LiFePO4 Batteries

The discharge cited above is pretty typical for LFP batteries. See my webpage for the measured discharge curves for the K2 LFP battery. The graph shows a very flat discharge followed by a sudden drop at the end of the cycle.

http://www.foxonecorp.com/index.php/...m-iron-battery

For anyone who is interested in a K2 battery, I will be in Cordele for the Region V South contest with a few K2's and chargers on hand.


Dave Springford
Fox One Corp

Does anyone have experience charging these with a battery tender plus? I've got a new K2 10ah battery and considering a specific charger.

What indications does the battery tender give? What's a typical time to charge?

Jeff,

The LFP batteries, while they can be charged with SLA chargers, are better charged by a dedicated LFP charger. The reason for this is they need to charge up to 14.6 volts to get a 100% charge. Most SLA chargers will give only 13.75 volts and this leaves the LFP battery around 80% charged and this pretty much defeats the purpose of buying the higher capacity LFP battery.

I have LFP chargers for $30 (see the address for my webpage in my previous post).


Dave Springford
Fox One Corp

A multi chemistry charger with firmware that is upgradable to accommodate changing battery technology is a better way to go. CellPro (and other knockoffs) has several chargers that will safely and accurately charge LiFePO4 batteries among many others with one charger.

I have used a Cellpro multi 4s charger to charge my Shorai lithium iron battery which does not have a battery management system for quite a while. It will also charge a lead acid, nimh, nicad, lipo and others.

You will be able to set the charge rate, monitor the health of the cells, balance the cells (still important for a LiFePO4).

Thanks guys

Just bought a Tenergy LiFePO4 12.8V 10ah + Charger from all-battery.com

It has the Battery Management System (BMS) with short circuit, over charge and under discharge protection.

QUESTION: Any recommendations from other glider pilots on whether I should ALSO add a fuse on the battery before installing the connector for my ship?

BTW.. all-battery.com had a good deal. Total price $164.56 included free 1.5amp charger, tax, shipping and a $19.20 discount. Battery was $159.99.

Walt Rogers WX

On Saturday, June 14, 2014 1:15:51 PM UTC-7, WaltWX wrote:
Just bought a Tenergy LiFePO4 12.8V 10ah + Charger from all-battery.com



It has the Battery Management System (BMS) with short circuit, over charge and under discharge protection.



QUESTION: Any recommendations from other glider pilots on whether I should ALSO add a fuse on the battery before installing the connector for my ship?



BTW.. all-battery.com had a good deal. Total price $164.56 included free 1.5amp charger, tax, shipping and a $19.20 discount. Battery was $159.99.



Walt Rogers WX

Personally I would ALWAYS install a fuse directly on the battery pack as close as practical to the terminal post. The purpose of a power distribution fuse is to protect the wiring on the load side. While your battery pack may have some form of short circuit protection for itself, you have no way of inspecting it or knowing if protection for it, might mean less than 30 amps draw which would happily torch your wiring - with no harm to the battery. The fuse you install should be the appropriate size for the smallest wire it serves.

I purchased the exact battery and charger set from all battery. The battery and charger are made by tenergy. I got it January of last year and the battery started to fail at the end of last season. I was running out of power about 3 hrs into my flight.

Most recently, the battery voltage goes down to 5 volts under 1 amp load.

I called temergy and they told me the pcb is bad. They also told me that they can sell me one and if I cut the case open I can simply install it myself and glue the case with jb weld. Not exactly what I wanted to hear after spending $160 on a battery that is supposed to outlast a regular sealed lead acid battery.

Keep Iin mind that their warranty is very short. I would buy somewhere where the warranty is much longer.

Marcin

Send me your battery (postage paid) and I'll happily repair it and use
it in my ship!

More seriously, I bought my Tenergy 10 Ah battery from Amazon for $153
and it included a charger and shipping. I installed a fuse within one
inch of the battery and, at least for a year, I will take the battery
home to charge rather than leave it plugged in at the airport. One
night I forgot to unplug it and, in the morning, it was cool to the
touch, fully charged, and accepting no current. I also have a Watts Up
inline power meter which records voltage, current, and power dissipation
and was surprised to see that my peak amperage is 2.8 amps in service!
I suppose that means when I transmit and my transponder is replying at
the same time, plus computer, Streak, etc...

Dan Marotta

On 6/14/2014 4:39 PM, Marcin S wrote:
I purchased the exact battery and charger set from all battery. The battery and charger are made by tenergy. I got it January of last year and the battery started to fail at the end of last season. I was running out of power about 3 hrs into my flight.

Most recently, the battery voltage goes down to 5 volts under 1 amp load.

I called temergy and they told me the pcb is bad. They also told me that they can sell me one and if I cut the case open I can simply install it myself and glue the case with jb weld. Not exactly what I wanted to hear after spending $160 on a battery that is supposed to outlast a regular sealed lead acid battery.

Keep Iin mind that their warranty is very short. I would buy somewhere where the warranty is much longer.

Marcin

Thanks for your offer Dan :-)

I ended up installing an additional battery http://www.bioennopower.com/collecti...ed-low-profile

So now I have over 30 Amp hours

They also offer a two year pro-rated warranty.

Marcin