Frequently asked questions relating to lead-acid batteries

1.What is the difference between an AGM valve regulated battery and a traditional open type flooded battery ?

A traditional open type flooded battery has no safety valve and is without the function of oxygen recombination in a sealed state.

It can only be used vertically as otherwise the liquid electrolyte in the battery could overflow and cause erosion if tilted or punctured.

In addition due to this vertical requirement and the high possibility of spillage, this kind of battery is not allowed to be transported by air , shipment or mailing without special protective packaging.  It is also prohibited for this type of open flooded cell to be used operationally very close to a source of electrical current. .

In the AGM battery, the electrolyte of AGM valve battery is absorbed in the plates and separators, which achieves oxygen recombination. The safety aspects of the sealed AGM battery allow it be transported as non-dangerous goods without a specialized individual battery packaging (could be installed with the equipment).
2. What is the difference between an AGM battery and a GEL battery?

Both Gel battery and AGM battery belong to the VRLA valve regulated battery type. The biggest structural difference lies in the specifications of the separator and the electrolyte.

 A GEL battery uses separators made of materials such as PVC or phenol-formaldehyde resin, while an AGM battery mainly uses absorbent glass mat separators. The electrolyte of Gel battery is in a state and consistency resembling gelatin and looks a bit like Vaseline, but the electrolyte of an AGM valve regulated battery is a liquid absorbed into the absorbent glass mat.

The performance difference caused by these structure differences is shown as below in figure 2-1.
Some advantages of a GEL battery focus on the increased service life and cycling capabilities, capacity stability and the absence of the risk of thermal-runaway.

Some advantages of an AGM battery lie in its excellent performance in high rate discharge ability over a shorter time for UPS and other similar types of applications and in it’s very competitive pricing level.


Figure 2-1 Difference comparison between GEL and AGM batteries.

3. Can the AGM and GEL battery be installed in the completely sealed battery cabinet?
No type of lead-acid battery GEL or AGM should be installed in a completely sealed container.

As stated above; In the VRLA AGM or GEL battery most gas generated (oxygen and hydrogen) will be recombinated instead of posing the possibility of venting or leakage as in a flooded battery. However even in a VRLA AGM or GEL battery some oxygen and hydrogen can escape from the battery under overcharge (for either types of battery). To be on the safe side even with VRLA AGM or GEL batteries these potential explosive gases must be feely released into the atmosphere instead of being trapped in any sort of a sealed container or room.
4. Can the AGM valve regulated battery be used as start-up battery?

An AGM battery can be used in SLI (starting, lighting and ignition) only if the charge voltage can be set on the fixed value. A VRLA AGM valve regulated battery is able to be applied to a large current discharge in a low temperature such as a cold start.

5. Can the GEL battery be held in storage for a long time without maintenance due to the Gel battery storage long life?

GEL batteries have a very good storage life after being fully charged and could be stored up to 2 years at 25 ambient temperature with the battery retaining a capacity is more than 50% and even after this length of storage the battery capacity could be restored to 100% of rated capacity with proper charging.

The above notwithstanding, it can still be harmful for a GEL battery to be in long storage and to realize a significant loss of power state. If at all possible and conditions permit it is advisable to perform periodic electrical maintenance according to the battery specific requirements to ensure the maximum service battery service life for a GEL battery in longer term storage.
6. What is meant be sulfating of batteries?

Sulfating is the formation or deposit of lead sulfate on the surface and in the pores of the active material of the battery’s lead plates. If the sulfating becomes excessive and large crystals are formed on the plates, the battery will not operate efficiently , may not work at all. and further may not be able to be restored by charging to a useable state.

Common causes of battery sulfating are standing a long time in a discharged condition, operating at excessive temperatures, or either incidences of prolonged under or over charging.
7. How long can a battery can last?

The rated service design life of a battery such as 10 years, 12 years ,15 years etc. represents a universally recognized battery Industry standard interned for the comparison of types of batteries and does not constitute a real expectation of usable battery life. The actual life of a battery varies considerably with how it is used, how the battery is maintained , how it is charged and by which type of charging schema and most dramatically by the operating and storage temperatures of the battery during its lifetime.

The rated life of 10 years, 12 years etc. can however be useful as a battery from one manufacturer can be loosely compared to a battery of the same rating from another battery manufacturer as to the life of both batteries given the same operating conditions.
8. Are lead acid batteries recyclable?

Lead acid batteries are 100% recyclable. Lead is the most recycled metal in the world today. The plastic containers and covers of old batteries can also be neutralized, reground and used in the manufacture of new battery cases.

The electrolyte can also be processed for recycled waste water uses, and in some cases the electrolyte can be cleaned and reprocessed and sold as battery grade electrolyte.

 In other instances, the sulfate content is removed as Ammonia Sulfate and van be used in fertilizers. The separators are often used as a fuel source for the recycling process.
9. What is battery rating?

The most common battery rating is the AMP-HOUR RATING. This is a unit of measurement for battery capacity, obtained by multiplying a current flow in amperes by the time in hours of discharge. (Example: A battery which delivers
5 amperes for 20 hours delivers 5 amperes times 20 hours, or 100 ampere-hours.)

 Manufacturers use different discharge periods to yield an different Amp-Hr. Rating for the same capacity batteries, therefore, the Amp-Hr. Rating has little significance unless it is qualified by the number of hours the battery is discharged and one battery is compared to another based on the same operational parameters.

 For this reason Amp-Hour Ratings are only a general method of evaluating a battery's capacity for selection purposes. The quality of internal components and technical construction within the battery will generate different desired characteristics without effecting its Amp-Hour Rating. For instance, there are 150 Amp-Hour batteries that will not support an electrical load overnight and if called upon to do so repetitively, will fail early in their life. Conversely, there are 150 Amp-Hour batteries that will operate an electrical load for several days before needing recharging and will do so for years. The following ratings must be examined in order to evaluate and select the proper battery for a specific application: COLD CRANKING AMPERAGE and RESERVE CAPACITY are ratings used by the industry to simplify battery selection.
10. What is the difference between series battery connections and parallel battery connections and how do they increase battery capacity and voltage?

In the SERIES CONNECTION, batteries of like voltage and Amp-Hour capacity are connected to increase the Voltage of the bank. The positive terminal of the first battery is connected to the negative terminal of the second battery and so on, until the desired voltage is reached. The final Voltage is the sum of all battery voltages added together while the final Amp-Hours remains unchanged. The bank's Voltage increases while its Amp-Hours, Cranking Performance and Reserve Capacity remain unchanged. In the PARALLEL CONNECTION, batteries of like voltages and capacities are connected to increase the capacity of the bank. The positive terminals of all batteries are connected together, or to a common conductor, and all negative terminals are connected in the same manner. The final voltage remains unchanged while the capacity of the bank is the sum of the capacities of the individual batteries of this connection. Amp-Hours Cranking Performance and Reserve Capacity increases while Voltage does not.

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