# running a SLA battery on it's side



## Juggernaut (Jun 6, 2008)

Just wondering if you can run/ charge a SLA battery on it’s side/top or what ever with out changing it’s performance. It’s not bad for it is it?


----------



## SilverFox (Jun 6, 2008)

Hello Juggernaut,

As long as the electrolyte doesn't spill out, it should be fine.

Tom


----------



## Juggernaut (Jun 6, 2008)

Thanks siverfox, so basically because it’s sealed and uses gel I’m good. Ok I just needed to know I wasn’t going to build a battery holder set up only to find it doesn’t work.


----------



## Turak (Jun 7, 2008)

Nowadays, most SLA batteries are not 'gel' cells anymore.

The are what is refered to as AGM (Advanced Glass Matt) batteries.

The electrolyte is absorbed into a fiberglass type material that looks alot like a thick papertowel. This is used as the separator material between the plates in the batteries.

Because there is no 'loose' liquid or 'gell' material, the modern AGM SLA batteries can be used in ANY orientation with no difference in performance.

The biggest problem with them is that they usually end up getting 'cooked' to death. They basically get overcharged until the glass matts dry out. The batteries then tend to develop an extreme high internal resistance and will no longer take a charge. I have tried to 're-moisten' the glass matts via the vent holes present in some of them, but have had maybe a 10% success rate.

These are the type of batteries you see advertised in almost every online battery store/outlet that lists 'SLA' batteries. Their average useful lifespan is approximately 2-7 years (manufacturers generally quote 3-5 years) depending on how they are treated over the course of their life.

They PREFER shalow discharges. They can be float charged or trickle charged practically forever if done using the correct methods and rates, although excessive overcharging increases the rate at which the separator materials dry out. They NEED to be maintenance charged if kept for any period of time.

I have about 10 'dead' ones stacked against the wall right now. Mostly 12v 18Ah batteries that came out of UPS's.


----------



## Wok (Jun 7, 2008)

Turak,

This would make the smaller batteries different to the larger [80Ah +] AGMs ? The large ones seem to have preferred C4 charge rates & up to C10 discharge? What rates do you suggest & up to what Ah capacity. 
I was going to use some small units but you have given me some doubts 



Turak said:


> [edit]
> 
> They PREFER shalow discharges. They can be float charged or trickle charged practically forever if done using the correct methods and rates, although excessive overcharging increases the rate at which the separator materials dry out. They NEED to be maintenance charged if kept for any period of time.


----------



## Patriot (Jun 7, 2008)

Turak said:


> The biggest problem with them is that they usually end up getting 'cooked' to death. They basically get overcharged until the glass matts dry out. The batteries then tend to develop an extreme high internal resistance and will no longer take a charge. I have tried to 're-moisten' the glass matts via the vent holes present in some of them, but have had maybe a 10% success rate.




Just so that I understand, how does the sealed AGM dry out if it can't vent. Also, how do you re-moisten a SLA-AGM if it doesn't have vents? Maybe you're referring to an AGM that does have vents or maybe my SLA-AGM does have vents and I don't know it...

Thanks for the good info. 

Paul


----------



## Mr Happy (Jun 7, 2008)

I would think it has safety vents that open if the internal pressure gets too high (for example from extreme overcharging). Although such vents are normally closed, there will always be microscopic cracks that can allow the slow escape of vapor over a period of years.


----------



## TorchBoy (Jun 7, 2008)

*Re: Running a SLA battery on its side*



Turak said:


> The are what is refered to as AGM (Advanced Glass Matt) batteries.
> 
> The electrolyte is *absorbed* into a fiberglass type material ...


Absorbent Glass Mat. That Wikipedia article claims that "AGM, rechargeable batteries usually come in large sizes." Does that imply smaller SLAs are still likely to be gel cells?


----------



## BVH (Jun 7, 2008)

The SLA's in the Costco HID are normally on their side as installed. IIRC, others of the same category are also not mounted terminal-side up.


----------



## Turak (Jun 7, 2008)

Hi Wok;

Many of the SLA batteries that I have seen actually have the charge specs printed right on the side of the battery. For the batteries that do not, you will have to go to the manufacturers site and locate the spec sheets for them.

For example;

Here are a couple of the 'dead' batteries that I have pulled from various UPS's.

Panasonic LCR-12V17CP
12V 17Ah/20Hr
Constant Voltage Charge
cycle use : 14.6~15.0V
(Initial current : less than 6.8A)
standsby use : 13.6~13.8V

YUASA NP2.6-12
12V 2.6Ah
Standby use : 13.50~13.80V Initial Current : No Limit
Cyclic Use : 14.4~15.0V Initial Current : 0.65A Max.


You will probably want the spec sheets anyways, so that you can see the safe recommended discharge rates.

The SLA batteries can have extremely HIGH disharge rates although they will only last a few minutes at some of the high rates.

For example,

A SLA Battery rated at 12V 17Ah (like the one above)....could be discharged at rates like;

1.0A for about 17 hours
4.0A for about 4 hours
17A for about 45 min.
34A for about 15 min.
51A for anout 10 min.

On another note....I recently bought a cheap 1,000,000 candlepower hand held rechargable light from Harbor Freight...it was $15 I think. It actually uses a small AGM SLA battery...6V 5.0Ah. They work fine in the smaller applications in my opinion.


Hi Patriot36;

MOST SLA batteries actually have vents, usually they are somewhat hidden. Many times there is a hard plastic strip or caps, tha once pryed/broken out of the way reveal the rubber pressure caps used to seal the vent holes. They periodically will 'burp' if the battery is exposed to overcharge or charging that causes a pressure buildup. 'Burping' is the nothing more then the pressure building to a point where the cap can no longer hold it back. The pressure escapes around the rubber seal and then when the pressure has lowered, the rubber cap usually will reseal itself. Problem is that you just lost a tiny bit of moisture.

But....even for the supposedly truly sealed batteries. I've got some news for you...plastic is a very porous material. Over a period of years, the heat and pressure produced by the charging/discharging will cause the moisture in the electrolyte to eventully evaporate and actually leak right through the plastic case. Now granted this process takes years.....typically about 3-7....hmmm isn't that just about how long the manufacturers indicate the overall life cycle is. Coincidence....Not at all.

Modern SLA batteries (especially the AGM types) are basically designed to be disposable. Their chief advantages might be that they can be used in any orientation, have extremely high discharge rates, and take a fair about of overcharge abuse. Their main disadvantages might be that they prefer shallow discharge/charge cyles (the tradeoff is overall number of cycles) and they need to be maintenance charged (again tradeoff is number of useful cycles).

I have probably tried to revive somewhere in the neighborhood of 50 or so SLA batteries of various capacities and have only had 'moderate' success with about 5 or 6 of them. Like I said, they are basically designed to be disposable. I even went to the length to build and experiment with some 'desulphanating' circuits on them....no-go. They do not seem to suffer from sulphate build-up like 'flooded' lead acid batteries (i.e. typical car batteries) do. They just tend to 'dry' out, building up extremely high internal resistances, to the point where they will not take a useful charge any longer and/or can not put out useful discharge currents for any reasonable period of time.


----------



## Turak (Jun 7, 2008)

*Re: Running a SLA battery on its side*



TorchBoy said:


> Absorbent Glass Mat. That Wikipedia article claims that "AGM, rechargeable batteries usually come in large sizes." Does that imply smaller SLAs are still likely to be gel cells?


 
I wouldn't count on 'everything' in Wikipedia to be totally up to date or accurate for that fact.

Maybe I am splitting hairs, but a TRUE GEL Cell SLA battery is considerably different from the modern AGM/Gel SLA varieties that are in common use today, even though many still just refer to both the varieties as 'gel' cells, in general.....which I guess is technically still correct from a certain perspective.

Almost every SLA battery that you are likely to see are now of the AGM/Gel SLA variety. The AGM batteries are much cheaper to produce than a TRUE older style 'GEL' cell and they have some considerable advantages over an older style true gel cell.

I have seen the AGM/Gel SLA variety batteries in voltages ranging from 2V~12V and in capacities ranging from 2.5Ah~245Ah.

For example...go check out the following site. It is a typical site that carries 'SLA' batteries. ALL of them listed on the SLA page are the AGM type SLA batteries. In fact, I did not see any 'true gel' cell types listed...

http://www.ragebattery.com/batterystore/sealedleadacidbatteries.html

My point is that the older TRUE 'gel' cells, while still available, in most applications have been replaced by the newer AGM/Gel SLA type batteries, which are available in quite a variety of voltages and capacities.


----------



## TorchBoy (Jun 7, 2008)

*Re: Running a SLA battery on its side*

Turak, I'm a bit confused by you referring to "AGM/Gel". Aren't SLAs one or the other? Edit: I thought the whole point of AGM was that the electrolyte _wasn't_ a gel.


----------



## lowatts (Jun 8, 2008)

Thanks for the SLA information Turak. Is it possible to test the health of these SLAa, assuming they do take a charge, without doing load testing on them? If I understand correctly, automotive SLAs can take a charge but might still fail a load test.


----------



## gary3911 (Jun 8, 2008)

You need the ACT Intelligent Battery tester


----------



## Darkpower (Jun 8, 2008)

Going back to the original topic, there may be a preferred side to the battery if not vertical. I bought several large APC ups backups, and they specifically state that the ups must be upright or on one specific side.


----------



## Kremer (Jun 9, 2008)

Darkpower said:


> Going back to the original topic, there may be a preferred side to the battery if not vertical. I bought several large APC ups backups, and they specifically state that the ups must be upright or on one specific side.



Look at where the vents and fans are on the case, it's likely for cooling reasons.


----------

