SLA batteries opinions?

Recently I tested two 12v SLA s which had been in use
sequentially for some years usually recharged before going
going flat, or at least within one day.
Both were run down to 10.5 v with a 10 ohm load and then recharged to 14v,

The Yuasa 7 AH bought 2005 was good for about 2.5 AH
the UB 1280 8AH 6 years old good for 2AH.
On this showing the Yuasa look like the better battery.
Both were used as panel supplies running at .5 A load.

Any opinions on competing SLA batteries?

John F

maanantai 2. huhtikuuta 2018 20.14.19 UTC+3 john firth kirjoitti:
Recently I tested two 12v SLA s which had been in use
sequentially for some years usually recharged before going
going flat, or at least within one day.
Both were run down to 10.5 v with a 10 ohm load and then recharged to 14v,

The Yuasa 7 AH bought 2005 was good for about 2.5 AH
the UB 1280 8AH 6 years old good for 2AH.
On this showing the Yuasa look like the better battery.
Both were used as panel supplies running at .5 A load.

Any opinions on competing SLA batteries?

John F

Most (incl. Yuasa) specify battery life as 3-5 years. Glider use (deep cycles, low temps) means 3 years max in our experience. To get any amperage from 13 years old battery is nothing short of miracle.

In your test, did you measure the AH capacity in the discharge or the recharge? The latter is of course generally an overestimate.

The Yuasa had to be really well made to last THAT long! Half the life at half the cost may be OK too though. 6 years is not bad.

The practical life of an SLA mostly depends on how it is treated, not the manufacturing quality. I've seen our club's batteries go dead in less than 2 years. I think that's in part due to sometimes being left in a glider that it tied out, where it gets quite hot. I left a spare battery in my glider trailer for one season, it was then dead, again perhaps due to heat. Other than keeping them cool (but not cold), make sure to fully charge right after use (within a day or two anyway), using a good "smart" charger that will not overcharge it.

On Mon, 02 Apr 2018 12:11:30 -0700, moshe.braner wrote:

In your test, did you measure the AH capacity in the discharge or the
recharge? The latter is of course generally an overestimate.

The Yuasa had to be really well made to last THAT long! Half the life
at half the cost may be OK too though. 6 years is not bad.

The practical life of an SLA mostly depends on how it is treated, not
the manufacturing quality. I've seen our club's batteries go dead in
less than 2 years. I think that's in part due to sometimes being left
in a glider that it tied out, where it gets quite hot. I left a spare
battery in my glider trailer for one season, it was then dead, again
perhaps due to heat. Other than keeping them cool (but not cold), make
sure to fully charge right after use (within a day or two anyway), using
a good "smart" charger that will not overcharge it.

I do a fully charged - discharge - recharge cycle once a year on my
batteries (Yuasa NP7-12 SLAs) and sling them when they drop below 2/3 of
the capacity measured when they are new.

I use a cheapish multi-chemistry charger of the type sold for charging
and monitoring RC model batteries, so its good for round 0.4 amp charge
and discharge rates. Mine is a Pro-Peak Prodigy II sold in the UK by
Ripmax and is now several years old (12 at a guess). Similar charge/
discharge units will be available almost anywhere.


--
Martin | martin at
Gregorie | gregorie dot org

That test is unlikeky to tell you anythibg useful about the battery quality.. If anything it might tell you how they are stored/abused. And storage/use/abuse is likelyvthe thing to worry about with SLA batteries,... they often get killed more than dying of old age.

Buy a good brand name SLA battery from a trusted/high volume dealer so it hopefully has a fresh manufacturing date and should arrive with a decent charge on it. Fully charge and then discharge test and write that date and tested current/capacity on the battery and repeat at every annual. The West Mountain Radio Computerized Battery Tester is a great investment, especially for clubs, FBOs, A&Ps etc. . When capacity gets to about 80% of spec (not initial measured capacity, which is likely higher) I would replace.

You may be better off using LiFePO4 batteries.

On Monday, April 2, 2018 at 4:29:49 PM UTC-4, Darryl Ramm wrote:
You may be better off using LiFePO4 batteries.

Well I've been wondering about that each time I buy a new SLA and still find that I cannot justify the much higher cost of the LiFePO4 batteries (5x to 10x, depending on size, brand, etc). The theoretical number of times the batteries of each type can be cycled is irrelevant if they will die of old age in a number of years, even if that's 10+ years for LiFePO4 and only 3-4 years for SLA in my use.

This depends also on how much capacity you need vs. the weight and volume needed to hold the battery(ies) in the glider. In my case my modest needs, in warm weather, are usually met by one 4AH SLA, and I can also use a 12AH when I want spare capacity (or a bit of ballast :-). If I had a fancier computer, plus transponder and FLARM, then the picture might be different, since the LiFePO4 can be discharged more deeply without damage while the SLA should only be taken to about half-full (and even when I test them I stop at about 11.5V).

On Monday, April 2, 2018 at 4:16:45 PM UTC-7, wrote:
On Monday, April 2, 2018 at 4:29:49 PM UTC-4, Darryl Ramm wrote:
You may be better off using LiFePO4 batteries.

Well I've been wondering about that each time I buy a new SLA and still find that I cannot justify the much higher cost of the LiFePO4 batteries (5x to 10x, depending on size, brand, etc). The theoretical number of times the batteries of each type can be cycled is irrelevant if they will die of old age in a number of years, even if that's 10+ years for LiFePO4 and only 3-4 years for SLA in my use.

This depends also on how much capacity you need vs. the weight and volume needed to hold the battery(ies) in the glider. In my case my modest needs, in warm weather, are usually met by one 4AH SLA, and I can also use a 12AH when I want spare capacity (or a bit of ballast :-). If I had a fancier computer, plus transponder and FLARM, then the picture might be different, since the LiFePO4 can be discharged more deeply without damage while the SLA should only be taken to about half-full (and even when I test them I stop at about 11.5V).

I did say "may be better off". :-)

tiistai 3. huhtikuuta 2018 2.16.45 UTC+3 kirjoitti:
The theoretical number of times the batteries of each type can be cycled is irrelevant if they will die of old age in a number of years, even if that's 10+ years for LiFePO4 and only 3-4 years for SLA in my use.


In my experience lifetime of LFP is not better than SLA. My first battery died completely in 6 months, second had much reduced capacity after 2 seasons. Idea that chinese LFPs last thousand cycles or decade is just false.

On Monday, April 2, 2018 at 11:14:19 AM UTC-6, john firth wrote:
Recently I tested two 12v SLA s which had been in use
sequentially for some years usually recharged before going
going flat, or at least within one day.
Both were run down to 10.5 v with a 10 ohm load and then recharged to 14v,

The Yuasa 7 AH bought 2005 was good for about 2.5 AH
the UB 1280 8AH 6 years old good for 2AH.
On this showing the Yuasa look like the better battery.
Both were used as panel supplies running at .5 A load.

Any opinions on competing SLA batteries?

John F

Just for reference, 4.5 hrs on Duracell 9AH to drop to 10.5V. This is running everything including PF and TX. No more than 2 seasons use. I buy one every season from local high volume outlet (Around 25 bucks). Will occasionally use a smaller tail battery as well.
The biggest determinant of longevity is the charger. I have been using SLA for decades for soaring and other applications and for some reason I have been having a hard time finding good chargers lately. Used the PowerSonic chargers for years (No longer made) but sold these with my last ship. Have fried more than one battery when the charger did not detect peak and shut of (Or float) before the battery got hot. I have never measured it but this always results in a noticeable reduction in capacity.
3 years max (With the right charger) sounds about right. We are only talking 20 some odd bucks.

On Monday, April 2, 2018 at 4:40:35 PM UTC-7, Darryl Ramm wrote:
On Monday, April 2, 2018 at 4:16:45 PM UTC-7, wrote:
On Monday, April 2, 2018 at 4:29:49 PM UTC-4, Darryl Ramm wrote:
You may be better off using LiFePO4 batteries.

Well I've been wondering about that each time I buy a new SLA and still find that I cannot justify the much higher cost of the LiFePO4 batteries (5x to 10x, depending on size, brand, etc). The theoretical number of times the batteries of each type can be cycled is irrelevant if they will die of old age in a number of years, even if that's 10+ years for LiFePO4 and only 3-4 years for SLA in my use.

This depends also on how much capacity you need vs. the weight and volume needed to hold the battery(ies) in the glider. In my case my modest needs, in warm weather, are usually met by one 4AH SLA, and I can also use a 12AH when I want spare capacity (or a bit of ballast :-). If I had a fancier computer, plus transponder and FLARM, then the picture might be different, since the LiFePO4 can be discharged more deeply without damage while the SLA should only be taken to about half-full (and even when I test them I stop at about 11.5V).

I did say "may be better off". :-)

I am switching to Odyssey batteries that use thin pure lead plates (PC680). Virtually all other SLA batteries are made with recycled lead, which is not pure (they claim 99.9%, but I doubt that is realistic - Odyssey guarantees 99.99% pure). They are designed for long life and severe environments.
http://www.odysseybattery.com/design_advantages.aspx
They are rated for deep discharge.

That said, I have had good luck with the Panasonic batteries that I have used in my ASH26e for 4 years, and recommend them for people on a budget.

Tom