glider battery duration problems

Don't confuse the Li-Ion batteries with the LiFePo4 batteries that are mentioned above. While the Li-Ion batteries have the instability problems associated with thermal runaway during rapid discharge, the Lithium-Iron-Phosphate (LiFePo4) chemistry is stable and do not have these problems.

There are many knock-off Chinese battery packs on the market that are called LiFePo, but be careful what you buy. I am a re-seller for K2 Energy batteries, and these are made in the USA, true LiFePo4 chemistry. I have spent hours on the phone with Mark Stoker at K2 comparing their batteries to some of the cheaper competition and some of the competitors numbers don't add up. The LiFePo4 chemistry is patented and K2 pays patent fees to the patent holder to use it, while many of the others don't. Visit the K2 website for more information at: http://www.k2battery.com/battery-packs-12v.html

Some of the advantages of the LiFePo4 chemistry over the SLA's (sealed Lead Acid) is that it holds peak voltage for much longer during discharge. The SLA's discharge curve is a continually declining slope that quickly reaches the 10 V level where things start to shut-off, while the LiFePo4 discharge curve is almost a straight line from the initial charge of 13 V. See the discharge curve he
http://www.foxonecorp.com/images/sto...0discharge.png

Advantages of the LiFePo4 batteries

provide much longer battery use during flight.

can be used for at least 2000 discharge-recharge cycles, compared to 300 for SLA's

hold their charge during the off-season loosing only 1% per month (unlike the SLA batteries that loose 25-30% per month)

don't have the special charge/discharge requirements of the early Li-ion types and can be charged with most normal SLA chargers as long as they can provide a 14.6 V peak charge voltage

The K2 batteries have the highest capacity available at ANY discharge rate available on the market.


Contact me if you would like more info

Dave Springford
www.foxonecorp.com

In response to 6PK about the charging:

Yes, the chargers are smart trickle chargers that can be left on the LiFePo4 packs indefinitely.

On Wednesday, October 2, 2013 4:15:29 PM UTC-7, Dave Springford wrote:
Don't confuse the Li-Ion batteries with the LiFePo4 batteries that are mentioned above. While the Li-Ion batteries have the instability problems associated with thermal runaway during rapid discharge, the Lithium-Iron-Phosphate (LiFePo4) chemistry is stable and do not have these problems.



There are many knock-off Chinese battery packs on the market that are called LiFePo, but be careful what you buy. I am a re-seller for K2 Energy batteries, and these are made in the USA, true LiFePo4 chemistry. I have spent hours on the phone with Mark Stoker at K2 comparing their batteries to some of the cheaper competition and some of the competitors numbers don't add up. The LiFePo4 chemistry is patented and K2 pays patent fees to the patent holder to use it, while many of the others don't. Visit the K2 website for more information at: http://www.k2battery.com/battery-packs-12v.html



Some of the advantages of the LiFePo4 chemistry over the SLA's (sealed Lead Acid) is that it holds peak voltage for much longer during discharge. The SLA's discharge curve is a continually declining slope that quickly reaches the 10 V level where things start to shut-off, while the LiFePo4 discharge curve is almost a straight line from the initial charge of 13 V. See the discharge curve he

http://www.foxonecorp.com/images/sto...0discharge.png



Advantages of the LiFePo4 batteries



provide much longer battery use during flight.



can be used for at least 2000 discharge-recharge cycles, compared to 300 for SLA's



hold their charge during the off-season loosing only 1% per month (unlike the SLA batteries that loose 25-30% per month)



don't have the special charge/discharge requirements of the early Li-ion types and can be charged with most normal SLA chargers as long as they can provide a 14.6 V peak charge voltage



The K2 batteries have the highest capacity available at ANY discharge rate available on the market.





Contact me if you would like more info



Dave Springford

www.foxonecorp.com

Dave.I have been using both 14 v and 12 v batteries; 14v10ah (Sonnechein) and 12v12ah (Power Sonic) .
The chargers are a 14v trickle charger and 12v "Battery Minder" both work fine
Am I to understand that both these chargers (even the 14v??)would work?
Thanks in advance.
6PK

The 14 V charger would probably work best as the LiFePo4 batteries need a 14.6 V max charge rate. I tried some 12 V chargers and they max out at 13.75 V and this will not give the full charge the LiFePo battery needs. The K2 battery comes with a Battery Management System that helps regulate the charge and discharge rates. This combined with the trickle on your charger will prevent over-charging.

Check the specs on your 14 V charger, these should be printed somewhere on the back of the charger, (ie Input 110-120 V AC 60 Hz, Output 13.75 V DC, Current 750 mA) If you can't find it on the charger, connect the charger to a battery and measure the voltage across the terminals with a Voltmeter.

Dave Springford wrote, On 10/2/2013 4:15 PM:
LiFePo4 batteries hold their charge during the off-season loosing
only 1% per month (unlike the SLA batteries that loose 25-30% per
month)

SLA's lose around 3% per month at 68 deg F, and less at the temperatures
typical in the winter off-season. Mine don't lose much more than that,
even in the higher summer temperatures. Any SLA that loses, say, over
10% during the winter, is defective and should be discarded.

Perhaps you were thinking of Ni-Cd or Nimh batteries?

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)

Further to Dave's comments, I've done some simple discharge testing on my K2 12V/10AH LiFePo4, and it's pretty impressive. At a discharge rate of over 1C, I'm seeing the nearly the full rated capacity (1.2A bulb simulating the load). It never drops below 11V until it starts to fall off rapidly and shuts itself off. I'm seeing 7 hours at that rate (the capacity is theoretically derived at a discharge rate of 1 Amp, so it "should" be a little less than 10AH at the higher discharge rate as I understand it. I use the same smart charger that I used to use for 12V SLA batteries, and it seems to be working just fine. I would love to see an even higher capacity version, even with the larger foot print. The energy density is such that it would still be significantly lighter than an equivalent SLA battery.

P3



On Wednesday, October 2, 2013 7:15:29 PM UTC-4, Dave Springford wrote:
Don't confuse the Li-Ion batteries with the LiFePo4 batteries that are mentioned above. While the Li-Ion batteries have the instability problems associated with thermal runaway during rapid discharge, the Lithium-Iron-Phosphate (LiFePo4) chemistry is stable and do not have these problems.



There are many knock-off Chinese battery packs on the market that are called LiFePo, but be careful what you buy. I am a re-seller for K2 Energy batteries, and these are made in the USA, true LiFePo4 chemistry. I have spent hours on the phone with Mark Stoker at K2 comparing their batteries to some of the cheaper competition and some of the competitors numbers don't add up. The LiFePo4 chemistry is patented and K2 pays patent fees to the patent holder to use it, while many of the others don't. Visit the K2 website for more information at: http://www.k2battery.com/battery-packs-12v.html



Some of the advantages of the LiFePo4 chemistry over the SLA's (sealed Lead Acid) is that it holds peak voltage for much longer during discharge. The SLA's discharge curve is a continually declining slope that quickly reaches the 10 V level where things start to shut-off, while the LiFePo4 discharge curve is almost a straight line from the initial charge of 13 V. See the discharge curve he

http://www.foxonecorp.com/images/sto...0discharge.png



Advantages of the LiFePo4 batteries



provide much longer battery use during flight.



can be used for at least 2000 discharge-recharge cycles, compared to 300 for SLA's



hold their charge during the off-season loosing only 1% per month (unlike the SLA batteries that loose 25-30% per month)



don't have the special charge/discharge requirements of the early Li-ion types and can be charged with most normal SLA chargers as long as they can provide a 14.6 V peak charge voltage



The K2 batteries have the highest capacity available at ANY discharge rate available on the market.





Contact me if you would like more info



Dave Springford

www.foxonecorp.com

I guess it depends on how one defines capacity. If you take it as voltage drop from 12V then it is probably the 3% value that you use. If you take it as the battery's ability to do work and the SLA stops doing useful work at 10 V, then you have a 2V range from which the percentage is calculated resulting in the larger drop I quote.

Of course, the thing about statistics is that they will tell you whatever you want if you torture them long enough.

On Wednesday, October 2, 2013 5:09:18 PM UTC-7, Dave Springford wrote:
The 14 V charger would probably work best as the LiFePo4 batteries need a 14.6 V max charge rate. I tried some 12 V chargers and they max out at 13..75 V and this will not give the full charge the LiFePo battery needs. The K2 battery comes with a Battery Management System that helps regulate the charge and discharge rates. This combined with the trickle on your charger will prevent over-charging.



Check the specs on your 14 V charger, these should be printed somewhere on the back of the charger, (ie Input 110-120 V AC 60 Hz, Output 13.75 V DC, Current 750 mA) If you can't find it on the charger, connect the charger to a battery and measure the voltage across the terminals with a Voltmeter.

Great information on RAS as usual.
Dave my 14v charger has no specs other than it is 14v
I did what you suggested, hooked it up to a battery and tested the terminal on the battery; it read 15.68 v.
Is that too high?
Regards. 6PK

I will confirm with K2, but it is likely too high.

6PK wrote, On 10/2/2013 6:48 PM:
On Wednesday, October 2, 2013 5:09:18 PM UTC-7, Dave Springford
wrote:
The 14 V charger would probably work best as the LiFePo4 batteries
need a 14.6 V max charge rate. I tried some 12 V chargers and they
max out at 13.75 V and this will not give the full charge the
LiFePo battery needs. The K2 battery comes with a Battery
Management System that helps regulate the charge and discharge
rates. This combined with the trickle on your charger will prevent
over-charging.



Check the specs on your 14 V charger, these should be printed
somewhere on the back of the charger, (ie Input 110-120 V AC 60 Hz,
Output 13.75 V DC, Current 750 mA) If you can't find it on the
charger, connect the charger to a battery and measure the voltage
across the terminals with a Voltmeter.

Great information on RAS as usual. Dave my 14v charger has no specs
other than it is 14v I did what you suggested, hooked it up to a
battery and tested the terminal on the battery; it read 15.68 v. Is
that too high? Regards. 6PK

DON'T use 12 volt single stage chargers (also known as "taper" or
"trickle" chargers) on these batteries, and ESPECIALLY DON'T use 14 volt
chargers of any type. Trickle chargers aren't even good choices for SLA
batteries. Buy the K2 charger (it's a $150 battery - it's worth charging
it properly, in addition to the safety aspects), or use a charger they
have specifically approved (likely a 3 stage charger for 12 volt batteries).

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)