Gel cell battery question

[rmcpb (Rob)]

Does anyone know if using a gel cell battery on its side has any bad effects? I can't think of any but would like to check first as I don't want it to leak all over my eq platform.

[Gama]

No, there is no side effects. This is one reason they chose GEL.
You can use it anyway you like. The internals have no liquid, and its just a GEL substance that is firm, and thus has no movement.


Theo

[bmitchell82 (Brendan)]

i have been doing a bit of research into these kind of batteries i cant remember what it was but something said that gel cell batteries arnt that great for deep discharges. im not 100% sure but do some googling!

[mswhin63 (Malcolm)]

They are not design to go upside down, but they can. One thing is to watch he temperature. If they over heat they can blow out. Have changed many UPS batteries in my time and they usually blow out. The last one I had the drill out the pop rivits on the frame the get the old ones out.

They have no maintenance but still need to be monitored. GEL is only a GEL when the temperature is low, Once the temperature get to high the GEL becomes a liquid and if you are running closed vent GEL batteries they blow out fortunately not blow up.

If you use vented GEL batteries which are nearly phased out they can leak. These have ever so tiny holes in the top where the terminals are to vent the bettery when the GEL gets a bit hot.

They also Sulphate the same as any other battery so they need contact charge and discharge.

I haven't used deep discharge/cycle batteries for a long time so not sure what is out there.

[Dennis]

Am I correct in thinking that you need a special (slow charge, low current) mains charger for these batteries? A standard car battery charger is not suited due to their higher charging current?

Cheers

Dennis

[mswhin63 (Malcolm)]

Lead acid batteries use Constant voltage charging. A lot simpler than NiCD and NiMH, so they not as fussy as those.

All you need correct voltage to charge, There are plenty of low cost chargers available usually quite good. There are so more intelligent chargers out there that could be used if less monitoring is required.

The batteries themselve have internal resistance to limit charginging current but if the charging voltage is increased to high the heat will rise proportionally.

Deep Discharge/Cycle though require a slightly different charging system. If the battery is really flat, it requires a slightly higher voltage to get it out of deep discharge. Then the voltage is reduce to normal when it charge is in normal operations. This is how is was when I was using DD batteries but technology has changed a lot since I used them so maybe they fixed this.

[xstream (John)]

Rob,

Before you fully decide on Gel-Cell you may like to read here and here.

My personal preference in Deep Cycle batteries is for AGM.

[Dennis]

Here is an article from Jaycar about SLA’s.

http://www.jaycar.com.au/images_uploaded/slabatts.pdf

WARNING: link opens pdf on line in a new window. Right click to download and save a copy.

Cheers

Dennis

[acropolite (Phil)]

Am I correct in thinking that you need a special (slow charge, low current)

Gel batteries have particular requirements (i.e. different to normal lead acid) for charging including very specific specifications for charging when flattened beyond a certain point.

There are (or at least were) circuits designed particularly for charging gel batteries (EA had one which I built many years ago). The chargers detect low voltage and if the battery is flattened beyond a certain level they apply a trickle charge untill a suitable voltage for bulk charge is reached, then a bulk charge of C/20 (capacity in AH/20 constant current) until another predetermined point where they are held at a constant voltage until charge is completed.

That said, most chargers are simple devices relying on slow charge at low currents usually with no regulation, probably why Gel batteries have a relatively short cycle life.

[Dennis]

Thanks Phil. My next question is….are Sealed Lead Acid (SLA) batteries the same design and construction as Gel Cell batteries?

The ones I have for general camping and casual observing sessions are all SLA’s.

Cheers

Dennis

[Wavytone]

SLA and Gel cell batteries are quite different.

[Dennis]

Ahh, thanks for that – the forum will make an electrician out of me, eventually! LOL!

Cheers

Dennis

[rmcpb (Rob)]

Thanks all for your input

[acropolite (Phil)]

Originally Posted by wavytone

SLA and Gel cell batteries are quite different.

not so, to quote from a couple of sources

Sealed Lead Acid Batteries


Sealed lead acid batteries are also known as valve regulated lead acid (VRLA) batteries, recombinant batteries and often called maintenance-free lead-acid batteries. Examples of VRLA batteries are:

• Absorbed glass mat (or AGM)
• Gel cells

The term term "seal lead acid battery" is misleading: a sealed battery would be a safety hazard due to overpressure risks the battery is overcharged. There is always a safety valve present, hence the name valve-regulated. Even the term "valve regulated" does not really describe this technology. These are really "recombinant" batteries. This means that oxygen evolved at the positive will mostly recombine with the hydrogen ready to evolve on the negative and thus prevent water loss. The valve is only a safety feature in case dangerous amounts of hydrogen are produced.

and

A gel cell or gelled electrolyte is a sealed battery containing semi-solid electrolyte and may also be identified as a sealed lead acid,

AFAIK the charging requirements are identical.

[Dennis]

Thanks for that Phil.

I quick but limited search that I ran did seem to indicate that there were some similarities and they were of the same family or type, although the gel cell models tended to be more expensive than the SLA models.

Anyhow, mine are (Jaycar) SLA’s and I also have a (Jaycar) SLA charger, so provided I charge them monthly, I trust I’m not going to blow up the garage!

Cheers

Dennis