A Simple Question About LiFePO4 Batteries

I have several LFP batteries, all different makes. The multiple chargers was an issue for me. I have had a very good experience with the CTEK Lithium US charger.
I was curious about CTEK since both of my newest cars came with CTEK trickle chargers, a Mercedes and a Porsche. I find it unusual that different manufacturers would use a common product.
I have been using the CTEK Lithium US for about one year. One charger for all my batteries and everything has been working perfectly.
Check it out. One charger works for all LFP batteries from 5Ah to 60Ah.

On 05/11/2018 02:28 PM, wrote:
But you can drain a lithium battery "all the way" (to the point
where the protection circuitry prevents further discharge) with not much
loss of battery life.


This assumes that all lithium batteries have a full-featured BMS circuit
that protects against battery abuse. That seems to be a bad assumption,
particularly for LiFePO4 batteries. Pfiffner has posted some
interesting failures he's seen there, in the previous incarnation of
this discussion.

On Friday, May 11, 2018 at 7:15:02 PM UTC-4, kinsell wrote:
This assumes that all lithium batteries have a full-featured BMS circuit
that protects against battery abuse. That seems to be a bad assumption,
particularly for LiFePO4 batteries. Pfiffner has posted some
interesting failures he's seen there, in the previous incarnation of
this discussion.

I really was just asking about the taller size battery (the PowerSonic # is PS-12100H if you want to look it up; it's about $10 more than the usual size) to see if there were a LiFePO4 equivalent.

That said, I've read Richard's posts as well as others from a few pilots who have reported relatively premature deterioration of LiFePO4 batteries. The verdict seemed very clear a few years ago. Now...? Having a $35 SLA start to slide after a few years wouldn't be as annoying as would a $100 to $150 LiFePO4 battery. Yes, the only advantage of SLA is cost...but if I have to replace both types at about the same time, that's definitive for me.

T8, I believe you were using Bioenno whereas most posts are about K2, with a few about Starkpower and one unanswered query about Dakota. I take it you're still happy with yours.

Chip Bearden

On Friday, May 11, 2018 at 11:59:03 PM UTC-4, wrote:
On Friday, May 11, 2018 at 7:15:02 PM UTC-4, kinsell wrote:
This assumes that all lithium batteries have a full-featured BMS circuit
that protects against battery abuse. That seems to be a bad assumption,
particularly for LiFePO4 batteries. Pfiffner has posted some
interesting failures he's seen there, in the previous incarnation of
this discussion.

I really was just asking about the taller size battery (the PowerSonic # is PS-12100H if you want to look it up; it's about $10 more than the usual size) to see if there were a LiFePO4 equivalent.

That said, I've read Richard's posts as well as others from a few pilots who have reported relatively premature deterioration of LiFePO4 batteries. The verdict seemed very clear a few years ago. Now...? Having a $35 SLA start to slide after a few years wouldn't be as annoying as would a $100 to $150 LiFePO4 battery. Yes, the only advantage of SLA is cost...but if I have to replace both types at about the same time, that's definitive for me.

T8, I believe you were using Bioenno whereas most posts are about K2, with a few about Starkpower and one unanswered query about Dakota. I take it you're still happy with yours.

Chip Bearden

I agree that there seems to be a wide range of quality out there and that higher price doesn't guarantee longevity (K2). Several guys have the Bioenno 12 AH battery. I know of no issues, but it's a very small sample (also worth noting the obvious fact that this technology is still evolving). I reported my test results earlier this Spring... 11.5 AH capacity after five seasons of use.

What we don't have a handle on is what all the eventual failure modes are. If it turns out that they frequently die suddenly, or sometimes die in some hazardous fashion, then that would take some of the luster off!

I may well replace mine after this season out of caution. I'm more concerned with performance and reliability than economy when it comes to batteries. I'll offer the old one for $25 so someone else can brag on economy :-).

best,
Evan Ludeman / T8

A g a i n ?

The -only- advantage of SLA is lower purchase price. And considering that "7 AH" is really about 3.5 useful, the "economy" here is dubious, at best.

A good battery is $100.

Some problems are hard to solve. Not this one.

best,
Evan Ludeman / T8

Chip, I think that QV (Richard's first ASG29, not Al's) had the same batteries when I bought it.
There were custom made hold-down straps.
I replaced the AGMs with 10Ah LiFePO4 and use the factory hold-down straps.
That larger battery size is unusual, haven't seen LiFePO4s that size.
Jim


On Friday, May 11, 2018 at 12:37:03 PM UTC-7, 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

On 05/11/2018 01:37 PM, wrote:

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.


If you have to replace batteries every year or two, you must be using
some crap brand like Werker or PowerSonic (sounds almost like Panasonic!)

On Friday, May 11, 2018 at 12:37:03 PM UTC-7, 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

If it's working for you and if there are no readily available replacements just keep using the SLA/AGM battery you already use. Personally I like the K2 batteries and the one in my ship is starting it's fifth year of service but it's not magic, just a good battery that fits my needs well. In the case of my glider it solved a space, weight and capacity requirement but it seems that the SLA/AGM is doing everything you need it to do.

Money isn't everything. However your lifetime allotment of cussing is a precious thing, not to be wasted on SLA batteries.

SF

The request was for a simple answer, so here ya go. I could have made it simpler, but I'm saving my allotment for windy contest days which I have grown to hate with a passion usually reserved for people driving slowly in the left lane.

I got my simple answer about the apparently non-existent larger size LiFePO4 battery.

Regarding the ensuing discussion, I didn't go the LiFePO4 route a few years ago even though the sentiment at the time seemed to "it's a no brainer; just do it." The current sentiment seems to be a bit more nuanced, which is good to know. Thx, all, for the candid inputs.

Chip Bearden