# Trojan 31-GEL · Solar battery 12V 102Ah

![Trojan 31-GEL · Solar battery 12V 102Ah](https://bateriasonline.es/3321-home_default/trojan-31-gel.jpg)

> Trojan 31-GEL: 102 Ah solar battery, 329×171×245 mm, GEL. Compare sizes and equivalents; 14-day returns.

**Category:** [Solar batteries for off-grid systems](https://bateriasonline.es/en/off-grid-solar-batteries) → [Trojan](https://bateriasonline.es/en/trojan-batteries)

- **Canonical URL**: https://bateriasonline.es/en/trojan-31-gel
- **Language**: en
- **Brand**: Trojan
- **Reference**: BOL-TROJAN-31-GEL
- **EAN**: 8404653001339
- **MPN**: 31-GEL
- **Price**: 777,63 € (VAT incl., Spain)
- **Last updated**: 2026-11-06

## Technical specifications

| Feature | Value |
|---|---|
| Brand | Trojan |
| Range | TROJAN GEL |
| Application | Solar and off-grid systems |
| Technology | GEL |
| Voltage | 12 V |
| Capacity | 102 Ah |
| Length | 329 mm |
| Width | 171 mm |
| Height | 245 mm |
| Weight | 32 kg |

## Quick description

Trojan 31-GEL: solar battery with 12 V and 102 Ah, measuring 329 × 171 × 245 mm.

## Description

## The Trojan 31-GEL at a glance

The Trojan 31-GEL is a deep-cycle battery for off-grid solar systems: it stores the day's energy for use at night and withstands years of charge and discharge cycles. Its capacity is rated at 20 hours (C20); at slower discharge rates the usable capacity is higher.
The 31-GEL belongs to the Trojan TROJAN GEL range. [See all Trojan batteries](https://bateriasonline.es/en/trojan-batteries)

## Equivalents and alternatives to the Trojan 31-GEL

We have no other battery with exactly the dimensions and polarity of the 31-GEL. Browse the rest of our [solar batteries for off-grid systems](https://bateriasonline.es/en/off-grid-solar-batteries) to compare close options.

## Trojan 31-GEL vs 27-GEL and 5SHP-GEL: which one to choose?

What sets the 31-GEL apart from its neighbours in the Trojan range:

| Model | Capacity | Dimensions (mm) | Weight |
|---|---|---|---|
| Trojan 31-GEL (this one) | 102 Ah | 329 × 171 × 245 | 32 kg |
| Trojan 27-GEL | 91 Ah | 324 × 171 × 234 | 29 kg |
| Trojan 5SHP-GEL | 125 Ah | 345 × 171 × 283 | 39 kg |

- Trojan 27-GEL: 11 Ah less, a different case (324 × 171 × 234 mm).
- Trojan 5SHP-GEL: 23 Ah more, a different case (345 × 171 × 283 mm).

## What it means that the 31-GEL is GEL

The 31-GEL is a gel battery: the electrolyte is immobilised in silica gel. The 31-GEL handles repeated deep discharges well, its strong point compared with an AGM.

## Before ordering the 31-GEL, check this

- The 31-GEL needs 329 × 171 × 245 mm of space: measure it with the hold-down clamp in place.
- With 102 Ah, the 31-GEL replaces an original battery of that capacity or slightly less.

## Part numbers and codes for the Trojan 31-GEL

Look for any of these 31-GEL codes on your current battery or in the manufacturer's catalogue:

| Commercial reference | 31-GEL |
|---|---|
| EAN | 8404653001339 |

## Frequently asked questions about the Trojan 31-GEL

### 31-GEL or 27-GEL: which one suits me?

Compared with the 31-GEL, the Trojan 27-GEL has 11 Ah less. With 102 Ah, the 31-GEL runs longer between charges than the 27-GEL (91 Ah). Mind the space: the 27-GEL measures 324 × 171 × 234 mm.

### How much does the Trojan 31-GEL weigh?

32 kg, with 102 Ah of capacity. For reference, the Trojan 27-GEL (91 Ah) weighs 29 kg.

### How far can I discharge the Trojan 31-GEL each day?

To make it last years, do not go below 50% routinely. Size the bank so daily consumption is half the installed capacity.

## More batteries to compare with the 31-GEL

- [More solar batteries for off-grid systems](https://bateriasonline.es/en/off-grid-solar-batteries)
- [The whole Trojan range](https://bateriasonline.es/en/trojan-batteries)
- [Trojan 24-GEL](https://bateriasonline.es/en/trojan-24-gel) · 77 Ah, 276×171×236 mm

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*bateriasonline.es — Batteries and accessories · 2026-11-10*