You don't know???????????????????????????????????

You don't know.

Engine starting is a very broad subject. What kind of engine?

Hurry, I can't wait to see your answer.

Before you ask such a question, you really should do this first. Then read the material you find. Then and only then post what you do not understand as a question here at CR4.

What exactly is a dry battery and how does it work?

Link

Dry basically means sealed and stand-alone without the need to top up liquid electrolyte (for example a car battery is not a dry type). There are many types of dry cell batteries (both rechargeable and non-rechargeable) so the AA format above may not be the one you are using to (say) start a traction engine.

Do you know what type and size of dry cell battery your (company) is proposing?

Engine: Engine - Wikipedia, the free encyclopedia

http://cr4.globalspec.com/thread/77433/Battery

There seems to be an issue here with confidence in performing searches over the internet.

It would be helpful to know some detail of the engine, its size, its location, its purpose, and so-on. For example, one will never get a 75kW diesel engine to crank on 4xAAA cells!

Dear Friend, did ever heard of "Firfly Energy"?

Please read this: http://www.fireflyenergy.com/index.php?option=com_content&task=view&id=52&Itemid=70

Uh, little problem there... http://gigaom.com/cleantech/latest-battery-startup-shutdown-firefly-energy/

Firefly is battery company started by Caterpillar.

This begs the question as to why such an important discovery was made by Caterpillar and not by a company directly involved in the battery industry. It's interesting to note that the previous major advancement in the lead acid battery industry was the valve-regulated lead acid (VRLA) battery. This invention was created, not by a battery manufacturing company, but by a rubber hose and belt company - Gates. The parallel is clear; smart materials scientists with the backing of major corporations, unconstrained by traditional mental roadblocks and preconceptions of how to design and optimize a battery!

http://gigaom.com/cleantech/latest-battery-startup-shutdown-firefly-energy/

Dear Mr.Pantaz, This is 2 year old article. They are now in to some micro corbon technology. But what I wanted to tell is " do not go for dry batteries. still VRLA is th only best solution" Even Flights use VRLA batteries. I worked for HBL who manufacture batteries for Flight starting as well as engine starting.

Dry battery is capacitor which is used to start all kind of engine. The size of capacitor changes based on starting amps and voltage needs

Hi,

A VRLA battery is a "recombinant" battery. This means that the oxygen normally produced on the positive plates of all lead-acid batteries is absorbed by the negative plate and recombined into H2O. This suppresses the production of hydrogen at the negative plate. Water (H2O) is produced instead, retaining the moisture within the battery, So you need not top up with water thus it becomes maintenamce free.

In case of the open-vented type, overcharge after completion of charge causes electrolysis of the water content of the electrolyte, which generates O2 gas at the positive plate and H2 at the negative plate. These gases are escaped from the inside of the battery, Since a drop in electrolyte level results, adding the water is occasionally needed - called maintenance.

Hope you are clear now.

cat batteries, dry seems to be non gassing?

By doing a little Googling, I find that VRLA batteries are Valve-Regulated Lead-Acid batteries - either gel or absorbed glass matt. These are sealed batteries that will not spill if turned over or even mounted at an angle.

By contrast, Caterpillar batteries - designed for use with their machinery or gen-sets - are basically standard lead-acid batteries. They can be supplied "dry" - meaning that they are not activated until the water is added to the the cell to create the electrolyte.

If your customer wants seal gel or glass-matt cells, the Caterpillar batteries are not what they are looking for.

"Dry" does not have a single, concrete meaning in regard to starting batteries. Odyssey and Hawker batteries (among others) have long been advertised as "dry". They are valve regulated lead acid. They are dry in the sense that if they fall over, nothing gets wet.

An alternative meaning, as used by Caterpillar in their promo literature (for which a link was provided) dry means "shipped dry." (Also sometimes called "dry charged") Acid is added at the customer or distributor site.

Aside from the temporarily dry batteries (in the Caterpillar sense) all lead acid batteries are wet inside. If they are VRLA or SLA, they are dry on the outside, and can often be tipped over without problem.

Most VRLA batteries are truly maintenance free -- you never need to add water. Many "dry shipped" batteries are not, even if they are called low maintenance or maintenance free. Traditional vented batteries are very definitely not maintenance free.

Ah-ha !

This is exactly the answer I am looking for !

I read through Caterpillar promo literature and I realised that you have to add acid to a dry battery.

So I am assuming that it is not a VRLA battery but rather, just a normal lead acid battery.

Yes, that's right. The Caterpillar "dry" batteries are normal lead acid. Happy to help.