Experience with Lithium Iron Phosphate Glider batteries?

During the winter of 2009 I was bored, and aggravated with the sealed lead acid batteries that I was using in my sailplane. They didn't hold the voltage above 12v for very long, they needed replacement every few years, and I had one die 5 miles away from the airport at the end of a 300K badge flight. My argument that I had 2,000 FT over final glide at that point didn't sway the FAI from rejecting that flight for my badge attempt.

My search at the time led me to the K2 (Lithium Iron Phosphate chemistry)batteries that were the subject of my spring of 2010 battery article in Soaring.

Reaction to the article was mixed, and a partial retraction was printed the following month after an FAA DER (Designated Engineering Reviewer)with experience in certifying Lithium Ion batteries for some type of usage in commercial airliners, objected to the use of Lithium Iron Phosphate batteries in sailplanes because they hadn't been certified for that use by the FAA.

It's now 2016, and I see a lot of K2 batteries in other sailplanes. Soaring supply companies in the U.S. seem to be providing K2 batteries or a similar battery from a different manufacturer on a regular basis. The K2 battery I purchased in 2009, and it's twin purchased a year later, are still providing power to my sailplane without incident. There seems to be no degradation in performance, and other than switching to Anderson Power Pole connectors, I have not made any changes to my battery set up.

Has anyone out there had an issue with the usage of Lithium Iron Phosphate chemistry batteries in sailplanes?

Just curious because, a lot of dire consequences were predicted after my article came out.

SF

On Tuesday, May 17, 2016 at 12:58:47 PM UTC-4, SF wrote:
During the winter of 2009 I was bored, and aggravated with the sealed lead acid batteries that I was using in my sailplane. They didn't hold the voltage above 12v for very long, they needed replacement every few years, and I had one die 5 miles away from the airport at the end of a 300K badge flight. My argument that I had 2,000 FT over final glide at that point didn't sway the FAI from rejecting that flight for my badge attempt.

My search at the time led me to the K2 (Lithium Iron Phosphate chemistry)batteries that were the subject of my spring of 2010 battery article in Soaring.

Reaction to the article was mixed, and a partial retraction was printed the following month after an FAA DER (Designated Engineering Reviewer)with experience in certifying Lithium Ion batteries for some type of usage in commercial airliners, objected to the use of Lithium Iron Phosphate batteries in sailplanes because they hadn't been certified for that use by the FAA.

It's now 2016, and I see a lot of K2 batteries in other sailplanes. Soaring supply companies in the U.S. seem to be providing K2 batteries or a similar battery from a different manufacturer on a regular basis. The K2 battery I purchased in 2009, and it's twin purchased a year later, are still providing power to my sailplane without incident. There seems to be no degradation in performance, and other than switching to Anderson Power Pole connectors, I have not made any changes to my battery set up.

Has anyone out there had an issue with the usage of Lithium Iron Phosphate chemistry batteries in sailplanes?

Just curious because, a lot of dire consequences were predicted after my article came out.

SF


My experience with K2 Lithium Iron Phosphate batteries has been very positive.
They have worked perfectly for long flights for 3-4 years and they are still working well.

I did purchase the chargers that are sold by K2 which charge to a bit over 14V

I switched to a K2 Energy LiFePO4 battery and charger three years ago when I installed Flarm and updated my flight computer/variometer. I have had no problems whatsoever with either the battery or charger. It seems to have more real world life on a charge than the same sized SLA/AGM batteries I was using and as a bonus it's also lighter. I can only accommodate a single PS1270 size battery in my glider so it was nice to find that the K2 could handle demands of a six or seven hour flight with no problem even with the additional avionics I installed.

As for FAA certification (or EASA, Transport Canada etc.) the only battery I can think of with regulatory authority approval for aircraft use is the MERT PS1270 sized lithium-ion unit which claims to be JAR certified. I think it costs around 500 Euros. The batteries I've seen come with brand new gliders seem to be plain commercial-standard SLA/AGM units anyways.

On Tuesday, May 17, 2016 at 1:56:12 PM UTC-7, wrote:
I switched to a K2 Energy LiFePO4 battery and charger three years ago when I installed Flarm and updated my flight computer/variometer. I have had no problems whatsoever with either the battery or charger. It seems to have more real world life on a charge than the same sized SLA/AGM batteries I was using and as a bonus it's also lighter. I can only accommodate a single PS1270 size battery in my glider so it was nice to find that the K2 could handle demands of a six or seven hour flight with no problem even with the additional avionics I installed.

As for FAA certification (or EASA, Transport Canada etc.) the only battery I can think of with regulatory authority approval for aircraft use is the MERT PS1270 sized lithium-ion unit which claims to be JAR certified. I think it costs around 500 Euros. The batteries I've seen come with brand new gliders seem to be plain commercial-standard SLA/AGM units anyways.

Been using mine, with the K2 chargers, for over 3 years. No problems. I fly with 2 of them, some flights up to and over 8 hours, never come close to running out of juice between the two powering Flarm, radio, transponder, ClearNav flight computer and vario.

Got a K2 a couple seasons ago. Best battery I've ever used. Flew with it for 5 hours over two days without recharging. Ran the radio, two varios, a GPS and a Kobo eReader. Still showed 12.9 volts on the meter afterwards.

On Tuesday, May 17, 2016 at 5:11:36 PM UTC-7, WB wrote:
Got a K2 a couple seasons ago. Best battery I've ever used. Flew with it for 5 hours over two days without recharging. Ran the radio, two varios, a GPS and a Kobo eReader. Still showed 12.9 volts on the meter afterwards.

I have been flying with the LiFeO batteries for 3 years. They are still delivering the amp hours advertised.

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

Richard
www.craggyaero.com

On Tuesday, May 17, 2016 at 5:26:55 PM UTC-7, Richard wrote:
On Tuesday, May 17, 2016 at 5:11:36 PM UTC-7, WB wrote:
Got a K2 a couple seasons ago. Best battery I've ever used. Flew with it for 5 hours over two days without recharging. Ran the radio, two varios, a GPS and a Kobo eReader. Still showed 12.9 volts on the meter afterwards.

I have been flying with the LiFeO batteries for 3 years. They are still delivering the amp hours advertised.

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

Richard
www.craggyaero.com

Flying with a K2 since they first became available.
I have two batteries but have never had to switch to the backup.
Radio, transponder, 302, Oudie, Flarm.
No voltage drop from cold soak during wave flights.

What are the differences between the K2 battery offered for $145 and the generic lifepo4 offered for $95, besides price?

Myself and several others I fly with have been using the STARK brand batteries sold by Ridge Soaring gliderport.

These batteries are excellent, no complaints from anyone after 2-3 seasons.