LiFePO4 Batteries

So I am in the market for a new battery for my Libelle. I was thinking it might be time to upgrade to a LiFePO4 battery.

Any recommendations/reviews from the community? I've seen people using the K2 and Stark Power batteries. Any preference between the two?

Thanks

Peter

On Monday, April 28, 2014 9:55:16 AM UTC-5, vontresc wrote:
So I am in the market for a new battery for my Libelle. I was thinking it might be time to upgrade to a LiFePO4 battery.



Any recommendations/reviews from the community? I've seen people using the K2 and Stark Power batteries. Any preference between the two?



Thanks



Peter

Hey Pete, I bought the battery and charger that Knauff sells. Has worked very well for my 3 long flights in the Cirrus this season. Still lots of Volts left even after 6.5 hrs of radio, vario, and transponder use. Lightweight too!

I recently got the Starkpower 12V 9Ah battery from Knauff. I've put it through one test charge/discharge cycle so far. I found...

1. It took about 10Ah when I charged it from 9V resting to full voltage (14.4V while charging for a 4 cell LiFeSO4). I imagine the advertised 9Ah rating accounts for aging after many load cycles.

2. It supplies 13.0V to 13.2V for a very long time under a 0.5A load. I'd like to see how it does under a 2A to 4A load.

3. The built-in Battery Management System (BMS) does terminate any charging attempt past 14.6V

4. The BMS does not terminate discharging at 10.5V as Starkpower's website advertises. I only brought the pack down to 9V, but other sources indicate the BMS terminates discharge at 8.2V.

On Monday, April 28, 2014 10:55:16 AM UTC-4, vontresc wrote:
So I am in the market for a new battery for my Libelle. I was thinking it might be time to upgrade to a LiFePO4 battery.



Any recommendations/reviews from the community? I've seen people using the K2 and Stark Power batteries. Any preference between the two?



Thanks



Peter

We have delivered many of these batteries with no complaints. They hold a charge extremely well. Our Duo has all the fancy electronics including transponder, etc, and we tested using only one battery for more than 6 hours, still showing full voltage. We actually have two batteries installed, so it is doubtful we could ever drain the very light weight batteries even on long ridge flights.

The required charger recharges in about two hours.

Tom Knauff
www.eglider.org

I have been using a K2 9.6AmpHr battery for three years in my LS-8. Compared to lead it is amazing. Very light. Holds 13 volts even in cold soak conditions like flying for hours at 17,000 feet. My lead batteries routinely drop below 11.5volts under short cold soaks. The lead battery in my ship is off to the recycle yard at the end of this year.

On Monday, April 28, 2014 2:18:09 PM UTC-7, wrote:
We have delivered many of these batteries with no complaints. They hold a charge extremely well. Our Duo has all the fancy electronics including transponder, etc, and we tested using only one battery for more than 6 hours, still showing full voltage. We actually have two batteries installed, so it is doubtful we could ever drain the very light weight batteries even on long ridge flights.



The required charger recharges in about two hours.



Tom Knauff

www.eglider.org

So I am considering replacing one of my batteries with LifePO4 and keep the Gel Cell as my second battery, at least for another season or two. My question is if I can cause any damage when operating them in parallel. My batteries operate in parallel for short time when switching from one to the other, as well as at the end of long flights to get enough power from two weak batteries. Will this be an issue when mixing batteries?

Ramy

Because of the grossly different voltages under load/discharge, I would not recommend running them in parallel. LifePO4's voltage falls off later and very abruptly as they run out of charge so it's unlikely you'd get anything extra out of it anyway.
On Saturday, May 17, 2014 4:47:58 PM UTC+10, Ramy wrote:
On Monday, April 28, 2014 2:18:09 PM UTC-7, wrote:

We have delivered many of these batteries with no complaints. They hold a charge extremely well. Our Duo has all the fancy electronics including transponder, etc, and we tested using only one battery for more than 6 hours, still showing full voltage. We actually have two batteries installed, so it is doubtful we could ever drain the very light weight batteries even on long ridge flights.







The required charger recharges in about two hours.







Tom Knauff



www.eglider.org



So I am considering replacing one of my batteries with LifePO4 and keep the Gel Cell as my second battery, at least for another season or two. My question is if I can cause any damage when operating them in parallel. My batteries operate in parallel for short time when switching from one to the other, as well as at the end of long flights to get enough power from two weak batteries. Will this be an issue when mixing batteries?



Ramy

On Monday, April 28, 2014 9:16:34 AM UTC-7, Andrew wrote:
I recently got the Starkpower 12V 9Ah battery from Knauff. I've put it through one test charge/discharge cycle so far. I found...



1. It took about 10Ah when I charged it from 9V resting to full voltage (14.4V while charging for a 4 cell LiFeSO4). I imagine the advertised 9Ah rating accounts for aging after many load cycles.



2. It supplies 13.0V to 13.2V for a very long time under a 0.5A load. I'd like to see how it does under a 2A to 4A load.



3. The built-in Battery Management System (BMS) does terminate any charging attempt past 14.6V



4. The BMS does not terminate discharging at 10.5V as Starkpower's website advertises. I only brought the pack down to 9V, but other sources indicate the BMS terminates discharge at 8.2V.



On Monday, April 28, 2014 10:55:16 AM UTC-4, vontresc wrote:

So I am in the market for a new battery for my Libelle. I was thinking it might be time to upgrade to a LiFePO4 battery.







Any recommendations/reviews from the community? I've seen people using the K2 and Stark Power batteries. Any preference between the two?







Thanks







Peter

I did a discharge test on the Stark Power 12v 9Ah. 1.4 amp draw got me 280 minutes.

The lead acid 12v 9Ah at 1.4amp got me 150 to 180 minutes.

The other great advantage to the LiFePO4 is if you drop one on your foot it doesn't hurt.

Richard
www.craggyareo.com

This test of actual battery performance is fantastic.
Now, can someone do the same test of each of the batteries that are for sale?
What a great project for SSA !!! This would be a real service to all glider pilots.

On Saturday, May 17, 2014 7:09:38 AM UTC-7, Richard wrote:
On Monday, April 28, 2014 9:16:34 AM UTC-7, Andrew wrote:

I recently got the Starkpower 12V 9Ah battery from Knauff. I've put it through one test charge/discharge cycle so far. I found...







1. It took about 10Ah when I charged it from 9V resting to full voltage (14.4V while charging for a 4 cell LiFeSO4). I imagine the advertised 9Ah rating accounts for aging after many load cycles.







2. It supplies 13.0V to 13.2V for a very long time under a 0.5A load. I'd like to see how it does under a 2A to 4A load.







3. The built-in Battery Management System (BMS) does terminate any charging attempt past 14.6V







4. The BMS does not terminate discharging at 10.5V as Starkpower's website advertises. I only brought the pack down to 9V, but other sources indicate the BMS terminates discharge at 8.2V.







On Monday, April 28, 2014 10:55:16 AM UTC-4, vontresc wrote:



So I am in the market for a new battery for my Libelle. I was thinking it might be time to upgrade to a LiFePO4 battery.















Any recommendations/reviews from the community? I've seen people using the K2 and Stark Power batteries. Any preference between the two?















Thanks















Peter



I did a discharge test on the Stark Power 12v 9Ah. 1.4 amp draw got me 280 minutes.



The lead acid 12v 9Ah at 1.4amp got me 150 to 180 minutes.



The other great advantage to the LiFePO4 is if you drop one on your foot it doesn't hurt.



Richard

www.craggyareo.com

Meaning: neither came anywhere close to their 9AH spec, at least at this discharge rate. Lead acid usually spec'd at the 20 hour discharge, not sure if there is a standard for LiFe. Peukert is alive and well?

So from that test we could conclude that they both sucked, but the LiFe sucked less.....


I just got a Stark Power 12AH, seems to hold the voltage up higher always, and last longer than the 12 AH AGM that it replaced.