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AGM vs GEL Battery | Difference Between AGM and GEL Battery

If you own a motorhome, a boat, a 4 × 4 or solar installation, for example in an isolated site, you must have asked yourself the question: should I choose a gel battery or an AGM battery? What differentiates them? How can I choose? To Choose The Best AGM Battery don’t forget to read the buying guide.

First of all, what is the GEL / AGM battery?

The GEL battery is a technology that relies on the electrolyte frozen by the addition of silica gel. In some batteries, phosphoric acid is added to improve the life cycle in deep cycling. In contrast, AGM’s“Absorbed Glass Mat” battery technology is based on an assembly of fiberglass blotters that are compressed between electrodes and impregnated with the electrolyte (70% water & 30% acid). The whole being sealed and wholly sealed in both cases gel and AGM.

But then what are the notable differences between these two types of batteries?

There are several differences between these two types of technologies. The first difference easily visible but not negligible is the price. Indeed the battery AGM is more competitive in price than the battery GEL because of its less expensive technology.
But we must not stop at this first point even if it is important. This difference in price has a reason GEL batteries have a discharge rate of 100%, that is to say, that you can completely discharge the battery, even with a long discharge, you will keep the initial performance of this one, they keep their properties in time. Do AGM batteries have a discharge rate of 80%? It is also a very acceptable discharge rate, but this means that a gel battery can be completely emptied before being recharged, which is not desirable on an AGM battery which must be recharged at 80% of its discharge. The consequence of this is that the duration of a gel battery will be slightly higher than that of an AGM of the number of higher cycles.

The GEL battery is ideal for repetitive cycles, so for daily use with slow and deep discharges. The AGM battery is ideal as a service battery as a marine battery and motorhome battery but can also be used, if necessary, as a starter battery.

In terms of temperature range, the GEL battery withstands temperature ranges from -15 ° to 50 ° while the AGM battery withstands temperatures from 0 ° to 40 °.

Gel and AGM batteries also called VRLA have three things in common: they are waterproof, they do not need any maintenance and are resistant to shocks and vibrations. This is a real plus for mobile uses on land or at sea. In addition to this, the gel batteries can be used in reverse position.


To complete this guide is to help you with your choice. You must know that there are different types of capacities, dimensions and terminals. These are important elements to take into account especially when you want to install them in small spaces but also when the question arises: should I take two batteries of 100 Ah or a single 200 Ah. The dimensions and average weight according to the capacities are the following ones (they are given as an indication because they can vary from one mark to the other):

  • 75A / h = 242mm X 175mm X 190mm. 22 Kg
  • 105 A / h = 330mm X 175mm X 240mm. 30 Kg
  • 200 A / h = 520mm X 230mm X 240mm. 66 Kg

Finally, there are four types of Terminals:

SAE Rod Terminals: Tapered rods manufactured to SAE standards so that all battery cable clamps can be connected to it.

Side bollards: molded in the wall, near the top edge; the battery cables are attached with a bolt that is screwed into the terminal.

L-shaped terminals: Mostly used on special application batteries for lawn and garden equipment, snowmobiles and light vehicles.

Stud  Terminals: Threaded terminals typically used on heavy duty batteries.

In conclusion

The difference between a gel battery and AGM will be slightly noticeable in the long run. Indeed on the duration of the gel batteries will be more efficient thanks to the number of possible cycles and will theoretically have a longer life. However, AGM batteries have fascinating characteristics; they are suitable for use in battery service; they are more efficient than conventional batteries (starter battery) and are more cost-effective to use. They, therefore, have an interesting price/performance ratio.

So for those who want to keep their batteries for as long as possible and who have an intensive use of the gel battery is a good choice. For those who have a “normal” use and want a competitive price/performance then the AGM battery will be a good choice.

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