maximum transmit power from radios and transponders.
>
>
>
>
> http://www.cumulus-soaring.com/bioenno.htm
>
>
>
>
> Best Regards,
>
>
>
>
> Paul Remde
>
>
> Cumulus Soaring, Inc.
>
>
>
>
>
> --
>
> Dan Marotta

I was wondering about this characteristic myself, but don't! I bought a Stark Power LiFePo4 battery and ran it until it was discharged. The voltage declined very slowly over the first 8 hours or so, then more rapidly over about the next 2 hours before I shut it off at 11.9 V. This led me to conclude that a) mine will last for a very long flight and b) the decline in voltage gives plenty of warning that it is near the end.

Before we decided to sell the Stark Power LiFePo4 battery, we installed two of them in our DUO Discus. The DUO has lots of electronics in both cockpits including a transponder, Flarm, flight computers, etc, etc.

We flew on one battery for two long days, just to see how long they might last, and it still had lots of power left. We obviously now have both installed, and connected as we did with the previous batteries.

We have sold a couple hundred of these with no complaints or problems, and they seem to be lower cost than others I am aware of. Even the important battery charger is reasonable in cost. They charge very quickly.

At this time, we do not suggest using them for high power applications such as used in self-launch gliders.

Tom Knauff
www.eglider.org

On Thursday, April 16, 2015 at 2:08:17 PM UTC-7, wrote:
> Before we decided to sell the Stark Power LiFePo4 battery, we installed two of them in our DUO Discus. The DUO has lots of electronics in both cockpits including a transponder, Flarm, flight computers, etc, etc.
>
> We flew on one battery for two long days, just to see how long they might last, and it still had lots of power left. We obviously now have both installed, and connected as we did with the previous batteries.
>
> We have sold a couple hundred of these with no complaints or problems, and they seem to be lower cost than others I am aware of. Even the important battery charger is reasonable in cost. They charge very quickly.
>
> At this time, we do not suggest using them for high power applications such as used in self-launch gliders.
>
> Tom Knauff
> www.eglider.org

I flew with the Stark Power Batteries for a flying season before I started selling them. Also did some tests with Electrofly charger battery discharger see results:

http://www.craggyaero.com/lifepo_battery.htm

Richard
www.craggyaero.com

Tom:

I am curious how you have two batteries wired in the DUO? Parallel, two switches to a common bus?

Inquiring minds want to know!

Thanks

Not Tom, but I have two LiFePO4 batteries with two toggle switches wired
to a common DC bus. Switchover is simple: raise the second switch,
lower the first.

On 4/18/2015 11:22 PM, wrote:
> Tom:
>
> I am curious how you have two batteries wired in the DUO? Parallel, two switches to a common bus?
>
> Inquiring minds want to know!
>
> Thanks

--
Dan Marotta

Thanks, Dan. There seems to be a plethora of over-thinking on this subject, but I could be wrong......

On Sun, 19 Apr 2015 18:51:52 -0700, markgrubb wrote:

> Thanks, Dan. There seems to be a plethora of over-thinking on this
> subject, but I could be wrong......

A little searching on RS, Farnells, and similar outlets will find break-
before-make changeover switches. If the momentary voltage drop as you
throw the switch causes problems, put a decently sized capacitor
(1000-2000 microfarad) across the output lines of the switch with a small
resistor 10-15 ohms) in series with it. The resistor may be unnecessary:
its mainly there to limit to power surge to about 1A when the battery is
connected and, as the panel only draws around 400mA with everything on,
is too small to cause a significant voltage drop while the switch is open
circuit.

The season before last I discovered that, if I kicked the XLR plug
feeding power to my panel when I was getting in, the momentary power drop
would switch my radio and main vario off Putting a 2000 microfarad
capacitoy and 10 ohm resistor across the panel side of the plug has been
a permanent cure.

I've watched it with a voltmeter across the panel side: it takes about a
second for the voltage to drop to zero when the battery is disconnected,
so the momentary disconnection if I kick the plug isn't nearly long
enough to drain the capacitor.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

On Mon, 20 Apr 2015 11:48:46 +0000, Martin Gregorie wrote:

I see I left a badly edited mess, so here is another try:

Another way of solving the battery switching problem is to use a break-
before-make change-over switch. These are often rotary switches.
A little searching on RS, Farnells, and similar outlets will find
suitable switches for 12 volts at the sort of currents we require.

If the momentary voltage drop as you
throw the switch causes problems, put a decently sized capacitor
(1000-2000 microfarad) across the output lines of the switch with a
small resistor (10-15 ohms) in series with it. The resistor may be
unnecessary: its mainly there to limit to power surge to about 1A when
the battery is connected.

The season before last I discovered that, if I kicked the XLR plug
feeding power to my panel when I was getting into my cockpit, the
resulting momentary power glitch would switch my radio and main vario off,
which was annoying. Putting a 2000 microfarad capacitor and 10 ohm
resistor across the panel side of the plug has been a permanent cure.

My panel only draws around 400mA with everything on so, even with the
resistor in circuit, the capacitor is able to supply enough voltage and
current to keep the panel alive over the short period while the
connection in the plug is lost: with the capacitor charged to 12v the 10
ohm resistor limits current to 1200 mA. As this is three times more than
the panel requires, it won't affect the operation of any instruments
while the capacitor is powering them.

To check this I put a voltmeter across the panel side of the connector
and, with a stable 12v shown, disconnected the battery. It took about a
second for the voltage to drop to zero. In other words the momentary
disconnection if I kick the plug isn't nearly long enough to drain the
capacitor and cause anything to switch off.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

I have used a "break before make" toggle switch in everyone of my gliders and they have worked perfectly. Never had an instrument shut down or restart. Makes life very simple while flying.

Don't you mean "make before break"? I use a rotary swithch with capacitors and a power resistor in parallel. Also works fine.

___________________

I have used a "break before make" toggle switch in everyone of my gliders and they have worked perfectly. Never had an instrument shut down or restart. Makes life very simple while flying.

Most small LiFePO4's are going to have a BMS (Battery Management System)
that disconnect the battery in event of excessive charging or
discharging, since they're hypersensitive to those events. That's what
you saw when the light went off instantly. If you were using an LED
flashlight, it has an active regulator to control the LED's. Which would
have hidden the voltage drop prior to cutoff. You can generally hear the
switching circuit put out RF noise if you hold it close to an AM radio.

-Dave


On Thu, 16 Apr 2015 09:04:01 -0600, Dan Marotta wrote:

> A comment on lithium batteries since I have two in my glider and a
> digital volt meter mounted on the panel... I don't notice much voltage
> drop as I did with lead batteries other than when I transmit. The data
> available for the batteries indicates a rapid decline and shutoff when
> the battery is nearly spent. I don't think that's a problem since the
> shutoff voltage is around 9.6 volts and your radio will quit
> transmitting before reaching that limit.
>
> The reason I post this is because I was using a lithium powered
> flashlight the other day while working on my car and, when the battery
> reached it's limit, it simply shut off. It was so sudden that I thought
> the bulb had burned out. No dimming as you're used to with standard
> batteries. Changing the bulb had no effect so I swapped batteries with
> my drill and the light worked again. Charging the battery took less than
> an hour.
>
> On 4/15/2015 11:27 PM, Paul Remde wrote:
>> Hi,
>>
>> I just added some new batteries to my web site tonight. They have been
>> highly recommended to me by several sailplane pilots.
>>
>> New - Bioenno Power Lithium Iron Phosphate LiFePO4 12V Glider Batteries
>>
>> - Enhanced cycle life - up to 2000 charge cycles! After 2000 charge
>> cycles, the battery still holds 75-80% of its original capacity.
>> - Lower weight - less than half the weight of lead-acid batteries! If
>> you are accustomed to using lead-acid batteries - you will be shocked
>> the first time you pick-up one of these batteries.
>> - Constant and stable discharge voltage - Lead-acid batteries gradually
>> lose voltage over time as they discharge - dropping below 12V early-on.
>> LiFePO4 batteries have a much more gradual decrease in voltage until
>> they are nearly fully discharged - staying at 13+V for most of their
>> discharge cycle - so they are able to power your sailplane radio and
>> instruments at higher voltages for longer periods of time. Higher
>> voltages assure maximum transmit power from radios and transponders.
>>
>> http://www.cumulus-soaring.com/bioenno.htm
>>
>> Best Regards,
>>
>> Paul Remde Cumulus Soaring, Inc.

Thanks Dave,

The flashlight in question has an incandescent bulb. By excessive
discharging I assume you meant low charge remaining, which was the case,
rather than excessive current. It was interesting to see it simply
switch off rather than dimming to nothing as the charge dissipated.

In the case of my glider the switch off voltage is 9.6 volts which, I
believe will still run my vario but will not run my radio. Therefore, I
manually switch batteries when the radio stops working.

On 4/21/2015 6:54 AM, David Kinsell wrote:
> Most small LiFePO4's are going to have a BMS (Battery Management System)
> that disconnect the battery in event of excessive charging or
> discharging, since they're hypersensitive to those events. That's what
> you saw when the light went off instantly. If you were using an LED
> flashlight, it has an active regulator to control the LED's. Which would
> have hidden the voltage drop prior to cutoff. You can generally hear the
> switching circuit put out RF noise if you hold it close to an AM radio.
>
> -Dave
>
>
> On Thu, 16 Apr 2015 09:04:01 -0600, Dan Marotta wrote:
>
>> A comment on lithium batteries since I have two in my glider and a
>> digital volt meter mounted on the panel... I don't notice much voltage
>> drop as I did with lead batteries other than when I transmit. The data
>> available for the batteries indicates a rapid decline and shutoff when
>> the battery is nearly spent. I don't think that's a problem since the
>> shutoff voltage is around 9.6 volts and your radio will quit
>> transmitting before reaching that limit.
>>
>> The reason I post this is because I was using a lithium powered
>> flashlight the other day while working on my car and, when the battery
>> reached it's limit, it simply shut off. It was so sudden that I thought
>> the bulb had burned out. No dimming as you're used to with standard
>> batteries. Changing the bulb had no effect so I swapped batteries with
>> my drill and the light worked again. Charging the battery took less than
>> an hour.
>>
>> On 4/15/2015 11:27 PM, Paul Remde wrote:
>>> Hi,
>>>
>>> I just added some new batteries to my web site tonight. They have been
>>> highly recommended to me by several sailplane pilots.
>>>
>>> New - Bioenno Power Lithium Iron Phosphate LiFePO4 12V Glider Batteries
>>>
>>> - Enhanced cycle life - up to 2000 charge cycles! After 2000 charge
>>> cycles, the battery still holds 75-80% of its original capacity.
>>> - Lower weight - less than half the weight of lead-acid batteries! If
>>> you are accustomed to using lead-acid batteries - you will be shocked
>>> the first time you pick-up one of these batteries.
>>> - Constant and stable discharge voltage - Lead-acid batteries gradually
>>> lose voltage over time as they discharge - dropping below 12V early-on.
>>> LiFePO4 batteries have a much more gradual decrease in voltage until
>>> they are nearly fully discharged - staying at 13+V for most of their
>>> discharge cycle - so they are able to power your sailplane radio and
>>> instruments at higher voltages for longer periods of time. Higher
>>> voltages assure maximum transmit power from radios and transponders.
>>>
>>> http://www.cumulus-soaring.com/bioenno.htm
>>>
>>> Best Regards,
>>>
>>> Paul Remde Cumulus Soaring, Inc.

--
Dan Marotta