A Simple Question About LiFePO4 Batteries

On Friday, May 18, 2018 at 10:16:07 AM UTC-7, Tom Kelley #711 wrote:
On Friday, May 11, 2018 at 1:37:03 PM UTC-6, wrote:
Not to start another chapter in "Battery Wars" but I have a simple question about "drop in" LiFePO4 battery replacements for SLA batteries in gliders.

For years, I've used an SLA battery with the same footprint as the common glider size of 7Ah to 9Ah--i.e., 5.95" x 2.56"--except a little taller--i.e., 4.61" high vs. 3.86" (specs are from the PowerSonic line but other brands are similar). It's an easy swap in my ASW 24, only requiring a different hold-down strap. There's about 20% more internal volume, which seems to equate to at least 20% more claimed capacity. I've used enough of these that I know they do perform longer than the conventional-size SLA batteries most pilots use.

However, I can't find a LiFePO4 equivalent for it. Does such a thing exist? All I've seen discussed here or available online seem to be the "traditional" size. I've been told that this is because there's already excess space inside the enclosure, that it's not packed to the gills with mat/chemicals as SLAs are, and that the extra 3/4" wouldn't allow adding additional cells. And besides, I don't need it anyway (I'm running PowerFLARM, radio, CNv vario, and PNA; no transponder yet).

Then I see that some LiFePO4 batteries are rated slightly higher for the same enclosure size. Even the K2 battery touted in adverts as "10 Ah" seems to be 9.6 Ah in the specs. And that's ignoring loads, discharge rates, temperatures, etc.

Given the price differential and the necessity for a new charger (although not according to the K2 site), and especially in light of the recent stories of LiFePO4 batteries crapping out long before their promised lifespans, maybe I should just continue to buy a new SLA battery every year or two and wait for this fad to pass.

As I said, a simple question.

Chip Bearden

I use these on my 29(sorry Richard), slides right in and my battery compartments are the same size as a 27.

https://www.bioennopower.com/collect...d-green-case-1

Not sure about your 24 size battery compartment. When measured are 5.95Lx2.96Wx3.66H. Last flight went over 6 hrs on one. My 10 amps are the same size and what I was using, I use about 1.32 amps per hour as I don't use the radio very much. Do have a Sandia transponder. When recharged it showed it had used 6.929 amps.
Used SLA's, now after using these would not go back. Have had no problems with them and 2 are now going on more than several years old and have well over 200 recharge cycles on them. I recharge them with my RC charger which I can set the charge rate. Been recharging them at 5 amps since new.

Ya, it's kinda late to your post, but may help someone else.

Best. Tom #711.

I used to sell Bioe until I got a bad batch 5AH for a 9 AH battery. They replaced but it took awhile.

Richard