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

Specifications

BrandTROJAN
Part number31-GEL
Voltage (V)12
Capacity (C20)102Ah (c20)
Capacity (C5)85Ah (c5)
TechnologyGEL
Length329.00 mm
Width171.00 mm
Height245.00 mm
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Price: €793.50
VAT included
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Brand: Trojan Batteries Part number: 31-GEL

Trojan 31-GEL 12V 102Ah is a solar battery designed for PV systems with daily charge/discharge cycles. Tolerates extreme temperatures well, with low self-discharge during winter shutdowns or between stays at vacation homes.

Why this solar battery?

  • Designed for solar systemsoptimised for daily charge/discharge cycles
  • Handles extreme temperaturesin technical rooms or outdoor installs
  • Minimal self-dischargewhen left idle over winter or holidays
Voltage
12 V
Capacity
102 Ah C20
Dimensions
329×171×245 mm
Technology
GEL
Weight
32 kg
Model
TROJAN GEL
Logo Trojan

Solar battery Trojan 31-GEL 102Ah 12V

12VVoltage
102AhCapacity
32kgWeight

The Trojan 31-GEL with GEL technology stores 102 Ah at 12 V for off-grid photovoltaic installations and storage systems. It replaces the original battery without adaptation in off-grid PV systems with a 329 × 171 × 245 mm format: same 102 Ah capacity.

  • Good tolerance to extreme temperatures.
  • Long life on float and moderate cycling.
  • GEL technology: gelled electrolyte, fully sealed and maintenance-free.
  • Optimised for daily charge and discharge cycles.

What the Trojan 31-GEL is for

Designed for off-grid photovoltaic installations and storage systems, the Trojan 31-GEL tolerates extreme temperatures and long periods of low activity. Check that it matches your current battery in dimensions, terminals and hold-down: this reference has a weight of 32 kg and 7 terminals.

Technology inside the Trojan 31-GEL

Trojan builds the 31-GEL to the same standards as the rest of its catalogue; what changes between references is capacity, format and terminal position.

In a GEL battery the electrolyte is gelled with silica: it is fully sealed, cannot spill and tolerates deep discharge very well. It is the preferred technology in electric mobility, marine service and heavy-cycling applications.

Dimensions, polarity and mounting

The Trojan 31-GEL is made in the 329 × 171 × 245 mm format and weighs 32 kg. It uses 7 terminals, the system that anchors and connects it in the vehicle. Checking the three dimensions and the terminal position before buying avoids the most common mistake when replacing a battery.

What Trojan does differently

Founded in 1925 in California, Trojan invented the golf cart battery and remains the standard in deep-discharge applications that demand thousands of cycles. We guarantee that every Trojan arrives new, charged and with the manufacturer's full warranty.

Usage and maintenance tips

In the darker months, check the voltage periodically and avoid full discharges. GEL batteries need lower charging voltages: always use a charger with a GEL mode so as not to damage the electrolyte.

Warranty and coverage

The Trojan 31-GEL comes with the manufacturer's official warranty against manufacturing defects. If it fails through a defect within the warranty period, we replace it at no cost to you.

Delivery times and returns

Order before 6:00 pm with stock available and it leaves today: mainland Spain and Portugal receive it in 24-48 working hours, the islands and the rest of the EU in 3 to 5 days. You have 14 days to return it if it has not been installed, with free collection on the mainland, and shipment tracking by email.

  • Reference
    BCOM-TROJAN-31-GEL

Data sheet

  • Brand
    TROJAN
  • Reference
    31-GEL
  • Model
    TROJAN GEL
  • Voltage (V)
    12
  • Length
    329.00 mm
  • Width
    171.00 mm
  • Height
    245.00 mm
  • Weight
    32 Kgs
  • Technology
    GEL
  • Terminal type
    7
  • Capacity (C20)
    102Ah (c20)
  • Capacity (C5)
    85Ah (c5)

Specific References

  • EAN13
    8404653001339
  • MPN
    31-GEL

Codes and references Trojan 31-GEL

Brand Trojan
Manufacturer range TROJAN GEL
Manufacturer part number (MPN) 31-GEL
Also known as 31GEL · 31 GEL
EAN-13 barcode 8404653001339
Dimensions (length × width × height) 329 × 171 × 245 mm (329x171x245)

Recommended accessories — complement the Trojan 31-GEL with a charger or tester

Frequently asked questions

Is the Trojan 31-GEL a GEL battery? What is GEL used for?

Yes, this model is a GEL battery: sealed lead-acid where the electrolyte is in gel form. It tolerates deep discharges very well and is ideal for cyclic use (solar, motorhomes, electric wheelchairs, motorcycles). Requires a GEL-specific smart charger — max charge voltage ~14.1 V (vs 14.4-14.7 V for AGM). Lifespan 6-10 years.

How is the Trojan 31-GEL battery installed in the vehicle?

In most devices it fits in 15-30 minutes with a 10 mm wrench; if the battery is under the seat or in the boot the time can double. See the step-by-step guide on our blog. Quick summary: 1) switch off the engine and remove the key; 2) locate the original battery (engine bay, boot or under seat); 3) disconnect the negative (−) terminal first, then the positive (+); 4) loosen the hold-down clamp and remove the old battery; 5) fit the new one in the same orientation — match the polarity shown on the product sheet; 6) connect the positive (+) first, then the negative (−). On devices with Start-Stop or BMS, register the battery via OBD so the alternator applies the correct charging profile.

What is the service life of the 31-GEL model?

Expected lifespan of the Trojan 31-GEL is 6 to 10 years in cyclic use (marine, caravan, solar) with controlled discharges. In cold regions it drops slightly due to cold-start stress; in very hot regions it also drops because of electrolyte evaporation. To extend its life: avoid deep discharges (headlights on with engine off), have the alternator checked yearly, and keep the battery clean and properly secured.

What are the dimensions of the Trojan 31-GEL battery?

Dimensions (length × width × height) are 329×171×245 mm — also written as 329x171x245 mm — following the European DIN standard. Always measure the space in your device before buying: even one extra millimetre can prevent the hold-down clamp from closing. The height shown includes the terminals.

What are the equivalents of the 31-GEL model?

Directly interchangeable batteries (same dimensions, same polarity, same Ah and CCA) are the OEM equivalents from leading brands: Bosch, Tudor, Exide and, depending on the model, Banner or Yuasa. Exact equivalence depends on technology — an EFB cannot be replaced with a conventional battery in Start-Stop devices. See the "Equivalents" section to view recommended options at the same performance level.


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