OPTIMA RedTop 34/78 AGM Starting Battery
- 12-Volt, 800 Cold Cranking Amps
- Dual SAE and GM posts
- 50 AH C20, 100 minutes reserve
- 10.06 x 6.94 x 7.88 in, 38.8 pounds
- 15x vibration resistance vs flooded
- Up to 3 times longer life claim
Last refreshed Sep 11, 2026 · Based on the Amazon listing and published specifications, not hands-on testing.
A larger RedTop AGM starter with more cranking power and reserve for bigger engines. It weighs more and remains a starting battery, not a deep-cycle unit.
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ASIN: B00075OSC4Model: RedTop 34/78Category: Vehicle Batteries
Overview
Not a deep-cycle accessory battery, the OPTIMA RedTop in this larger group size is a sealed SpiralCell starting battery with extra cranking amps. Dual posts suit both top and side terminal vehicles.
Higher cranking power and reserve help big engines start in cold or hot extremes. Its weight and case size need a tray that fits the larger dimensions.
Who it's for
Pickups, SUVs and performance cars with larger engines suit it. Small cars may not need the extra size or weight.
Pros and cons
- High cold cranking
- Larger reserve capacity
- Dual SAE and GM posts
- Sealed and non-spillable
- Heavy to lift
- Not deep cycle
- Warranty terms unclear in listing
Performance notes
The spiral cell design packs pure lead plates tightly, which delivers high current and resists shaking apart. Reserve capacity covers short periods of running lights or electronics with the engine off.
Specifications
| Brand | OPTIMA |
|---|---|
| Model | RedTop 34/78 |
| Dimensions & fit | |
| Size | 10.06 x 6.94 x 7.88 inches |
| Item weight | 38.8 pounds |
| Capacity & performance | |
| Battery capacity | 50 AH (C20) |
| Reserve capacity | 100 minutes |
| Power & efficiency | |
| Voltage | 12 volts |
| Battery Type | Lead acid, sealed AGM |
| Other details | |
| Terminal | Dual SAE and GM posts |
| Number Of Cells | 6 |
| Cold cranking amps | 800 |
Frequently asked questions
What comes with the OPTIMA 34/78 RedTop?
The battery only.
Is the OPTIMA 34/78 RedTop a deep-cycle battery?
No. It is a starting battery for cars, trucks and SUVs.
How big is it?
10.06 inches long, 6.94 inches wide and 7.88 inches tall, weighing 38.8 pounds.