P-mag and Lithium Battery

[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]

Originally Posted by 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!

Paul, I stand corrected. I misread the weight.

Originally Posted by Aerovoltz

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/aerovo...ithium-battery

[erich weaver]

[quote=jgnunn;753058]
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]

Originally Posted by Ironflight

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]

Originally Posted by ColoRv

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.