What Type of Battery Is an Interstate SRM-31?

The Interstate SRM-31 is a maintenance-free, lead-acid AGM (Absorbent Glass Mat) battery designed for marine and RV applications. It provides reliable starting power and deep-cycle capabilities, resistant to vibration and spillage. With 750 cold-cranking amps (CCA) and a 31-group size, it’s optimized for dual-purpose use in harsh environments.

What Is a Group Size 24 Battery?

How Does the Interstate SRM-31 Compare to Other Marine Batteries?

The SRM-31 outperforms flooded batteries in vibration resistance and lifespan. Unlike standard deep-cycle batteries, its AGM technology allows faster recharging (3–4 hours) and 2× longer cycle life. It’s 15% lighter than equivalent gel batteries while maintaining higher discharge rates for trolling motors and electronics.

When compared to lithium-ion alternatives, the SRM-31 offers significant cost advantages while maintaining comparable vibration tolerance. Its charge acceptance rate of 1.2C (compared to 0.5C in flooded batteries) makes it particularly suitable for applications with irregular charging patterns. Marine technicians often recommend it for twin-engine configurations due to its stable voltage output under simultaneous starting loads.

What Are the Technical Specifications of the SRM-31?

Key specs include: 12V voltage, 100Ah capacity, 31.8L x 20.3W x 24.4H cm dimensions, 29.5kg weight. Performance metrics: 750 CCA, 150-minute reserve capacity, 200+ cycles at 50% depth of discharge. Operating range: -30°C to 60°C. Meets SAE J537 and BCI Group 31 standards.

Parameter	Specification	Industry Average
Cycle Life (50% DoD)	200 cycles	120 cycles
Self-Discharge Rate	3% per month	5% per month
Vibration Resistance	6G acceleration	4G acceleration

The battery’s 150-minute reserve capacity indicates it can deliver 25 amps for 6 hours before reaching 10.5V. Its optimized plate thickness (2.4mm) balances cranking performance with deep-cycle endurance. The copper-calcium terminals provide 35% better conductivity than standard lead terminals, reducing voltage drop during high-current demands.

Where Is the Interstate SRM-31 Most Commonly Used?

Primary applications include offshore fishing boats (saltwater corrosion resistance), RV house batteries (low gas emission), and commercial marine starters. Secondary uses: backup power for solar systems, golf carts, and heavy-duty construction equipment requiring vibration-proof energy storage.

Why Choose AGM Technology in the SRM-31?

AGM construction eliminates electrolyte leakage risks while enabling 360° installation flexibility. The glass mat separator reduces internal resistance by 40% compared to flooded batteries, achieving 98% recharge efficiency. This technology also prevents sulfation during long storage periods (up to 12 months at 25°C).

When Should You Replace an SRM-31 Battery?

Replace when capacity drops below 80% of rated Ah (typically 3–5 years). Warning signs: voltage below 12.4V at rest, slower engine cranking, or swelling beyond 5% of original dimensions. Use a load tester: if voltage drops below 9.6V at 50% CCA load, immediate replacement is advised.

How to Maintain an Interstate SRM-31 Battery?

Maintenance steps: 1) Clean terminals quarterly with baking soda solution 2) Keep surface charge above 12.7V 3) Store at 10°C–25°C when inactive 4) Equalize charge every 6 months using 15.5V for 2–4 hours 5) Avoid discharges below 50% capacity. No water refilling required due to recombinant AGM design.

For optimal performance, use a smart charger with AGM-specific profiles. Terminal cleaning should include brushing both the post and connector interior, followed by application of anti-corrosion gel. When storing, maintain state of charge between 70-80% using a maintenance charger. Avoid exposing the battery to direct engine heat – installation in insulated compartments can extend lifespan by up to 18% in hot climates.

What Makes the SRM-31’s Warranty Unique?

Interstate offers 18-month free replacement plus 84-month pro-rated warranty. Coverage includes manufacturing defects and premature capacity loss (below 70% within first 3 years). Exclusions: physical damage, over-discharge below 10.5V, or charging above 14.8V. Warranty requires proof of proper voltage maintenance (monthly logs recommended).

“The SRM-31’s calcium-alloy grids reduce gassing by 85% compared to traditional antimony designs. Our testing shows 1,200+ start cycles in salt spray environments – exceptional for non-lithium marine batteries. Its recombination efficiency exceeds 99%, meaning virtually no water loss over its lifespan.” – Marine Power Systems Engineer (12 years battery industry experience)

FAQ

Can the SRM-31 Be Used in Solar Systems?

Yes, when paired with a compatible charge controller (max 14.4V absorption). Its 100Ah capacity supports daily 20% depth of discharge cycles. Ensure ambient temperatures stay below 45°C for optimal lifespan.

Does Cold Weather Affect SRM-31 Performance?

CCA drops 33% at -18°C compared to 25°C. Use battery blankets below -10°C. The AGM design prevents freezing damage down to -50°C when fully charged.

How to Recycle an SRM-31 Battery?

Interstate dealers accept old units (core charge applies). 98% recyclable – lead plates and polypropylene case get reprocessed. Never dispose in landfills; $10–$25 recycling fees typically apply.