[jgnunn]

I am planning for dual P-mags. Last night I stumbled across this snippet of info on the tips and tricks page at emagair.com:

Customers should also be aware that many of the new non-traditional (non lead-acid) batteries (gel-cell, lithium-ion, lithium-iron phosphate, etc) frequently have different charging profiles. Anytime a battery is unable to absorb/buffer output from the alternator, the excess will likely go out to all the appliances on the buss, including our ignition.

I already have the lightweight aerovoltz 16 cell battery in the mix. Comments, anyone?

 

[Toobuilder]

I had some recent struggles with my dual PMags, well documented on this site. Discussion with Brad did bring the potential "dirty" power theory to light as one of my potential issues. However, he did say that the 114 boards are more resistant to this issue than the earlier 113 series. Of course, it appears that this malfunction is so rare that it is still just a theory. This is one of the reasons why I now think its a good idea to be able to isolate ships power from the 113 while in flight.

In the end however, I'd say this tip from emagair is just their attempt to keep everything above board. They can't possibly test every electrical system configuration a home builder can dream up, so they throw every possible problem out to the world, no matter how improbable.

 

[N941WR]

First off, why do you want to go with the aerovoltz 16 cell battery? The thing costs almost $300 and weighs more than the Odyssey PC680. Weight is the single largest performance killer with any airplane, more so with an RV.

As for dealing with issues with the P-mag, I have not had any issues with the battery causing ignition problems but then again, I'm using a PC680.

 

[Ironflight]

Uh....the reference I saw to the Aerovoltz 16 cell's weight is 3 lbs Bill - considerably less than a 680. So if his goal is to increase performance by reducing weight, that's a pretty good solution.

Of course, I still believe that the best way to save a few pounds is to take it off the pilot!

 

[N941WR]

Uh....the reference I saw to the Aerovoltz 16 cell's weight is 3 lbs Bill - considerably less than a 680. So if his goal is to increase performance by reducing weight, that's a pretty good solution.

Of course, I still believe that the best way to save a few pounds is to take it off the pilot!

Paul, I stand corrected. I misread the weight.

The stock battery in most experimentals weighs 12.4lbs to 25lbs while the Aerovoltz 12 Cell for example weighs less than 2.5lbs. That?s a 10 lbs to 20lbs+ saving for less than $190 dollars!
http://www.aerovoltz.net/p/55/aerovoltz-16-cell-lithium-battery

 

[erich weaver]

Anytime a battery is unable to absorb/buffer output from the alternator, the excess will likely go out to all the appliances on the buss, including our ignition.[/I]/QUOTE]

It's pretty much a myth that batteries serve as an electrical absorber/buffer (read up on the AeroElectric forum), but regardless,. I don't see any special connection here to lithium batteries. I would think a working regulator, over voltage protection, and fuses/circuited breakers would suffice, just as for a PC-680 or whatever. If a battery cant handle a continuous 14 volt application from an alternator that would surprise me and certainly limit it's sales potential.

Erich

 

[ColoRv]

Perhaps I've been in one to many race car fires. I've decided that fire isn't my thing. I know the argument that Li-X-po isn't the same as Li-Y-po or whatever, but then someone told Boeing that too....

The FAA's test said:

The results of the tests show that the Li-ion a
nd Li-Po battery cells can react violently when
exposed to an external fire. During the single-
cell test for battery type 2, the vents failed to
open, resulting in an explosion of the battery cell.

Two of the tested cells were lithium iron phosphate (as is aerovolt's battery?) and both burned violently, one exploded. I do love experimental and the fact that we can embrace technology that is new and exciting....but.....be careful out there.

I am watching this technology with high hopes and an inquisitive mind...but there are disturbing tests and videos out there and the battery in my RV8 is inside the firewall....and having been on fire more than once (race cars), I'm a chicken.

Someone please convince me otherwise, as I do want to save the weight and my mind is open.

 

[jgnunn]

Of course, I still believe that the best way to save a few pounds is to take it off the pilot!

A better way: Take it off the pilot AND off the plane...

 

[jgnunn]

I am watching this technology with high hopes and an inquisitive mind...but there are disturbing tests and videos out there and the battery in my RV8 is inside the firewall....and having been on fire more than once (race cars), I'm a chicken.

Someone please convince me otherwise, as I do want to save the weight and my mind is open.

I stumbled across this response on the zenith forum:

I can truly appreciate your concern and that last thing I would ever want to experience is an in air fire of any form. Our batteries have been utilized in the powersports market for over four years before I was willing to bring them to the aircraft market.

The batteries had to undergo severe testing for us to be able to ship them worldwide under a global standard called UN-DOT. During the testing the batteries are overcharged, shorted out, crushed, frozen, taken to high altitudes for cold and low pressure under charge, excessive heat, and vibration testing. During this testing all of the batteries are taken to failure in one test or another and none resulted in fire or bursting.

One of the key elements is the makeup of our batteries. The batteries that will pop and burst and cause fire are Lithium Polymer which is what is in our cell phones and laptops. You can find video after video of these types of batteries going out of control.

Our batteries are lithium Iron phosphate which is dry cell battery and not a gel like the Polymer type. Also, our batteries are made up individual cells internally and each cell has a vent hole in the casing to allow for pressure release should the batteries become over heated or shorted to the point of failure. We have a ceramic board on the inside bottom of the battery where the vent holes are located so that no hot battery material can escape the case or damage surrounding components. In each failure test the cells can grow like a marshmallow but will not burst the case due to the vent holes in each cell. There is an air gap in the top of the battery to allow for any growth of the cells or release to keep any failure contained.

To date we have thousands of batteries in service in dirt bikes, atv?s, UTV?s, racecars, jet ski?s, snowmobiles, drag motorcycles and cars, sports cars, and of course aircraft. We have sold well over 300 batteries in the last two years in aviation have several OEM manufactures using our batteries right from the factory. Kit Fox here in the US, Back Country Super Cubs, Titan Aircraft, and Pipistrel in Slovenia has been a steady customer for two years now. We even had a pair of our batteries fly around the world last year in a Pipistrel Aircraft. Here is a link to the website: http://www.worldgreenflight.com/

We have dozens of customers around the world that have sent us pictures and testimonials on how well the batteries are working for them and how nice it is to install a dry cell battery that can be mounted in any position or location that it fits.

Aircraft Spruce, Leading Edge Airfoils, Wicks Aircraft, Back Country Cubs, Titan, and Great Northern air are all dealers for us currently and have had great success. The only two ways to damage the batteries are leave the master switch on and kill the cells which damages the batteries ability to hold the volume of electricity it needs to perform again at peak cranking amps or to severely overcharge the battery to point of severely overheating the cells which will result in the marshmallow effect and damage to the cells and the battery will no longer hold a charge due to the damage internally in the cells.

The UN-DOT testing was extensive and expensive but was necessary from a safety standpoint for both shipping and our customers.

We do offer an aluminum battery box designed just for our batteries to make mounting easier and give the customer a safe and contained battery mounting location. Regardless of who makes the battery in an airplane I would always recommend a full closer battery box, especially with a lead acid battery that can explode with just a spark or overheating. I am more concerned with an Alternator fire than anything in the airplane due to the high power and heat being generated and the power being directly driven into it by the engine rotation.

I hope this helps a little to make you feel more comfortable with your purchase and feel free to call me if you have any specific questions or concerns. I have attached an image of the battery box as well for your reference as I do not have it up on the website yet as most customers build their own specific to their aircraft.


Kind regards

Steve Johnson
Everything Aero LLC
Aerovoltz

 

[ColoRv]

That is encouraging. I wonder how the lithium iron phosphate in the aerovolts differ from the two lithium iron phosphate batteries that the FAA test references. Better containment is a great thing, but is there a chemical difference? If that containment fails, are we still talking about an explosive material? 300 seems a very small amount of sales over two full years. Some independent test results would certainly be nice.

 

[Steve Ashby]

Aerovoltz battery box

Steve,
Where can I find the aluminum battery box you discussed?
Thanks!

 

[Walt]

Anytime a battery is unable to absorb/buffer output from the alternator, the excess will likely go out to all the appliances on the buss, including our ignition.[/I]/QUOTE]

It's pretty much a myth that batteries serve as an electrical absorber/buffer (read up on the AeroElectric forum), but regardless,. I don't see any special connection here to lithium batteries. I would think a working regulator, over voltage protection, and fuses/circuited breakers would suffice, just as for a PC-680 or whatever. If a battery cant handle a continuous 14 volt application from an alternator that would surprise me and certainly limit it's sales potential.

Erich

Do you have a link to the Aeroelectric forum that you are refering to?
If you don't think the battery acts a filter, you've likely never seen the output of an alternator on an oscilloscope.

 

[Brantel]

Do you have a link to the Aeroelectric forum that you are refering to?
If you don't think the battery acts a filter, you've likely never seen the output of an alternator on an oscilloscope.

I agree...while a battery can't absorb all things that get thrown at it, it does a pretty good job on most of it...

Batteries like the PC680 have super low internal resistance and can flow huge currents for short periods of time. This makes em a pretty good buffer.

 

[erich weaver]

Can't seem to get the search function on the AeroElectric list working for me to track this down, but will try a bit more later and report back
Regards
Erich

 

[chaskuss]

Can't seem to get the search function on the AeroElectric list working for me to track this down, but will try a bit more later and report back
Regards
Erich

I must read a different AeroElectric list than you do. Bob always stated that the battery acts electrically, in a similar manner as a fluid dampener or accumulator would on a hydraulic system.

Charlie

 

[erich weaver]

I must read a different AeroElectric list than you do. Bob always stated that the battery acts electrically, in a similar manner as a fluid dampener or accumulator would on a hydraulic system.

Charlie

Bob has stated more than once that he believed this for many years but eventually came to realize it wasn't true. It's on me now to find his posts on this, unless another individual that reads both forums comes to my rescue. Stay tuned.
E

 

[ColoCardinal]

LiFePo

Bill, I did not see a reference to the FAA testing of the LiFePo (Iron) batteries other than to include them in the "Lithium" class of battery. This is NOT the battery that Boeing is using in the 787, if that makes you feel any better. THere's a lot of good information out there. Aerovoltz and Shorai and even Wiki, all have good explanations of the construction of this type of battery. Often I read about Lithium Ion Batteries catching on fire and in the same article LiFePo batteries are grouped with the subject battery despite being a different animal than the subject battery. I think, that is what often happens with the Iron batteries.

 

[ColoRv]

Bill, I did not see a reference to the FAA testing of the LiFePo (Iron) batteries other than to include them in the "Lithium" class of battery. This is NOT the battery that Boeing is using in the 787, if that makes you feel any better. THere's a lot of good information out there. Aerovoltz and Shorai and even Wiki, all have good explanations of the construction of this type of battery. Often I read about Lithium Ion Batteries catching on fire and in the same article LiFePo batteries are grouped with the subject battery despite being a different animal than the subject battery. I think, that is what often happens with the Iron batteries.

I'm admittedly ignorant of all of this but I am trying to come up to speed. On page three of that FAA test it describes the three battery cells tested. Two of them were lithium iron phosphate, one sprayed highly flammable electrolyte forcefully and ignited while the other exploded and burned. This test was exposing the cells to heat, not the run away test which is another subject I'm trying to wrap my head around.

I thought the Shorai's were made of lithium iron phosphate, though I could well be mistaken. The question in my mind is, the plane has crashed, my battery is in my cockpit...does the lithium iron phosphate add a flammable substance inside with us that is more or less dangerous than the PC680.

I am trying to keep up with this technology but it isn't easy to track. Still, it's a technology that I would love to use so I am trying to understand it.

 

[erich weaver]

Do you have a link to the Aeroelectric forum that you are refering to?
If you don't think the battery acts a filter, you've likely never seen the output of an alternator on an oscilloscope.

Below is a March 10 2013 quote from Bob Nuckolls on the Aeroelectric List that I found for your consideration. Would be interested to hear reactions; did I overstate the case in my previous post?
regards,
erich

"Later on I offered a revision to the ol' mechanic's
tale that a battery was one of the 'best filters of
noise' on the bus. I used to subscribe to that
notion myself. My colleagues believed it.

But consider that a battery has three states of
existence in the properly functioning system.
We KNOW that an engine driven power source must
be adjusted for at LEAST 13.8 volts in order to
fully charge a battery at 20C. Setting it somewhat
higher, say 14.2 to 14.6 overs a faster replenishment
of charge after cranking the engine and perhaps
a prolonged battery-only pre-flight activity.

At the same time, we know that turning the
alternator off allows system voltage to fall
quickly to 12.5v or so . . . it marches downward
from there with time.

So what happens in the range of 12.5 to 13.8
volts? Not much. The battery is incapable of
taking on significant energy below 13.5 and
doesn't start delivering significant energy
at more than 12.5 volts. I.e. the battery becomes
'unhooked'. The idea that it takes on the role
of some 'super capacitor' for the smoothing
of noise is without foundation. I've verified
this both on cars and airplanes where disconnection
of the battery while the alternator is running
produces a only a small rise in bus noise.

A 14v alternator is a low impedance source with
about 1.5v pk-pk ripple built in as an artifact
of 3-phase rectification. This is a given that
drives DO-160/Mil-STD-704 requirements that
qualified devices be designed to function
as advertised in the presence of such noise.
The noise spectrum to be tolerated is plotted
here . . .

http://tinyurl.com/b3rhjwq

This is a 28v system plot where worst case
noise is 1Vrms over the range of 1 to 5KHz
and falls off on each side. 1Vrms sine wave
is 2.8Vpk-pk. Any departure from sine wave
allows the pk-pk values to rise markedly. In
short, the battery is not an effective filter
for anything except gross brown-out events and
standing off a runaway alternator for tens
of milliseconds required for the ov protection
system to assert system shutdown.

This ol' dog didn't learn it until about half
way through a 40+ year career. Not that it
was hard to figure out . . . just didn't have
a reason to question what was proffered as
common sense."

 

[Walt]

Below is a March 10 2013 quote from Bob Nuckolls on the Aeroelectric List that I found for your consideration. Would be interested to hear reactions; did I overstate the case in my previous post?
regards,
erich
"

What I gather from this is that even with the additional ripple on the bus from the alternator that the equipment "should" be able to tolerate it. This is probably a true statement with modern avionics. However, would I want to take the battery out of the system with my high $$ avionics on, not!

Using that same philosophy, how many folks use an avionics master to "protect" their avionics, same thing applies, modern equipment "should" not be affected by transients but do I really want to test it, nope.

 

[erich weaver]

The contention stated in multiple earlier posts was that the battery acts as a good buffer/filter/absorber. All I am saying is that it appears to me that Bob Nuckolls disagrees:

"The idea that it takes on the role
of some 'super capacitor' for the smoothing
of noise is without foundation."

"In short, the battery is not an effective filter
for anything except gross brown-out events and
standing off a runaway alternator for tens
of milliseconds required for the ov protection
system to assert system shutdown."

erich

 

[NTex]

I am planning for dual P-mags. Last night I stumbled across this snippet of info on the tips and tricks page at emagair.com:

Customers should also be aware that many of the new non-traditional (non lead-acid) batteries (gel-cell, lithium-ion, lithium-iron phosphate, etc) frequently have different charging profiles. Anytime a battery is unable to absorb/buffer output from the alternator, the excess will likely go out to all the appliances on the buss, including our ignition.

I already have the lightweight aerovoltz 16 cell battery in the mix. Comments, anyone?

Hate to revive an old thread, but did you ever get answer to this? The thread took a left turn there at the end.

I'm thinking of installing pmags and an aerovoltz battery as a backup, but want to make sure this combination is OK.

Thanks

 

[NTex]

Hate to revive an old thread, but did you ever get answer to this? The thread took a left turn there at the end.

I'm thinking of installing pmags and an aerovoltz battery as a backup, but want to make sure this combination is OK.

Thanks

Spoke with Brad at Emagair regarding the compatibility of Pmag 114 models with LiFeO4 batteries. He said it's not a problem unless you are charging the battery, in which case just be sure to switch the electronic ignition off (or pull the breaker).

So, in summary Pmags and lithium batteries appear to play nice. Just be careful when charging the battery.

 

[grayforge]

I have P-Mags and am thinking of using one of these lithium batteries as my primary/only battery... so it'll be charging after engine start. :-(

 

[Bevan]

I have P-Mags and am thinking of using one of these lithium batteries as my primary/only battery... so it'll be charging after engine start. :-(

I don't think anyone is saying that charging the LiFePo battery after engine start with the onboard alternator will be a problem. I believe the concern comes when ground charging using the special balancing charger and the P-mags "powered". Just turn the P-mags off or pull their breaker as suggested.

Bevan

 

[grayforge]

Ah, that makes sense. Thanks.

 

[NTex]

I don't think anyone is saying that charging the LiFePo battery after engine start with the onboard alternator will be a problem. I believe the concern comes when ground charging using the special balancing charger and the P-mags "powered". Just turn the P-mags off or pull their breaker as suggested.

Bevan

That's exactly right - at least that's the word I got from Brad.

Apparently the newer style batteries and chargers use pulses to "hammer" the battery with energy to charge it, and this can play havoc on the pmag's internal circuitry.

This is only a problem when you are charging the battery on the ground station (i.e. engine not running). You wouldn't (shouldn't) have your Pmags on during the ground charging evolution anyway, so it's a non-factor.

 

[Camillo]

We do offer an aluminum battery box designed just for our batteries to make mounting easier and give the customer a safe and contained battery mounting location. Regardless of who makes the battery in an airplane I would always recommend a full closer battery box, especially with a lead acid battery that can explode with just a spark or overheating. I am more concerned with an Alternator fire than anything in the airplane due to the high power and heat being generated and the power being directly driven into it by the engine rotation.

Steve Johnson
Everything Aero LLC
Aerovoltz[/I]

Steve, I would also like to know where to buy that battery box (for a 16-cell). On your website no email is given.
Thanks.
Camillo