OPTIMA® RedTop®

Technical Specs

STARTING BATTERIES
MODEL NUMBER	RT S 4.2 RT R 4.2	RT F 4.2	RT U 4.2	RT U 3.7	RT S 3.7 RT R 3.7	RT S 2.1
PERFORMANCE
Voltage (V)	12	12	12	12	12	6
Cold Cranking Amps @ -18°C (A)	815	815	815	730	730	800
Cranking Amps @ 0°C (A)	1000	1000	1000	910	910	1000
Reserve Capacity (Minutes)	100	100	100	90	90	100
Capacity (C/20 Rate)(Ah)	50	50	50	44	44	50
Internal Resistance (ohms)	0,003	0,003	0,003	0,003	0,003	0,0019
PHYSICAL SPECS
Length (mm)	254	254	254	237	237	254
Width (mm)	172	185	172	172	172	83
Height (mm)	200	184	200	197	197	200
Mimimum Weight (kg)	17,2	17,5	17,6	15	14,4	8,4
Type Terminal	SAE	GM	Dual SAE & GM	Dual SAE & GM	SAE	SAE
BCI Group	34 & 34R	78	34/78	75/35	25 & 35	-

Charging Info

All OPTIMA® RedTop Batteries
These batteries are designed for engine starting applications. They are NOT recommended or warranted for use in deep cycle applications.

Recommended charging information:

Alternator:
13.3 to 15.0 volts, no amperage limit.

Battery charger:
13.8 to 15.0 volts, 10 amps maximum, 6-12 hours approximate.

Rapid Recharge:
Maximum voltage 15.6 volts (regulated).
Maximum current: No limit as long as temperature < 50°C (125°F).
Maximum recharge time: Charge until current drops below 1 amp.

Float charge:
13.2 to 13.8 volts, 1 amp maximum current, time indefinite (at lower voltage).

All limits must be strictly adhered to.

Safety Information:

Always wear safety glasses when working with batteries.

Always use a voltage regulated battery charger with limits set to the above ratings. Overcharging can cause the safety valves to open and battery gasses to escape, resulting in premature failure. These gasses are flammable! You cannot replace water in sealed batteries that have been overcharged. Any battery that becomes very hot or makes a hissing sound while recharging should be disconnected immediately.

Failure to fully charge a battery can result in poor performance and a reduction in capacity