<span class="highlight">AGM</span> <span class="highlight">batteries</span>

G'day Rockape,

Thanks for the prompt response. You just confirmed what I was thinking. Thanks. That sure will make life a little easier fitting it in.

Cheers,

Dave

Hi Dave,

batteries are usually designed to sustain maximum shock/vibration forces along the vertical axis.

Have a look at this drawing which shows the bottom support of the plates by the battery case, but only marginal support by the softer glass matting on the sides.
If you install the battery on its side, the glass matting won't support the heavy plates much, which in turn strains the area around the bussbar mount which could lead to early grid failure.
This is even more of a problem as the battery ages due to an effect called grid embrittlement.
Dave's referring to spiral wound AGM batteries which are a bit better in that they have softer grids plus 360 degree support by the cylinder shaped casing.
Still, if you mount these on the side, any shocks coming from underneath will unevenly affect the pore structure inside the matting and consequently the current density distribution around the spiral wound grid.
Not ideal, but you could get away with it for a while, depending on the type of terrain, vehicle suspension and so on.

Bummer, I can't upload the image...
Sorry.

cheers, Peter

Dave, Peter,

I was just following what the manufacture stated. HERE

Have a good one,
RA.

Good on you Peter, another battery myth busted, Regards Keith.

Keith,
I don't know what your myth is but if the manufacturer and others involved in the industry say they can be mounted on their side then for me that is the case.

Quote from another industry source,

"They are totally sealed against any type of leakage and classed as spill proof.
Never need to check fluid level, ever! as previously stated they are recombinant.
They can be mounted on their side or end to suit space or environment.
They can be mounted inside your car, 4WD, caravan, camper or motor home, truck or marine vessel.
They do not need to be in a sealed box vented to the outside.
Because they have low internal resistance, they can be fully recharged at a lower voltage and accept a larger current (amps).
From a standard car, 4WD or truck alternator they will recharge quickly from full use in about 2 to 3 hours. A deep cycle wet cellbattery can take 8-12 hours to achieve only 70% to 80% of its potential charge.
They can be drained (discharged) much deeper than conventional deep cyclebatteries without any major damage.
An AGM battery when left unattended will only discharge at a rate of up to 3% per month and even after 12 months sitting idle can be recharged and put back into full service with no ill side effects. A normal wet cell battery discharges at a rate of up to 4% per week.
AGM batteries were originally developed for the military. They are designed and built tough, and will take an enormous pounding."

The manufacture warrants his product mounted in this position but what would he know.
We use the optima battery's at work on a critical piece of equipment They are on their side and they have never failed. They also get on hell of a shaking around.

RA.

OH... that optima site linked.

follow the links thru further downloads and find the safety document........the story is different there.

particularly look at the section titled "engineering controls".

then look at the specifications sheet for the particular battery in question in particular the charge current limitations and the temperature range.

there are also a few interesting statement that may seem inocuous.

such as

" all charge limits must be stricly adhered to"

" all charge recomendations assume an average room temperature of 25C"

cheers

Bantam,
I may have missed something here. I don't quite know what you mean about charge current limits and temperature range.

We were talking about whether an AGM can be mounted on it's side.

As for charging the 2 under my bonnet don't have any problem at all and that is in a 75series which are noted for high temperatures. There isn't much room left with a 6.5l chev diesel in there.

Not defending or pushing Optima battery's at all just saying the manufacture warrants them mounted on their side.

Have a look on the net about mounting AGM batteries. The quote I pulled off the net was just about which way you can mount them.

Peter from Battery value is a great source of info. It is just this time I disagree with him as I have first hand knowledge of these battery's mounted on their side over the past 12 years. The number of battery's used in this application is 8 and none have failed at all. They have been replaced early as they are on a critical piece of equipment. I also believe I have given Peter my vehicle charge rates and the length of time my Optima batteries have lasted in and earlier post.

Hope this clears things up,

RA.

Thanks everyone for your valuable input. I certainly see both sides of this argument and feel I now have any information to make an informed decision about mounting the battery.

Dave O

Rockape, my point is that the operating of these batteries out of position is dependent on how the temperature and charge rate is managed.

Not all sealed batteries are the same or can be relied upon to operate out of position.

The optima batteries (originaly the "gates cyclon" battery) are one of the few I would operate on their side if there was no other option.

The performance of the optima, particularly operating out of position is far from typical of sealed batteries in general.

Back in the late 70 early 80's when these VRLA sealed batteries started to become economical and they replaced wet cell motorcycle style batteries in most burgular allarms, lots of allarm manufacturers and installers (taking the marketing at face value) fitted sealed batteries on their sides or on their ends to save space.......I personnaly replaced many batteries that leaked acid.

Further as the battery ages they seem to be more prone to failure, as the charge characteristic deteriorates and as seals in the vent valves fail one way or another.

I have replaced many sealed batteries that have blown up like balloons because the valves have stuck with heat and age.

We may well get away with a variety of ill advised practices in a majority of cases, but there will be a significant number of cases where there are failures for one reason or the other......these are not freak failures....to those who do their homework these are completly avoidable failures..

The point remains the same..when you have read the technical documents of a variety of manufacturers as I have,two things will be obviuos.

NEVER UNDER ANY CIRCUMSTANCES INSTALL ANY LEAD ACID BATTERY IN A SEALED ENCLOSURE, ALWAYS PROVIDE VENTILATION.

UNLESS THERE IS ABSOLUTLY NO OTHER OPTION,
INSTALL BATTERIES UPRIGHT IN VEHICLES

cheers